EMJ Radiology 6.1 2025

Volume 6.1 April 2025 emjreviews.com

Radiology

Review of the

ECR 2025 Interviews:

Feature:

Katherine Halliday and Kicky van Leeuwen discuss national guidelines and AI in radiology

The Good, the Bad, and the Ugly of AI in Medical Imaging

Contents 04

Editorial Board

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Welcome

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Foreword

Congress Review 10

Review of the European Congress of Radiology (ECR) 2025

Congress Features 24

Sustainability and Equity: AI in Radiology

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Novel Therapies Require Novel Imaging

Victoria Antoniou Helena Bradbury

Abstract Reviews 31

Evaluation of Sustainable Diagnostic Approaches for Metastatic Breast Cancer Masperi et al.

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Early Health Technology Assessment for an AI Tool to Detect Incidental Pulmonary Embolisms on CT Kemper et al.

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Patients’ Perception of Radiographers’ Communication Skills During Planar X-Ray Imaging: A Single Centre Study Zarb et al.

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Diagnostic Performance of Neural Network Algorithms in Skull Fracture Detection on CT Scans: A Systematic Review and Meta-Analysis Hajibeygi et al.

Congress Interviews 38

Andrea Rockall

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Patrizia Cornacchione

Interviews

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Katharine Halliday

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Kicky van Leeuwen

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Feature 53

The Good, the Bad, and the Ugly of AI in Medical Imaging Resühr and Garnett

Articles 56

Editor's Pick: Whole-Body MRI in Oncology: Focus on 3D Sequences in Musculoskeletal Oncology Ghasemi et al.

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Microwave Ablation for Renal Cell Carcinoma: A Literature Review and Clinical Insights Golden et al.

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Ultrasound Guided Percutaneous Splenic Biopsy: Diagnostic Accuracy and Complications Razak and Khan

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Acute Form of Sarcoidosis (Löfgren Syndrome): A Case Report

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Neuroimaging in Rabies Encephalitis: An Uncommon Sight

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Imaging Features of Leydig-Cell Tumour of the Testis: A Case Report

Abduljabbar Gupta et al.

Adke and Varrior

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"GIANT, through its extensive network of health-tech innovators, supports all individuals within healthcare"

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Editorial Board Editor-in-Chief Dr Yasmeen Malik St George's University of London, UK Malik is Senior Lecturer Therapeutic Radiography, Postgrad Research Lead, and Course Admissions Tutor at the Kingston and St George’s Joint Faculty, Faculty of Health, Social Care and Education, School of Allied Health, Social Care & Midwifery St George’s University of London, UK

Prof Christian Jürgens

Prof Eduard Ruiz-Castañé

BG Trauma Hospital Hamburg, Germany

Fundació Puigvert, Spain

Dr Olusola Michael Adeleke NHS Clinical Entrepreneur Fellow, NHS England, UK

Prof Aad van der Lugt

Prof Roger Dmochowski

Erasmus University Medical Center, the Netherlands

Vanderbilt University Medical Center, USA

Dr Sophie Willis Health Education England, UK

Dr Luke Dixon

Dr Cetin Erol

Imperial College Healthcare NHS Trust, UK

Ankara University, Türkiye

Dr Sanjog Kalra Einstein Medical Center, USA

Dr Paul Bezzina

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Prof Jean de la Rosette

University of Malta, Malta

Academic Medical Center (AMC), the Netherlands

Dr Nicholas Kipshidze

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New York Cardiovascular Research, USA

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Aims and Scope EMJ Radiology is an open access, peer-reviewed eJournal committed to helping elevate the quality of radiology practices globally by publishing high-quality content on the latest developments in medical technologies.

The journal is published annually, six weeks after the European Congress of Radiology (ECR), providing the latest developments in the field, and features highlights from this congress, alongside interviews with experts in the field, reviews of abstracts presented at the congress, as well as in-depth features on congress sessions. Additionally, it covers advances within the clinical and pharmaceutical arenas by publishing sponsored content from congress symposia, which is of high educational value for healthcare professionals. This undergoes rigorous quality control checks by independent experts and the in-house editorial team.

EMJ Radiology also publishes peer-reviewed research papers, review articles, and case reports in the field. In addition, the journal welcomes the submission of features and opinion pieces intended to create a discussion around key topics in the field and broaden readers’ professional interests. EMJ Radiology is managed by a dedicated editorial team that adheres to a rigorous double-blind peer-review process, maintains high standards of copy editing, and ensures timely publication.

EMJ Radiology endeavours to increase knowledge, stimulate discussion, and contribute to a better understanding of radiology and the latest technological advances in the field.

Our focus is on research that is relevant to radiologists. We do not publish veterinary science papers or laboratory studies not linked to patient outcomes. We have a particular interest in topical studies that advance knowledge and inform of coming trends affecting clinical practice in radiology.

Editorial Expertise EMJ is supported by various levels of expertise:

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Guidance from an Editorial Board consisting of leading authorities from a wide variety of disciplines.

Invited contributors who are recognised authorities in their respective fields.

Peer review, which is conducted by expert reviewers who are invited by the Editorial team and appointed based on their knowledge of a specific topic.

An experienced team of editors and technical editors.

Peer Review On submission, all articles are assessed by the editorial team to determine their suitability for the journal and appropriateness for peer review.

Editorial staff, following consultation with either a member of the Editorial Board or the author(s) if necessary, identify three appropriate reviewers, who are selected based on their specialist knowledge in the relevant area.

All peer review is double blind.

Following review, papers are either accepted without modification, returned to the author(s) to incorporate required changes, or rejected.

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Submissions We welcome contributions from professionals, consultants, academics, and industry leaders on relevant and topical subjects. We seek papers with the most current, interesting, and relevant information in each therapeutic area and accept original research, review articles, case reports, and features.

We are always keen to hear from healthcare professionals wishing to discuss potential submissions, please email: editorial.assistant@emjreviews.com To submit a paper, use our online submission site: www.editorialmanager.com/e-m-j Submission details can be found through our website: www.emjreviews.com/contributors/authors Reprints All articles included in EMJ are available as reprints (minimum order 1,000). Please contact hello@emjreviews.com if you would like to order reprints.

Distribution and Readership EMJ is distributed through controlled circulation to healthcare professionals in the relevant fields across Europe.

Indexing and Availability EMJ is indexed on DOAJ, the Royal Society of Medicine, and Google Scholar®; selected articles are indexed in PubMed Central®.

EMJ is available through the websites of our leading partners and collaborating societies. EMJ journals are all available via our website: www.emjreviews.com

Further details on coverage can be found here: www.emjreviews.com

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Editorial staff have final discretion over any proposed amendments.

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Open Access This is an open-access journal in accordance with the Creative Commons Attribution-Non Commercial 4.0 (CC BY-NC 4.0) license.

Congress Notice Staff members attend medical congresses as reporters when required.

This Publication Launch Date: 2020 Frequency: yearly Online ISSN: 2633-9978 All information obtained by EMJ and each of the contributions from various sources is as current and accurate as possible.

However, due to human or mechanical errors, EMJ and the contributors cannot guarantee the accuracy, adequacy, or completeness of any information, and cannot be held responsible for any errors or omissions. EMJ is completely independent of the review event (ECR 2025) and the use of the organisations does not constitute endorsement or media partnership in any form whatsoever. The cover photo is of Vienna, Austria, the location of ECR 2025.

Front cover and contents photograph: Vienna, Austria © Tryfonov / stock.adobe.com

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PODCAST

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Welcome Dear Readers,

Editor Evgenia Koutsouki Managing Editor Darcy Richards Copy Editor Noémie Fouarge Editorial Leads Helena Bradbury, Ada Enesco Editorial Co-ordinators Victoria Antoniou, Jenna Lorge, Bertie Pearcey Editorial Assistants Katie Wright, Katrina Thornber, Aleksandra Zurowska Creative Director Tim Uden Design Manager Stacey White Creative Artworker Dillon Benn Grove Designers Owen Silcox, Fabio van Paris, Shanjok Gurung Business Unit Head Darren Brace Senior Project Manager Michael Stevenson Marketing Director Kristina Mestsaninova

It is a great pleasure to welcome you to the 2025 issue of EMJ Radiology. Our team had the opportunity to attend this year’s European Congress of Radiology (ECR) in Vienna, Austria. This year, the theme was Planet Radiology, and sustainability was at the forefront of all discussions. With AI being increasingly used across clinical disciplines and, in fact, becoming an indispensable part of radiological practice, resource requirements of AI systems are growing, placing sustainability at the top of the agenda.

As a passionate advocate for AI applications, I am excited about the advances AI can bring across several disciplines. Whilst AI has the potential to improve efficiency and diagnosis in radiology, one must also face up to the reality of its environmental impact, such as increased greenhouse gas emissions.1 Thus, developing and using AI in ways that minimise environmental impact and promote green clinical practices, including usage of renewable energy sources, is of immense importance. Sustainable AI applications would have undisputable long-term advantages that would enable harnessing the benefits of AI, whilst future-proofing the discipline by minimising its environmental repercussions.

The EMJ team is proud to feature a lot of great content in this year’s issue, covering an array of pertinent topics. I would like to take this opportunity to thank all our reviewers, our amazing contributors, and our Editorial Board for their valuable input into this journal. I hope you enjoy reading through this issue, and we look forward to your feedback and insights.

Reference 1.

Chief Content Officer Justin Levett

Doo FX et al. Radiology. 2024;310(2):e232030.

Chief Commercial Officer Dan Healy Founder and Chief Executive Officer Spencer Gore

Evgenia Koutsouki Editor

Contact us Editorial enquiries: editor@emjreviews.com Sales opportunities: salesadmin@emjreviews.com Permissions and copyright: accountsreceivable@emjreviews.com

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Reprints: info@emjreviews.com Media enquiries: marketing@emjreviews.com

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Foreword It is with great pleasure that I present to you the latest issue of EMJ Radiology. This year’s issue is packed with fascinating peer-reviewed articles on some of the most pressing matters and insightful topics in the field, including the accuracy of ultrasound-guided percutaneous splenic biopsy and the imaging of an atypical case of rabies encephalitis. Between these pages, you will also find insightful interviews with leading experts in the field, an excellent feature on the use of AI in imaging, and an indepth review of this year’s European Congress of Radiology (ECR).

With world-renowned speakers and imagination-defying visuals, ECR 2025 was an event not to be missed Another excellent abstract explores the appropriateness of high kVp technique for digital chest radiography.

ECR 2025 saw healthcare professionals from around the world come together to discuss sustainability, in keeping with this year’s theme of Planet Radiology. The event included dozens of lectures, infocus sessions, symposia, and hundreds of abstracts covering not only the latest research and innovation in radiology, but also delving into how everyone can change their practice to make the field more sustainable and create a better future for healthcare. With world-renowned speakers and imagination-defying visuals, ECR 2025 was an event not to be missed!

What’s more, this year EMJ has interviewed a host of radiology experts at the forefront of innovation, with Katherine Halliday discussing the complexity of imaging in cases of suspected physical abuse and updates to the relevant guidelines, while Kicky van Leeuwen elaborated on the regulations involved in ensuring AI solutions are both safe and effective for clinical use. Andrea Rockall and Patrizia Cornacchione also gave eye-opening interviews about their ECR highlights and how we can all work together to improve sustainability in radiology.

As a part of our extensive ECR coverage, EMJ Radiology 6.1 features summaries of the most groundbreaking abstracts presented at the congress, with a detailed evaluation of sustainable approaches to diagnosing metastatic breast cancer and an assessment of an AI tool built to detect incidental pulmonary embolisms on CT.

Lastly, I would like to thank everyone who has contributed to this wonderful issue, including each author, peer reviewer, interviewee, and Editorial Board member. The success of this issue could not have been achieved without every one of these contributions. I hope you enjoy reading this journal.

Yasmeen Malik St George’s University of London, UK

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Congress CongressReview Review GIANT ### 2024 2023 ● ●

ECR 2025 Insights From The Global Innovation and New Technology (GIANT) Health Event 2023

Caring for our planet is an integral part of caring for our patients At a Glance

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Congress Review Review of the European Congress of Radiology (ECR) 2025 Location:

Vienna, Austria

Date:

26.02.25–02.03.25

Citation:

EMJ Radiol. 2025;6[1]:10-23. https://doi.org/10.33590/emjradiol/SJRG5839

A SPECTACLE as always, this year’s European Congress of Radiology (ECR) in Vienna, Austria, opened with a wealth of entrancing performances, ranging from dancers and acrobats imitating the natural world to dazzling singers gracing the stage. As the first dancers slipped off stage and the crowd erupted into applause, this year’s ECR President, Andrea Rockall, Imperial College London, UK, took the stage to welcome over 20,000 attendees from all over the world and to introduce the theme of ECR 2025: Planet Radiology. Sustainability was at the forefront not only of the opening ceremony but of every insightful session at this year’s congress, as experts from around the globe gathered to share knowledge, research, and innovation, with the hope of creating a more sustainable and inclusive future for us all.

At this year’s opening ceremony, aptly entitled ‘WONDER’, Rockall began her introduction by discussing the vow that all healthcare professionals take, ‘do no harm’, and the unintentional harm caused by the first doctors to use radiation in imaging.

This led to some of the most vital early research and innovation in the field. Today, the radiation dose of a hand X-ray is 1,500 times less than it was originally, well over 100 years ago, and the image quality is far superior. However, Rockall went on to point out that the world now faces another invisible harm: global warming. "Global warming has been identified by the WHO as the biggest threat to health in our time," and, seeing the temperature changes in recent decades presented on the screen during her introduction, it is no wonder that this is the case. “Caring for our planet is an integral part of caring for our patients,” emphasised Rockall, demonstrating to the captive audience why they should CC BY-NC 4.0 Licence

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care about these rising temperatures, and urging them to engage with the theme of this year’s congress.

Rockall went on to discuss the work of the European Society of Radiology (ESR) and their industry partners in influencing policy and legislation, as well as education.

This includes efforts such as the new European School of Radiology Sustainability Course, and the ESR Green Imaging Scheme, joined by over 20 departments since the beginning of 2025. To highlight the collaboration between ESR and other organisations throughout Europe, Patrizia Cornacchione, President of the European Federation of Radiographer Societies, joined Rockall on stage. Cornacchione expressed her hope that ECR 2025 will bring people together and that the connections and knowledge gained at this year’s congress will go on to shape radiology and radiography practices in the future.

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In 2024,

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Roughly 40% of ESR members were women

Only 21% of ESR members in the ‘baby boomer’ generation were women

The first part of the opening ceremony closed with an inspiring speech from Emma Baines, Deputy Head of Mission at the British Embassy, Vienna, Austria, highlighting the profound impact of international collaboration in the face of increasingly complex global challenges.

Baines described the work being done by the UK government to safeguard the planet for future generations, including the Design For Life Roadmap, aiming to avoid single-use medical technology. However, she emphasised the need for collaboration across borders to bring together the brightest minds from across the globe and help save our planet.

The partnership between ESR and the International Atomic Energy Agency was highlighted during Rockall’s subsequent speech, as she elaborated on their work to harness the power of imaging in order to enhance healthcare, ensure patient safety, and drive innovation worldwide.

To speak more about this, Rafael Grossi, Director General of the International Atomic Energy Agency, was invited to the stage. Explaining the vital work done by the agency around the world, Grossi delved into the ways in which industry partners, AI, cloud-based solutions, and interdepartmental collaboration can impact the future of imaging in healthcare. He also emphasised the importance of not leaving anyone behind, highlighting the necessity of capacity building and educational efforts in low- and middle-income countries.

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50% of Generation Z members were female

Rockall’s subsequent talk only sought to drive this point home further. The theme for this year, she excitedly told the audience, was not simply Planet Radiology, but was focused on radiologists fixing the world.

She had searched high and low throughout the imaging community to find the most inspiring projects with this in mind. A social campaign simply titled, ‘Share Your Story’, asked individuals to send their projects to ESR, and the response was overwhelming.

Over 230 applicants from 72 countries, including industry researchers, practicing radiologists, charities, and more, submitted their heartwarming projects, detailing how they hope to do their part in fixing the world with their incredible work. The ‘In-Focus’ programme at ECR this year gave each of these applicants a platform to share their remarkable work taking place around the world, often with few resources.

Angela Ammirabile, Humanitas University, Milan, Italy, took to the stage to discuss one essential part of fixing the world: gender equality in radiology. In 2024, roughly 40% of ESR members were women; however, this varied vastly between generations. Only 21% of ESR members in the ‘baby boomer’ generation were women, while 50% of Generation Z members were female. This positive trend is the result of education efforts around Europe; however, there are still vital gaps. Only five women have held the title of President of ESR in its long history, a number that will grow to six next year. Additionally, there is a

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ECR 2025

noticeable lack of female first and last authors in papers, as well as on the editorial boards of ESR journals.

Ammirable pointed out that although there is promising work happening to entice women to the field, more needs to be done to achieve true equality.

As the opening ceremony continued, gold medals were presented to notable figures such as Rosemarie Forstner, Associate Professor of Radiology, University of Salzburg, Austria, and first female president of the Austrian Society of Radiology, and David Howlett, Consultant Radiologist, Eastbourne Hospital, UK, for their pioneering work in the field. Harriet Thoeny, Professor and Chair of Radiology, University Hospital Freiburg, Germany, was also amongst the extraordinary radiologists

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receiving a gold medal, though this may have paled in comparison to her partner joining her on stage to propose.

The ceremony was certainly one to remember for everyone watching, emphasising the need for collaboration, communication, and education in order to build a better and more equal world for future generations. ECR 2025 started as it went on, and the following days were filled with insightful abstracts, expert lectures, and fascinating research, as the best and brightest in the field of radiology came together to align on building a more sustainable practice. Read on for more insights into this year’s congress, and be sure to return for our coverage of ECR 2026, which will once again be held in Vienna, Austria, from 4th–8th March 2026.

Although there is promising work happening to entice women to the field, more needs to be done to achieve true equality

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Key Imaging Insights into Orbital Pathologies A THOROUGH understanding of orbital pathologies is essential for accurate diagnosis and treatment planning, given the wide range of conditions affecting this complex anatomical region. Recent research presented at ECR 2025 has highlighted the critical role of imaging in distinguishing between various orbital disorders, from post-traumatic injuries to tumours, inflammatory diseases, and vascular anomalies.1 Orbital trauma remains a significant concern, with fractures of the orbital walls often resulting in complications such as herniation of orbital fat, extraocular muscle entrapment, and, in severe cases, globe rupture. Imaging plays a crucial role in evaluating these injuries, ensuring prompt identification of structural damage and guiding surgical intervention when necessary. Advanced CT and MRI techniques are instrumental in detecting subtle fractures, assessing ocular integrity, and ruling out associated vascular complications such as carotid-cavernous fistulas.

Beyond trauma, orbital tumours present a diagnostic challenge due to their diverse origins and imaging characteristics. Primary tumours such as lymphoma and optic nerve glioma exhibit distinct imaging patterns that aid in differentiating them from secondary metastatic lesions, commonly arising from lung and breast cancer. MRI remains the modality of choice for evaluating these tumours, with contrast-enhanced sequences providing essential details on tumour margins, vascular involvement, and potential malignancy.

Inflammatory and infectious conditions, including Tolosa-Hunt syndrome, dacryocystitis, and orbital cellulitis, also require careful imaging assessment. These conditions can often mimic neoplastic processes, necessitating a detailed evaluation of orbital fat stranding, sinus involvement, and soft tissue enhancement to guide appropriate management.

Similarly, optic neuritis, frequently linked

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to autoimmune conditions such as multiple sclerosis, presents with characteristic MRI findings, including T2 hyperintensity and gadolinium enhancement of the optic nerve.

Vascular pathologies, including carotidcavernous fistulas and orbital varices, represent another crucial area of orbital imaging. These conditions can lead to significant visual impairment if not promptly diagnosed. Imaging findings such as proptosis, enlargement of the extraocular muscles, and abnormal vascular enhancement serve as key indicators, assisting clinicians in determining the appropriate course of treatment.

These conditions can often mimic neoplastic processes

Recognising orbital pathologies on imaging requires a comprehensive understanding of anatomy and disease processes. Recent advancements in neuroimaging techniques continue to refine diagnostic accuracy, improving patient outcomes. The integration of multimodal imaging approaches offers deeper insight into the underlying mechanisms of orbital disorders, paving the way for more targeted and effective therapeutic strategies.

Reference 1.

Lopez et al. In plain sight: unveiling overlooked orbital findings. Poster C-12569.

ECR 2025, 26 February-2 March 2025.

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Identifying Non-Odontogenic Jaw Lesions Through Advanced Imaging NON-ODONTOGENIC jaw lesions encompass a broad spectrum of pathologies ranging from benign inflammatory conditions to aggressive malignant tumours.

These lesions can significantly impact both adult and paediatric populations, necessitating a detailed understanding of their presentation and imaging characteristics. A poster presented at ECR 2025 highlighted that accurate diagnosis is essential to guide appropriate treatment and management.1 The identification of non-odontogenic jaw lesions relies heavily on imaging techniques, such as orthopantomography (OPG), which provides an initial panoramic view of the jaw, useful for detecting radiolucent or radiopaque lesions. Ultrasound (US) helps evaluate soft tissue involvement, vascularity, and cystic changes, while CT offers detailed anatomical information, including bone destruction and calcifications. MRI assesses soft tissue extension and marrow involvement, aiding in the differentiation of malignant versus benign lesions.

The poster discussed many conditions, such as fibrous dysplasia, a developmental bone disorder where normal bone is replaced by fibrous connective tissue, for which imaging studies reveal a groundglass appearance on CT, hypointensity on T1-weighted MRI, and variable signal intensity on T2-weighted MRI. Early recognition can prevent misdiagnosis as a more aggressive pathology. Lipomas, though rare in the mandible, present as homogeneous, hyperechoic masses on US, with fat attenuation on CT and hyperintensity on T1-weighted MRI, distinguishing them from other soft tissue tumours. Hemangiomas, benign vascular tumours, exhibit a honeycomb pattern on

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OPG, a hypoechoic signal on US, and strong enhancement on post-contrast CT and MRI due to their vascular nature. Osteosarcoma, a primary malignant bone tumour, displays mixed radiolucent-radiopaque areas on OPG, cortical destruction on CT, and heterogeneous enhancement on MRI.

Utilising multimodal imaging techniques enhances detection and differentiation, ultimately improving patient outcomes Non-odontogenic jaw lesions vary widely in origin and imaging appearance, and a comprehensive understanding of their characteristics, combined with a patient’s clinical background, aids in accurate diagnosis and optimal management. The research concluded that utilising multimodal imaging techniques enhances detection and differentiation, ultimately improving patient outcomes.

Reference 1.

Jejedor Toquero J et al. A pictorial review of non-odontogenic jaw lesions. Poster C-11884.

ECR 2025, 26 February-2 March 2025.

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BT-RADS: A Game-Changer in Brain Tumour Imaging ACCURATE post-treatment imaging of primary malignant brain tumours is critical for guiding management decisions, yet distinguishing between true tumour progression and treatment-related changes remains a major challenge in clinical practice. An educational poster presented at ECR 2025 aimed to introduce radiologists to the Brain Tumor Reporting and Data System (BT-RADS).1 Conventional MRI interpretation is often complicated by pseudoprogression and pseudoresponse, phenomena that can mislead clinicians and lead to inappropriate treatment strategies. While the MacDonald criteria and Rapid Assessment in NeuroOncology (RANO) guidelines have been widely used in clinical trials, their complexity and variability in interpretation have limited their routine application. In response to these challenges, a multidisciplinary team at Emory University, Atlanta, Georgia, USA, developed BT-RADS, a structured reporting system designed to standardise MRI assessment of treated brain tumours and improve communication between radiologists and referring physicians. The system employs a numerical scoring model (0–4) with additional subdivisions to enhance precision, linking each category directly to specific management recommendations.

BT-RADS 0 applies to baseline or nondiagnostic studies, while BT-RADS 1a indicates reduced tumour burden, often reflecting a positive treatment response. BTRADS 1b signifies improvement due to steroid therapy or bevacizumab. Stable disease is classified as BT-RADS 2. Categories 3a–3c represent various degrees of worsening, with 3a indicating treatment effects, 3b denoting an indeterminate mix of tumour growth and treatment response, and 3c signifying increasing tumour burden. BT-RADS 4 confirms definite tumour progression.

The system also includes a structured reporting format covering clinical indication, technique, comparative analyses, and overall impression, ensuring clarity and consistency across multidisciplinary teams.

Preliminary research suggests that BT-RADS holds promise in distinguishing true tumour progression from post-treatment changes.

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as a critical threshold, strongly associated with recurrence and poorer prognosis, potentially guiding early intervention strategies. Validation studies have demonstrated high inter-rater reliability, reinforcing the system’s potential for standardised application across institutions.

Furthermore, BT-RADS serves as an educational tool for junior radiologists, enhancing their ability to interpret posttreatment brain tumour imaging.

While BT-RADS primarily relies on FLAIR and contrast-enhanced T1-weighted images, future refinements may incorporate advanced imaging modalities such as perfusionweighted and diffusion-weighted imaging to improve diagnostic accuracy. Ongoing collaborations with the American College of Radiology, Virginia, USA, aim to integrate BTRADS into the broader family of established RADS reporting systems, ensuring its continued evolution and adoption.

Preliminary research suggests that BT-RADS holds promise in distinguishing true tumour progression from post-treatment changes

With its structured approach and strong clinical relevance, BT-RADS has the potential to revolutionise brain tumour imaging, optimising patient outcomes through improved diagnostic precision and multidisciplinary communication.

Reference 1.

Parillo M et al. Brain Tumor Reporting and Data System (BT-RADS) for monitoring patients with primary brain tumors. Poster C-20813. ECR 2025, 26 February-2 March 2025.

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MR Defecography Aids Pre-operative Planning for Pelvic Floor Dysfunction INSIGHTS on the value of MR defocography (MRD) in surgical planning and the management of common pelvic floor pathologies were shared via a poster presentation at ECR 2025.1 Staggeringly, 40–60% of women who have given birth experience pelvic organ prolapse, and this often affects multiple compartments. The management and prognosis of pelvic floor dysfunction depend on the compartments involved. For example, those with rectal prolapse often have concurrent advanced pelvic organ prolapse requiring both urogynaecological and colorectal surgical intervention. With surgical success rates ranging from 19–97%, researchers reviewed the role of MRD in surgical planning with the aim to provide a standardised reporting algorithm for interpreting radiologists.

The findings highlighted that the MRD examination can be performed in the seated or standing position and that rectal contrast is required. Conversely, the researchers found that vaginal contrast is not routinely needed to complete the examination. They also stressed that MRD findings and quality are dependent on patient effort during defaecation (good, moderate, or poor) and patient concordance with the steps of the examination.

The authors recommended an MRD reporting template that included measurements of the H-Line, M-Line, anorectal angle, and urethral axis at rest; the status of the bladder, cervix, and levator ani at rest; comments on the presence or absence of incontinence at rest; and contraction, including the anorectal angle and urethral axis.

Additionally, they suggested that the report should include the defaecation H-line and M-Line; and details on the anterior compartment, middle compartment, and posterior compartment; as well as postdefaecation information including rectal retention and prolapse reduction.

Regarding MRD’s role for surgical planning, the authors noted that whilst the examination was reliable for evaluating the anterior and middle compartments, its greatest value was provided in evaluation of the posterior compartment. They suggested that for those with posterior compartment disorders, the primary surgical service to refer to would be colorectal surgery, whereas for anterior and middle compartment disorders, the primary surgical service would be urogynaecology/ female urology. Importantly, they stressed that multidisciplinary management may be required for those with multiple compartments affected.

Overall, the research confirmed MRD as a valuable tool in the pre-operative assessment of individuals with pelvic floor disorders, particularly for those with posterior compartment disorders and for identifying individuals who may require multidisciplinary management.

Reference 1.

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Venugopal N et al. Getting to the bottom of the pelvic floor: a primer of MR defecography technique, reporting and implications for surgical management. Poster C-12027.

ECR 2025, 26 February-2 March 2025.

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How to Classify Vascular Malformations with MRI MRI IS the most accurate diagnostic tool for evaluating vascular malformations, offering superior classification, morphological analysis, and spatial mapping of these complex anomalies. An educational poster presented at ECR 2025 aimed to introduce radiologists to the International Society for the Study of Vascular Anomalies (ISSVA) categorisation of vascular malformations.1 Despite its advantages, MRI interpretation of soft-tissue vascular malformations in children remains a challenge for general radiologists unfamiliar with these rare conditions, which are often first suspected by paediatric surgeons following inconclusive ultrasound examinations. Vascular anomalies encompass a broad spectrum of disorders affecting blood and lymphatic vessels, varying widely in structure, severity, and anatomical distribution.

The ISSVA classification system, revised in 2018, categorises vascular anomalies into vascular tumours and vascular malformations, with malformations further divided into simple, combined, or associated subtypes based on their haemodynamic characteristics. Low-flow malformations, including capillary, venous, and lymphatic types, lack an arterial component, whereas high-flow malformations, such as arteriovenous malformations and arteriovenous fistulas, involve abnormal arterial connections.

Capillary malformations typically present as congenital pink or red skin lesions, most commonly found on the neck. Venous malformations, congenital defects of the venous system, frequently affect the skin, soft tissues, and mucous membranes. They manifest as bluish, compressible lesions that enlarge with the Valsalva manoeuvre.

MRI findings include septated lesions with intermediate signal intensity on T1-weighted images and high intensity on T2-weighted sequences. The presence of phleboliths, appearing as low-signal foci, aids in diagnosis.

A recently recognised subtype within this group is glomuvenous malformations.

Arteriovenous malformations are abnormal direct connections between arteries and

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veins, often presenting as purple or reddish skin discolouration, local hyperthermia, and pulsatile masses. Severe cases may lead to pain, ulceration, or haemorrhage. MRI findings include enlarged feeding arteries, draining veins, and early venous filling on contrast-enhanced sequences. These malformations grow with the child and may be single, multiple, or associated with genetic syndromes.

Lymphatic malformations, the second most common vascular malformation type, appear as soft, non-compressible masses, typically in the neck and axilla. Frequently associated with venous malformations, they are classified into macrocystic, microcystic, and mixed types. MRI reveals septated, lobulated masses with high signal intensity on T2weighted images. Macrocystic forms exhibit rim and septal enhancement after contrast administration, while microcystic lesions generally lack significant enhancement.

With its unparalleled accuracy in characterising vascular anomalies, MRI remains indispensable for precise diagnosis and treatment planning, ensuring optimal outcomes for affected children. The ISSVA classification system provides a standardised framework for categorising these anomalies, aiding radiologists in distinguishing between different subtypes and guiding appropriate management. Early recognition and specialist interpretation are key to effective management of these complex conditions.

Reference 1.

Leo L et al. Soft-tissue vascular malformations in children: less difficult than you think.

Categorization and MR Imaging. Poster C-15268.

ECR 2025, 26 February-2 March 2025.

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The Latest Neuroimaging Insights into Perivascular Spaces in Glymphatic System Pathologies UNDERSTANDING the anatomy and pathophysiology of perivascular spaces (PVS) is crucial for diagnosing conditions associated with glymphatic system dysfunction. Therefore, researchers at ECR 2025 presented the key neuroimaging features that mark the relationship between abnormal dilatation or enhancement of PVS and various pathological disorders.1 The glymphatic system, a recently characterised waste clearance pathway in the brain, has garnered significant attention in neuroscience research. This system plays a vital role in removing metabolic waste products and potentially toxic proteins from the brain parenchyma. Perivascular spaces, also known as Virchow-Robin spaces, are key components of this system and can be visualised with neuroimaging techniques.

Abnormalities in PVS have been linked to various neurological disorders, including Alzheimer's disease, Parkinson's disease, and cerebral small vessel disease. As such, a thorough understanding of PVS anatomy and function is essential for accurate interpretation of neuroimaging findings, and subsequent diagnosis of glymphatic system-related pathologies.

The authors presented recent studies that have employed advanced neuroimaging techniques to assess glymphatic system function in vivo. One such method is diffusion tensor image analysis along the perivascular space, which provides a quantitative measure of glymphatic activity.

Research using diffusion tensor image analysis along the perivascular space has shown reduced glymphatic function in patients with neurodegenerative disorders compared to healthy controls. For instance, studies have reported lower ALPS index CC BY-NC 4.0 Licence

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values in patients with Parkinson's disease and rapid eye movement sleep behaviour disorder compared to healthy individuals.

These findings suggest that impaired glymphatic function may be a common feature across various neurodegenerative conditions and could potentially serve as an early biomarker for disease progression.

A thorough understanding of PVS anatomy and function is essential for accurate interpretation of neuroimaging findings The growing body of evidence linking PVS abnormalities to neurological disorders highlights the importance of incorporating glymphatic system assessment into clinical practice. The researchers emphasised the importance of understanding the anatomy and pathophysiologic basis of neuroimaging manifestations of PVS, and the potential implications for patient care.

Reference 1.

Kancharla M et al. Decoding the black-box of perivascular spaces: updates and insights into physioanatomy and neuroimaging of related pathologic disorders. Poster C-16231. ECR 2025, 26 February-2 March 2025.

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Exploring Brachial Plexus Anatomy Through Advanced MRI Imaging A POSTER presented at ECR 2025 explored the challenges of evaluating the brachial plexus using MRI.1 The brachial plexus, a complex neural network, provides sensory and motor innervation to the chest, shoulder, arm, and hand.

It arises from the C5–T1 spinal nerves, although anatomical variations can occur, such as a prefixed plexus with contributions from C4–C7 or a postfixed plexus involving fibres from C6–T2. In rare cases, both variations may be present. This intricate anatomy, combined with the plexus’s long course, makes radiological assessment particularly challenging, especially when diagnosing conditions like trauma, infections, neoplasms, and vascular abnormalities.

MRI plays a crucial role in assessing brachial plexopathies, which can arise from both traumatic and non-traumatic causes. A comprehensive understanding of the brachial plexus’s normal anatomy is vital for distinguishing pathological changes. The brachial plexus originates from the neural foramen, where the ventral and dorsal roots merge. The dorsal root ganglion, located just proximal to the union of the roots, is an essential landmark in MRI imaging, helping to differentiate preganglionic from postganglionic injuries.

for identifying pathology and planning preoperative interventions effectively.

Reference 1.

Manoharan N, Kumar S. Untangling the intricate brachial plexus: exploring its twists, turns and plexopathies. Poster C-21540.

ECR 2025, 26 February-2 March 2025.

On MRI, the roots of the brachial plexus are positioned anteriorly toward the interscalene triangle, a key anatomical landmark. In sagittal images, the roots appear as five stacked points, with the T1 root located below the first rib and the C8 root above it.

As these roots pass through the interscalene triangle, formed by the anterior and middle scalene muscles, they converge into three trunks: upper, middle, and lower. These trunks are each anatomically related to the subclavian artery in distinct ways.

As the trunks progress, they divide into anterior and posterior divisions, forming a triangular cluster of six points visible on MRI. The cords, grouped around the axillary artery, take on a distinctive “paw-print” shape in sagittal imaging. At the lateral border of the pectoralis minor muscle, the cords split into the terminal branches: the median, musculocutaneous, radial, ulnar, and axillary nerves, arranged around the axillary artery. Understanding these critical anatomical landmarks is essential 20

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Simplifying the Interpretation of Paediatric Chest X-rays for Accurate Diagnosis AT ECR 2025, researchers presented a structured approach to interpreting paediatric chest X-rays (CXR), aiming to improve diagnostic accuracy and clinical decision-making.1 Given the frequent use of CXR in paediatric care, recognising abnormal lung densities, hyperlucencies, and key radiographic patterns is essential for accurate diagnosis and effective management.

Paediatric CXR abnormalities primarily fall into four density categories: air, soft tissue, bone, and metallic. Air-related abnormalities such as pneumothorax, pneumomediastinum, and pneumopericardium often result from barotrauma, asthma, or mechanical ventilation. Hyperlucencies, which indicate increased lung transparency, may suggest congenital conditions like lobar overinflation or acquired issues such as air trapping from obstruction. Reviewing a patient’s history and prior imaging is essential to narrowing differential diagnoses.

Soft tissue opacities, including lung consolidations and patchy infiltrates, require careful localisation, as certain conditions affect specific lobes

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Soft tissue opacities, including lung consolidations and patchy infiltrates, require careful localisation, as certain conditions affect specific lobes. Recurrent consolidation may indicate congenital anomalies or immune deficiencies. Additionally, conditions like aspiration pneumonia and foreign body aspiration are more common in the lower lobes, while congenital lobar overinflation often affects the upper lobes.

This research highlights the importance of a structured, systematic approach to paediatric CXR interpretation. By integrating clinical history with radiographic findings, clinicians can enhance diagnostic precision, leading to improved patient care and optimised treatment strategies.

Reference 1.

Samaan S et al. Reading abnormal pediatric chest x-ray made easy. Poster C-10496.

ECR 2025, 26 February-2 March 2025.

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A Systematic Approach to Detecting Non-Parenchymal Metastases with Cranial MRI THE FREQUENCY and location of non-parenchymal metastases visible on cranial MRI have been thoroughly examined and reviewed by researchers, who presented a comprehensive checklist and imaging guide at ECR 2025.1 The detailed findings aim to enhance the identification of these often-overlooked lesions.

Up to 20% of brain metastases detected via cranial MRI involve non-parenchymal structures, necessitating systematic evaluation to avoid missed diagnoses.

Cranial MRI remains the gold standard for detecting brain metastases, with guidelines increasingly advocating its use for screening and monitoring. While parenchymal metastases are well-documented, nonparenchymal metastases, affecting bone, dura, ventricles, pituitary gland, and orbital structures, account for 20% of cases. These lesions, often overlooked without deliberate assessment, require meticulous imaging evaluation to guide treatment decisions.

This study reviewed imaging data and clinical records to catalogue non-parenchymal metastases, developing a checklist to standardise MRI assessments. Bone metastases emerged as the most frequent non-parenchymal type (primary cancers: breast [30%], lung [25%], prostate [20%]), identifiable via T1-weighted imaging as hypointense lesions replacing fatty marrow.

Diffusion-weighted imaging highlighted restricted diffusion in lytic metastases from breast and lung cancers, though less reliably in prostate cases. Another key finding was that contrast-enhanced MRI improved detection of dural invasion, which was present in 15% of bone metastases.

The authors also examined rare metastases, including dural (1% of intracranial tumours), ventricular/choroid plexus (1%), and pituitary lesions. Dural metastases, often mimicking meningiomas, showed diffuse or nodular enhancement, while pituitary metastases were suggested by diabetes insipidus or hypothalamic involvement. Extracranially, orbital metastases manifested as infiltrative or focal masses, exhibiting diffusion restriction and contrast enhancement.

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Contrast-enhanced MRI improved detection of dural invasion, which was present in 15% of bone metastases

The findings advocate integrating a structured checklist into routine cranial MRI protocols to ensure comprehensive evaluation of all potential metastatic sites.

Enhanced detection of non-parenchymal metastases, particularly through advanced sequences like diffusion-weighted imaging and post-contrast imaging, facilitates earlier diagnosis and tailored therapies, ultimately improving outcomes for patients with metastatic disease.

Reference 1.

Chen Zhou ZH et al. Beyond the brain: a comprehensive review of non-parenchymal metastases in cranial MRI: tips and pitfalls. Poster C-12754. ECR 2025, 26 February-2 March 2025.

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Imaging in Shoulder Arthroplasty: Role and Relevance SHOULDER arthroplasty is a successful procedure for treating joint conditions like arthritis and fractures, with imaging playing a critical role in both preoperative assessment and postoperative monitoring. A report, presented at ECR 2025, examines the various types of shoulder replacement, the imaging techniques used, and the key findings related to postoperative complications, with an emphasis on their implications for clinical practice.1 Shoulder arthroplasty involves different prosthetic options, including hemiarthroplasty, total shoulder arthroplasty, and reverse shoulder replacement, each suited to specific conditions like arthritis, rotator cuff injuries, or fractures. Imaging techniques such as plain radiographs, CT, MRI, and ultrasound are essential at different stages of the process. Radiographs are commonly used for initial evaluations, while CT scans provide a detailed assessment of complex bony structures and are used when more precision is required. MRI and ultrasound are useful for soft tissue evaluation, particularly of the rotator cuff. Findings from the study show that imaging is vital in detecting complications such as infection, nerve injury, and periprosthetic fractures, all of which can impact the success of the procedure.

Notably, infection is a rare but serious complication, affecting 0.98% of cases, while heterotopic ossification occurs in 45% of patients within the first year after surgery.

Integration of imaging techniques in shoulder replacement surgeries significantly enhances both preoperative planning and postoperative monitoring

The methods for imaging include standard radiographs for both preoperative and postoperative assessment, CT scans to evaluate bone quality and prosthesis alignment, and MRI for soft tissue analysis.

Postoperative complications, such as scapular notching or instability following

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20-33% With complication rates ranging from 20–33%, these diagnostic methods are indispensable in managing patient outcomes

reverse shoulder arthroplasty, are often detected through these imaging techniques, with CT scans proving valuable in identifying issues not easily visible on radiographs. With complication rates ranging from 20–33%, these diagnostic methods are indispensable in managing patient outcomes.

In conclusion, the integration of imaging techniques in shoulder replacement surgeries significantly enhances both preoperative planning and postoperative monitoring. Clinicians must be adept at interpreting radiographs and CT scans to identify complications early, improving patient outcomes. Future advancements in imaging technology could further refine the detection of complex postoperative issues, making early intervention even more effective in clinical practice.

Reference 1.

Azpeitia Arman FJ et al. A comprehensive guide to radiology in shoulder arthroplasty: essential insights for evaluating shoulder replacements. Poster C-18367. ECR 2025, 26 February-2 March 2025.

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Sustainability and Equity: AI in Radiology Author:

Victoria Antoniou, EMJ, London, UK

Citation:

EMJ Radiol. 2025;6[1]:24-26. https://doi.org/10.33590/emjradiol/XKWV2311

THIS YEAR’S European Congress of Radiology (ECR) saw experts in the field flock to Vienna, Austria, for insights and updates presented in fascinating abstracts, exciting plenary lectures, focused presentation sessions, and riveting new horizon sessions. One such talk, ‘Sustainability and equity in radiology AI: ensuring a fair future’, expertly chaired by Daniel Truhn, Aachen University, Germany, explored many aspects of sustainability in radiology, ranging from what health technology companies can do to make their practices greener to the impact and bias of AI in clinical practice.

THE SHARED RESPONSIBILITY OF SUSTAINABLE AI To give the first perspective on the role of AI in ensuring a more sustainable future for radiology, Sophie Thornander, Philips, Amsterdam, the Netherlands, took to the stage to give an overview of the uses and benefits of AI in radiology. AI is already proving helpful in providing better patient outcomes, streamlining workflow and operations, and expanding access to care in medically underserved communities.

Innovation with AI is not only helping radiologists and patients, but in many ways, it is also benefitting the planet.

Thornander described novel imaging techniques that use a significantly lower dosage and have an improved low-contrast detectability, as well as noticeably less noise. This results in less contrast media, which is better for patients on the one hand, but additionally means fewer raw materials are used, as significant amounts of packaging are used for contrast media.

The environmental impact of digital healthcare is expected to grow in the coming years, with the increased use of phones, laptops, digital servers, and data centres, to mention a few. There are specific data demonstrating that despite its many benefits, AI negatively impacts the environment. Thornander pointed out that 24

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given the many benefits and disadvantages, it is the entire life cycle of AI and digital healthcare that we need to be looking at.

Health technology companies need to consider the environmental trade-offs, as well as factors such as patient safety, when considering the future of AI in radiology.

The environmental impact of digital healthcare is expected to grow in the coming years The key aspect of sustainable AI, Thornander emphasised, is collaboration.

Partnerships between industry, clinics, non-governmental organisations, as well as those outside of healthcare, are a vital part of introducing new technologies and AI into radiological practice. Sharing insights, methods to optimise cloud capabilities, and strategy will make not only for incredible innovation in the field but will also help to make it a more sustainable practice overall.

HOW GREEN IS CLINICAL AI? There is no doubt that the future of AI in healthcare is exciting and full of opportunity; however, there remains the question of how environmentally friendly

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it is at present. To expand on some of Thornander’s points and explore the carbon impact of AI in clinical practice, Jan Niklas Clusmann, Dresden University of Technology, Germany, was next to speak.

may allow us to reduce the number of MRIs taking place, further decreasing carbon emissions. This is only one example of the potential environmental benefits of increasing AI use in radiological practice.

“The climate catastrophe is the number one cause of morbidity and mortality,” Clusmann pointed out, as he showed the audience figures depicting just how much temperatures have risen in recent decades.

With this statement came the question of whether healthcare professionals are indeed doing more harm than good, as their practice contributes significantly to the climate crisis, which is in itself a serious medical crisis. This moral question is not limited to the clinic either, as Clusmann pointed out the immense amounts of carbon emitted each year solely by attendees flying to congresses. Additionally, as technologies become more sustainable, the demand increases, creating somewhat of a paradox.

Clusmann’s presentation showed that although it is not as simple as using AI wherever possible to reduce the environmental impact of medicine, it is a powerful tool, and if used correctly with monitored demand, the use of AI could indeed make clinical radiology a greener practice.

And so, how does AI help clinicians to be more sustainable in their practice?

Clusmann went on to show that AI has the potential to reduce MRI scan times by 25%, meaning that the CO2 emitted through AI use is far less than would be emitted in that extra time by an MRI. Moreover, AI

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EQUITY AND BIAS OF AI IN RADIOLOGY “If the model doesn’t work well for anyone, that’s not a biased model.

But if the model doesn’t work well for a specific group of patients, that’s a biased model,” said Judy Gichoya, Emory University, Atlanta, Georgia, USA, as she began her presentation. Taking a break from discussing environmental impacts and climate change, Gichoya gave a different perspective than that of her colleagues during this session, speaking about equity in the use of AI in radiology.

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Gichoya pointed out that a biased model, though often accurate, would be greatly improved by factoring in an equitable outcome. For example, if a patient is unlikely to attend an MRI appointment, a biased model might suggest double-booking the slot to avoid wasting time, but a model with an equitable outcome would mean clinicians looking into the ‘why’ of the patient’s lack of attendance. This could include transport issues, an inability to leave work, or any other reason. Factoring this in, however, could still lead to a slot being lost, and so Gichoya emphasised the need to move away from the usual mathematical models to factor in bias, and figure out a way to understand the complexities of bias and equity when considering treatment.

In order to create such models, we must use shortcuts. However, Gichoya pointed out, program shortcuts use patterns learnt from several previous examples, and so their ability to understand something out of the ordinary is limited.1 There are many examples of computer models being unable to understand an image unlike the others in the dataset. A well-known example of this issue in radiology occurred when a pneumonia model used shortcuts to diagnose the condition; however, the model never actually looked at the lungs. Instead, it analysed another part of the image to determine whether or not the patient was in the intensive care unit and diagnosed pneumonia based on this, as most patients having chest imaging done whilst in the intensive care unit had pneumonia.2 These examples go to show that mathematical models are not foolproof, and it can be difficult to create medical imaging datasets.

Gichoya closed her talk by emphasising the importance of such models, highlighting how they can streamline processes and improve patient care. However, at the same time, she urged radiologists to check their shortcuts and bear in mind that these models are not perfect.

References 1.

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Geirhos R et al. Shortcut learning in deep neural networks. Nature Machine Intel. 2020;2:665-73.

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A PATIENT'S PERSPECTIVE AND CONCLUDING REMARKS Erik Briers, European Prostate Cancer Coalition, Antwerp, Belgium, brought the session to a close with his insights into AI in radiology from a patient perspective.

As a patient, he remarked, he does not need to know the ins and outs of how the programming works, the way that a radiologist might want to. However, AI platforms can make information more generally accessible to patients and can help to bridge the gap between healthcare providers and their patients. Although there are risks and inaccuracies, and some patients may find the concept overwhelming, there is a lot of potential when it comes to AI for patients and radiologists alike.

This insightful session shed light on the many aspects of sustainability and equity in radiology AI, proving that although there are many exciting opportunities on the horizon, there are multiple factors to consider that may not appear obvious at first. The use of AI can, in many ways, damage the environment further, and models implemented in clinics can make mistakes, causing inaccuracies on the one hand. On the other hand, AI has the potential to reduce time taken in imaging, therefore reducing carbon emissions, and can make information more accessible for patients.

If the model doesn’t work well for a specific group of patients, that’s a biased model

The future of radiology is undoubtedly rooted in automation and AI, and it has become clear from sessions like this that there are countless factors to consider and several risks associated with its use.

Zech JR et al. Variable generalization performance of a deep learning model to detect pneumonia in chest radiographs: a cross-sectional study.

PLoS Med. 2018;15(11):e1002683.

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Novel Therapies Require Novel Imaging Author:

Helena Bradbury, EMJ, London, UK

Citation:

EMJ Radiol. 2025;6[1]:27-30. https://doi.org/10.33590/emjradiol/YSHP1279

WITH an impressive attendance of 20,522 participants from 131 countries, the European Congress of Radiology (ECR) 2025 was an epicentre for innovation, collaboration, and advancement. Under the theme of ‘Planet Radiology’, this year’s congress highlighted the importance of sustainability and global health equity in the world of medical imaging and beyond. Featuring an expert panel, this particular session presented a deep dive into the role of novel therapies that require new imaging techniques.

NOVEL CELLULAR THERAPIES Lucien Beer, Medical University of Vienna, Austria, opened his talk by summarising the history and current landscape of anti-cancer therapies. Until the development of radiotherapy in the 1890s, surgery was initially the only viable treatment strategy for cancer. Following radiotherapy, cytotoxic chemotherapies were then developed in the 1940s. Targeted therapies then emerged in the 2000s, which addressed many of the limitations of chemotherapy, including the multitude of side effects and non-specificity. Finally, within the last 15 years, immunotherapy has emerged as another pillar in cancer treatment. There are several different types of immunotherapies: adoptive cell transfer, immune checkpoint inhibitors, T cell antigen-directed antibodies, and vaccines.

Immune checkpoint inhibitors are the most common type of immunotherapy.

Following recognition of the tumour cell by the immune cell and interaction via the T-cell receptor and antigen, tumour cells can additionally express co-stimulatory molecules that can interact with the T cell and inhibit the immune attack. Examples of these ligands include B7 and PDL-1, which can bind with the T cell co-receptors, CTLA4 and PD1, respectively. Anti-PD-1 and anti-CTLA4 antibodies have thus been developed for therapeutic intervention that CC BY-NC 4.0 Licence

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blocks this co-stimulation, therefore boosting the immune system's potential in attacking tumour cells. As highlighted

by Beer, immunotherapy does not come without its adverse effects, and the response pattern can vary among patients.

Finally, within the last 15 years, immunotherapy has emerged as another pillar in cancer treatment

Secondly, Beer touched on adoptive cell transfer based therapies, discussing tumour-infiltrating lymphocyte therapy (TIL) as an example. In this approach, the tumour is first surgically removed and the population of T cells that have already attacked the tumour in vivo are isolated, expanded, and then reinfused into the patient. A different approach is chimeric antigen receptor T-cell (CAR-T) therapy, whereby a patient blood sample is extracted. The T cells are isolated and genetically modified through viral insertion and translation of a chimeric antigen receptor, expanded, and then reinfused back into the patient. Whilst both approaches involve the extraction, expansion, and reinfusion of immune cells, CAR-T therapy does not involve the surgical removal of the tumour itself and instead genetically modifies the immune cells.

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So, what are chimeric antigen receptors, and what is all the fuss about? The answer is the versatility. Endogenous T cell receptors can only bind with antigens presented by the major histocompatibility complex class of proteins; however, the CAR-T receptor is able to bind any antigen. Nonetheless, whilst effective and aggressive, this line also carries limitations and significant factors to be considered.

Firstly, the target tumour antigen must be one that is limited to the cancer to prevent unnecessary damage to healthy cells and must also be expressed on every cancer cell to maximise the efficacy of the therapy.

In a process known as antigen modulation, tumours can also downregulate the expression of the target antigen in attempts to avoid attack. Neurotoxicity and cytokine release syndrome have also been reported.

Finally, CAR-T is not proving as effective in solid tumours and central nervous system disease as it is in haematologic diseases.

In recent years, cancer vaccines have also shown promise as an effective form of immunotherapy. For this, a tumour sample is taken, and DNA is sequenced to identify potential neoantigen targets that are specific to the cancer. Once selected,

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a therapeutic vaccine is then developed to target it. Cancer vaccines, however, also carry delivery and administration challenges and limited immunogenicity.

NOVEL THERAPY MONITORING: HYBRID AND FUNCTIONAL IMAGING Following on from Beer, Nicola Mulholland, King’s College Hospital, London, UK, subsequently took the stage to delve deeper into the disruptive nature of CAR-T therapy and its impact in recent years in treating haematological malignancies. Some examples of the propriety products available in the UK include lisocabtagene maraleucel for relapsed or refractory large B cell lymphoma and ciltacabtagene autoleucel for relapsed or refractory multiple myeloma, amongst others.

So, who are the ideal patients for CAR-T therapy, and how is the response monitored? Mulholland first highlighted the balance needed when selecting patients for CAR-T. If the tumour volume is too great, you risk overwhelming the CAR-T cells. Conversely, too little tumour antigen and you risk not promoting enough in vivo expansion to fight the tumour.

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As explained by Mulholland, the response to CAR-T is usually assessed using PET CT imaging at multiple timepoints, including one baseline scan at pre-lymphodepletion, then routinely at 1 month and 3 months.

This baseline scan can also guide the decision on subsequent bridge therapy, which is treatment administered to manage a patient’s condition while waiting for a more definitive therapy or procedure to take effect. If the patient has a complete response to CAR-T at 3 months, then 6-month imaging is not necessary. However, if the patient does not have a complete response according to the Lugano Criteria Deauville scores, then a 6-month scan would need to be performed.

This imaging approach is a good predictor of treatment response and long-term remission. If patients show partial or complete response at the 3-month mark, this is generally a good predictor of longterm remission. Complete response at 3-months corresponds to a 70% chance of ‘cure’ at 2 years, whilst a partial response at 6 months is linked to a shorter overall survival and progression-free survival.

In summary, PET CT is used to monitor response to CAR-T cell therapy for large B cell lymphoma and can also help predict treatment outcome. Serial PET CT imaging can additionally provide dynamic, ontreatment risk stratification to facilitate early identification of CAR T-cell therapy failure.

IMAGING PATTERNS OF TYPICAL (AND NOT SO TYPICAL) ADVERSE EVENTS IN CT AND MRI Sandra Baleato-González, Hospital Clínico Universitario de Santiago de Compostela, Spain, opened her talk similarly to Beer, discussing the pillars of anti-cancer treatment, namely targeted therapies, immunotherapies, and cellular therapies.

She acknowledged some of the common adverse events, including colitis, hepatitis, pneumonitis, pericarditis, or encephalitis, amongst others. Baleato-González noted that different imaging techniques are

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also favoured for each adverse event.

For instance, CT may be recommended for enteritis, whilst ultrasound and MRI are recommended for hepatitis and pericarditis, respectively.

Whilst 70% of all adverse events can be depicted in imaging, certain challenges still remain for radiologists. For instance, adverse events can occur in any organ, system, or tissue as well as at any timepoint from the outside, during or after treatment. Regarding the classification of adverse events, there is the Common Terminology Criteria for Adverse Events (CTCAE), which is a scale from Grade 1–5 that corresponds to a particular clinical observation and associated treatment recommendation. The severity of the clinical features ranges from asymptomatic (Grade 1) to death (Grade 5). Interestingly, she also shared a timeline for the presentation of immune-related adverse events. Cutaneous manifestations, such as dermatitis and rash, are typically the first to present, appearing within 4 weeks. This is followed by gastrointestinal manifestations, such as colitis and diarrhoea, at 5–10 weeks, and then lung manifestations, such as pneumonitis (9 weeks), and endocrine manifestations, including thyroiditis and hypophysitis (9–11 weeks).

Baleato-González discussed various imaging patterns and adverse events related to cancer treatments, including those caused by immunotherapy and targeted therapies. She covered conditions like organising pneumonia, pneumonitis, pulmonary haemorrhage, colitis, thyroiditis, T cell therapy side effects, intestinal lymphangiectasia, and pleural effusion.

Notably, she emphasised the importance of distinguishing treatment side effects from disease progression, highlighting mimickers such as adrenalitis, sarcoidosis-like reaction, granulomatous prostatitis, and pancreatitis.

In her concluding remarks, she stressed the radiologist’s role in identifying these conditions, offering differential diagnoses, and recognising emergency manifestations to help manage patients effectively.

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IMAGING PATTERNS OF TYPICAL ADVERSE EVENTS IN HYBRID IMAGING Manil Subesinghe, Guy’s and St Thomas’ Hospital, London, UK, closed the session drawing on the imaging patterns of typical adverse events in hybrid imaging. Opening his presentation, Subesinghe discussed the use of monoclonal antibodies in cancer immunotherapy, particularly focusing on immune checkpoint inhibitors that block natural immune "handbrakes", allowing T cells to attack tumour cells. The two key immune checkpoint interactions are CD86/ CTLA-4 and PD-L1/PD-1, which tumours exploit to evade the immune system.

Following on, Subesinghee explained that immune-related adverse events are common side effects of immunotherapy, caused by immune system attacks on healthy tissues.

These side effects vary by organ/system (e.g., heart, endocrine, gastrointestinal, lungs, and kidneys) and are more frequent

Early detection is crucial, and fluorodeoxyglucose PET CT imaging plays a key role in identifying these adverse events before clinical symptoms appear

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with combination therapy. Early detection is crucial, and fluorodeoxyglucose PET CT imaging plays a key role in identifying these adverse events before clinical symptoms appear. As highlighted by Subesinghe, it allows for both functional and anatomical assessment, providing valuable insights into treatment response and side effects. He also spoke on the importance of clinical history and lab results in accurately diagnosing immune-related adverse events.

In conclusion, while immune-related adverse events are concerning, they often correlate with a positive response to treatment. The use of fluorodeoxyglucose PET CT is recommended for monitoring both tumour progression and immunerelated side effects in immunotherapy.

CONCLUSION In conclusion, as CAR-T, immunotherapies, and cellular therapies evolve, so must imaging approaches. Hybrid and functional imaging, such as PET CT, offers invaluable insight into treatment responses and adverse events, ensuring early detection and improved patient management.

The session underscored the importance of adapting imaging strategies to keep pace with these groundbreaking therapies, fostering better outcomes and advancing the field of oncology.

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Abstract Reviews Dive into the latest findings in radiology with these novel abstracts presented by experts from institutions around the world at the European Congress of Radiology (ECR) 2025. Read on for insights into the cutting edge field of radiology.

Evaluation of Sustainable Diagnostic Approaches for Metastatic Breast Cancer Authors: *Andrea Masperi,1 Cristiano Michele Girlando,1 Giuseppe Petralia1 1.

European Institute of Oncology (IEO), Milan, Italy *Correspondence to andrea.masperi@ieo.it Disclosure: The authors have declared no conflicts of interest.

Keywords: Cancer, CT, metastases, MR, next-generation imaging, oncology, PET-CT, sustainability, technology assessment, quality assurance.

Citation: EMJ Radiol. 2025;6[1]:31-33. https://doi.org/10.33590/emjradiol/HJEW9930

BACKGROUND AND PURPOSE Bone is the most common site of metastasis in metastatic breast cancer (MBC), yet no standardised imaging method accurately assesses treatment response.1 CT has limitations in evaluating bone metastases, while RECIST 1. considers bone lesions non-measurable without soft tissue involvement. Bone scans (BS) can produce misleading ‘flare’ reactions, and 18-Fluoro-deoxyglucose (FDG)-PET/CT may miss inactive bone metastases.2 Whole-body MRI (WB-MRI) is emerging as the most effective imaging tool, offering superior sensitivity without ionising radiation or contrast agents.3-6 Additionally, radiology contributes to global greenhouse gas emissions,7 making sustainable techniques8,9 like WB-MRI crucial for reducing environmental impact while ensuring diagnostic accuracy.

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This study aimed to measure the energy consumption and greenhouse gas (GHG) emissions of various imaging modalities, aiming to determine the most sustainable and effective option for patients with MBC. The findings could help develop a model for radiology departments worldwide to balance clinical effectiveness with environmental sustainability.

METHODS Seventy-eight patients with MBC who underwent imaging between 2019–2024 were analysed. Three diagnostic pathways were compared: 1.

WB-MRI (diagnostic line [DL] 1): Non-contrast imaging with sagittal and axial sequences.

2. FDG-PET/CT (DL2): Imaging with a PET/CT scanner following glucose level assessment.

3. BS with CT chest-abdomen-pelvis (CT-CAP; DL3): Bone scintigraphy combined with contrast-enhanced CT of the chest, abdomen, and pelvis.

Total scan time (T-Total) was converted into hours to facilitate energy consumption and GHG emission calculations.10 Data were compared across individual imaging modalities and grouped diagnostic lines (DL1, DL2, DL3).

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Figure 1: Estimated imaging energy consumption for DL1, DL2, total and individually for DL3 (Bone scans and CT chest-abdomen-pelvis).

Imaging Modalities Energy Consumption 18 16 14

Diagnostic Lines

kVh/pt

12 10

MRI DL1

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FDG-PET DL2

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BS

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CT

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BS+CT DL3

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BS: bone scan; DL: diagnostic line; FDG: 18-fluoro-deoxyglucose.

Binary comparisons of scan times, energy consumption, and GHG emissions were conducted using T-test. Average dose values for CT-CAP, FDG-PET/CT, and BS, along with average contrast agent administration data, were calculated.

CONCLUSION

FINDINGS

These results emphasise the importance of seeking the best and most innovative diagnostic approaches to balance diagnostic accuracy with energy efficiency and biological sustainability. Such advancements could help not only radiology departments become greener but also ensure that patients receive quality and sustainable care.

Scan Times

DL2 had the shortest mean scan time (0.27 hours), followed by DL1 (0.37 hours) and DL3 (0.56 hours).

The new horizons of advanced imaging techniques, especially in oncology, will increasingly have to consider not only the aspect of diagnostic accuracy but also the energy sustainability and biological costs.

Energy Consumption and GHG Emissions DL2 was the most energy-efficient (4.92 kWh/patient), while DL1 (11.10 kWh) and DL3 (12.05 kWh) consumed significantly more. DL2 reduced emissions by 55% compared to DL1 and DL3 (Figure 1).

References 1.

Woolf DK et al. Assessing response to treatment of bone metastases from breast cancer: what should be the standard of care?

Ann of Oncol. 2015;26(6):1048-57

2.

Tateishi U et al. Bone metastases in patients with metastatic breast cancer: morphologic and metabolic monitoring of response to systemic therapy with integrated PET/CT. Radiology. 2008;247(1):189-96.

3.

Padhani AR, Gogbashian A. Bony metastases: Assessing response to therapy with whole-body diffusion MRI. Cancer Imaging.

2011;11 Spec No A(1A):S129-45.

Radiation Exposure and Contrast Use WB-MRI (DL1) had no radiation exposure or contrast media use, unlike DL2 and DL3. FDG-PET/CT (DL2) and BS/CT-CAP (DL3) involved high radiation doses and radiopharmaceutical injections.

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4.

Zugni F et al. The added value of whole-body magnetic resonance imaging in the management of patients with advanced breast cancer.

PLoS One. 2018;13(10):e0205251.

5.

Kosmin M et al. The addition of wholebody magnetic resonance imaging to body computerised tomography alters treatment decisions in patients with metastatic breast cancer. Eur J Cancer. 2017;77:109-16.

6.

Petralia G et al. Whole-body magnetic resonance imaging (WB-MRI) in oncology: recommendations and key uses. Radiol Med. 2019;124(3):218-33.

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McKee H et al. Planetary health and radiology: why we should care and what we can do.

Radiology. 2024;311(1):e240219.

8.

Martin M et al. Environmental impacts of abdominal imaging: a pilot investigation.

J Am Coll Radiol. 2018;15(10):1385-93.

9.

Alshqaqeeq FY et al. Choosing radiology imaging modalities to meet patient needs with lower environmental impact. Resour Conserv Recycl. 2020;155:104657.

10. Mariampillai J et al. The green and sustainable radiology department.

Radiologie (Heidelb). 2023;63(Suppl 2):21-6.

Early Health Technology Assessment for an AI Tool to Detect Incidental Pulmonary Embolisms on CT Authors: Erik H.M. Kemper,1 Ken Redekop,2 Frans Vos,1,3 Maarten IJzerman,2 Martijn P.A. Starmans,1,4 *Jacob J. Visser1 1.

Department of Radiology and Nuclear Medicine, Erasmus University Medical Center Rotterdam, the Netherlands 2. Erasmus School of Health Policy & Management, Erasmus University Rotterdam, the Netherlands 3. Department of Imaging Physics, Delft University of Technology, the Netherlands 4. Department of Pathology, Erasmus University Medical Center Rotterdam, the Netherlands *Correspondence to j.j.visser@erasmusmc.nl Disclosure: Kemper, Redekop, Starmans, Vos, and Visser acknowledge funding by LSH-TKI (Health~Holland Dutch Top Sector Life Sciences and Health) 23024.

Keywords: AI, early-stage value assessment, pulmonary embolisms, value-based imaging.

Citation: EMJ Radiol. 2025;6[1]:33-34. https://doi.org/10.33590/emjradiol/LXPX1647

PURPOSE Incidental pulmonary embolisms (IPE) on CT are missed in up to 70% of cases. While AI tools for IPE detection exist, an evaluation on if and how these tools can provide actual value, e.g., fit patients and end-users’ needs (i.e., radiologists), has never been performed.1 The aim of this early health technology assessment is to determine the requirements for a value-based AI tool for IPE detection on CT. CC BY-NC 4.0 Licence

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METHODS A comprehensive early assessment of radiology-AI was proposed and conducted for IPE. A literature search, structured interviews, focus groups, and evaluation meetings were performed with the identified stakeholders to define criteria and scenarios for a multiple criteria decision analysis. A representative survey was developed and circulated to weigh the importance of the criteria and assess the performances of four possible AI designs. Multiple criteria decision analysis on the survey helps quantify the value requirements.

RESULTS Consultations with radiologists, treating physicians, patients, radiology technologists, AI specialists, legal experts, and ethicists resulted in 14 sub-criteria and five main criteria: patient impact, model performance, physician support, environmental impact, and costs (Figure 1).

Preliminary outcomes indicate that although patient impact due to missed or delayed diagnosis is deemed the most important criterion, increasing the model performance and extending the physician support meaningfully improves the value of the AI tool.

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Figure 1: Four evaluated alternative AI model design proposals for detection of incidental pulmonary embolisms.

VALUE OF IPE DETECTION MODELS Alternative 1 Current Practice

Weighted Score 24%

Alternative 2 Compact 39% Alternative 3 Comprehensive 70% Alternative 4 Commercially Available 45% Patient Impact

Model Performance

Physician Support

Enviromental Costs Impact

The five main criteria, based on the expert elicitation, have been defined as patient impact, model performance, physician support, environmental impact, and costs. Their relative importance is depicted by the lengths of each of the bars. The potential performance of the alternative for each criterion is shown by the bar infill, where a longer infill means a higher score. The weighted average for each alternative is provided.

IPE: incidental pulmonary embolism.

Reference

CONCLUSION

1.

Development of impactful AI, which improves patient outcomes meaningfully and meets the needs of end-users, requires a broad assessment before development.

Early health technology assessment is a structured method that provides insight on what will be impactful.

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Kemper EHM et al. ESR essentials: how to get to valuable radiology ai: the role of early health technology assessment—practice recommendations by the european society of medical imaging informatics. Eur Radiol. 2024; DOI:10.1007/s00330-024-11188-3.

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Abstract Review

Patients’ Perception of Radiographers’ Communication Skills During Planar X-Ray Imaging: A Single Centre Study Authors: *Francis Zarb,1 Paul Bezzina,1 Dean Ciantar1

RESULTS

1. University of Malta, Msida, Malta *Correspondence to francis.zarb@um.edu.mt

Mean scores were either 3 (satisfied) or 4 (very satisfied). There were no significant (p>0.05) discrepancies when comparing the different demographics. Females provided significantly (p<0.05) higher mean rating scores than males. Patients’ scores varied the most in the statement ‘radiographers informed me of what they had to do next’.

Disclosure: The authors declare no conflicts of interest. No funding was received for this study.

Ethical permission for this study was sought and obtained from the Faculty of Health Science Research Ethics Committee (FREC), University of Malta.

Keywords: Communication skills, patient perception, planar X-ray imaging, radiographers.

CONCLUSION

Citation: EMJ Radiol. 2025;6[1]:35. https://doi.org/10.33590/emjradiol/GGLL9160

This is the first study of its kind performed locally evaluating patients’ perceptions of radiographers’ communication skills. The mechanism in place locally for training radiographers in patient communication appears to be effective, as patients are given instructions clearly and without undue discomfort. To make it simpler for patients once they have completed the X-ray and put their minds at ease during their entire stay at the hospital, a clearer pathway should be implemented. Having radiographers with good communication skills improves the patients’ experience when attending for imaging services.

PURPOSE To explore patients’ perception of radiographers’ communication skills during planar X-ray imaging examinations at a general hospital in Malta.1

METHODS A random sample of patients attending for planar x-ray examinations at a medical imaging department at a general hospital in Malta filled out a self-designed questionnaire consisting of demographic data, and scored a series of statements on a Likert scale of 1–4, with 1 being ‘very unsatisfied’, 2 being ‘unsatisfied’, 3 being ‘satisfied’, and 4 being ‘very satisfied’. Data was collected and analysed to identify trends and understand patients’ perception of radiographers’ communication skills. The Friedman test and Kruskal-Wallis test were used to analyse the gathered data.

LIMITATIONS The limitations of this study include a small sample size, potential response bias introduced by participants filling the questionnaire, and a number of radiographers being non-nativespeakers, which could contribute to communication challenges.

Reference 1.

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Zarb F et al. Patients’ perception of radiographers’ communication skills during planar X-ray imaging: a single centre study. RPS 2214. ECR 2025, 26 February-02 March, 2025.

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Diagnostic Performance of Neural Network Algorithms in Skull Fracture Detection on CT Scans: A Systematic Review and Meta-Analysis Authors: Ramtin Hajibeygi,1 Guive Sharifi,2 Mobina Fathi,3 Ashkan Bahrami,4 Reza Eshraghi,4 Irene Dixe de Oliveira Santon,5 Arshia Mirjafari,6 Janine S. Chan,7 *Long H. Tu5 1.

Tehran University of Medical Sciences, School of Medicine, Iran 2. Skull base Research Center, Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran 3. School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran 4. Student Research Committee, Faculty of Medicine, Kashan University of Medical Science, Iran 5. Department of Radiology and Biomedical Imaging, Yale School of Medicine, Connecticut, USA 6. Department of Radiological Sciences, University of California, Los Angeles, USA 7. Keck School of Medicine of USC, Los Angeles, California, USA *Correspondence to long.tu@yale.edu

Studies published before 2024 that employed CNN models to identify skull fractures on CT scans were found using PubMed, Scopus, and Web of Science.

Sensitivity, specificity, accuracy, and the area under the curve (AUC) were all analysed. To evaluate publication bias, Egger's and Begg's tests were employed with STATA version 15.

RESULTS

Citation: EMJ Radiol. 2025;6[1]:36-37. https://doi.org/10.33590/emjradiol/UVCK5966

A meta-analysis of 11 trials including 20,798 patients was conducted. When pre-training for transfer learning was incorporated into CNN training model, the pooled average AUC was 0.96±0.02. The combined averages for specificity and sensitivity were 0.93 and 1.0, respectively. An accuracy of 0.92±0.04 was achieved. Research revealed heterogeneity, which was accounted for by variations in training models, validation methods, and model topologies. No significant publication bias was seen.

BACKGROUND AND AIM

CONCLUSION

Radiologists who evaluate CT scans have diagnostic challenges due to the complexity of underlying anatomy and the potential intricacy of skull fractures. The lack of radiologists and the increasing need for quick and precise fracture diagnosis have highlighted the need for automated diagnostic technologies.1,2 Deep learning (DL) is used by convolutional neural networks (CNN), a promising new class of medical imaging technology, to increase the accuracy of diagnoses. This systematic review and meta-analysis study aims to evaluate CNN's ability to identify skull fractures on CT scans.3

CNN models are effective in detecting skull fractures on CT scans. The results indicate that CNN models have the potential to increase diagnostic accuracy in the imaging of acute skull trauma, despite significant variability and potential publication bias. Future research could focus on the usefulness of DL models in prospective clinical trials to further improve these models' practical application.4,5

Disclosure: The authors declare they have no conflict of interest.

Keywords: Convolutional neural networks, deep learning, fracture, skull.

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References 1.

Gakuu LN. The challenge of fracture management in osteoporotic bones. East African Orthopaedic Journal. 2011;DOI:10.4314/eaoj.v4i1.63606.

2.

Scheyerer MJ et al. Osteoporotic fractures of axial skeleton. Praxis. 2012;101(16):1021-30.

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3.

Chung SW et al. Automated detection and classification of the proximal humerus fracture by using deep learning algorithm. Acta Orthop.

2018;89(4):468-73.

4.

Lindsey R et al. Deep neural network improves fracture detection by clinicians. Proc Natl Acad Sci U S A.2018;115(45):11591-6.

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5.

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Blüthgen C et al. Detection and localization of distal radius fractures: deep learning system versus radiologists. Eur J Radiol. 2020;126:108925.

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Congress Interviews The following interviews explore the highlights and key takeaways from the European Congress of Radiology (ECR) 2025, held in Vienna, Austria, from 26ᵗʰ February–2nᵈ March. Andrea Rockall, President of ECR 2025, dives deeper into the theme of ‘Planet Radiology’, discussing how we can make radiology a more sustainable practice; and Patrizia Cornacchione, President of the European Federation of Radiographer Societies (EFRS) covers her plans for the Federation and what ‘Planet Radiology’ means to her.

Featuring: Andrea Rockall and Patrizia Cornacchione

Citation:

EMJ Radiol. 2025;6[1]:38-40. https://doi.org/10.33590/emjradiol/RDQA4886

Q1

Since our interview last year, you have stepped into the role of President of the European Society of Radiology (ESR); what have you done differently this year with regards to the society and congress?

With the European Congress of Radiology (ECR) being Planet Radiology, I wanted to make sure that I had a focus on building up the sustainability subcommittee and their actions during the year, as well as in the Congress itself.

The Congress In Focus theme was ‘images fixing the world’, which was all about radiologists finding ways to improve access to care for patients or people that are at the periphery, who don't necessarily have easy access to care, as well as a sustainability agenda. So, with the sustainability subcommittee, we took a few actions over the past year whilst I was President.

Now, I am actually Chair of the ESR Board of Directors, since we change over at the end of the Congress, but during my year

Andrea Rockall Clinical Chair in Radiology, Imperial College London, UK; European Society of Radiology (ESR) President 2025; Chair of the ESR Board of Directors

The Congress In Focus theme was ‘images fixing the world’, which was all about radiologists finding ways to improve access to care for patients

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as President we developed a green imaging department certification scheme, and we developed a European School of Radiology (ESOR) sustainability teaching course as well.

Q2

What are the goals of the ESR Green Imaging Scheme, and how do you hope to achieve these?

Together with the subcommittee members, we developed a whole list of items that radiology departments could be doing to bear down on their energy use and waste. We then developed it into a scheme in which people can be awarded points depending on what actions they're doing within their department. The idea is that you can start off with, say, the bronze level, and then move up to the silver level, and then get to the gold level. We haven't quite decided what the levels will be as such, but we piloted the scheme in January and February 2025 and that will be reviewed. We'll hopefully launch the

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scheme in early summer this year. So, that was one big thing that we did over the past year.

Q3

Can you explain briefly for our readers what the ESOR sustainability course will consist of and how you hope it will affect radiology practices?

The course will be free. People have to register onto the ESR Connect platform in order to join the events, but they will be bitesized, lunchtime lectures. What we decided to do was to have each session in two parts. One part will be a lecture about the topic, and then the second part is a case study, describing how somebody in a particular department has been able to implement one of these items; for example, making sure that single use plastic waste goes into the right waste stream, which, incredibly, has a big impact on costs in the department, but also on carbon. So, each lunchtime bite-size session will comprise a short lecture and then a case study. We're looking forward to the launches in April.

Q4

You attended and chaired many fascinating sessions and lectures at the ECR this year. What stood out to you and what might have surprised you during them?

All of the plenary lectures were just fantastic. We had Simon Reeve (London, UK), who gave an ‘outside radiology’ perspective called ‘Around the World with Simon Reeve’. He spoke about the importance of how each individual can actually make a difference in communities and not to stop trying to do things, even in the face of quite overwhelming challenges. He was fantastic, we had a lot of great feedback about his lecture.

The two key takeaways from his lecture that people mentioned to me was: one, there's a lot of talent everywhere, but not always opportunity, it is for us to make sure people have opportunities to thrive in their life and work; and the second thing was his saying, “less screen time, more green time”.

A lot of people took that away.

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Congress Interview

The second plenary was Roland Illing (Chief Medical Officer and Director of International Government Health, Amazon Web Services (AWS); University College London, UK), who talked to us about the importance of big data and computer power in radiology and AI, which was really an eye-opener when we're looking at the amounts of data and data storage that we use in radiology and how that interacts with cloud computing, cloud data storage, and cybersecurity.

That was really excellent.

Next was Linda Moy (New York, USA, Editor of Radiology), who spoke on ocean-safe imaging.

She discussed the use of contrast media and how that ends up in the watercourse. She mainly focused on gadolinium in this lecture and on the fact that in the water processing plants, there's no system at the moment for removal of gadolinium within the water processing. Her takeaway sort of message was, “every drop counts”. We need to make sure that the way we're giving contrast

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means that we use it properly, that we don't waste it, because any waste ultimately ends up in the watercourse. She discussed how multi-patient giving sets are now in use and also discussed some developments in different types of gadolinium contrast media that may help us bear down on the amount of gadolinium.

She touched on the use of AI to help us reduce the amount of gadolinium we're using. Overall, we were very fortunate with our plenary lectures this year.

Q5

How does the use of AI in healthcare impact the environmental impact of radiology?

It’s a real balancing act, AI and radiology. On the one hand, significant energy is used for the development of AI models, which involve huge amounts of data collection, and therefore, data storage on the servers, with energy and water use, and also a lot of work using graphic processing units to train the models, which can take and can be highly intensive in terms of energy usage. In the past year, there has been growing use of large language models and foundation models, which use even more energy and data. As such, we have had a substantial and increasing energy use, and therefore, a carbon burden on the AI development side. On the other hand, the potential benefit side, we have AI that may help us improve radiation doses to patients, resulting in some lower dose techniques, both on CT and on MRI, which will end up reducing the energy usage and, therefore, carbon usage.

Radiology

The biggest thing that we really need to be working on at the moment involves implementation and use of good clinical decision support software to be sure that we're doing the correct imaging for each patient at every stage in their patient pathway. There are also many areas of AI development on the administrative and workflow side that are likely to help reduce waste therefore reduce energy use.

beyond the big things that industry is doing. For instance, reducing helium in scanners, reducing the energy of idle time, transportation of the large machinery, changing to green energy, etc. We can't do that on a daily basis, but I hope that radiologists will go home and say, actually, there's quite a lot that we can do in our daily practice that will save us quite a bit of money, and save carbon and reduce waste to help the planet, and that they start incorporating these things just into their daily working practice.

I think that's where we hope the green imaging department scheme will come in, where you can see a whole list of items of things that you can do that are actually achievable. Some steps may be more challenging, but becoming a sustainable department also makes financial sense and can improves public health. Ultimately, I hope we create a shift in how people approach their daily work, embedding sustainability as a natural part of their practice.

Q6

What do you hope are the main takeaways for attendees after ECR this year?

My dream would be for people to realise that they need to incorporate sustainable practices in everything that they do, just as we incorporate radiation protection in everything we do. We always use the ALARA principle, the ‘as low as reasonably achievable’ for using radiation, and we should be using the same principle with our use of resources.

What I'm hoping for with ECR 2025 is that is that, during the course of the event, delegates could find every day opportunities of bearing down on our energy use and our waste, which can be relatively simple things that we can do,

We also have AI assisting in correcting errors and artifacts in MRI, including patient positioning issues. It enhances scan alignment to minimise positioning errors, 40

aids in dose reduction, mitigates artifacts, and ensures that the appropriate protocol is used based on the patient's indication.

One major area where we use automation, though not entirely AI-driven, is decision support software, a type of computerised support system. In radiology, one of the most significant contributors to carbon impact occurs when a patient undergoes an incorrect test and must return for the appropriate one. This results in unnecessary patient travel, additional imaging, increased data storage, and extra use of resources such as contrast media and tubing.

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We always use the ALARA principle, the ‘as low as reasonably achievable’ for using radiation, and we should be using the same principle with our use of resources

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Citation:

Q1

Assistant Professor, Università Cattolica del Sacro Cuore, Rome, Italy; President, European Federation of Radiographer Societies (EFRS)

While it does not have a simple answer, I must acknowledge the remarkable work of my predecessors, who have dedicated great effort and commitment to the EFRS. As the newly appointed President, my primary goal is to further enhance collaboration, inclusiveness, and innovation within our Federation.

Collaboration will be the foundation of my mandate. We will strengthen dialogue and partnerships, first with EFRS members and then with other stakeholders, either scientific societies or associations within the radiography field, fostering joint projects and shared objectives. But our vision goes beyond that; we will seek new synergies with related professions, building bridges that reinforce and enrich us all. A key priority is to empower the next generation of radiographers, actively encouraging and facilitating their participation to ensure they have meaningful opportunities to engage, contribute, and advance professionally. At the same time, we aim to grow from within, strengthening our committees

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EMJ Radiol. 2025;6[1]:41-43. https://doi.org/10.33590/emjradiol/WKTN3908

As the newly appointed President of the European Federation of Radiographer Societies (EFRS), what do you hope to bring to the Federation and what do you wish to do differently to your predecessor?

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and creating new working groups to tackle emerging challenges.

Every idea, every contribution, and all our collective energy will be crucial in driving innovation and propelling the EFRS to new heights.

Each member of our federation, through their dedication and passion, has the power to shape a future where radiographers are recognised and respected.

Building on the significant progress already made by my predecessors, I also intend to place an even greater emphasis on education. My goal is to support the development of comprehensive and accessible educational programmes that equip radiographers with the skills needed for modern practice. Digital transformation will be another key pillar of the mandate, with a focus on integrating advanced technologies, such as AI and digital imaging tools, into our profession. Lastly, together with the entire EFRS Executive Board, we are committed to promoting sustainability in radiography, driving initiatives that reduce the environmental impact of radiology practices, encouraging energy-efficient equipment, and supporting sustainable clinical workflows. Together, through collaboration, innovation, and shared vision, we can lead the EFRS toward a future of excellence.

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Q2

What do you hope that radiographers throughout Europe can gain from the collaboration between European Society of Radiology (ESR) and EFRS? Radiographers across Europe can gain significantly from our collaboration with ESR. Firstly, the European Congress of Radiology (ECR) serves as the official congress for both the ESR and EFRS, allowing radiographers to share the floor with radiologists and bringing together radiology/radiography, debating and discussing the present and the future at the same time, and encouraging interdisciplinary engagement.

Secondly, as already done in some subcommittees or working groups, we can particularly benefit through shared educational resources and joint research initiatives.

This collaboration can lead to improved professional recognition, broader career opportunities, and enhanced quality of patient care. The experience at the last ECR strengthened this relationship further. In my personal experience this year, I have also been able to appreciate the beauty of small gestures, which in the importance of relationships have 42

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a very important value. It was especially touching when Andrea Rockall, ESR President, warmly embraced me during the opening ceremony of the congress before my speech. This moment was truly emotional and reassuring, marking the beginning of a meaningful connection. From that point on, we continued to collaborate closely, and now we are looking forward to initiating exciting new projects together.

Q3

The theme of ECR this year was ‘Planet Radiology’. In what ways could radiography as a practice be more sustainable?

It’s worth remembering that radiographers encompass clinical work with a particular emphasis on patient and occupational safety, management, quality control, image processing, research, and education. With such a wider range of interactions, radiographers play a crucial role in sustainability.

For this reason, radiography can become more sustainable by, for example, adopting new approaches to reduce waste, employing energy-efficient equipment, optimising existing technologies, and promoting sustainable resource management practices. Educational initiatives

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focused on sustainability, alongside increased awareness about the environmental impact of radiological procedures, can significantly contribute to greener practices.

Radiographers encompass clinical work with a particular emphasis on patient and occupational safety

As EFRS, we have already organised valuable webinars on sustainability, including ‘Sustainability in medical imaging and radiotherapy’ and another focusing on ‘Sustainability in nuclear medicine’. These resources are precious tools available to radiographers on our website,1 helping professionals integrate sustainable practices effectively into their daily operations, and more recently, EFRS has issued a “position statement on sustainability for the radiography profession”.2 Moreover, EFRS bodies, such as committees and working groups are periodically considering initiatives related to the topic.

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Q4

How do you believe that EFRS can help shape the future of radiology and radiography to make it a more sustainable practice, and what do you hope to do towards this as President?

EFRS can shape a sustainable future by promoting best practices, facilitating research on environmental sustainability in radiography, and advocating for policies that reduce the ecological footprint of radiological practices.

As President, I plan to prioritise initiatives aimed at reducing waste, advocating for green procurement, and incorporating sustainability into education and training curricula.

Q5

Outside of EFRS, you are well renowned for your work in education; do you incorporate sustainability into your radiography teaching, and do you think this is necessary?

Yes, I think that sustainability should be part of the educational approach. I regularly integrate sustainability concepts into radiography teaching, emphasising responsible practice, efficient resource management, and the role radiographers play in minimising environmental impact. I believe embedding sustainability in education is essential for shaping responsible future practitioners.

Q6

At this year’s ECR, you chaired a session about transforming radiotherapy practice in the AI era. What do you think the future of radiotherapy looks like in an AIdriven world?

The future of radiotherapy in an AIdriven world is promising, featuring enhanced precision, personalised treatment, and increased efficiency.

AI will assist in treatment planning, image interpretation, and quality

assurance, reducing variability and enhancing patient outcomes.

Radiographers will play a critical and crucial role in navigating these technological advancements, ensuring ethical use and patientcentred care. Their expertise will be essential in balancing innovation with compassion, ultimately shaping a future where AI enhances, rather than replaces, human judgement in radiotherapy.

Q7

Did anything that was shared in this session surprise you?

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innovation, patient care, and environmental responsibility.

The congress reinforced the critical role of education and continuous professional development in shaping the future of radiography.

References 1.

European Federation of Radiographer Societies (EFRS). EFRS research committee webinar series 2024 episode 3. 2024. Available at: https:// www.efrs.eu/webinars/77. Last Accessed: 12 March 2025.

2.

Sarchosoglou A et al.; EFRS Executive Board. A European Federation of Radiographer Societies (EFRS) position statement on sustainability for the radiography profession. Radiography (Lond). 2024;30(Suppl 1):19-22.

Yes, it was surprising to see how rapidly AI tools are becoming clinically integrated and the extent to which diagnostic and radiotherapy radiographers are already adapting their practice to embrace these innovations.

The session underscored the importance of proactive training to manage the evolving responsibilities effectively.

The future of radiotherapy in an AI-driven world is promising, featuring enhanced precision, personalised treatment, and increased efficiency

Q8

What were your main takeaways from this year’s congress?

My main takeaway from this year's ECR was the necessity of adapting to digital and sustainable practices promptly. It was inspiring to witness the extensive collaboration among healthcare professionals dedicated to

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Interviews For this issue of EMJ Radiology, we had the honour of speaking to key opinion leaders Katherine Halliday and Kicky van Leeuwen, whose interviews not only delve into their extensive and impressive careers, but give us a glimpse into the cutting edge innovation and research taking place in the field today. Read on for more insights into national guidelines and the problems facing radiology departments today, as well as the promising use of AI in imaging, and the challenges that come with this.

Featuring: Katharine Halliday and Kicky van Leeuwen

Citation:

EMJ Radiol. 2025;6[1]:44-48. https://doi.org/10.33590/emjradiol/LLHJ2992.

Q1

What inspired you to specialise in paediatric radiology, and how has your career evolved since becoming a consultant in 1998?

Katharine Halliday President of The Royal College of Radiologists (RCR); Clinical Director for Radiology, Nottingham University Hospitals, UK

The thing about paediatric radiology is you cover all different systems. You'll be doing the musculoskeletal system, the gastrointestinal system, the respiratory system, you do all sorts of different things, and there are also opportunities to do intervention (I don’t do intervention, but there are opportunities). It's great from that point of view. It's

AI is already being used in more than half of the departments in the country

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Well, honestly, the reason I got a paediatric radiology job was because there was one going in a town where I wanted a job. I think it's easy to find all areas of radiology really interesting, and there was a paediatric radiology job, and the people who worked in it were really nice. I thought, they were really nice colleagues that would be great to work with; and I never regretted it, we worked together for years.

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also great in terms of interacting, because you do a lot of ultrasound scanning, and you're doing it with the parents there. So, your communication skills are really important; you need to persuade children to get on the couch, and that's not always easy, and the parents are obviously very anxious often about their children; you need to communicate with them all the time about what you're finding and what it means. It's got a lot of different aspects, and I must say that even now, after all these years as a radiologist, every week I come across things that I've never seen before, and it just keeps it really fresh. It's great!

Q2

You have a special interest in the imaging of suspected physical abuse in children, which must be an often difficult subject to navigate. What are some of the unique challenges that come with this area of expertise?

Initially, I started doing more and more of it because I was quite

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intimidated by it, and I thought, well, this is quite a difficult area, so I better try and do as much as I can to get better at it. Then I discovered I started to attract it because I had taken that role. But it's very tricky for the paediatricians, who have to be face to face with the parents and deal with the consequences of getting it wrong either way; either saying a child is being abused when in fact they're not, or missing the fact that they're being abused. The consequences either way are very serious for the child and the family. These are very big decisions that weigh very heavily on everybody involved. That's one thing that is difficult.

Then, of course, there this dealing with the police, which can be quite intimidating. I mean, I have found that the police are always very professional and supportive, and they do a very difficult job.

Goodness me, it's so difficult. But I've really enjoyed working with the police, and, again, one of the good things about this role is you work with all sorts of different people.

Then, there's working with lawyers

and going to court, which can be a real challenge because of the scheduling. It's very difficult to schedule things with any accuracy because of all the things they deal with. They're always trying to get you to keep 2 weeks free for a case, which of course, you can't really do with a busy clinical job.

Quite often, you'll keep some time free and then be asked to go to court, and then they say, ‘Could you come back tomorrow?’ Appearing in court and giving evidence can also be quite intimidating, quite adversarial; and rightly so, your opinion is thoroughly dissected by the lawyers. It's important that the right decision is reached. It's also important that you express yourself in a way that is without jargon and that everybody in the court can understand, which are real skills.

The thing to remember is, it's not about you. So, even though it may feel as if you are being attacked, it's not that. It's just that it's important to understand whether they're making the right decision. And overall, I think the process works pretty well.

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Q3

Can you tell us more about your role in updating the guidance for imaging in cases of suspected physical abuse? What impact has this had on clinical practice?

Well, I was just the chair of the group that updated the guidance in 2018. We had real experts in that group, people from the paediatricians from the Royal College of Paediatrics and Child Health (RCPCH), and also radiologists, neuroradiologists from the RCR, and more; those were the real experts, the people who'd done the research. I just sort of drew them together, and we had great support from both of those Royal Colleges.

I think the thing was, before 2018, there was quite a lot of variation in the way people used to image children with physical abuse. There was quite a lot of confusion about what the right referral process was, who should have CTs of the head and who shouldn't, which views you should do, etc. When we did the guidance, we brought together

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Q4

all these experts and all the evidence, and then we distilled it down into a simple step-bystep guide. That was really helpful for people, because previously, there was so much information, which was really confusing.

How did your appointment as the National Clinical Lead for the Getting It Right First Time (GIRFT) programme for Radiology in 2017 shape your approach to improving radiology services across the UK?

Now it is almost like a flow diagram: do this, do that, do the other. What that meant was that people started behaving in a more uniform fashion. Staff found it very supportive, because once you have something that's really clear; as I say, it's an area that people get really, really nervous about, so it is very reassuring for staff. Now that we have started imaging these children in a more uniform fashion, what that means is that we're now able to get much more data to collect that in a more standardised fashion, and we're able to say, well, looking back at this guidance, how much benefit is doing a CT head in everybody between 6 months and 1 year old?

Amaka Offiah from the University of Sheffield, UK, who was on the original team, is putting all that together with her team, and will be then updating the guidance with the information from that. So, in many ways, it was really helpful.

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It was such a privilege. It was really transformative for me. I went around 143 radiology departments, taking with me a data pack. The whole GIRFT team supported me; there was a data manager who helped get that data and a project manager, and then I was able to go to departments and say: ‘This is where you are on the national scale.’ It's a marvellous process designed and created by Tim Briggs from the Royal National Orthopaedic Hospital, Middlesex, UK, and he really transformed surgical practice with it and then rolled it out to various other places. I was really lucky to be part of that process, and I think it showed huge variation across all areas of practice, but highlighted some major themes that came through about lack of staff, or poor IT, for example.

Also, the amount of time that staff were wasting trying to get new

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equipment, for instance, or doing business cases again and again, which isn't actually within clinical staff skill set. These were common themes that came out and it confirmed my interest in service improvement and supporting people. If you have the right people in the room, from the executive level to all the people who work in the department, having that conversation around the data can be really supportive and transformative. It was a real privilege.

Q5

The Radiology GIRFT report was published in 2020. What were the most significant findings of the report, and were there any which surprised you?

I think workforce, and the fact that everybody was struggling.

This was just before the pandemic, so everybody was struggling, and it showed us that we were on the brink, only just managing.

Of course, the pandemic really pushed us over the edge then, and so we haven't really been able to recover waiting times since the pandemic, because we were just at that point then.

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As for surprising things, well, people are so innovative, staff are so innovative! You discover things that people were doing, and you just think, gosh, I can't believe I've never thought of that. Things like natural sleep MRI, for instance.

So normally, when you're doing an MRI scan on a child, it takes ages and it's quite noisy. If it's a toddler, they can't stay still, so you give them a general anaesthetic or sedation or something like that.

But there were people across the countries, various little pockets of people, who thought, well actually, my toddler stays asleep pretty well if it's a bedtime. So, they invented a process where they bring the children in at bedtime with a sort of travel cot, and their bottle or blanket, put them to sleep, put a couple of little headphones on, carry them onto the MRI scanner and do a 45 minute MRI with a child asleep. It's so much better for them. I've been a paediatric radiologist for years, and I had never thought of that!

In the first place I encountered it, it was one of the helpers who suggested this idea, and they’ve just gone with it and done it.

Now it's quite common. Now, because of the GIRFT project, and because we were able to highlight it and spread that knowledge,

it's quite common. There are all sorts of examples of really good practice. People just thinking, ‘Oh yeah, I think I could make that better.’ One of the great things was being able to spread that.

By the time you've been to a few people, when you are faced with a problem, you say, well over there they're doing it this way, and that's something that I've been able to continue through my career subsequently. The people I met were just amazing.

Q6

As former Clinical Director for Radiology at Nottingham University Hospitals since 2021, what strategic changes have you implemented to enhance patient care and department efficiency?

I stepped away from being Clinical Director when I became President of the RCR because I didn't have time to do both. But it was great to be able to bring my GIRFT experience to that, to realise the things that you need to invest in are the staff. We instigated having one-to-ones with the radiologists, which is common practice in other organisations, but isn't really that common in the NHS, to understand what people did, support them them, support training, and also advocate for better IT.

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The estate that we had also wasn't working for us and was causing delays for patients and real frustration for staff. The staff just want to look after patients properly, and if you put things in their way that prevent them from doing it, it's just difficult. So, we started Big Estates project, which is still going on now. I really enjoyed it, again. I found it a real privilege.

Q7

What do you consider your proudest moment during your tenure as President of the RCR? I mean, I am still so proud to have been elected. To have that faith put in you by your peers is an incredible feeling, and I'm determined to do my best not to let people down.

But also, I think the things that make me proud are when we make a difference. We're able to stand up for the things that are important.

We've become quite influential in the digital sphere, and we're able to advocate for better digital and IT services, and also talk a lot about AI and what the potential advantages are and why we can't push it further. At the RCR, we're able to do that. We're also able to highlight the issues around workforce. We have a national

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census across all four nations, which has a 100% response rate, so we get really good data on how many radiologists and oncologists we have and what their problems are. This allows us to really use that to advocate for them and to raise the profile of our specialities.

We have done that, and so I'm very proud of all of that.

a slightly older generation, we're quite slow typists. Voice recognition doesn't work very well either, so on the whole, it slows us down.

But what we need to do is to be leading the change so that we can make sure that, instead of slowing us down, it enhances our work.

Radiology is a popular specialty, we have about 10:1 people applying for each post, and one of the reasons is because of the innovation that's involved. I think that really excites people.

Q8

One of the most talked-about aspects of radiology nowadays is the role of AI. How do you believe AI will shape your own practice? What challenges do you think radiologists will have to overcome as AI becomes more commonly used?

Q9

It's a very exciting time for radiologists. We are the natural leaders in this because most of the activity is happening in radiology. After all, we're already digital and we've got loads of really great experts in radiology.

AI is already being used in more than half of the departments in the country. Again, that's data from our census, so it's in there, but there is a considerable amount of attention being paid to it, and rightly so, because we do really need to harness the opportunities that digital and AI can bring.

However, there are real barriers to its implementation. Some of the things I've mentioned include digital infrastructure, lack of data standardisation, and poor interoperability between systems.

At the moment, digital often actually slows the doctors down.

You’ve got to open lots of different systems with lots of different passwords, and they don't speak to each other. You quite often have to copy and paste, you're quite often typing, and particularly for us of

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At the RCR, we are working on giving people the tools they need to make that change

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Looking to the future, what are the key challenges and opportunities for radiology in the UK, and how do you envision the speciality evolving over the next decade?

The biggest challenge is the difference between the amount of workforce and the capacity.

So, the biggest problem is lack of capacity and the demand for imaging continues to rise and continues to outstrip our workforce. We need to work differently, and we need to innovate. At the college, we're embracing new ways of working.

The staff are going to be absolutely key. It's going to be about leadership, about pushing forward innovation, saying this is where innovation will help us, and this is where it won't. I think our role will change. The traditional role of a radiologist is to be beavering away in a darkened room just producing reports, but our role will become much more consultative about leadership and patient pathways, innovation, that sort of thing. It doesn't seem to be putting people off; people are very excited by it. At the RCR, we are working on giving people the tools they need to make that change.

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Citation:

EMJ Radiol. 2025;6[1]:49-52. https://doi.org/10.33590/emjradiol/SRLQ2042

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My background is in technical medicine, where I learned some programming but also spent several years in the clinic, shadowing doctors, much like medical students do. This combination was very insightful because, at the same time, I was developing AI models. However, I quickly realised the long and complex journey required to translate these models into clinically valuable tools.

I think we’ve already made significant progress, which is a positive sign. In radiology, AI has been around for quite some time. When I started my journey, I worked in the radiology department at Radboud University Medical Center in the Netherlands because radiology was at the forefront of AI adoption. However, one of the biggest challenges remained the business case and financial sustainability of AI in healthcare.

What inspired you to transition from building AI models yourself to focusing on their validation and implementation in healthcare?

Kicky van Leeuwen Co-founder and consultant, Romion Health & Health AI Register, Utrecht, the Netherlands

One major challenge is regulatory clearance, which involves multiple steps before an AI model can even be used. Also, a model alone is not a complete solution or a software product. It requires many other steps to integrate it into hospital IT systems and make it truly functional in practice.

I believe it is critical for healthcare organisations to understand the regulatory landscape when adopting AI

This realisation was a turning point for me. Understanding both the technical and clinical worlds, I wanted to bridge the gap between them. My focus shifted to ensuring that the AI research being conducted could actually reach clinical practice, benefit doctors, and, ultimately, improve patient care.

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In your experience, what are the biggest barriers to the responsible adoption of AI-based medical software in healthcare, specifically radiology?

AI should contribute to a more future-proof healthcare system that remains accessible to all who need it. However, for that to happen, it must also prove to be cost-effective in the long run. Right now, AI is often implemented as an ‘add-on’ to existing workflows, rather than replacing certain tasks. This raises the question: if AI increases costs, who is going to pay for it? In the future, AI should ideally shift towards an ‘instead of’ model, replacing certain tasks rather than just supplementing them. That would make the financial case clearer, but we’re not quite there yet for many of the applications.

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We also observe the financial challenges from the AI companies’ side. Many AI vendors struggle to generate sustainable revenue, and we’re seeing increasing market consolidation. Recently, one company ceased operations, and another was sold for only €1 million, far below its original investment.

These financial struggles are deeply interconnected: if healthcare organisations find it difficult to adopt AI due to cost concerns, AI companies also struggle to sell their products at a sustainable price.

Q3

Could you describe how Romion Health, the company that you co-founded, helps healthcare organisations with AI strategy, procurement, and implementation?

With the rapid evolution of AI in healthcare, it can be challenging for caregivers and healthcare organisations to stay informed about available solutions and how to use them effectively.

At Romion Health, our goal is to support organisations in the responsible adoption of AI in clinical practice. We help ensure they take an effective approach, 50

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selecting solutions that truly fit their needs, rather than adopting AI simply because they want AI. Responsible adoption also means ensuring that users have sufficient AI literacy and understand the associated risks. These risks can be financial, such as investing in AI without seeing the expected benefits, or clinical, where improper use could negatively impact patient care. Our mission is to minimise these risks as much as possible.

We do this in three main ways.

First with consultancy and project management. We support healthcare organisations with AI implementation projects, helping them navigate the entire adoption process. Second, through education that increases AI Literacy. We provide education and training to healthcare professionals, ensuring they understand how to use AI safely and effectively. And third, through Health AI Register. This is a register of all the CE-marked AI solutions in healthcare to increase transparency in the field. This helps organisations gain a clear overview of available AI tools, understand their differences, April 2025

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and make informed procurement decisions that align with their specific clinical needs.

Q4

What role do regulatory bodies play in ensuring that AI solutions are both safe and effective for clinical use?

During my PhD, I worked for a notified body, a regulatory organisation accredited by the European Union (EU) to grant CE marks for medical devices.

AI software is often classified as a medical device, especially when it influences patient pathways or clinical decisionmaking. In these cases, regulatory bodies play a crucial role in determining whether AI solutions meet the necessary safety and performance standards.

For example, AI used in diagnosis, detection, or patient follow-up is considered a medical device. To enter the market, these solutions must obtain a CE mark, which requires manufacturers to provide extensive documentation to the notified body. This includes demonstrating how they ensure the quality of their AI solution, proving that its performance is on

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par with the state of the art, and outlining measures to maintain its safety over time.

However, not all AI solutions in healthcare are classified as medical devices. A common example is AI scribes, which use voice-to-text technology to transcribe and summarise patient consultations. These systems are gaining popularity, but because they are considered administrative tools rather than medical devices, they do not fall under the same regulatory oversight. Unlike medical AI, AI scribes are not reviewed by a notified body (in the EU), an accredited body (in the UK), or the FDA (in the USA). This means there is no third-party authority ensuring their quality and reliability. As a result, healthcare organisations must take on the responsibility of assessing these AI tools themselves. They need to evaluate what mechanisms companies have in place to maintain the safety and effectiveness of their algorithms.

I believe it is critical for healthcare organisations to understand the regulatory landscape when adopting AI solutions.

Q5

You have previously written about the potential of AI in breast imaging.

Could you go into more detail about the current technologies that use AI for breast imaging, and what you think the future holds?

I find AI in breast imaging particularly exciting for two main reasons. First, breast cancer screening is a well-defined, singletask application. It is focused on one objective: analysing mammograms to detect potential malignancies and determining whether a woman should be referred to a hospital for further examination. This is a decision that radiologists traditionally

make, but because it is such a specific and repetitive task, it is highly suited for AI. While we are now seeing AI models evolve to be more comprehensive, many of the current AI solutions remain highly task-specific, which makes this a promising area for AI adoption.

The second reason is the scale. Breast cancer screening programmes involve large populations, so implementing AI doesn’t just benefit a small group, it impacts a vast number of people. In the Netherlands alone, around one million women are screened annually. This makes AI particularly valuable, as it can help optimise workflows and improve efficiency at a large scale.

Currently, there are multiple AI vendors with relatively mature solutions that are already being used in daily practice. Countries like Sweden and Denmark are leading the way in AI adoption for breast screening, implementing AI not just as an additional tool but in a way that actually reduces workload, an ‘instead of’ rather than an ‘on top of’ approach, as I mentioned before.

Traditionally, in Europe, two radiologists review each mammogram to determine whether further examination is needed. With AI, this process is changing. AI now serves as a second reader, meaning that in low-risk cases where AI and the first radiologist are confident that no cancer is present, a second human radiologist is no longer required. However, in higher-risk or uncertain cases, the traditional two-radiologist approach is maintained. This shift is particularly exciting because it represents a true efficiency gain, moving towards ‘not doing something anymore’ rather than simply adding AI on top of existing workflows.

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We are thrilled that with our company, we lead the implementation of AI in a national breast cancer screening programme, and we can work on such a high-impact application of AI in healthcare.

Q6

What are some common misconceptions about AI in radiology that you frequently encounter?

One of the biggest misconceptions I still encounter is the belief that using AI in radiology means that all patient data will be shared with the vendor and used to retrain their algorithm. In reality, this is not the case unless specific agreements (such as collaboration agreements) explicitly allow data sharing. By default, patient data remains with the hospital. In some cases, data may need to be temporarily shared for processing, such as when using a cloud-based solution, but that does not grant vendors the right to use it for further development or retraining.

This is an important distinction that not everybody is aware of.

Another common misconception is that AI models are continuously retrained in real-time based on user interactions and feedback. In practice, this is quite limited. AI algorithms are typically deployed in specific versions that are periodically updated. A hospital may receive a new version of the algorithm, but in most cases, individual hospitals do not have their own AI models that are continuously retrained while in use. There are exceptions though. For example, in breast cancer screening, one company allows authorised users to provide feedback that can be incorporated into model retraining. However, this is the exception rather than the norm.

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A regulatory misconception, particularly common outside of radiology, is the assumption that having a human in the loop exempts an AI solution from medical device regulations or the AI Act. Some vendors claim that because a human is required to approve AI-generated decisions (e.g., by clicking a button), their solution does not qualify as a medical device and does not require regulatory oversight.

However, this is not how medical device regulations or AI-related risk assessments work. While human oversight is an important safeguard, it does not eliminate potential risks or remove the need for regulatory scrutiny.

in imaging acquisition (e.g., the introduction of a new machine), shifts in patient populations, or AI system updates that may unexpectedly alter performance.

To support this, AI platforms and AI marketplaces are beginning to offer tools, dashboards, and solutions for more effective monitoring. As these technologies continue to mature, I look forward to seeing an increasing responsibility for AI, while ensuring that AI-driven decision-making remains safe, transparent, and accountable.

Q8

Q7

What developments in AI for radiology are you most excited about in the coming years?

One of the most exciting developments in AI for radiology is the growing focus on postmarket surveillance and postdeployment monitoring. Postmarket surveillance is already a regulatory requirement for AI vendors: they must continuously monitor their solutions once they are deployed in clinical practice. However, healthcare organisations also share the responsibility of assessing how these AI solutions perform in their specific settings, which is why the term 'post-deployment monitoring' is increasingly used.

This is a crucial prerequisite for moving toward more autonomous AI. If we want AI to take on greater responsibility in decision-making, potentially without a human involved in every single decision, there must still be oversight to ensure it operates safely and as expected. Monitoring is essential to detect deviations caused by factors such as changes in data distribution, modifications 52

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understanding potential biases in AI outcomes and recognising when AI suggestions should be questioned. By ensuring sufficient AI literacy across healthcare teams, we can ensure that AI is used responsibly, ultimately improving patient safety and clinical decision-making.

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If you could give one piece of advice to healthcare organisations looking to adopt AI, what would it be?

AI is here to stay, and ideally, it will become so seamlessly integrated into healthcare systems and workflows that it eventually feels like just another tool, something you don’t even consciously notice.

As AI becomes more embedded, it remains essential for healthcare organisations to build knowledge and expertise in this area.

That doesn’t mean every healthcare professional needs to know how to build or program AI models, but they do need to understand how to use AI responsibly and be aware of its risks. I see a strong parallel with cybersecurity. In an organisation, not everyone is a cybersecurity expert, but staff members are still expected to follow basic security practices. Many organisations provide annual e-learning modules or phishing awareness exercises to ensure employees understand their role in maintaining security.

I believe we need a similar approach for AI: ongoing education to keep healthcare professionals up to speed on their responsibilities. This includes

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The Good, the Bad, and the Ugly of AI in Medical Imaging Authors:

*David Resühr,1 Colleen Garnett1 1. Heersink School of Medicine, Department of Cell, Developmental & Integrative Biology, University of Alabama at Birmingham, Alabama, USA *Correspondence to resuehr@uab.edu

Disclosure:

The authors have declared no conflicts of interest

Received:

06.12.24

Accepted:

04.02.25

Keywords:

AI, image interpretation, machine learning, radiology.

Citation:

EMJ Radiol. 2025;6[1]:53-55. https://doi.org/10.33590/emjradiol/JTPO7801

INTRODUCTION AI has rapidly emerged as a transformative force in various fields, including healthcare. In the realm of medical imaging, AI-powered tools are revolutionising the way radiologists interpret images and make diagnoses.

While the potential benefits of AI in medical imaging are immense, it is also crucial to acknowledge the potential risks and limitations of its use within the medical field.1

THE GOOD: POTENTIAL BENEFITS OF AI IN MEDICAL IMAGING Enhanced Accuracy and Efficiency

AI algorithms can analyse medical images with remarkable accuracy and speed, often surpassing human capabilities. By identifying subtle patterns and anomalies that may be missed by the human eye, AI can improve diagnostic accuracy and reduce the risk of misdiagnosis and false negatives.2-4

Improved Efficiency and Productivity AI can automate routine tasks, such as image segmentation and measurement, freeing up radiologists’ time to focus on complex cases and patient care.5 In ultrasound, for example, AI is already CC BY-NC 4.0 Licence

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being employed by several companies, including GE Healthcare (Chicago, Illinois, USA) and Butterfly Network (Burlington, Massachusetts, USA), to automate measurements and calculations such as cardiac ejection fraction or bladder volume. The use of advanced techniques, such as deep learning and convolutional neural networks, has improved diagnostic accuracy.6,7 This increased efficiency can lead to shorter wait times for diagnostic results, increase the predictive accuracy of screening, and improve patient satisfaction and care.8,9

Early Detection and Prevention

AI-powered tools can be used to screen for early signs of disease, such as cancer or cardiovascular disease.2,7 Early detection can lead to timely intervention, which may have otherwise taken years to be implemented.

For instance, AI-powered systems have been shown to detect lung cancer at earlier stages, leading to improved patient outcomes.2 Additionally, these screenings can be scaled to large populations of patients, further improving care.

Personalised Medicine

AI can analyse patient data, including medical history, genetic information, and imaging results, to identify personalised

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treatment plans. This can lead to more effective and targeted therapies.

THE BAD: POTENTIAL RISKS AND LIMITATIONS AND CONTROVERSIES OF AI IN MEDICAL IMAGING

The majority of AI algorithms focus on a specific task, modality, or anatomic region, narrowing their general applicability, and they need to be trained on large datasets.3 In medical imaging, this will involve a large quantity of correctly identified, labelled, and interpreted imaging studies.6 If these datasets are biased, for instance, due to errors in the interpretation of the source data or a narrow data set, the AI system may perpetuate those biases. This can lead to incorrect or even discriminatory outcomes, particularly for marginalised populations.

For example, an AI system trained on a predominantly Caucasian population may be less accurate in diagnosing diseases that are more frequent in individuals from other ethnic backgrounds. Groups have been successful in addressing these potential biases from AI algorithms, for example, in the case of COVID-19 and predicting mortality rates.10 Future work should continue to address these biases for all uses of AI in the medical field.

In addition, all patients’ data (including imaging) are protected (by the Health Insurance Portability and Accountability Act [HIPAA] in the USA), and consent must be obtained to use patient data.5 Privacy must be protected by de-identifying or otherwise securing these sensitive data.

Given the numerous global data breaches that have occurred in the past, this could be a serious concern. Ultimately, patients will have to agree to either give up their data for free or get reimbursed in some form; as their information will contribute to the development of profit-generating software, the notion that the contributing patients “deserve a cut” is entirely reasonable.

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AI algorithms can be complex and difficult to interpret, making it challenging to understand how they arrive at their decisions.5 This lack of transparency can hinder trust and limit the accountability of AI systems.

Ethical Concerns

Bias and Discrimination

Data Security

Lack of Transparency

The use of AI in healthcare raises ethical questions, such as the potential for job displacement and the impact on patient– physician relationships.5 It is crucial to ensure that AI is used ethically and responsibly, with careful consideration of the potential social and economic implications.

THE UGLY: REAL-WORLD CHALLENGES FOR AI, EMERGING CONTROVERSIES, AND EXPERT OPINIONS Data Quality and Quantity

AI algorithms require high-quality, labelled data to train effectively.5,6 The availability and quality of medical image data can vary widely, posing challenges for the development and deployment of AIpowered tools.

Regulatory Hurdles and Expert Opinions Regulatory approval processes for AIpowered medical devices can be complex and time-consuming. This can hinder the adoption of innovative AI solutions in clinical practice.4 As AI continues to evolve and become integrated into daily life, many companies are working diligently to create policies that focus on protecting the use of AI to help progress.11 AI-specific reporting guidelines (e.g., extensions to SPIRIT/ CONSORT and upcoming STARD-AI) aim to standardise medical AI research, promoting transparency and rigorous evaluation of findings. The FDA is approving AI, particularly machine learning (a type of AI) products at an accelerating rate.12 The American College of Radiology (ACR) Artificial Intelligence Resource Centre and

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The Hastings Centre - Bioethics in the Digital Age are good starting points for those who would like to delve deeply into this matter.

• Transparent and explainable AI: developing AI systems that are transparent and interpretable, allowing clinicians to understand the reasoning behind the system’s decisions.

Human Expertise Remains Crucial

• Ethical guidelines and regulations: establishing ethical guidelines and regulations to govern the development and deployment of AI in healthcare.

While AI can enhance diagnostic accuracy and efficiency, it is essential to remember that it is not a substitute for human expertise, it is a tool to supplement it. The joint performance of human and machine is superior to the performance of either alone, achieving higher sensitivity and reduced false-positive rates.6,7 Radiologists must continue to play a crucial role in interpreting images, making clinical decisions, and providing patient care. AI is more likely to work alongside radiologists to improve efficiency and accuracy rather than entirely replace them.

Balancing Benefits and Risks

To maximise the benefits of AI in medical imaging while mitigating the risks, a multifaceted approach is needed. This includes: • Rigorous testing and validation: ensuring that AI algorithms are accurate, reliable, and free from bias.

References 1.

2.

Topol E. High-performance medicine: the convergence of human and artificial intelligence. Nat Med. 25(1):44-56.

Bradbury H. Cancer screening and detection: can AI change the game?

EMJ Radiol. 2024;5(1):12-4.

3.

Liu JA et al. Artificial Intelligence (ai) for lung nodules, from the AJR special series on AI Applications. AJR Am J Roentgenol. 2022;219(5):703-12.

4.

Yoo H et al. AI-based improvement in lung cancer detection on chest radiographs: results of a multi-reader study in NLST dataset. Eur Radiol.

2021;31:9664-74.

5.

Brady AP. Artifical intelligence in

• Responsibility: who is to be held accountable for errors due to AI use?

• Collaboration between humans and machines: fostering collaboration between radiologists and AI systems to optimise diagnostic performance. Building user trust in AI.

CONCLUSION In conclusion, AI has the potential to revolutionise medical imaging, leading to improved patient outcomes and healthcare efficiency. However, it is essential to approach AI with caution and address the potential risks and challenges associated with its implementation. By carefully considering and weighing the pros and cons, such as potential ethical implications, data security, transparency, and accountability, we can harness the power of AI to improve healthcare for all.

radiology: an exciting future, but ethically complex. EMJ. 2021(1):54-7.

service: a randomized clinical trial.

Front Pediatr. 2022;10:929834.

6.

Kumar Y et al. Artificial intelligence in disease diagnosis: a systemic literature review, synthesizing framework and future research agenda. 2022;14(7):84559-86.

10. Gu T et al. Mitigating bias in AI mortality predictions for minority populations: a transfer learning approach. BMC Med Inform Decis Mak. 2025;DOI:10.1186/ s12911-025-02862-7.

7.

Rezazade Mehrizi MH et al.

Applications of artificial intelligence (AI) in diagnostic radiology: a technography study. Eur Radiol.

2021;31(4):1805-11.

11. Schmidt J et al. Mapping the regulatory landscape for artificial intelligence in health within the European Union. NPJ Digit Med. 2024;DOI: 10.1038/s41746024-01221-6.

8.

Khalifa M, Albadawy M. AI in diagnostic imaging: revolutionising accuracy and efficiency.

2024;5:100146.

12. Rajpurkar P et al. AI in health and medicine. Nat Med. 2022;28:31-8.

9.

Li X et al. Using artificial intelligence to reduce queuing time and improve satisfaction in pediatric outpatient

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Whole-Body MRI in Oncology: Focus on 3D Sequences in Musculoskeletal Oncology Editor's Pick

My Editor’s Pick is an insightful review article analysing whole-body MRI (WB-MRI) in oncology, with a focus on 3D sequences in musculoskeletal oncology. WB-MRI plays a vital role in tumour detection, characterisation, and assessment of treatment response. 3D WBMRI has improved image resolution, making this an alternative to PET-CT. Çetin Erol Ankara University, Türkiye

Authors:

Ali Ghasemi,1 Shivani Ahlawat,1 *Laura Marie Fayad1-3 1. The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA 2. Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA 3. Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA *Correspondence to lfayad1@jhmi.edu

Disclosure:

The authors have declared no conflicts of interest.

Received:

31.05.24

Accepted:

06.11.24

Keywords:

Cancer, diffusion MRI, MRI, tumour, whole-body imaging.

Citation:

EMJ Radiol. 2025;6[1]:56-70. https://doi.org/10.33590/emjradiol/MTIT1424

Abstract Whole-body magnetic resonance imaging (WB-MRI) has significantly improved oncological disease management by enabling comprehensive visualisation of the entire body in a single scan, facilitating the diagnosis, staging, and monitoring of various cancers. Its integration with diffusion-weighted imaging and apparent diffusion coefficient mapping offers quantitative insights into tumour biology, notably enhancing treatment planning and response evaluation. The evolution from 2D to 3D WB-MRI has improved image resolution and reduced scan times. This review underscores the pivotal role of WB-MRI in oncology, highlighting its efficiency in detecting and characterising tumours and assessing treatment response with a focus on 3D techniques.

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Key Points 1. In oncology, whole-body magnetic resonance imaging (WB-MRI) plays an invaluable role in tumour detection, characterisation, and assessment of treatment response, offering a fast, comprehensive assessment of multiple body parts.

2. 3D WB-MRI techniques have improved WB-MRI with respect to image resolution, allowing multiplanar visualisation and improved detection with faster scan times.

3. With the addition of diffusion-weighted imaging, WB-MRI is an alternative to PET-CT, avoiding radiation exposure, and furthers the ability of MRI to characterise detected lesions.

INTRODUCTION As a safe and comprehensive imaging modality that visualises a wide area of the body, whole-body magnetic resonance imaging (WB-MRI) plays an invaluable role in diagnosis, staging, surveillance, and assessment of response to treatment in various diseases, most notably in oncology.​ 1 ​With WB-MRI, one imaging study can be performed instead of multiple local MRI examinations of different body parts. Employment of WB-MRI in the management of patients with cancer has been associated with lower healthcare costs and shorter staging times.2 WB-MRI has been widely employed in the staging of bone and soft tissue malignancies​.3-7 WB-MRI also aids in the assessment of tumour burden needed for treatment planning in multiple myeloma, lymphoma, and neurofibromatosis.​8-10​ In cases of metastatic cancers, WB-MRI can visualise tumour deposits throughout the body with superior efficacy compared to conventional imaging modalities, for both bone and soft tissue disease, and the role of WB-MRI has been studied in the management of various metastatic cancers including prostate, lung, breast, and ovary​.3,11-14 The addition of functional imaging with diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) mapping to WB-MRI protocols provides quantitative insight into the management of oncologic patients.​15​DWI sequences assess the Brownian movement of water molecules in the tissues and have been used to differentiate between malignant CC BY-NC 4.0 Licence

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and benign lesions throughout the body.16​ Treatment planning, the assessment of response to neoadjuvant treatment, and surveillance for disease recurrence are other advantages of WB-MRI with DWI.17,18​ WB-MRI sequences are traditionally 2D sequences consisting of T1-weighted and fluid-sensitive sequences (with either T2weighted images or short-tau inversion recovery (STIR) sequences), although for some protocols the WB-STIR is used alone.19​2D WB-MRI is performed with image acquisitions in different planes, although often the coronal plane is prioritised to reduce overall acquisition time; with 2D WB-MRI, information is limited to the plane of acquisition. However, with 3D WB-MRI, images are obtained in a single acquisition (typically in the coronal plane) with isotropic or almost-isotropic resolution, and images are reformatted to other planes of interest such as the axial or sagittal planes.​9​3D acquisition therefore renders the duration of WB-MRI significantly shorter and offers higher spatial resolution.​19​Furthermore, 3D WBMRI allows for a volumetric measurement of the tumours providing more accurate sizing and quantitative assessment of the tumour burden throughout the body.​20​ Despite the advantages, 3D WB-MRI also has disadvantages, the most salient being that it is more vulnerable to motion artefacts.

Because the images are reconstructed, patient movement during the scan impacts all the subsequent reconstructed images.

In this review article, the applications of WB-MRI in musculoskeletal oncology are discussed, with a focus on the

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development of 3D WB-MRI and the role of WB-MRI in the management of musculoskeletal oncologic diseases.

EVOLUTION OF WHOLE-BODY MRI IN ONCOLOGY The application of WB-MRI in oncologic settings is rising.​21​A whole-body approach incorporated with the highquality MRI of bone and soft tissues makes WB-MRI an excellent modality for the management of various types of cancers.

For example, WB-MRI has an established role in the management of cancers with bone metastases.​17,22-25​ 2D WB-MRI has been the conventional method of WB-MRI and usually includes T1-weighted and STIR sequences in the coronal plane.​26​Due to single-planarity, 2D WB-MRI fails to provide high-resolution images in other planes. Adding multiple planes, on the other hand, increases the scan time significantly and is typically not done for clinical examinations.​27​ The advent of 3D MRI and functional MRI techniques have made WB-MRI a reliable alternative for previously established whole-body diagnostic methods, in particular CT and PET scans.​3​By acquiring the images in a single plane and reconstructing them into multiplanar 3D images, 3D MRI offers shorter acquisition time which may translate into increased patient satisfaction and a decreased chance of motion artifacts, all while avoiding radiation exposure imparted by PET and CT imaging.​27​

CURRENT 3D WHOLEBODY MRI SEQUENCES 3D T1-Weighted Fast Spin Echo

3D T1-weighted fast spin echo (FSE) sequences have been developed by a variety of vendors and most widely include 3D turbo spin-echo sampling perfection with application-optimised contrast using different flip angle evolutions (SPACE, Siemens Medical Systems, Erlangen, Germany) as well as CUBE (General 58

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Electric, Boston, Massachusetts, USA) and volume isotropic turbo spin echo acquisition (VISTA, Philips, Amsterdam, the Netherlands). The SPACE method has been particularly studied for WB-MRI; this sequence has been shown to enhance the signal-to-noise ratio (SNR) significantly compared to conventional 2D T1-weighted WB images.​26​To further shorten the acquisition time and increase the isotropic resolution, Controlled Aliasing in Parallel Imaging Results in Higher Acceleration (CAIPIRINHA), a parallel imaging technique, has been employed for 3D imaging.28

3D Gradient Echo

In addition to 3D FSE sequences, a variety of vendors have also developed ultrafast 3D T1-weighted gradient echo sequences (Figure 1), mainly for post-contrast imaging (Figure 2 and 3). These were originally used in abdominal imaging and provide high-spatial resolution images during breath holding for a short period of time.29​ These types of sequences are based on T1-weighted, fat-suppressed images and have short repetition time (TR). The short TR, utilisation of uneven k-space sampling, and zero-filling interpolation in the sectionselect direction allow for high-resolution, isotropic images with an overall shortened scan time,​29​all ideal for contrast-enhanced imaging. This 3D WB MRI technique has been proposed as a reliable method for tumour staging,4,30​with comparable diagnostic capabilities to conventional 18F-fluorodeoxyglucose (18F-FDG) PET/CT techniques in the evaluation of recurrence of non-small cell lung cancer.13​Furthermore, dynamic contrastenhanced images can be obtained using 3D sequences; dynamic contrast-imaging has shown promising results in metastasis detection in various types of cancer.​30​

3D T1-Modified Dixon Gradient Echo

A 3D modified Dixon (mDixon) sequence has been proposed as an addition to the WB-MRI protocol to further shorten the acquisition time. Essentially an anatomical T1-weighted sequence, 3D mDixon gradient echo (GRE) utilises a modified 2-point Dixon fast field echo platform to reconstruct in-

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Figure 1: A 13-year-old male with T5 and T8 vertebra plana (arrows).

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An efficient 2D WB-MRI, comprised of A) coronal STIR and B) T1 weighted images, was performed to evaluate other sites of diseases. Due to single-planarity, 2D WB-MRI fails to provide high-resolution images in other planes and each additional plane of image requires a separate acquisition and additional scan time.

STIR: short tau inversion recovery; WB-MRI: whole-body magnetic resonance imaging.

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Figure 2: A 24-year-old male with multifocal osteonecrosis.

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Single coronal 3D isotropic volumetric SPACE (Siemens Medical Systems, Erlangen, Germany) STIR sequence A) enables the generation of high-resolution multiplanar reformations in the B) sagittal and C–E) axial plane. Note osteonecrosis (arrows) involving the bilateral mid to distal femoral diaphysis extending into the epiphyses, bilateral proximal tibia extending into the epiphyses, bilateral humeral heads with reactive bilateral glenohumeral and hip joint effusions.

STIR: short tau inversion recovery.

Figure 3: An 8-year-old child with history of germline RB1 mutation and at high risk for sarcomas and soft tissue tumours.

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Annual surveillance whole body MRI comprised of 3D sequences including post-contrast 3D T1 GRE-based FS subtraction images acquired in the A) coronal plane with multiplanar reformations in the B) sagittal and C–E) axial plane. Note several skeletal lesions (arrows) within the thoracic spine and sacrum.

FS: fat-suppressed; GRE: gradient echo.

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phase, out-of-phase, water, and fat images.​ 31 This method significantly decreases the acquisition time while maintaining an acceptable diagnostic performance. Also, the reconstructed fat images of 3D WB mDixon GRE have been shown to have a superior tissue-lesion contrast compared to the 3D WB FSE method.​31​Relative fatfraction mapping is a technique that relies on both ultrafast GRE and Dixon sequences to produce images using the water and fat images of Dixon. This technique has shown promising results in detecting bone marrow lesions in various metastatic cancers.​32​

3D T2-Weighted/ Short-Tau Inversion Recovery

STIR sequences have inherent capabilities to produce both T1- and T2-weighted images.​9​Most notably, STIR often offers superior and more uniform fat signal nullification compared to fat-suppressed T2-weighted sequences.​19​2D STIR has been extensively included in WB-MRI scans of various cancers.​9,33,34​The combination of T2-weighted FSE SPACE sequence with STIR allows for high-resolution, 3D fatsaturated images that can be reconstructed in multiple planes to improve the identification of lesions of bone marrow or other fat-surrounded lesions.​35​ Employment of 3D T2-weighted STIR in WB-MRI has shown promising results in the detection of bone marrow metastasis.36​ Notably, some authors have reported an equal diagnostic performance of a single 3D T2-weighted WB STIR sequence compared to a WB MRI protocol of T1-weighted, DWI, and 3D T2-weighted WB STIR in paediatric patients (Figure 4), thus reducing the acquisition time for WB MRI in children.​37​

3D Diffusion-Weighted Imaging

DWI with ADC mapping is a functional imaging technique that offers useful information for detecting and characterising lesions, through the study of the diffusion of water molecules in the target tissues (Figure 5). As an isotropic sequence, DWI can be readily reformatted

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into multiple planes as well as provide 3D images.​25​DWI with ADC mapping complements a WB-MRI protocol by aiding in lesion detection, characterisation, and assessment of response to treatment in various oncologic diseases.​17,24,38,39​ DWI also shortens the WB-MRI interpretation time.​40​Moreover, by precisely predicting the resectable lesions, WB DWI has been shown to be decisive in the treatment planning of patients with cancer.​41​ The combination of single-shot spinecho echo-planar DWI with STIR yields a sequence called DWI with background body signal suppression (DWIBS).​42​DWIBS is a technique that allows the suppression of signal from the tissues in the background of the target lesion and is useful for detection, staging, and follow-up of neoplastic disease.​43,44​It has also been shown to be approximately 80% less expensive than the alternative whole-body test, FDG-PET/CT, for the detection of metastatic disease.​45​

FIELD STRENGTH CONSIDERATIONS: 1.5T VERSUS 3.0T MRI The choice between 1.5T and 3.0T MRI systems has implications for image quality, scan time, and susceptibility to artefacts. While 3.0T MRI systems offer higher SNR and potentially higher spatial resolution, they are also more susceptible to artefacts, particularly with DWI sequences.4 In practice, many centres find that DWI performs better and more consistently with fewer artefacts at 1.5T, especially in whole-body imaging where geometric distortions and susceptibility artefacts can be more pronounced at higher field strengths.​46​ Additionally, 1.5T systems may provide more uniform fat suppression and fewer artefacts from implants or metallic hardware. Therefore, the selection of field strength should consider the specific clinical application, patient population, and available equipment, balancing the desire for higher SNR against the potential for increased artefacts.

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Figure 4: A 5-day-old infant with a clinically visible vascular malformation in the chest and left lower extremity hemihypertrophy.

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A–C) Sequential 3D SPACE (Siemens Medical Systems, Erlangen, Germany) STIR WB-MRI reveal extensive right greater than left chest wall and flank lymphatic malformation (solid arrows) with left chylothorax (dashed arrow). Given associated asymmetric left lower extremity hypertrophy, the patient was diagnosed with Klippel-Trenaunay syndrome.

STIR: short tau inversion recovery; WB-MRI: whole-body magnetic resonance imaging.

Figure 5: A 27-year-old man with neurofibromatosis Type 1 and extensive multi-spatial superficial and deep left lower extremity plexiform neurofibroma.

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Neurofibromatosis Type 1 and extensive multi-spatial superficial and deep left lower extremity plexiform neurofibroma (arrow) that is incompletely imaged on A) coronal 2D STIR and B) T1 weighted images as it traverses traditional imaging planes. Subsequently, the patient underwent WB-MRI using C) coronal SPACE (Siemens Medical Systems, Erlangen, Germany) STIR and D) T1-weighted images. WB-MRI enables the determination of overall tumour burden in a single imaging session.

STIR: short tau inversion recovery; WB-MRI: whole-body magnetic resonance imaging.

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Table 1: Summary of 3D whole-body MRI techniques.

Sequence

MRI Contrast

Application in Oncology

3D T1-weighted FSE (typically combined with parallel imaging)

T1- based

Improved SNR and spatial resolution for T1-weighted imaging

3D GRE

T1- based

Often employed with fat suppression for post-contrast T1-weighted imaging

3D T1-modified Dixon GRE

T1- based

Creation of in-phase and opposed-phase imaging, fat- and water-only imaging Enable rFF mapping

3D T2-weighted/STIR

T2-based

Method of fluid-sensitive imaging with high-resolution

3D DWI

T2-based

Method of function imaging with high spatial resolution

3D DWIBS

T2-based

Improved background fat suppression functional imaging with high spatial resolution

DWI: diffusion weighted imaging; DWIBS: diffusion weighted imaging with body background signal suppression; FSE: fast spin echo; GRE: gradient echo; rFF: relative fat-fraction; STIR: short tau inversion recovery.

ROLE OF INTRAVENOUS CONTRAST WITH WHOLE-BODY MRI While contrast-enhanced imaging can enhance the characterisation (as well as detection) of lesions, particularly with the use of T1-weighted fat-suppressed sequences, concerns regarding the accumulation of gadolinium-based contrast agents, especially in patients requiring frequent imaging, have led to the consideration of non-contrast protocols or gadolinium-sparing approaches.​5,47​ Noncontrast WB-MRI protocols, particularly those utilising DWI and STIR sequences, have been shown to be effective in the detection of metastatic disease and in the treatment response assessment.24,48,49 Furthermore, T1-weighted fast spin echo sequences, in combination with DWI, are advocated for the investigation of patients with myeloma, without the use of intravenous contrast. In patients who undergo serial imaging, such as those with genetic cancer predisposition syndromes or those undergoing surveillance for metastatic CC BY-NC 4.0 Licence

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disease, minimising the use of gadolinium contrast agents can reduce the potential risks associated with gadolinium deposition.

For patients who do receive contrastenhanced imaging, dynamic sequences such as 3D time-resolved imaging with stochastic trajectories can provide valuable information regarding lesion vascularity and enhancement patterns.​6,50​These dynamic sequences can aid in the characterisation of lesions and assessment of treatment response, although they are limited to a regional evaluation (rather than the whole body). Additionally, subtraction techniques, where pre-contrast images are subtracted from post-contrast images, can improve lesion conspicuity and aid in the detection of areas of subtle enhancement (Figure 3).​32​

STANDARDISATION AND QUALITY CONTROL IN WHOLE-BODY MRI Ensuring consistency and reproducibility in WB-MRI across different imaging

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Figure 6: A 47-year-old adult with multiple hereditary exostosis.

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A) Coronal 3D SPACE (Siemens Medical Systems, Erlangen, Germany) STIR and B) post-contrast T1-weighted, and C) post-contrast T1-weighted subtraction images reveal multifocal sessile osteochondromas (arrows) and distal femoral Erlenmeyer flask deformity but no suspicious features of malignant transformation.

STIR: short tau inversion recovery.

centres and scanners is a significant challenge. Variations in scanner hardware, software, and imaging protocols, as well as radiologists’ comfort with particular sequences, can lead to differences in image quality and quantitative measurements, such as ADC values in DWI. To address these challenges, standardisation efforts include the use of standardised imaging protocols, phantom studies for quality assurance, and daily quality control (QC) procedures.

Phantoms, which are standardised objects with known properties, can be used to calibrate scanners and assess performance across different systems.

Regular phantom imaging allows for the monitoring of scanner performance, identification of drifts or deviations, and correction of discrepancies between scanners.​51​This is particularly important in multicentre studies or when patients are imaged on different scanners over time.

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Daily QC procedures, including the assessment of image uniformity, SNR, and artefact evaluation, help maintain consistent image quality. Artefact mitigation strategies, such as patient coaching to minimise motion, the use of motion correction algorithms, and the application of advanced imaging techniques (e.g., parallel imaging, respiratory gating), can improve image quality and reduce artefacts.​52​ Finally, the development and adoption of standardised reporting systems, such as the METastasis Reporting and Data System for Prostate Cancer (METRADS), Myeloma Response Assessment and Diagnosis System (MY-RADS), and Oncologically Relevant Findings Reporting and Data System (ONCO-RADS) guidelines, also contribute to consistency in image acquisition, interpretation, and reporting.​53-55​ By adhering to standardised protocols and incorporating QC measures, the reliability and utility of WB-MRI in clinical practice can

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be enhanced, although serial imaging of patients is most efficient and effective when performed at the same centre with the same protocol in place. Table 1 summarises the currently used 3D WB-MRI sequences.

3D WHOLE-BODY MRI APPLICATIONS Given its comprehensive nature and lack of need for radiation exposure, WB-MRI is an invaluable asset in the management of oncologic patients who are generally in need of multiple imaging studies over the course of their disease. Understandably, the applications of WB-MRI have been established in the treatment guidelines of some cancers, namely breast, prostate (MET-RADS), and multiple myeloma (MY-RADS).​53,54,56 Also, WB-MRI can be an invaluable asset in the screening and surveillance of patients diagnosed with genetic cancer-predisposing syndromes such as NF-1, schwannomatosis, or Li-Fraumeni syndrome (LFS).33,57​ Furthermore, the ONCO-RADS has been introduced to standardise the acquisition, interpretation, and reporting of WB-MRI in these oncologic diseases.​ 55 ​The applications of 3D WB-MRI can be classified into the categories below.

Tumour Detection: Assessment of Tumour Burden and Metastatic Disease WB-MRI has been widely utilised for the detection of bone and soft tissue tumours.

Notably, genetic tumour predisposition syndromes can benefit from WBMRI. These syndromes, such as NF-1, schwannomatosis, and LFS, commonly necessitate routine surveillance scans and tumour burden assessments (Figure 6). WB-MRI enables the determination of overall tumour burden and the detection of metastatic deposits in a single imaging session. The application of WB-MRI in NF-1 and schwannomatosis syndromes has shown promising results and has been recommended in the management of patients with NF-1 and higher tumour burden.​9,38​Annual WB-MRI has also been recommended for cancer screening in patients with LFS.​57​ CC BY-NC 4.0 Licence

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The diagnostic accuracy of 2D WB-MRI for the detection of metastatic disease in various types of cancers has been compared with PET/CT scans and studied to a greater extent than 3D WB-MRI, showing that the supplanting of 18F-FDG PET/CT with WB-MRI can also have positive economic implications.​ 45 ​In their meta-analysis, Medeiros T et al.58 showed that a protocol of 2D WB-MRI with DWI has a comparable diagnostic efficacy in the assessment of metastasis in non-small cell lung cancer compared to 18F-FDG PET/ CT.​5 A study on 30 patients with naïve indolent lymphoma has shown comparable diagnostic accuracy between 2D WB-DWIBS/ T2-STIR and 18F-FDG PET/CT in staging of the disease, although the authors have reported a higher sensitivity for WB-MRI for the detection of extra-nodal lesions.59​ Similarly, a meta-analysis has found high sensitivity and specificity for 2D WB-MRI for the detection of nodal and extra-nodal lesions in patients with lymphoma.​5​ WB-MRI can aid in the detection of bone lesions, particularly with the use of a high b value DWI on which metastatic lesions will retain signals against normal background marrow elements. Notably, WB-MRI has superior sensitivity and specificity than other conventional techniques in visualising bone marrow malignant lesions.​47​ A comparable accuracy between 2D WBMRI and 18F-FDG PET/CT for the detection of bone metastases in various types of cancer has been reported.48​For myeloma, a haematologic neoplasm involving bone marrow and causing osteolytic lesions, WB-MRI benefits are substantial in that it provides invaluable insight into the diagnosis of myeloma, even before the formation of osteolytic lesions.​47​ The assessment of bone metastasis in patients with prostate cancer is another utility of WB-MRI.​24​Multiple studies have shown better diagnostic accuracy of WB-MRI compared to bone scintigraphy and equal efficacy as 18F-FDG PET/CT in the diagnosis of metastatic disease in patients with prostate cancer.​60-62​ However, studies on prostate-specific tracers such as 68Ga-Prostate Specific Membrane Antigen (PSMA) with PET/CT scans have shown preferable diagnostic performance

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Figure 7: A 38-year-old woman with left lower extremity myxoid liposarcoma (dashed arrow on a) underwent whole-body magnetic resonance imaging for staging purposes.

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A) Coronal 3D SPACE (Siemens Medical Systems, Erlangen, Germany) STIR shows a right hemi-sacral skeletal lesion (arrow), which is conspicuous on B) inverted scale axial high b-value DWI, C) axial ADC map, and D) post-contrast 3D T1 GRE images through the pelvis. E) This lesion was occult on concurrent axial CT. As such, the patient underwent a biopsy, and this histologically confirmed as a site of myxoid liposarcoma metastasis. WB-MRI has superior sensitivity and specificity than other conventional techniques in visualising bone marrow malignant lesions, particularly with the use of a high b value DWI on which metastatic lesions will retain signal against normal background marrow elements.

ADC: apparent diffusion coefficient; DWI: diffusion weighted imaging; GRE: gradient echo; STIR: short tau inversion recovery; WB-MRI: whole-body magnetic resonance imaging.

Tumour Characterisation

compared to WB-MRI in the staging of metastatic prostate cancer.​49​ 3D WB-MRI techniques have further improved WB-MRI with respect to image resolution, planes of acquisition, and scan time.​19​A study on various cancer types that compared WB 3D VIBE MRI with scintigraphy showed outperformance of WB-MRI in diagnosing metastatic bone involvement.​30​In patients with prostate cancer, 3D WB-MRI has shown comparable or better diagnostic performance with shorter acquisition time than 2D WB-MRI for the detection of bone and lymph node metastasis.​19,63​Finally, for patients with breast cancer, WB-MRI protocols with 3D sequences have shown on par diagnostic outcomes compared with PET/CT scans in patients with a high risk of metastasis.​6​

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The addition of DWI to a WB-MRI protocol enhances lesion detection by WB-MRI, particularly bone lesions (Figure 7). Yet, the importance of DWI is to improve lesion characterisation, once detected by WBMRI​.9,38​Using ADC maps, DWI can help quantitatively distinguish malignant from benign lesions, which is advantageous, especially in the management of genetic tumour predisposition syndromes where malignant degeneration amongst numerous benign tumours can occur.​50​Serial imaging studies are crucial for early detection of malignant transformation in benign lesions, and WB-MRI with DWI provides a comprehensive overview of tumour deposits in the body. Debs P et. al.64 have reported comparable accuracy of WB-MRI compared to localised MRI in patients with NF-I and schwannomatosis,​​

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thus confirming that a protocol of WB-MRI with DWI sequence can replace multiple, local MRIs, which are necessary for surveillance of detected lesions. Although there is no standardised threshold, it has been widely accepted that malignant lesions tend to have lower ADC values.​16​

Assessment of Treatment Response

WB-MRI can demonstrate changes in tumour size or composition. By employing DWI in particular, WB-MRI can aid in the assessment of treatment response for various bone and soft tissue malignancies.

This application has been studied in myeloma, prostate cancer, and lymphoma.​ 39,65-68 ​Besides a decrease in tumour size and signal intensity in T2/STIR images, which can signify a response to treatment, ADC mapping can provide a quantitative metric for determining treatment response in patients with myeloma.​66,69​ Posttreatment WB-MRIs have shown drastically higher ADC values after chemotherapy or autologous stem cell transplant, compared to pre-treatment scans.​69,70​ Increased ADC values are associated with intralesional necrosis, a feature of response to treatment,67​although tumours can also respond by forming post-treatment sclerosis rather than necrosis (also observed to have increased ADC values compared with viable tumours). Although the ADC values have not been standardised yet, post-treatment ADC values significantly correlate with standardised tracer uptake measures in PET/CT scans.67​ DWI WB-MRI can accurately visualise response to radionuclide in metastatic bone lesions in patients with castration-resistant prostate cancer.​39​

and colorectal cancers.​71,23​In breast cancer, for example, WB-MRI has been shown useful to detect metastatic lesions with high sensitivity, aiding in staging and treatment planning.​6,71​In prostate cancer, WB-MRI is well suited to evaluating both bone and soft tissue metastases, guiding decisions on systemic therapies.​23,24​For colorectal cancers, WB-MRI can assess the extent of disease spread, which is crucial for surgical planning and determining eligibility for curative interventions.​2​ The integration of WB-MRI data into radiomics is another promising development in oncological imaging. Radiomics involves extracting a large number of quantitative features from medical images, such as texture, shape, and intensity, which can reveal patterns correlating with disease characteristics and patient outcomes.​72​ By applying advanced algorithms to WB-MRI data, radiomics can help predict tumour behaviour, likelihood of response to specific treatments, and potential for recurrence.​73​ Machine learning and AI, as well as almost every other aspect of radiologic studies, have impacted the WB-MRI acquisition and interpretation. As an emerging trend, the application of AI-driven methods such as deep learning or neural networks in WBMRI studies has introduced faster WB-MRI scans while providing denoised images.​74,75​

LIMITATIONS AND CHALLENGES

FUTURE PERSPECTIVES IN ONCOLOGICAL IMAGING

Despite the benefits, 3D WB-MRI has some drawbacks. Like other 3D MRI techniques, 3D WB-MRI is vulnerable to patient motion during the scan. Also, bulk movements of the heart and the adjacent mediastinal components can result in artefacts, especially in soft tissue neoplasms such as lymphoma.​18​

Individualised management of oncologic patients is a novel approach and a trending topic in recent studies. A 3D WB-MRI scan is an invaluable modality for patienttailored, thorough imaging of patients with cancer and has the potential to be further incorporated into the individualised medical management of breast, prostate, pancreatic,

Some authors have reported instances of false-positive or false-negative cases in paediatric neuroblastoma patients, thus lower accuracy of WB-MRI compared to PET/CT scan.​76​However, recent studies have emphasised the diagnostic accuracy of WB-MRI and its comparability with PET/CT scans in paediatric patients.​77​

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Inherent variations in MRI scanners and protocols can pose challenges when using WB-MRI to track complex patients over time, particularly when compared to PET/CT imaging, which is more standardised.

To ensure consistency between acquisitions and across different scanners, additional centre-specific work is required to standardise the imaging protocols and calibration. This includes the use of phantoms for calibration, adherence to standardised imaging protocols, and regular QC procedures.​51​Despite these efforts, some variability may remain, and radiologists must be aware of these limitations when interpreting serial WB-MRI studies.

Although variable in different parts of the world, the cost of WB-MRI should be considered as a limiting factor in its application.​78​Ultimately, the interpretation of WB-MRI scans might be challenging for inexperienced radiologists and a possible pitfall of WB-MRIs.​9​ Given that not all scanning centres offer WB-MRI images, and the precarious state of oncological patients, care must be taken in standardised reporting of the scans, preferably by experienced radiologists.

References 1.

​​Morone M et al. Whole-body MRI: current applications in oncology. AJR Am J Roentgenol. 2017;209(6):W336-49.

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CONCLUSION WB-MRI is evolving into a routine method for evaluating oncology patients for whole-body tumour burden and metastatic disease. With the addition of DWI to a WB-MRI protocol, the characterisation of detected lesions for malignancy and the assessment of treatment response is more optimal. Additionally, with the advent of 3D WB-MRI techniques, higher resolution whole body imaging can be obtained with faster acquisition times and higher resolution, thereby advancing the feasibility of performing WB-MRI for routine clinical practice in oncology patients.

To maximise the clinical utility of WB-MRI, efforts to standardise imaging protocols, employ appropriate field strengths, and minimise artefacts are essential. Ultimately, through continued advancements in imaging technology and collaborative efforts to establish standardised guidelines, WB-MRI is poised to become an integral component of oncological imaging in routine clinical practice.

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Article

Microwave Ablation for Renal Cell Carcinoma: A Literature Review and Clinical Insights Authors:

*Edwarda D. Golden,1 Ali Mutlu,1 Erica M. Knavel-Koepsel,1 J. Louis Hinshaw,1 Paul F. Laeseke,1 Chris L. Brace,1,2 Timothy J. Ziemlewicz,1 Daniel D. Shapiro,1 E. Jason Abel,1 John F. Swietlik,1 Fred T. Lee, Jr.1 1.

University of Wisconsin School of Medicine and Public Health, Madison, USA 2. University of Wisconsin, Madison, USA *Correspondence to egolden2@uwhealth.org Disclosure:

Abel has received consulting fees from Neuwave unrelated to this work.

Knavel-Koepsel has acted on the medical advisory board for Boston Scientific, which has had no bearing on this work. Lee has received consulting fees from Ethicon, Inc., and royalties from Medtronic. Lee has served on the Board of Directors for HistoSonics, Inc. and the Board of Medical Advisors for Canon, Inc., which has had no bearing on the current work.

Hinshaw has received consulting fees from Neuwave unrelated to this work. Laeseke has received consulting fees from Neuwave, Ethicon, and Johnson & Johnson, unrelated to this work. Ziemlewicz has received consulting fees and research funding from Histosonics, Ethicon, and consulting fees from Elephas, all unrelated to the current work.

All other authors have declared no conflicts of interest.

Received:

06.01.25

Accepted:

17.02.25

Keywords:

Locoregional therapy, microwave ablation, renal cell carcinoma (RCC), ultrasound.

Citation:

EMJ Radiol. 2025;6[1]:71-85. https://doi.org/10.33590/emjradiol/MQUZ3849

Abstract Microwave ablation is an effective treatment modality for T1a and selected T1b renal cell carcinoma (RCC). Independent of the type of thermal ablation techniques used, there are important technical considerations for the successful destruction of targeted tumours while minimising complications, including the use of ultrasound for antenna placement and ablation monitoring, immediate post-procedure contrast-enhanced CT for detection of incomplete treatment and early detection of complications, and hydrodissection and hydroureter for prevention of intraprocedural complications. A review of the existing clinical literature demonstrates a low rate of local tumour progression (LTP) following microwave ablation, aswell as a shorter hospitalisation and potentially fewer complications compared to surgery. However, not all patients are candidates for microwave ablation, which can be user-dependent and technically challenging. Overall, microwave ablation is a valuable modality for the minimally invasive treatment of RCC. The purpose of this article is to summarise the literature concerning microwave ablation of RCC with comparisons to other thermal ablation techniques, as well as partial and radical nephrectomy. Technical and clinical considerations are also discussed, with an emphasis on antenna placement, hydrodissection, imaging guidance, and follow-up.

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Key Points 1. Thermal ablation is a recommended first-line treatment for the management of small renal masses and is considered a viable treatment alternative for larger renal masses in patients who are not good surgical candidates.

2. In a narrative review of the current literature, microwave ablation is shown to be an excellent choice for the treatment of certain cases of renal cell carcinoma due to minimal invasiveness, preservation of renal function, and excellent oncologic outcomes.

3. Many of the limitations of microwave ablation such as risk of thermal injury to surrounding structures, collecting system, ureteral injuries, and incomplete treatment, can be mitigated with appropriate techniques, including the use of hydrodissection, pyeloperfusion, and real-time monitoring with ultrasound.

INTRODUCTION Image-guided percutaneous thermal ablation is widely accepted as an alternative to partial nephrectomy in patients with small localised renal cell carcinoma (RCC) due to a lower risk of complications, shorter hospital stays, and disease-specific mortality indistinguishable from surgery.

The most recent guidelines from the American Urologic Association (AUA) and the European Association of Urology (EAU) reflect this consensus, with ablation now considered an alternative first-line therapy to surgery.1,2 Additionally, percutaneous ablation may be an acceptable alternative to surgery for larger renal masses in select high-risk surgical patients.3 The choice of thermal ablation technique varies considerably from centre to centre and is largely based on local experience and expertise. The most widely studied thermal ablative modalities with the longest follow-up data are radiofrequency (RF) ablation and cryoablation. Microwave (MW) ablation is a more recent addition and has potential advantages over both of these modalities, including rapid tissue heating, no requirement for grounding pads, no limitations from charring or desiccation, a low risk of post-procedural bleeding, and penetration of all biological tissues.4 The purpose of this article is to review percutaneous MW ablation for the treatment of renal tumours. Topics that will be covered include a discussion on the mechanism of action, particularly as compared to RF and cryoablation, a review of unique technical 72

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considerations when treating RCC with MW, and a review of the literature on microwave ablation-related local tumour control, complications, and disease-specific survival.

Additionally, there will be a discussion on patient selection procedural and imaging follow-up, and the important role of a multidisciplinary team.

MICROWAVE ABLATION MECHANISM OF ACTION AND A COMPARISON WITH RADIOFREQUENCY AND CRYOABLATION MW heating is created primarily by the agitation of water molecules by alternating electromagnetic fields at 915 MHz or 2.4 GHz in clinical systems.5 Cell death (tissue ablation) occurs within hours in tissues exposed to temperatures above 42 ℃ and within seconds above 60 ℃.6 Note that boiling occurs in tissue at temperatures above 100 ℃, and thus, cell death can occur even without the formation of visible gas.

MW energy is produced in a controlled amplification system, or generator, and applied to tissue through an antenna that is specifically designed to radiate efficiently in biological tissues. A coaxial cable is used to carry power from the generator to the antenna. The power delivery cable and antenna delivery system contain imperfect conductors and dielectric materials, so some MW power is absorbed in those materials and converted to heat. Active cooling with water or cryogenic gas is employed in most MW ablation systems to

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mitigate the risk of burns along the antenna or cables. Cryogenic gas cooling can be applied in small-diameter antennas and provide a small freeze zone near the distal tip to 'stick' the antenna in place to prevent movement prior to heating.7 Water cooling can be applied with minimal equipment infrastructure, and when it encompasses the entire radiating structure, it may help stabilise antenna performance during the course of MW ablation.8 MW ablation can be performed with a single antenna or an array of antennas.

Multiple antennas can be powered either by a single generator, from which power is divided or by multiple individual generators.

The synchronous application of MW power using multiple antennas has been shown to create larger and more uniform ablation zone geometries when compared to the sequential application of power by a single antenna.9,10 The details of MW system architecture are beyond the scope of this article, but there are several reviews available on this topic.11-14

MICROWAVE VERSUS RADIOFREQUENCY Both MW and RF ablation destroy targeted tissue by heating, but the mechanisms of action are different. RF relies on the conduction of an electrical current between the applied electrode and a separate ground pad. The impedance along this pathway can vary from patient to patient. Thus, the amount of current deposited in tissue can also vary resulting in unpredictable heating.

During RF ablation, increases in tissue temperatures can cause boiling and charring if unchecked. Subsequent rises in impedance decrease current flow, limiting ablation zones to ~1.0 cm.15 To compensate, RF systems need to either be cooled (limiting tissue temperatures to <100 ℃ to avoid boiling and charring), used multiple times to distribute heat spatially, coupled with a liquid infusion, or heating must be performed slowly and below boiling temperatures.16,17 In contrast, MW heating occurs by an applied electromagnetic field, not an electrical current. As a result, there is no CC BY-NC 4.0 Licence

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need for grounding pads, and MW energy will propagate through any biological tissues, including those with low water content. The high temperatures associated with MW ablation (>150 ℃ in some cases) reduce the influence of flowing blood and other heat sinks.18 Another difference from RF is tissue contraction, in which heated tissue shrinks around the MW antenna. This effect is correlated to water vaporisation and is, therefore, much more pronounced during MW ablation.19,20 Such tissue contraction is likely a factor in the superior local control seen in many studies comparing MW and RF in various tissue types.5 Finally, the real-time imaging changes observed during thermal ablations, including soft tissue gas and surrounding tissue hypoechogenicity or hypoattenuation on ultrasound and non-contrast CT, respectively, are more predictive of the kill zone for MW ablation than RF.21

MICROWAVE VERSUS CRYOABLATION Cryoablation involves the percutaneous placement of cryoprobes, which rapidly remove heat from the surrounding tissue.22 One of the major advantages of cryoablation is that tissue freezing can be directly visualised by both CT and ultrasound.23,24 However, an associated pitfall is that the visualised iceball (i.e., the 0 ℃ isotherm) is larger than the lethal zone (the -20 ℃ isotherm).25,26 The lethal zone is unable to be visualised, and therefore, the visible iceball needs to be larger than expected to account for both the lethal isotherm as well as an ablative margin. To obtain larger lethal zones, a large number of cryoprobes and largediameter probes are often required.27 Tissue ablation is more rapid with MW than cryoablation. After antenna or cryoprobe placement, MW ablations typically last 5– 10 minutes, whereas cryoablation requires multiple freeze-thaw cycles, which are more time-intensive (15–25 min per freezethaw cycle, multiple usually required).

Finally, cryoablation can be complicated by clinically significant haemorrhage, which may require subsequent embolisation. In an effort to mitigate this

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risk, some centres perform pre-ablation selective embolisation as a preventative strategy.28,29 The bleeding risk with cryoablation increases with tumour size and with the size and number of probes.30

MICROWAVE ABLATION OF RENAL TUMOURS: SPECIAL CONSIDERATIONS If and When to Biopsy Renal Masses Scheduled for Ablation

Current AUA guidelines recommend renal mass biopsy prior to ablation as a separate procedure as the preferred approach over biopsy at the time of ablation.31 There are several advantages to this strategy. Up to one-third of small renal masses are benign and may only require surveillance.32 For patients undergoing ablation, a biopsy performed on a separate pre-ablation date is more likely to yield a diagnostic result (with the opportunity for re-biopsy in nondiagnostic cases). A pre-ablation biopsy model avoids prolonged imaging surveillance (often lasting decades) for patients without a definitive cancer diagnosis.33 From a technical standpoint, concurrent biopsy at the time of ablation can make the ablation procedure more complex due to haemorrhage and the introduction of air, which can degrade the acoustic window and obscure visualisation of the ablation target.

Preservation of Renal Parenchyma: Lessons Learned from the Surgical Literature

In addition to the risks of kidney cancer, it is critical to consider the risk of worsening chronic kidney disease (CKD) and the impact on overall survival. Nephron-sparing approaches such as partial nephrectomy are prioritised over radical nephrectomy for T1 tumours and for select T2 tumours because of favourable oncologic outcomes while minimising loss of renal function.34 The development of CKD frequently competes with cancer as a potential cause of mortality in patients treated for RCC, and poor presurgical estimated glomerular filtration rate (eGFR) or a marked drop in eGFR after nephrectomy are associated with increased 74

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all-cause mortality.35 In terms of the ideal size of surgical margins, a large metaanalysis concluded that tumour enucleation (1 mm normal renal parenchyma included) was non-inferior to partial nephrectomy (1 cm normal renal parenchyma included) for local and intra-renal recurrence.36 In the absence of definitive literature to the contrary, this concept of narrow but negative margins should be extended to the ablation of RCC. Positive margins after surgery or incomplete ablation are associated with patient anxiety and worse recurrence-free survival.37,38 Compared to RF and cryoablation, MW creates precise ablation zones with a narrow zone of partial necrosis between treated and untreated tissue that may help minimise unwanted destruction of normal renal parenchyma.21,39

Injury to the Collecting System and Ureter with Microwave Ablation

Injuries to the collecting system, renal pelvis, and ureter have been reported with all thermal ablation modalities but are likely higher with heat-based modalities, given the relative preservation of collagenous structures with cryoablation.40,41 Urothelial injuries from MW can be severe due to the high temperatures and power applied to the tissue. Injuries to isolated calyces adjacent to the targeted tumour are common and generally of no consequence.

However, if a calyceal injury and a proximal infundibular stricture are concomitantly created, a patent probe track can lead to urinoma formation. This complication can be avoided using a tangential probe path (Figure 1), avoiding direct collecting system punctures, and forgoing track cautery.42 Rarely, more severe injuries involving the renal pelvis or ureter can result in ipsilateral kidney loss. The mechanism of these injuries is likely due to high applied powers, generally seen with multiple MW antennas, which can create steam within the collecting system, causing urothelial injury and scarring.40 This complication can generally be avoided by careful attention to probe number, power, and ablation time, as well as real-time monitoring of the ablation with ultrasound. Retrograde pyeloperfusion is another protective measure that has

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been shown to reduce urothelial injuries during cryoablation and, anecdotally, is also effective for use with MW.43 Patients should be well informed of the small risk of collecting system injury and impact on future renal function.

MICROWAVE ABLATION TECHNIQUE System and Setting

Renal MW ablation technique varies by institution. At the authors’ institution, renal MW ablation is performed by a multidisciplinary team of abdominal/ interventional radiologists and urologic oncologists. Most commonly, patients are treated in the contralateral decubitus position, although oblique or prone positioning may be used. Ultrasound is preferred for guiding antenna placement.

Rarely, if the tumour is not well visualised by ultrasound, CT fluoroscopy, or a CT-based needle navigation system (Imactis CTNavigation, GE Healthcare, Chicago, Illinois, USA) is utilised. Non-contrast CT is used to confirm accurate antenna placement and spacing prior to energy delivery. MW is performed with a multiprobe, gas-cooled, 2.45 GHz system with synchronous energy delivery (Neuwave Medical, Johnson & Johnson, New Brunswick, New Jersey, USA). Ablations are performed under general anaesthesia with high-frequency jet ventilation (HFJV), which is known to decrease kidney motion and improve targeting and monitoring.44

Probe Number, Antenna Placement, and Energy Delivery

One to three MW antennas are used in each case at the discretion of the operator. In general, tumours ≤2 cm in diameter can be treated with a single antenna, tumours 2–4 cm are treated with two antennas, and tumours >4 cm require three antennas.

When compared with exophytic tumours of a similar size, endophytic tumours may require more antennas due to greater heat sink from surrounding renal parenchyma compared to perirenal fat. It is essential to understand the expected size, shape, and location of the ablation zone relative CC BY-NC 4.0 Licence

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to the antenna tip(s) for a given set of ablation parameters (input power, ablation time). However, manufacturer-provided data in “lookup tables,” obtained in ex vivo tissue, may not accurately reflect results in clinical cases. These differences can be pronounced for tumours in highly perfused tissue, such as endophytic renal tumours.45 Antennas are ideally placed tangential to the tumour, avoiding collecting system puncture to avoid urinomas and collecting system injuries (Figure 1).42 Ablations are usually performed using maximum energy delivery (power), typically 65 watts for 5 minutes, and adjusted based on real-time ultrasound monitoring. Power is decreased if the ablation zone has grown to an adequate size and there is concern for overtreatment or injury to critical structures. If there is inadequate tumour coverage based on realtime monitoring, additional time is added as MW ablation zones can continue to grow for up to 15 minutes.46 Proximity to vulnerable extrarenal structures, such as the bowel, pancreas, or body wall, can generally be managed with hydrodissection, discussed in greater detail below, using 2% iohexol in normal saline.47 Following ablation, the antennas are removed without cautery to avoid creating coagulated tracts that may lead to urinomas. An immediate contrastenhanced diagnostic CT is performed in the interventional suite to determine adequacy of treatment, with retreatment if necessary, and to assess for early complications such as haemorrhage.48 Careful patient selection and MW technique are necessary when considering treatment of larger T1b (4–7 cm) renal tumours. Compared to T1a tumours, T1b tumors require a great number of antennas, longer treatment times, and higher power, which can increase the probability of complications and the risk of incomplete treatment compared to T1a tumours.3,49 At the authors’ institution, the decision to treat a T1b tumour with MW is a multidisciplinary one, with surgery as the preferred option for these patients.

A primary consideration for favouring MW over surgical treatment are patients

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Figure 1: T1a/T1b renal cell carcinoma probe placement.

A

B

D

C

E

F

T

G

H

I

Potential consequences of incorrect antenna positioning and proper antenna positioning in MW ablation of T1a/T1b RCC. A–C) T1a RCC treated with MW ablation with incorrect probe placement. A) Non-contrast CT performed during probe placement. Note the deep placement of the probes into the collecting system (red arrow). B) Immediate post-treatment contrast-enhanced CT. Track cautery (not recommended) results in a patent fistulous connection (yellow arrow) between the collecting system and perirenal space. C) 24-month follow-up contrast-enhanced MRI demonstrating an asymptomatic urinoma (red arrow).

D–E) T1a RCC (separate patient) treated with MW ablation with the recommended tangential probe placement avoiding collecting system puncture. D) Non-contrast CT performed during probe placement demonstrates tangential placement of antennas avoiding the collecting system. E) Immediate post-treatment contrastenhanced CT with adequate treatment of the tumour, a small margin, and no evidence of complications.

F–I) T1b 6.3 cm T1 RCC treated with MW ablation with multiple probes. F) Contrast-enhanced CT performed pre-ablation. G) Non-contrast CT during probe placement (red arrow). H) Immediate post-treatment contrastenhanced CT demonstrates a lack of tumour enhancement and no evidence of post-procedure complications.

I) 15-month follow-up contrast-enhanced MRI shows a continued lack of enhancement of the tumour (*).

MW: microwave; RCC: renal cell carnioma.

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who are high risk surgical candidates, usually due to significant comorbidities.

An additional consideration that can favour MW over surgery is the primacy of preserving renal parenchyma, either due to prior nephrectomies or the expectation that future nephrectomies will be required, as in the case of patients with genetic renal tumor syndromes. Anatomic factors that facilitate the use of MW ablation for the treatment of T1b tumours are tumours that are at least partially exophytic, those removed from the renal hilum, and those in locations where hydrodissection is feasible.

Treatment of T1b tumours is virtually always accompanied by hydrodissection to decrease the potential for damage to non-targeted structures (bowel, pancreas, ureter), and there is a low barrier to the use of pyeloperfusion to protect the collecting system. During and after probe placement and during application of MW energy, liberal use of both ultrasound and CT monitoring is recommended to both assure coverage of the tumour and to monitor for complications in a similar manner as with T1a tumours.

Tumour Location: Implications for Microwave

Certain tumour locations increase treatment complexity, complications rates, and risk of treatment failure.50 In general, tumours that are peripheral and located in the lateral or posterior kidney are at decreased risk of injury to adjacent structures with MW. Endophytic lesions can be more challenging to visualise than exophytic lesions and risk collecting system injury. Medial lesions abutting the psoas muscle risk genitofemoral nerve injury.24 Anterior lesions risk bowel or pancreatic injuries. Upper pole lesions can be challenging due to proximity to the diaphragm and intervening pleura, and are more likely to require use of advanced imaging techniques for targeting and monitoring including CT fluoroscopy, CT/ US fusion, and electromagnetic navigation for off-axial approaches. Lastly, particular attention needs to be paid to anterior-inferior tumours where ureteral injury becomes possible. In most cases, injury to nontargeted structures can be mitigated with adequate hydrodissection, which should be used liberally when in doubt.51 CC BY-NC 4.0 Licence

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Ultrasound versus CT Monitoring

Ultrasound monitoring is favoured as it can continuously monitor the growing ablation zone and is more predictive of the pathologic zone of necrosis than non-contrast CT.21 However, if visualisation becomes limited by gas or intervening structures, intermittent CT is recommended. In the rare cases when CT fluoroscopy is utilised for antenna placement, ultrasound is still used to monitor the ablation, given its superior visualisation of the evolving treatment changes in realtime. Ultrasound is particularly effective for multiplanar monitoring, as proximity to the bowel may not be fully appreciated on axial CT fluoroscopy. Ultrasound also allows for real-time monitoring of hydrodissection to determine whether additional fluid is necessary to maintain adequate displacement of critical structures during treatment.

Hydrodissection

Hydrodissection is frequently used to protect adjacent structures, such as the bowel and body wall, from thermal injury.

Normal saline (0.9% NS) with 2% iohexol injected through a purpose-designed blunt-tipped needle (Gangi Hydroguard, AprioMed, Uppsala, Sweden) can be easily distinguished from bowel, solid organs, and muscle without causing beam-hardening artefact (Figure 2A).47 Care must be taken to avoid injecting gas bubbles, which limit ultrasound visualisation during probe placement and monitoring.

Nephroureteral Stents and Retrograde Pyeloperfusion

Ureteral injury from heat can potentially be mitigated using indwelling ureteral stents or placement of an internal-external retrograde catheter for pyeloperfusion with cooled saline.24 There is no consensus as to the most effective method to prevent urothelial injuries, although pyeloperfusion is highly effective for this purpose during cryoablation (Figure 2B).43

Post Ablation Imaging Follow-Up

Follow-up imaging with contrast-enhanced CT or MRI is important to ensure early

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Figure 2A: Hydrodissection to displace colon and small bowel.

A

B

C

D

A) Non-contrast CT demonstrates close contact of the tumour with colon, which would likely be injured without hydrodissection. B) Non-contrast CT after probe placement and administration of hydrodissection fluid (red arrow).

The colon is now displaced away from the tumour, and it is safe to proceed with ablation. C) Immediate post-treatment contrast-enhanced CT. The probes have been removed, and the displacement between the tumour and colon remains.

Note that the tumour has substantially contracted, which is typical of MW. D) 8-month follow-up contrast-enhanced CT. The tumour continues to shrink, the hydrodissection fluid is resorbed, and there is no evidence of bowel injury.

C: colon; MW: microwave.

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Figure 2B: Retrograde pyeloperfusion.

A

B

C

D

E

T1a RCC (3.5 cm) in close proximity to the renal pelvis, which is at risk of injury. A, D) Contrast-enhanced CT performed pre-ablation in the axial (A) and coronal (D) planes. Note the close proximity of the tumour (T) and renal pelvis (yellow arrow). B) Non-contrast CT demonstrating probe placement. C, E) Immediate post-treatment contrastenhanced CT (C axial, E coronal) demonstrates lack of tumour enhancement. Note the distention of the renal pelvis (yellow arrow) by the retrograde injection of cooled saline through a ureteral stent (not shown). A small amount of air was injected with the fluid and is present in the renal pelvis (red arrow). The renal pelvis and collecting system were not injured despite the close proximity of the ablation zone in this central tumour.

detection of residual tumour and to evaluate for local recurrence. Preferred imaging modality and interval vary by ablation modality, operator preference, and institutional resources. In general, contrast-enhanced CT should be performed immediately post-treatment to ensure adequate tumour coverage with immediate retreatment if necessary.48 On postcontrast imaging, the ablation zone roughly correlates with the zone of altered signal intensity or decreased perfusion, with areas of viable but malperfused tissue CC BY-NC 4.0 Licence

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occasionally seen peripheral to the ablation zone. Residual viable tumour or recurrence typically manifests as a nodular or masslike area of enhancement with imaging characteristics similar to the treated tumour.

The interval between ablation and first follow-up should be guided by the histologic grade of the tumour, reinforcing the critical nature of biopsy prior to treatment, but the first follow-up imaging examination can safely be performed at 6 months for nearly every tumour treated with ablation.52

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LENGTH OF HOSPITALISATION AND PROCEDURE TIME, QUALITY-OF-LIFE IMPACT, AND COST-BENEFIT One of the most significant advantages of MW ablation, and all percutaneous ablation modalities, is a significantly shorter length of hospitalisation compared to surgical interventions. At the reference institution, most patients are discharged either the same day or the following morning. The median hospitalisation length for patients treated with MW is between 1.8–3.6 days shorter compared to those treated with surgery.3,53,54 Although there is no significant difference in hospitalisation length between thermal ablation methods, the mean procedure time for MW ablation is significantly shorter than RF ablation or cryoablation.55,56 Quality-of-life measures after each of the percutaneous ablation techniques demonstrate minimal impact and a shortterm advantage versus partial nephrectomy, likely due to the less invasive nature of the procedure. However, the data in this area is not robust, and there are a paucity of studies directly comparing MW to other percutaneous ablation modalities as well as partial nephrectomy.57,58 Cost-effectiveness data on MW versus partial nephrectomy is likewise sparse, but available studies suggest that MW may be competitive with PN based on total life years, quality-adjusted-life-years, and lifetime costs.59,60

COMPLICATIONS AND PRESERVATION OF RENAL FUNCTION

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TECHNICAL SUCCESS/ INCOMPLETE TREATMENT Technical success is defined as a complete treatment of the targeted tumour on immediate post-procedure imaging.64 MW ablation shows technical efficacy comparable to RF ablation and cryoablation, with success rates surpassing 94% for the complete treatment of T1a lesions.56,63,65 Increasing tumour size can be associated with lower rates of technical success.

Although high efficacy has been observed for the treatment of T1b (>4 to <7 cm) renal tumours at experienced centres, this experience is not universal, with others reporting higher rates of incomplete treatment with larger lesions requiring repeat ablation.3,49

LOCAL TUMOUR PROGRESSION

Treatment of RCC with MW ablation is Cassociated with a low and predominantly minor (Clavien-Dindo Grade I-II or CIRSE I) complication rate with a similar safety profile to other thermal ablation methods.42,56,61 Partial nephrectomy may be associated with a higher but not significant major complication rate.53 MW appears to effectively preserve renal function, with no significant change in the estimated glomerular filtration rate post-procedure.61 Comparative studies suggest that MW is less likely to cause acute kidney injury and preserves renal function more effectively 80

than laparoscopic partial nephrectomy but is similar to RF and cryoablation.53,62,63 For T1b tumours, eGFR decline is comparable between MW ablation and partial nephrectomy. Both partial nephrectomy and MW preserve renal function to a higher degree than radical nephrectomy.3 In many series, although patients treated with MW were older and had more comorbidities, they did not have a higher risk of serious complications compared to partial or radical nephrectomy.

However, high-grade complications after MW are more common in T1b tumours than with smaller renal masses.3

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Local tumour progression (LTP) is defined as the emergence of a tumour at the edges of an ablation zone on follow-up imaging after a technically successful treatment.64 MW ablation is associated with a low local tumour progression rate, ranging from 0–7.5% when treating small renal cell carcinomas.49,56,61,63,66 Comparative studies show that MW ablation achieves similar or lower LTP rates compared to other ablative techniques, such as RF ablation and cryoablation, while maintaining high technical success (Table 1).49,55,63 A meta-analysis further supports these findings, indicating that MW is associated with a significantly lower 1-year local tumour

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progression rate compared to cryoablation.71 Retrospective studies comparing MW ablation with partial nephrectomy report no significant differences in LTP between the modalities, highlighting MW ablation as a less invasive but effective alternative for managing small RCC in appropriately selected patients.3,53 These studies must be interpreted in the context of their observational nature and patient selection biases.

OVERALL SURVIVAL MW ablation offers similar overall survival rates compared to RF and cryoablation.71 A single meta-analysis comparing MW ablation and cryoablation concludes that there is no significant difference in overall survival rates between MW ablation and cryoablation.63 Several studies demonstrate worse overall survival for MW ablation versus partial nephrectomy but comparable cancer-specific survival.3,53 It is important to note that disease-specific survival or cancer-specific survival is a better metric to compare ablation to surgery, as overall survival may be confounded by non-cancerrelated factors, such as a higher Charlson comorbidity index in specific patient groups.53 This is especially important since ablation is more commonly utilised in older patients with increased comorbidities.72

LIMITATIONS/FUTURE RESEARCH NEEDS Although studies with high levels of evidence are included in this review, the observational and retrospective nature of the bulk of the available clinical data presents a limitation. Additionally, available studies varied in follow-up duration, had an unequal distribution of comparison groups, and were conducted in centres with different levels of experience.3 An important limitation in comparing percutaneous ablation to surgery is the inherently different patient populations usually treated by each group. For example, as noted above, most ablation cohorts are older and more morbid than surgical patients. Future randomised controlled trials and observational studies with propensity matching of the different CC BY-NC 4.0 Licence

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cohorts that account for these and other variables will be important steps towards addressing these limitations.

CONCLUSION Percutaneous MW ablation is an effective alternative to partial or radical nephrectomy for T1a renal tumours, particularly for patients who prefer a less invasive option or who are high-risk surgical candidates that still require tumour control. For T1b renal tumours, surgical excision is the preferred approach; however, percutaneous ablation can be considered for patients with substantial comorbidities or contraindications to surgery at experienced institutions. Observational studies of MW ablation demonstrate comparable local tumour progression and cancerspecific survival rates compared to partial nephrectomy, shorter hospitalisation lengths, lower complication rates, and similar renal functional preservation.

However, MW ablation remains user- and technique-dependent, and local expertise is critical. MW offers several advantages compared to other thermal ablation modalities, including speed, effectiveness in destroying targeted tumours, accurate real-time intraprocedural monitoring with ultrasound, and single or multiple applicator use. MW ablation requires caution when treating tumours in the central kidney or adjacent to the renal pelvis and ureter due to the risk of strictures and urinomas.

Important considerations for a successful MW ablation programme for the treatment of RCC include multidisciplinary input, attention to anaesthesia technique with consideration of the use of jet ventilation, intraprocedural monitoring with ultrasound, placement of antennas parallel and outside of the collecting system, careful hydrodissection technique, retrograde pyeloperfusion for ureteral protection, and systematic longitudinal imaging follow-up.

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Table 1: Literature summary for MW ablation of renal cell carcinoma.

Median Follow-up (mo)

Mean Tumor Size

Local Tumor Progression

Author

Study Design

Moreland et al.,61 2014

Retrospective observational, MW, n=55

8

cT1a

0%

Zhou et al.,63 2019

Retrospective comparative, MW (n=27) versus RF (n=244) versus CA (n=26)

24

cT1a

0%

Aarts et al.,49 2020

Retrospective observational, MW, n=108 (100 patients)

19

Hou et al.,62 2020

Retrospective cohort, MW (n=158) versus PN (n=158)

Continuous every 6 mo

De Cobelli et al.,56 2020

Retrospective comparative, MW (n=32) versus CA (n=51) (72 patients)

MW: 22 mo CA: 20 mo

Key Conclusions

N/A

11% No major complications

No LTP or metastasis at 8 mo.

Low complication rate and stable renal function

100%

RF 22.9% CA 15.4% MW 7.4%

Fewer complications and significantly lower mean ablation time of MW Significantly higher efficacy and lower complication rate for T1a tumours than T1b.

85 T1a 23 T1b

2% T1a 8% T1b

100% CSS

Major Complication: T1a: 2% T1b: 13% (p=0.05)

cT1a

Not reported

5-year OS rate: AKI patients: 73.5%.

Non-AKI patients: 94.8% (p < 0.001)

AKI was more frequent in NSS compared to MW

Comparable overall survival between MW ablation and partial nephrectomy

cT1a

MW: 3.3% CA: 6.4% (NSD)

CA 9.8% MW 6.3% (NSD)

Comparable posttreatment eGFR. Significantly lower treatment time with MW ablation

100% CSS

cT1a

MW: 3.2%, PN: 0.5% (NSD)

CSS MW:2.2% PN:3.8% (NSD)

Major complications MW: 2.2% LPN: 4.9% (NSD)

MW: 34 mo PN: 35 mo RN: 49 mo

cT1b

MW: 5% PN: 1.4% RN: 0.5%

5-year CSS 100% MW 97.6% PN 95.5% RN (NSD)

Major complications: MW 10%, PN 5%, RN 3% (NSD)

MW is a crucial alternative to surgery in select patients with T1b RCCs

24

Bilateral RCC (Mean maximum of a single lesion 2.74 cm (0.7-6.2)

Retrospective comparative, MW (n=185) versus PN (n=185)

MW: 42 mo PN: 40.6 mo

Shapiro et al.,3 2020

Retrospective comparative, MW (n=40) versus PN (n= 74) versus RN n=(211)

Retrospective observational, MW, n=20 tumors (eight patients)

Lucignani et al.,67 2022

Retrospective comparative, MW (n=50) versus CA (n=116)

CA: 26 mo MW: 24 mo

Pandolfo et al.,55 2023

Multicenter retrospective, MW (n=50) versus RFA or CA (n=739)

CA or RFA: 53 months.

MW: 26 months

82

Complication Rate

Comparable LTP, CSS, distant metastasis and complication rates.

MW results in less blood loss and smaller changes in renal function

Yu et al.,53 2020

Zhang et al.,66 2021

Overall Survival/ Disease-Specific Survival

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25%

cT1a

MW: 7.1% CA: 9.5% (NSD)

cT1a, cT1b

CA or RFA: 8.2% MW ablation: 2% (NSD)

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N/A

No major complications

Technical success 100% with no severe complications. No significant changes in renal function post-MW ablation (p=0.683)

OS 95% MW 91% CA (p = 0.77).

CSS 100% MW 97.4% (NSD)

Overall: MW 24%, CA 36.2% (NSD) Major: MW 5.4%. CA 1.7% (NSD)

Comparable complications, median decline of eGFR, recurrence rate and overall survival.

Shorter procedural time with MW ablation

94% MW 89.6% CA or RFA (NSD)

Overall MW 14% RFA or CA 7.4% (NSD).

Major: MW 0%, CA or RFA 2% (p<0.001)

Shorter operative times, similar technical success (98.6% of cases.), and comparable recurrence rates with MW

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Table 1: Continued.

Author

Study Design

Median Follow-up (mo)

Retrospective observational, MW versus RFA, n=44 (43 patients)

Grbanović et al.,65 2023

Foret et al.,68 2024

Retrospective observational, MW, n=108 (104 patients)

Radros et al.,54 2024

Retrospective cohort MW or RFA versus surgery, n= 188 ablations, 256 PN and RN

3

cT1a

22.68

cT1a

N/A

cT1a

Jannello et al.,69 2024

Retrospective comparative, MW (n=373) versus RFA (n=158)

24

Sun et al., 2024

Retrospective comparative, MW (n=88 )versus CA (n=191), 257 patients

CA: 3.9 years.

MW: 1.1 years.

70

Mean Tumor Size

Local Tumor Progression

Overall Survival/ Disease-Specific Survival

N/A

Complication Rate

Key Conclusions

MW: 18.5% RFA: 0% No major complications

Technical success: 100% for both.

Primary efficacy and complications versus RFA: p=0.65 (NSD), p=0.14 (NSD), respectively

96% OS

Major complications: 3.7%

MW is safe and effective with minimal complications. eGFR decline >30 days post-ablation was significant (p<0.0001), but overall renal function remained stable

N/A

Ablation 2.1% Surgery 6.3% OR 0.34; (p=0.002)

Lower complications with thermal ablation with comparable readmission rates Complete ablation rates: 93.3% versus 86.7% (P<0.001), Operation times: 105 minutes versus 115 minutes (P=0.002).

MWA: higher complete ablation rates, fewer complications, better kidney function preservation, shorter op times compared to RFA Comparable survival rates. Shorter procedure duration with MW

N/A

86% 5-year local recurrence-free survival

N/A

cT1a, cT1b

MW: 4.6% RFA: 13.3%, (NSD)

N/A

No major complications, no ≥30% decrease in eGFR: 84.2% versus 72.2% (P=0.001)

cT1a

MW: 3.5% CA: 2.7% (NSD)

Cancer-specific survival 100% MW 98.2% CA (NSD)

MW: 4.5% CA: 9.4% (NSD)

Major complications defined as Clavien-Dindo Grade ≥3.

AKI: acute kidney injury; CA: cryoablation; CSS: cancer-specific survival; MW: microwave; NSD: no significant difference; OS: overall survival; PN: partial nephrectomy; RCC: renal cell carcinoma; RFA: radiofrequency ablation; RN: radical nephrectomy.

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14. Brace CL. Microwave ablation technology: what every user should know. Curr Probl Diagn Radiol.

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27. Littrup PJ et al. Lethal isotherms of cryoablation in a phantom study: effects of heat load, probe size, and number. J Vasc Interv Radiol JVIR. 2009;20(10):1343-51.

28. Salei A et al. Transarterial embolization of T1b and T2a renal cell carcinoma prior to percutaneous cryoablation: a retrospective comparative study.

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29. McElroy KM et al. Long-term renal function outcomes after renal cryoablation complicated by major hemorrhage requiring selective transarterial embolization. Abdom Radiol NY. 2021;46(9):4898-907.

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16. Solbiati L et al. Hepatic metastases: percutaneous radio-frequency ablation with cooled-tip electrodes. Radiology.

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17. Brace CL. Radiofrequency and microwave ablation of the liver, lung, kidney, and bone: what are the differences?. Curr Probl Diagn Radiol.

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30. Atwell TD et al. Complications following 573 percutaneous renal radiofrequency and cryoablation procedures. J Vasc Interv Radiol.

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31. Campbell SC et al. Renal mass and localized renal cancer: evaluation, management, and follow-up: AUA guideline: part II. J Urol.

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18. Wright AS et al. Radiofrequency versus microwave ablation in a hepatic porcine model. Radiology.

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32. Corcoran AT et al. A review of contemporary data on surgically resected renal masses—benign or malignant? Urology. 2013;81(4):70713.

19. Brace CL et al. Tissue contraction caused by radiofrequency and microwave ablation: a laboratory study in liver and lung. J Vasc Interv Radiol JVIR. 2010;21(8):1280-6.

33. Wells SA et al. Renal mass biopsy and thermal ablation: should biopsy be performed before or during the ablation procedure? Abdom Radiol.

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20. Liu D, Brace CL. Evaluation of tissue deformation during radiofrequency and microwave ablation procedures: influence of output energy delivery.

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34. Mir MC et al. Partial nephrectomy versus radical nephrectomy for clinical T1b and T2 renal tumors: a systematic review and meta-analysis of comparative studies. Eur Urol.

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21. Ziemlewicz TJ et al. Radiofrequency and microwave ablation in a porcine liver model: non-contrast CT and ultrasound radiologic-pathologic

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39. Cornelis FH et al. A comparative study of ablation boundary sharpness after percutaneous radiofrequency, cryo-, microwave, and irreversible electroporation ablation in normal swine liver and kidneys. Cardiovasc Intervent Radiol. 2017;40(11):1600-8.

40. Schmitz JJ et al. Renal microwave ablation resulting in ureteropelvic junction stricture remote from the ablation site. J Vasc Interv Radiol.

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41. Thompson SM et al. Introduction of microwave ablation into a renal ablation practice: valuable lessons learned. Am J Roentgenol.

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42. Klapperich ME et al. Effect of tumor complexity and technique on efficacy and complications after percutaneous microwave ablation of stage T1a renal cell carcinoma: A single-center, retrospective study. Radiology.

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43. Marion JT et al. Safety and efficacy of retrograde pyeloperfusion for ureteral protection during renal tumor cryoablation. J Vasc Interv Radiol.

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44. Denys A et al. Use of high-frequency jet ventilation for percutaneous tumor ablation. Cardiovasc Intervent Radiol.

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45. Winokur RS et al. Characterization of in vivo ablation zones following percutaneous microwave ablation of the liver with two commercially available devices: Are manufacturer published reference values useful? J Vasc Interv Radiol. 2014;25(12):193946.e1.

46. Hui TC et al. Microwave ablation of the liver in a live porcine model: the impact of power, time, and total energy on ablation zone size and shape. Int J Hyperthermia. 2020;37(7):668-76.

47. Campbell C et al. Contrast mediadoped hydrodissection during thermal ablation: optimizing contrast media

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48. Koebe SD et al. Contrast-enhanced CT immediately following percutaneous microwave ablation of cT1a renal cell carcinoma: optimizing cancer outcomes. Abdom Radiol.

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50. Schmit GD et al. Usefulness of R.E.N.A.L. nephrometry scoring system for predicting outcomes and complications of percutaneous ablation of 751 renal tumors. J Urol.

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51. Maciolek KA et al. Tumor location does not impact oncologic outcomes for percutaneous microwave ablation of clinical T1a renal cell carcinoma. Eur Radiol. 2019;29(12):6319-29.

52. Dreyfuss LD et al. Development of a risk-stratified approach for follow-up imaging after percutaneous thermal ablation of sporadic stage one renal cell carcinoma. Urology. 2019;134:14853.

53. Yu J et al. Percutaneous microwave ablation versus laparoscopic partial nephrectomy for cT1a renal cell carcinoma: a propensity-matched cohort study of 1955 patients.

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54. Radros J et al. Ablative or surgical treatment for small renal masses (T1a): a single-center comparison of perioperative morbidity and complications. Curr Oncol.

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ablation for small renal mass: a multicenter comparative analysis.

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56. De Cobelli F et al. Percutaneous microwave ablation versus cryoablation in the treatment of T1a renal tumors. Cardiovasc Intervent Radiol. 2020;43(1):76-83.

57. Junker T et al. Impact of partial nephrectomy and percutaneous cryoablation on short-term healthrelated quality of life—a prospective comparative cohort study. Eur Urol Open Sci. 2022;45:99-107.

58. Atwell TD et al. Patient-reported outcomes after percutaneous renal ablation: initial experience. Am J Roentgenol. 2019;212:672-6.

59. Yeaman C et al. Cost-effectiveness analysis: percutaneous microwave ablation vs robotic-assisted partial nephrectomy for small renal masses.

Abdom Radiol. 2022;48:411-7.

60. Xia Q et al. Cost-effectiveness analysis of microwave ablation versus robot-assisted partial nephrectomy for patients with small renal masses in Australia. Urol Oncol Semin Orig Investig. 2025;43:62.e15-26 (2025).

61. Moreland AJ et al. High-powered microwave ablation of T1a renal cell carcinoma: safety and initial clinical evaluation. J Endourol.

2014;28(9):1046-52.

62. Hou Q et al. Acute kidney injury after nephron sparing surgery and microwave ablation: focus on incidence, survival impact and prediction. Int J Hyperthermia.

2020;37(6):470-8.

63. Zhou W et al. Radiofrequency ablation, cryoablation, and microwave ablation for T1a renal cell carcinoma: a comparative evaluation of therapeutic and renal function outcomes. J Vasc

Interv Radiol. 2019;30(7):1035-42.

64. Ahmed M et al. Image-guided tumor ablation: Standardization of terminology and reporting criteria—a 10-year update. Radiology.

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65. Grbanović L. Short-term outcomes of percutaneous radiofrequency and microwave ablation in the treatment of small renal masses. Acta Clin Croat.

2023;62(2):6.

66. Zhang R et al. Ultrasound-guided percutaneous microwave ablation of bilateral renal cell carcinomas: focus upon safety and efficacy. J Cancer Res Ther. 2021;17(4):803-7.

67. Lucignani G et al. Percutaneous microwave ablation is comparable to cryoablation for the treatment of T1a renal masses: results from a cross-sectional study. Clin Genitourin Cancer. 2022;20:e506-11.

68. Foret A et al. Clinical safety and efficacy of microwave ablation for small renal masses. Int Braz J Urol.

2024;50:277-86.

69. Jannello LMI et al. Microwave vs radiofrequency ablation for small renal masses: perioperative and oncological outcomes. BJU Int. 2025;135:156-65.

70. Sun G et al. Percutaneous microwave ablation versus cryoablation for small renal masses (≤4 cm): 12-year experience at a single center. J Vasc Interv Radiol. 2024;35:865-73.

71. McClure T et al. A comparison of microwave ablation and cryoablation for the treatment of renal cell carcinoma: a systematic literature review and meta-analysis. Urology.

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72. Doolittle J et al. Evolving trends for selected treatments of T1a renal cell carcinoma. Urology. 2019;132:136-42.

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Ultrasound Guided Percutaneous Splenic Biopsy: Diagnostic Accuracy and Complications Authors:

*Sairah Razak,1 Atif Khan1 1. St James’s University Hospitals, Leeds Teaching Hospitals NHS Trust, Great George Street, Leeds, UK *Correspondence to sairah.razak1@nhs.net

Disclosure:

This study was not supported by any funding. The authors declare that they have no conflict of interest.

Disclaimer:

Ethical committee approval was not required for this research, as the study utilised anonymised NHS data collected as part of standard clinical care.

Received:

31.12.24

Accepted:

04.02.25

Keywords:

Haemorrhage, interventional radiology, lymphoma, safety, spleen.

Citation:

EMJ Radiol. 2025;6[1]:86-94. https://doi.org/10.33590/emjradiol/JMVR8857

Abstract Aims: Ultrasound (US) guided percutaneous splenic biopsies are uncommon and are ordinarily done in the context of an indeterminate splenic lesion with a probable underlying malignancy, and where there is no other safe accessible site to obtain tissue, or where the diagnosis of a splenic metastasis would impact management. The authors aimed to assess the diagnostic accuracy and complication rate of US-guided percutaneous biopsy of the spleen.

Materials and methods: The authors assembled a list of 43 biopsies between 2005–2023 at St. James’s University Hospital in Leeds, UK. Results: Twenty-two biopsies (51%) were performed to assess progression in the context of known or previous malignancy, 22 were performed to assess for malignancy in patients with no prior malignant history, and the remaining six (14%) biopsies were conducted to assess for infection. Three patients had a prior splenic biopsy, and 30 experienced one needle pass. Thirty-seven of the 43 samples (86%) proved to be diagnostic. Positive samples included both benign and malignant abnormal splenic tissue. Malignant diagnoses included diffuse large B cell lymphoma, Hodgkin’s lymphoma, leukaemia, and metastases. Benign conditions included non-specific reactive changes, infection, sarcoidosis, and haemangioma.

The authors established there were 30 true positives and zero false positives. There were five true negative biopsies and one false negative. The overall diagnostic yield and accuracy are 86% and 84%, respectively. There were no major complications and two minor complications; two patients developed perisplenic haematomas, which were conservatively managed.

Conclusion: The authors concluded that US-guided percutaneous splenic biopsy is a safe procedure with a high diagnostic yield and relatively high accuracy.

Level of evidence: Level 4, retrospective cohort.

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Key Points 1. Ultrasound (US)-guided percutaneous splenic biopsy is not typically a first-line investigation for indeterminate splenic lesions due to complications such as haemorrhage.

2. A retrospective study conducted at the authors' tertiary centre looked at every US-guided percutaneous splenic biopsy performed, including the indication of the biopsy, histopathology results, and complications.

3. US-guided percutaneous splenic biopsy and histopathological examination remain the best diagnostic options in certain cases. This study demonstrated it is a safe procedure with a high diagnostic yield and relatively high accuracy.

INTRODUCTION Splenic abnormalities usually present as a focal lesion(s) or diffuse splenomegaly outside the context of trauma. Most splenic lesions are incidental and benign, such as a simple cyst or infarct, and therefore do not require further investigation. However, some may display malignant characteristics or present in the context of a known malignancy posing diagnostic uncertainty.

Ultrasound (US)-guided percutaneous splenic biopsies are uncommon and are ordinarily done in the context of an indeterminate splenic lesion with a probable underlying malignancy (i.e., lymphoma), and where there is no other safe accessible site to obtain tissue, or where the diagnosis of a splenic metastasis would impact on management.1 Splenic biopsies are typically not a first-line investigation because of the perceived risk of haemorrhage as well as other complications such as pneumothorax, bowel perforation, and renal injury.1 Table 1 is a summary of indications and contraindications of USguided percutaneous splenic biopsy. The laboratory parameters in Table 1 are utilised from the authors’ hospital’s guidelines for nonvascular interventional procedures.

AIMS The authors aimed to assess the diagnostic accuracy and complication rate of US-guided percutaneous needle biopsy of the spleen.

OBJECTIVES After reviewing the relevant literature, the authors identified the following parameters CC BY-NC 4.0 Licence

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to measure: indication of biopsy, number of previous biopsies, number of needle passes, results of the biopsy, and complications.

The results of the biopsy included whether the sample was diagnostic (i.e., of sufficient yield to allow analysis) and the histology.

Abnormal splenic tissue was considered a positive biopsy, including benign conditions or reactive changes. Normal splenic tissue was labelled as a negative biopsy. False positives and negatives were described in cases where results were contradicted by biopsy of an organ other than the spleen and/or follow-up imaging. Complications were classified into major and minor using the guidelines produced by Omary et al.2 Major complications included haemorrhage requiring intervention (such as transfusion or embolisation), pneumothorax requiring chest drain, other significant intra-abdominal injury such as bowel perforation, and death.2 Minor complications included conservative haemorrhage management including overnight admission for observation.2

METHOD The authors liaised with the Radiology Information Team at St James’s University Hospital, a tertiary centre in Leeds, UK, to provide them with a list of patients with every US request and report including 'spleen' and 'splenic'. This data span from 2005–2023 and produced over 200,000 patients. They looked through the reports in retrospect via radiology imaging software and assembled a list of 43 US-guided splenic biopsies that were performed on 40 patients. Electronic medical records were reviewed for histology results, post-biopsy complications, and follow-up. Paediatric patients, percutaneous aspirations and

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Table 1: Indications and contraindications of ultrasound-guided percutaneous splenic biopsy.

Indications

Contraindications

Indeterminate splenic lesion suspicious for malignancy, and no other/safe accessible site to obtain tissue for histology

Coagulopathy including laboratory parameters of: Haemoglobin <80 g/L Platelets <75 x 109/L INR >1.4

Exclude splenic metastasis in the context of known malignancy

N/A

INR: international normalised ratio; N/A: not applicable.

drainages of splenic lesions, and biopsies of extrasplenic masses were excluded.

Examining the biopsy reports, written consent was gained for the procedure, and the WHO checklist was documented.

1% lidocaine was the choice of local anaesthetic, and every procedure was either performed by a radiology doctor (registrar or consultant) or a consultant ultrasonographer.

18-gauge (18G) core needle biopsy needles were used in all patients. Post-procedure care included 4-hour bed rest with regular clinical observations.

RESULTS A total of 43 splenic biopsies were performed on 40 patients. Three patients had a prior splenic biopsy that either was negative and clinical concerns persisted for a malignant process, was of insufficient yield for further analysis, or was of necrotic material and therefore undiagnostic. There was documentation of a fourth patient who had a previous biopsy in a different region (London, UK), and therefore this was not included in the study.

There was some overlap in the requests for splenic biopsy with a number of requests querying both malignancy and infection.

Twenty-two biopsies (51%) were performed to assess progression in the context of known or previous malignancy, 22 were performed to assess for malignancy in patients with no prior malignant history, and the remaining six biopsies (14%) were conducted to assess for infective lesions 88

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such as abscess. The spleen was biopsied because it was either the only site of abnormality and demonstrated suspicious characteristics, i.e., increasing in size on serial imaging, or proving that the biopsied lesion was a metastasis would have an impact on management, i.e., chemotherapy regimen, or histology was needed to guide treatment regimen. In one patient, the liver was previously biopsied but was not of sufficient quality, and therefore the spleen was biopsied.

Thirty of the 43 biopsies (71%) documented only one needle pass (coaxial needles were used in three of these), nine biopsies included two needle passes, one patient endured three passes, and one patient endured four passes, the latter of which was due to patient movement. For two of the biopsies, there was no documentation of the needle passes, they each documented two or three samples obtained.

Thirty-seven of the 43 samples (86%) proved to be diagnostic as there was sufficient sample yield for analysis to provide a diagnosis, as demonstrated in Table 2. Positive samples included both benign and malignant abnormal splenic tissue. Fourteen patients were diagnosed with lymphoma: diffuse large B cell lymphoma (DLBCL; n=9), Hodgkin’s lymphoma (n=4), and grey zone lymphoma (n=1). Two patients were diagnosed with leukaemia (n=2) and three patients were diagnosed with metastases from renal, endometrial, and oesophageal primaries.

Benign conditions included non-specific reactive changes (n=5); infection (n=3), one

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Table 2: Diagnosis of the ultrasound-guided splenic biopsies.

Diagnosis

Number of biopsies

Normal

6

Benign

12

Malignant

19

Nondiagnostic

6

N/A: not applicable.

of which was an Epstein-Barr virus (EBV) pseudotumour; granulomatous diseases such as sarcoidosis (n=2); and haemangioma (n=1). Figures 1–3 are CT and US images of a patient with DLBCL, sarcoidosis, and oesophageal metastasis, respectively.

Tables 3 and 4 summarise the histological diagnoses of the positive biopsies.

After reviewing the patient’s medical records and follow-up imaging, the authors concluded that there were 30 true positives and zero false positives. There were five true negative biopsies, which meant that of the six histologically normal splenic tissue samples, five were truly normal. These results are summarised in Table 5. The one negative biopsy was proven to be false as the patient had a biopsy of an alternative site (clivus), which proved to be a diffuse large B cell lymphoma, with a histologically normal splenic biopsy. As a result, the overall diagnostic yield and accuracy were 86% and 84%, respectively. Excluding the repeat biopsies, the diagnostic yield was 93%.

The remaining six of the 43 samples were undiagnostic as there was insufficient sample yield for analysis. Three of these undiagnostic biopsies were repeated, which revealed a DLBCL, infection, and normal splenic tissue. With regards to the other three undiagnostic splenic biopsies, the first patient proceeded to a liver biopsy which revealed epithelioid angiosarcoma (felt to be most likely from a splenic primary), the second patient received follow-up imaging to monitor the splenic lesion (revealed to CC BY-NC 4.0 Licence

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be stable), and the third patient received an endoscopic US core needle biopsy that revealed a granulomatous disease.

After reviewing the electronic medical records, there were two minor complications (4.7%) where two patients developed small perisplenic haematomas. The first patient presented with hypotension and pain following the procedure, and therefore, had a triple-phase contrast-enhanced CT abdomen, which demonstrated a perisplenic haematoma with no evidence of active bleeding. Whereas the second patient developed tachycardia and a drop in haemoglobin and, interestingly, had an US of the abdomen, which also revealed a perisplenic haematoma with no further fluid or haematoma elsewhere in the abdomen.

Both patients were conservatively managed with overnight admission. There were no major complications, although one patient died 1 month following the splenic biopsy, this was attributed to multi-organ failure secondary to underlying lymphoma rather than the biopsy procedure.

DISCUSSION US-guided splenic biopsies are performed only when necessary due to the perceived risk of haemorrhagic complication. Splenic biopsy is a safer option compared to other alternatives such as a splenectomy which is associated with higher risk of morbidity (37%) and mortality (3%).3,4 Complications associated with splenectomy include

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Figure 1: Diffuse large B cell lymphoma.

A

B

Patient presented with weight loss and early satiety. Contrast-enhanced CT Abdomen A) revealed a large heterogeneous splenic mass (arrow) and contiguous large volume lymphadenopathy (asterisk) in the upper abdomen.

US-guided core needle biopsy of the spleen B) confirmed diffuse large B cell lymphoma.

US: ultrasound.

Figure 2: Sarcoidosis.

A

B

Contrast-enhanced CT abdomen A) was performed in this patient with palpable splenomegaly revealing a diffuse infiltrative enlarged spleen (arrow). US showed no focal splenic lesion, US-guided biopsy of the spleen B) confirmed sarcoidosis.

US: ultrasound.

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Figure 3: Oesophageal metastasis.

A

B

Contrast-enhanced CT abdomen A) in a patient newly diagnosed with oesophageal cancer demonstrated a solitary heterogeneous expansile mass in the spleen (arrow). US-guided core needle biopsy of this splenic mass B) revealed to be a metastasis (from the oesophageal primary).

US: ultrasound.

thromboembolism and haemorrhage in the postoperative period, in addition to lengthier recovery times and hospital admission.3,4 On the contrary, in 41 of the 43 biopsy procedures performed, patients were discharged on the same day with no complication. Impaired immune response predisposing to a lifelong greater risk of infection and malignancy is the worrying long-term consequence of splenectomy.3,4 Percutaneous splenic biopsy allows the spleen to be preserved without the major complications associated with surgery.

In the authors’ study, the main indication of obtaining a splenic tissue sample was to assess for malignancy, either new malignancy or progression in the context of a known malignancy. On imaging alone, it is difficult to characterise a splenic lesion, particularly if it is a solid or a diffuse infiltrative lesion, and therefore, patients are referred for US-guided biopsy.5 Like any other organ, the spleen can be affected by many different disorders, such as malignancy, the most common of which are of haematological origin, such as lymphoma and leukaemia, as demonstrated in the authors’ study.6 Although it is rarely an organ to be infiltrated by metastases of CC BY-NC 4.0 Licence

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non-haematological primaries, three of the authors' samples demonstrated metastases from endometrial, oesophageal, and renal origin. Other lesions include benign tumours, infection, and granulomatous diseases such as sarcoidosis, as evidenced in the authors’ study.

The remainder six out of 43 samples produced insufficient yield for analysis.

Most of the biopsy reports (70%) documented only one needle pass, and therefore, only one core tissue was obtained; this could have produced insufficient tissue for analysis. Increasing the number of needle passes increases the amount of tissue available for analysis, but this must be weighed against the risk of complication, particularly haemorrhage.

Furthermore, malignant lesions can outgrow their vascular supply and develop necrotic centres that, if biopsied, will not provide useful information and render the biopsy nondiagnostic. The three splenic biopsies that were repeated revealed DLBCL, infection, and normal splenic tissue, and therefore, were valuable in repeating the biopsy. The other three patients endured a subsequent liver or endoscopic splenic

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Table 3: Malignant histological diagnosis of the positive US-guided splenic biopsies.

Diagnosis

Number of biopsies

Lymphoma

Diffuse large B cell lymphoma

9

Hodgkin’s lymphoma

4

Grey zone lymphoma

1

Chronic lymphocytic leukaemia

1

Aggressive natural killer cell leukaemia

1

Renal cell carcinoma

1

Oesophageal squamous cell carcinoma

1

Endometrial carcinoma

1

Leukaemia

Metastasis

Total

19

US: ultrasound.

Table 4: Benign histological diagnosis of the positive US-guided splenic biopsies diagnosis.

Diagnosis

Number of biopsies

Reactive

5

Infection

No organism isolated

2

EBV pseudotumour

1

Sarcoidosis

2

Haemangioma

1

Extramedullary haematopoiesis

1 Total

12

EBV: Epstein-Barr virus; US: ultrasound.

biopsy or received follow-up imaging, with the latter demonstrating stability.

The authors’ study revealed two minor complications (4.7%) in which two patients developed small perisplenic haematomas.

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There were no major complications, specifically no large or active haemorrhage that would necessitate intervention. The authors did not include pain as a minor complication, as this is a common and expected symptom following a biopsy.

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Table 5: Efficacy results of the US-guided splenic biopsies parameter number of cases.

Parameter

Number of cases

Number of true positive findings

31

Number of true negative findings

5

Number of false positive findings

0

Number of false negative findings

1

Undiagnostic

6

US: ultrasound.

Nonetheless, this has been classified as a minor complication in other studies, whether post-procedural pain is a true complication is subject to debate. The rate of overall complications in other studies ranged from 2–16.7%, major complications specifically occurred in up to 1.9% of all biopsies. Patel et al.1 reported a 2% minor complication rate, with only one of 52 cases developing a subcapsular haematoma requiring no intervention, using an 18G core needle.1 On the other side of the spectrum, Tam et al.5 reported a complication rate of 16.7% (1.9% major, 14.7% minor) using a 22G core needle. Major complications included splenic rupture and perisplenic haematoma requiring intervention, most of the minor complications were postprocedural pain.5 Olson et al.7 reported an 8.2% complication rate, encompassing a 7.2% rate for minor complications, including pain and perisplenic haematoma, and a 1% major complication rate, including haemothorax needing a chest drain and embolisation of an intercostal artery pseudoaneurysm.

However, the study performed by Olson et al.7 included CT as well as US as an imaging modality aiding biopsy of the spleen, utilising 18G core needles. Sangiorgio et al.8 reported a 6.7% complication rate, which were all minor complications, with 16–20G core needle biopsies.

References 1.

Patel N et al. (2015). Ultrasoundguided percutaneous splenic biopsy using an 18-G core biopsy needle: our experience with 52 cases.

Overall diagnostic yield and accuracy were 86% and 84%, respectively, which are comparable to prior studies. For example, Tam et al.5 reported 92.3% and 84.7%, respectively; Patel et al.1 reported a diagnostic yield of 89.4%; and Olson et al.7 reported a diagnostic yield of 87.6% and a higher accuracy of 94.1%.1,2,7 These demonstrate the relatively high diagnostic yield and diagnostic accuracy of US-guided splenic biopsies.

The main limitation of the authors’ study was the sample size of 43 across 18 years; this is a relatively small sample number to extrapolate conclusions from but demonstrates how uncommon US-guided splenic biopsies are performed.

CONCLUSION Despite other diagnostic methods, ultrasound-guided percutaneous splenic biopsy and histopathological examination remains the best diagnostic option in certain cases. The authors’ study at a tertiary centre has demonstrated it is a safe procedure with a high diagnostic yield and relatively high accuracy.

The British Journal of Radiology.

2015;88(1055):20150400.

2.

Omary RA et al. Quality improvement guidelines for the reporting and archiving of interventional radiology

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procedures. Journal of Vascular and Interventional Radiology.

2003;14(9):S293-5.

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Cadili A, de Gara C. Complications of splenectomy. The American Journal of Medicine. 2008;121(5):371-5.

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Tam A et al. Percutaneous imageguided splenic biopsy in the oncology patient: an audit of 156 consecutive cases. JVIR. 2008;19(1):80.

6.

7.

Thipphavong S et al. Nonneoplastic, benign, and malignant splenic diseases: cross-sectional imaging findings and rare disease entities.

American Journal of Roentgenology.

2014;203(2):315-22.

Olson MC et al. Safety and accuracy of percutaneous image-guided core

biopsy of the spleen. American Journal of Roentgenology. 2016;206(3):655-9.

8.

Sangiorgio V et al. Radiologically guided percutaneous core needle biopsy of the spleen: a reliable and safe diagnostic procedure for neoplastic and reactive conditions.

Histopathology. 202;78(7):1051-5.

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Article

Acute Form of Sarcoidosis (Löfgren Syndrome): A Case Report Author:

*Ali Abduljabbar1 1. Regional Hospital Viborg, Denmark *Correspondence to Bcc.ali.thamir@gmail.com

Disclosure:

The author has no conflicts of interest to disclose.

Received:

02.07.24

Accepted:

11.11.24

Keywords:

Acute sarcoidosis, Löfgren syndrome, multiple joint swelling, skin lesions.

Citation:

EMJ Radiol. 2025;6[1]:95-98. https://doi.org/10.33590/emjradiol/JZXP4963

Abstract Sarcoidosis is a disorder that affects multiple systems with unclear causes and is relatively rare. The defining characteristic of this disease is the presence of granulomas in various organs in the human body. The incidence and presentation are changeable according to many factors, such as geography, ethnicity, sex, and genetic background. It is highest in Scandinavians. Löfgren syndrome represents a sudden manifestation of sarcoidosis, constituting approximately 10% of all cases. The classical signs and symptoms include bilateral symmetric hilar lymphadenopathy, fever, multiple joint swelling, and skin lesions known as erythema nodosum. Diagnosis of the disease can be quite challenging owing to its infrequent occurrence and the limited availability of sensitive and specific diagnostic tools, tests, and changeable clinical pictures that may suggest different aetiologies. Early diagnosis of Löfgren syndrome will ensure rapid treatment and fewer complications. This review presents the case of a 27-year-old healthy female with sudden onset of bilateral knee joint pain, swelling, erythema nodosum, and fever. Laboratory tests revealed elevated inflammatory parameters. Chest CT and chest X-ray revealed mediastinal and hilar lymphadenopathy, suggesting Löfgren syndrome. This report emphasises the broad spectrum of mimicry observed in cases of acute sarcoidosis, with a focus on the clinical picture and standard differentials that must be carefully evaluated to exclude other inflammatory and malignant conditions. The patient achieved full remission following symptomatic treatment.

Key Points 1. Löfgren syndrome is a rare disease with clinical manifestations similar to other syndromes.

Therefore, it is a challenging diagnosis that is diagnosed by excluding other differential diagnoses.

2. Presentation of the acute form of sarcoidosis and its management.

3. Early diagnosis of sarcoidosis is crucial for rapid remission and preventing serious complications.

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INTRODUCTION Löfgren syndrome is an acute form of sarcoidosis first documented by Sven Löfgren in 1953.1 Sarcoidosis is an idiopathic multisystem autoimmune disorder in which the immune system reacts abnormally to unknown triggers to form granulomas and small clumps of inflamed cells.2 The typical manifestations of this condition primarily target the pulmonary and thoracic lymph nodes but can also extend to the integumentary system, ocular structures, hepatic tissue, cardiac muscle, and nervous system. It occurs most often in adults aged between 20–39 years.2 Sarcoidosis is a relatively rare disease, with an annual incidence rate of 11.5 per 100,000 people in northern Europe, with a higher tendency for sarcoidosis in women than in men.3 Löfgren disease is a frequent presentation of acute sarcoid arthritis, occurring in approximately 5–10% of sarcoid cases.2 The clinical manifestations of sarcoidosis vary depending on the organ involved. The usual clinical features include long-lasting cough, dyspnoea, chest pain, tiredness, fever, weight loss, skin lesions, eye inflammation, and joint or muscle pain.4 Unlike the often reported slow progressive course of sarcoidosis, Löfgren syndrome usually presents with an acute breakthrough of signs and symptoms, including the sudden onset of erythema nodosum, bilateral symmetric hilar lymphadenopathy, fever, and multiple joint swellings.2 Difficulty breathing, dry coughing, and chest pain can occur due to inflammation of the lungs. In addition, patients may experience pain and swelling in the ankles, redness, soreness of the eyes, sore throat, and general fatigue.1,2 Diagnosing Löfgren disease involves a combination of the patient’s symptoms, physical examinations, imaging modalities, blood tests, and biopsies. It is important to rule out other similar diseases to provide proper treatment as the symptoms may resemble those of other malignant and inflammatory conditions.3,4 The majority of individuals diagnosed with Löfgren syndrome experience full and spontaneous recovery, while a subset of patients may require the use of steroids 96

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and immunosuppressive drugs to achieve remission.1 Chronic sarcoidosis is considered in patients with active symptoms for more than 2–5 years. In some chronic patients, about 10–20% may develop complications due to permanent scarring, especially in the lungs, which leads to pulmonary hypertension.

CASE PRESENTATION A 27-year-old otherwise healthy female who smoked 1.75 pack-years, presented with a sudden onset of swelling and erythema nodosum around the ankles that extended to both legs for 1-month duration and was accompanied by a feeling of fever. The patient also experienced pain in the ankles, knees with right-sided predominance, and elbows. In addition, the patient had a mild rash under the left eye, irritation, dry throat, and dry cough especially in the morning, chills, pronounced night sweats, and fatigue throughout the course. No weight loss, itching, chest pain, or palpitations were noted. The patient had no family predispositions to any specific disease.

Blood tests have shown high inflammation parameters with C-reactive protein (CRP) of 98.3 mg/L (normal: 8–10 mg/L), leucocytosis of 16,000 /µL (normal: 4,000–11,000 / µL) with 85.2% neutrophils, IgM 2.68 g/L (normal: 0.8–3.9 g/L), P.interleukin-2: 5,356 kU/L (normal: 158–623 kU/L), and angiotensin-converting enzyme (ACE) 98 U/L (normal: 12-60 U/L). Spirometry showed a forced vital capacity of 3.71 (93%), forced expiratory volume in 1 second of 3.12 (90%), forced expiratory volume in 1 second/ forced vital capacity of 84.4, and diffusion capacity of the lungs for carbon monoxide of 70. Initially, chest radiography revealed bilateral hilar lymphadenopathy with no signs of calcification (Figure 1). A CT scan was performed for further diagnosis and exclusion of other conditions, showing mediastinal and hilar lymphadenopathy without classifications and multiple small nodules in the lungs (Figure 2 and 3). There was no pleural effusion, lung or soft tissue tumour, or pathology in the thoracic bone cage. A definitive diagnosis is achieved by clinical assessment and exclusion of other alternative diagnoses.

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Figure 1: Chest X-ray showed bilateral hilar lymphadenopathy with no signs of calcification.

Figure 2: Axial CT scan showing mediastinal and hilar lymphadenopathy without classifications as well as multiple small nodules in the lungs.

Figure 3: Coronal CT scan showing mediastinal and hilar lymphadenopathy without classifications as well as multiple small nodules in the lungs.

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The patient got ibuprofen 600 mg three times daily and paracetamol 1,000 mg four times daily, with good symptomatic relief.

After fluctuating between 50 and 100, CRP decreased to 13.1 mg/L. After 5 weeks, IL-2 reduced to 2,389, as well as leukocytes to 7,000/µL and ACE to 97 U/L, with almost full remission of symptoms. The patient was discharged and scheduled for follow-up for 3 months.

DISCUSSION The diagnosis of Löfgren syndrome can be challenging because its symptoms and findings can vary considerably.3,4 Bilateral lymphadenopathy, erythema nodosum, fever, and polyarthritis are the main symptoms of Löfgren syndrome.

It is challenging to make the diagnosis, which is made by ruling out other possible differential diagnoses, because the clinical manifestations of fever, joint pain, and erythema nodosum are not limited to sarcoidosis, as they can be induced by various other stimuli, such as penicillin, sulfa drugs, oral contraceptives, and immunisation. Other differential diagnoses include conception and other immunemodulating diseases such as inflammatory bowel disease, lupus, and Behcet disease.5 Furthermore, there are no definitive tests available for diagnoses of this syndrome.1 Blood tests assess immune system activity and, most importantly, inflammatory markers such as ACE, alkaline phosphatase, and CRP.5 Chest radiography is often the first imaging modality performed.

1.

Typical findings include enlarged hilar lymph nodes with or without calcification and interstitial lung changes. Imaging modalities are necessary to rule out other pathologies.

Although most cases resolve spontaneously, patients presenting with symptoms are initially managed with non-steroidal antiinflammatory drugs. In contrast, individuals with persistent or refractory manifestations may need treatment with glucocorticoids or other immunomodulatory agents.1,2 Histological diagnosis may be required in case of deviation from the classical course or failure to achieve remission within the expected timeframe.5

CONCLUSION Löfgren syndrome is the usual presentation of acute sarcoid arthritis, occurring in approximately 5–10% of sarcoid cases. Sarcoidosis symptoms can differ significantly from one patient to another depending on the particular organ affected by the disease. Typical signs and symptoms include fever, bilateral symmetric hilar lymphadenopathy, multiple joint inflammation, and erythema nodosum; however, since these symptoms are not specific to sarcoidosis, and there is no definitive test for sarcoidosis, accurate diagnosis is difficult and sometimes requires advanced clinical tests. Early detection of Löfgren’s syndrome is crucial for immediate treatment and to minimise potential complications such as blindness, renal failure, and pulmonary hypertension.4

References

3.

Flores R et al. Clinical presentation, clinical course, and literature review.

Cureus. 2023;15(1):e33651.

Arkema EV, Cozier YC. Epidemiology of sarcoidosis. Ther Adv Chronic Dis. 2018;9(11):227-40.

4.

WebMD. Sarcoidosis. 2024.

Available at: https://www.webmd.com/ lung/arthritis-sarcoidosis.

Last assessed: 12 March 2024.

2.

Chauhan A et al. Acute arthritis, skin rash and Lofgren's syndrome. BMJ Case Rep. 2021;14(6):e239239.

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5.

Brown F et al. Lofgren Syndrome [Internet] (2024) Treasure Island: StatPearls Publishing. Available at: https://www.ncbi.nlm.nih.gov/books/ NBK482315/. Last accessed: 31 July 2023.

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Article

Neuroimaging in Rabies Encephalitis: An Uncommon Sight Authors:

Vidushi Gupta,1 *Aanchal Bhayana,1 Sudhanshu Kathpalia,1 Navroop Kaur,1 Amita Malik1 1. Department of Radiodiagnosis and Intervention Radiology, VMMC and Safdarjung Hospital, New Delhi, India *Correspondence to aanchalbhayana@gmail.com

Disclosure:

The authors have declared no conflicts of interest.

Received:

10.05.24

Accepted:

30.01.25

Keywords:

Acute disseminated encephalomyelitis (ADEM), brain, cervical spine, MRI, rabies, radiological imaging.

Citation:

EMJ Radiol. 2025;6[1]:99-103. https://doi.org/10.33590/emjradiol/SWOU4513

Abstract Rabies is one of the oldest communicable viral diseases affecting the nervous system of humans, caused by a rhabdovirus. It is almost always fatal, with a handful of reported survival cases. The rapid and aggressive nature of this disease poses a diagnostic challenge. Although, classical clinical history may guide the diagnosis, confirmation is obtained through microbiological tests. Radiological imaging with MRI can prove to be useful not only in the early detection of rabies but also in distinguishing it from other viral encephalitis. The authors present the clinico-radiological features of rabies encephalitis in a 3.5-year-old girl who was bitten on the left side of her face by a dog.

Key Points 1. Rabies is a rare but fatal viral disease affecting the nervous system, with a rapid and aggressive course that makes early diagnosis challenging. Imaging findings are underreported due to its swift progression.

2. This case report describes the MRI findings of rabies encephalitis in a 3.5-year-old girl following a dog bite, adding to the limited literature on imaging in rabies cases.

3. MRI can aid in the early detection of rabies encephalitis, particularly in atypical cases, helping distinguish it from other viral encephalitis and guiding public health measures to prevent further transmission.

INTRODUCTION Rabies is one of the oldest communicable diseases known to humans and is almost always fatal, with very few cases of survival reported.1,2 It is a viral illness that primarily affects the nervous system, caused by a rhabdovirus. The rapid and aggressive nature of the disease makes it challenging to diagnose using imaging techniques.

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While the definitive diagnosis is made through microbiological tests, such as isolating the virus or detecting its antigens/ antibodies, the diagnosis is typically based on clinical presentation and supported by radiological imaging, particularly MRI. MRI can be useful in the early detection of rabies and also in distinguishing it from other forms of viral encephalitis.

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Figure 1: T2-weighted MRI Brain axial sections.

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T2-weighted MRI Brain axial sections show A) hyperintensity involving bilateral basal ganglia, posterior thalami (yellow arrows), B) bilateral substantia nigra & peri-aqueductal grey matter (yellow circle), bilateral hippocampi (red arrows), C) pontine tegmentum (orange rectangle), D) and dorsal part of medulla (red circle).

E–H) Corresponding T1-weighted axial sections show hypointense signal in these areas.

The novelty of this paper lies in the fact that rabies encephalitis is so fatal and aggressive that there is usually no time available for imaging, and thus it is not performed in the majority of clinically suspected cases. Owing to this reason, limited reports are available in the radiology literature describing the MRI brain findings of rabies encephalitis.

The authors contribute to the previously existing paucity of literature by adding one case of fatal rabies encephalitis, depicting the detailed MRI imaging features in a dog-bitten child (Figure 1 and 2).

Having knowledge about the imaging features would help in dispensing the early appropriate diagnosis, thereby guiding clinicians towards adequate management.

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CASE REPORT A 3.5-year-old girl was bitten on the left side of the face by a dog. She received partial immunisation in the form of three doses of the anti-rabies vaccine and had rabies immunoglobulin locally infiltrated.

Fourteen days after the bite, she showed prodromal symptoms, starting with a sudden onset fever and feeling unwell. It was followed by weakness in both her legs that worsened to complete paralysis over a period of 3 days. She also developed left-sided ptosis. Later, she experienced confusion and began talking to herself.

On physical examination, the girl had several lacerations on the left side of

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Figure 2: T2-weighted brain and cervical spine MRI sagittal section.

T2-weighted brain and cervical spine MRI sagittal section show linear hyperintense signal intensity extending from brainstem to involve upper cervical spinal cord.

her face near her eye. Her vital signs were stable with normal fundus examination. She exhibited decreased muscle tone in all four limbs with areflexia. There were no signs of meningitis. Cerebrospinal fluid analysis showed 90% lymphocytes, indicating a viral cause. Viral screen of the cerebrospinal fluid was negative for herpes, Japanese B, and West Nile viruses.

To investigate other potential causes of her neurological symptoms, an MRI of the brain and cervical spine was conducted on the 10th day after symptoms began. The MRI revealed ill-defined, bilaterally symmetrical, hyperintense areas on T2/FLAIR images involving the basal ganglia, substantia nigra, peri-aqueductal grey matter, and pontine tegmentum, as well as the dorsal aspect of the medulla. Hyperintense lesions were also present in the bilateral posterior thalami and hippocampi. A linear, T2 hyperintensity also extended into the cervical spinal cord, involving the central grey matter. These areas appeared hypointense on T1-weighted images.

Diffusion-weighted imaging showed no signs of restricted movement. There was no evidence of blooming or contrast enhancement. The cortical grey matter and CC BY-NC 4.0 Licence

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white matter in both hemispheres showed normal signal intensity. These findings were consistent with those reported in previous cases of rabies encephalitis.

The patient’s neurological condition continued to deteriorate, necessitating intubation. Unfortunately, 5 days later, the child passed away. Due to the distinct clinical presentation and the swift progression of the disease leading to death, laboratory confirmation was not obtained.

DISCUSSION Rabies is a severe and often deadly central nervous system (CNS) infection caused by a neurotropic virus belonging to the Rhabdovirus family.3 Typically, it spreads through the bite of a rabid dog, through aerosol transmission in caves inhabited by bats, or through contamination of open wounds or mucous membranes. Rarely, it can also be transmitted through corneal or organ transplantation.4,5 The incubation period ranges from 2–8 weeks and depends on factors such as the amount of virus transmitted and the proximity of the site of bite to the CNS.6,7

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The virus first replicates in the muscle tissue, attracted by its affinity for nicotinic cholinergic receptors, before reaching the CNS through the neuromuscular spindles or the motor end plates.6 Alternatively, it can also impact the sensory nerve endings and travel retrogradely into the CNS at a relatively constant rate of 12–24 mm per day.8 After the variable incubation period and prodromal phase, characterised by symptoms like burning, itching, and numbness, patients with rabies develop neurological symptoms.

The acute neurological phase involving the CNS presents in two clinical forms: classic encephalitic or furious and paralytic or dumb rabies.3,7,9 The encephalitic form is more common, accounting for approximately 80% of cases.7 The encephalitic and paralytic forms of rabies differ both in their clinical presentations and to some extent in their imaging findings as well.3,9 In the encephalitic form, patients initially exhibit hyperactivity, which progresses to periods of fluctuating consciousness. They may also experience phobic spasms, aerophobia, and hydrophobia, with even the mention of water triggering these hallmark symptoms.

In contrast, the paralytic form typically begins with early motor weakness that advances to quadriparesis and facial weakness.3,9,10 In the early stage, the encephalitic form of rabies exhibits a preference for affecting the brainstem and cerebrum, particularly involving the limbic system. Progression of the disease may also involve deep grey matter structures such as the basal ganglia and thalami.3,9,10,11 Additionally, cortical grey matter and white matter can be affected.2 In contrast, paralytic rabies affects the medulla and spinal cord, alongside brain involvement similar to that of the encephalitic form.10,11 Initially, lesions are typically bilaterally symmetrical and are best visualised on T2/FLAIR sequences. In rare cases of rabies survival, chronic stages may show persistent lesions in deep grey matter with areas of demyelination affecting the white matter of cerebral hemispheres, brainstem, and cerebellum.2 There is a paucity of literature on the neuroimaging findings of rabies encephalitis, and despite a thorough literature search, the authors could find only two previous studies 102

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mentioning the time of MRI study from the onset of symptoms. The MRI brain findings were mostly reported within 5-8 days of onset of symptoms in these two studies

by Rao et al.2 and Jassi et al.12 MRI typically reveals ill-defined and hyperintense lesions on T2/FLAIR images, with corresponding areas appearing hypointense on T1-weighted images. In a case series documented by Jassi et al.12 in 2016, MRI findings revealed ill-defined T2/FLAIR hyperintense lesions in the brainstem, affecting the dorsal medulla, pons, periaqueductal gray matter, midbrain, cerebellar peduncles, including the thalami, hypothalamus, hippocampi, and basal ganglia in a bilaterally symmetrical fashion. A similar pattern of involvement was also reported by Awasthi et al.13 in 2001, Rao et al.2 in 2017, and Jain et al.14 in 2013. In the case reported by Awasthi et al.,13 abnormal T1/T2 hyperintense lesions were observed involving the basal ganglia and thalami, attributed to extracellular methaemoglobin resulting from neuronal damage and petechial haemorrhages.

Contrast enhancement is usually absent in the early stages; however, mild-tomoderate enhancement can be observed in lesions affecting the brainstem nuclei, hypothalami, grey matter of the spinal cord, and intradural nerve roots in the cervical region, particularly in later stages when the patient is in a comatose state.15 An exception is seen in the brachial plexus, which may exhibit enhancement during the prodromal phase of the disease.9 While MRI findings of diffusion restriction in rabies are infrequent, it’s important to note that restriction is not characteristic of rabies encephalitis.

Nonetheless, a few case reports have documented instances of restricted diffusion in the acute stages of encephalitis.2 Diagnosing rabies becomes more straightforward when a patient presents with encephalitic symptoms. However, in cases like the authors’ where the presentation is in a paralytic form, diagnosis is often delayed due to clinical features resembling other rapidly progressive illnesses such as Guillain-Barré syndrome or acute disseminated encephalomyelitis (ADEM). Guillain-Barré syndrome manifests

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as an acute inflammatory demyelinating illness with lesions primarily affecting the nerve roots of the cauda equina. Conversely, ADEM typically occurs following viral infections or vaccination and is characterised by large confluent T2/FLAIR hyperintense lesions involving the white matter, along with cortical and deep grey matter involvement.

In this case, a history of dog bite on the face with typical clinical symptoms and absence of confluent lesions in the white matter, along with the preferential involvement of specific areas such as the thalami, basal ganglia, brainstem, spinal cord, and hippocampi, coupled with the rapid progression of the disease, led the authors to the diagnosis of rabies encephalitis.

Definitive diagnosis of rabies requires laboratory confirmation. Traditionally, diagnosis was made through demonstration of viral antigen by direct immunofluorescence test in corneal/ conjunctival smears and skin biopsies,16 which otherwise have a low sensitivity.

The advent of newer techniques such as RT-PCR has shown increased detection due to higher sensitivity and specificity of ~95–100%.17 However, poor availability of these tests may further delay the

References 1.

2.

Netravathia M et al. Unique clinical and imaging findings in a first ever documented PCR positive rabies survival patient: a case report.

J Clin Virol. 2015;70:83-8.

Rao A et al. Serial brain MRI findings in a rare survivor of rabies encephalitis. Indian J Radiol Imaging. 2017;27(3):286-9.

3.

Co SF et al. Rabies Encephalitis.

RadioGraphics. 2015;35:235-8.

4.

Constantine DG. Bat rabies in the southwestern United States. Public Health Rep. 1967;82(10):867-88.

5.

Gibbons RV. Cryptogenic rabies, bats, and the question of aerosol transmission. Ann Emerg Med. 2002;39(5):528-36.

6.

Mrak RE, Young L. Rabies encephalitis in humans: pathology, pathogenesis

confirmation of this fatal illness. In such scenarios, characteristic MRI imaging findings might help in early diagnosis and implementing necessary measures.

CONCLUSION Rabies, a rare and fatal illness known for its swift disease progression, is seldom subjected to imaging, with only a handful of case reports detailing the imaging findings. Additionally, diagnosing the paralytic form is challenging as it closely resembles other rapidly progressing illnesses clinically. However, demonstrating characteristic imaging findings on MRI, showing classical absence of fluffy, cloud-like white matter lesions may aid in distinguishing it from other forms of encephalitis, especially ADEM. While early diagnosis of rabies may not significantly alter patient management, timely identification through MRI, as in this case, can facilitate the implementation of early public health measures and ensure proper handling of body fluids and biological tissues.

Moreover, pinpointing the animal responsible for disease transmission can prevent further spread of infection to other individuals.

and pathophysiology. J Neuropathol Exp Neurol. 1994;53:1-10.

7.

8.

9.

Tirawatnpong S et al. Regional distribution of rabies viral antigens in central nervous system of human encephalitic and paralytic rabies.

J Neurol Sci. 1989;92:91-9.

Mahadevan A et al. Perspectives in diagnosis and treatment of rabies viral encephalitis: insights from pathogenesis. Neurotherapeutics.

2016;13:477-92.

Rao AS et al. Case Report: magnetic resonance imaging in rabies encephalitis. Indian J Radiol Imaging. 2009;19(4):301-4.

10. Kucera P et al. Pathways of the early propagation of virulent and avirulent rabies strains from the eye to the brain. J Virol. 1985;55(1):158-62.

11. Mani J et al. Magnetic resonance

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imaging in rabies. Postgrad Med J. 2003;79(932):352-4.

12. Jassi P et al. MR imaging in rabies encephalitis: a rare entity. Ann Indian Acad Neurol. 2016;19:125-8.

13. Awasthi M et al. Imaging findings in rabies encephalitis. AJNR Am J Neuroradiol. 2001;22(4):677-80.

14. Jain H et al. MRI in rabies encephalitis. BMJ Case Rep. 2013;2013:bcr2013201825.

15. Laothamatas J et al. MR imaging in human rabies. AJNR Am J Neuroradiol. 2003;24(6):1102-09.

16. Plotkin SA. Rabies. Clin Infect Dis. 2000;30:4-12.

17. Biswal M et al. Role of reverse transcriptase polymerase chain reaction for the diagnosis of human rabies. Indian J Med Res. 2012;135(6):837-42.

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Imaging Features of Leydig-Cell Tumour of the Testis: A Case Report Authors:

Shrishail Adke,1 *Ajith Varrior1 1.

Department of Radiology, Seth GS Medical College and KEM Hospital, Mumbai, India *Correspondence to ajithvarrior@gmail.com Disclosure:

The authors have declared no conflicts of interest.

Received:

27.06.24

Accepted:

03.02.25

Keywords:

Leydig cell tumour (LCT), sex-cord tumour, testicular tumour.

Citation:

EMJ Radiol. 2025;6[1]:104-109. https://doi.org/10.33590/emjradiol/GKQU9079

Abstract Leydig cell tumours (LCT) are rare sex-cord gonadal tumours that account for less than 5% of testicular neoplasms. They are often discovered incidentally during imaging or as part of infertility evaluations. The authors report a case of a 19-year-old male who presented with complaints of small testes. Apart from raised 17-alpha-hydroxy-progesterone (6 ng/mL), the rest of the hormonal and tumour marker workup was normal. On ultrasound, there was a heterogeneously hypoechoic lesion in the right testis with a hyperechoic rim and peripheral vascularity, on a background of multiple microliths. The lesion was hard on elastography.

On MRI, it was hypointense on T2 and short tau inversion recovery (STIR) sequences and was iso-hyperintense on the T1 sequence. There was no diffusion restriction. The patient underwent right orchidectomy. Histopathology showed features of LCT. Common differentials include seminoma (not markedly hypointense on T2, central vascularity, heterogeneous enhancement kinetics, raised tumour markers), Leydig cell hyperplasia (multifocal, bilateral, and asymptomatic), and testicular adrenal rest tumours in children (associated with congenital adrenal hyperplasia and is bilateral). The key radiological features for diagnosing LCTs are subcentimetric size, well-defined margins, hyperechoic rim with peripheral vascularity on ultrasound, and marked hypointensity on T2 sequences without diffusion restriction.

Key Points 1. Leydig cell tumours (LCT) account for less than 5% of testicular tumours. It is essential to accurately diagnose these tumours and to differentiate them from common testicular malignancies such as seminoma.

2. This is a case report of an LCT in a 19-year-old male, highlighting its imaging features on ultrasound, elastography, and multiparametric MRI. It also explains how to distinguish it from common differentials, such as seminoma.

3. LCTs are solitary, subcentimetric homogenous lesions that are hypoechoic on ultrasound with a hyperechoic rim and peripheral vascularity. It is hard on elastography, and is hypointense on T2 sequences with homogenous enhancement.

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INTRODUCTION

DISCUSSION

Leydig cells are found in the testes, specifically in the interstitial space between the seminiferous tubules.1 They are responsible for secreting testosterone, which has a paracrine effect on the seminiferous tubules, thereby contributing to spermatogenesis.1,2 Leydig cell tumours (LCT) are classified as sexcord gonadal tumours and account for less than 5% of testicular neoplasms.2 Although these tumours are rare, they are the most common type of sex-cord stromal tumours. LCTs are often discovered incidentally during imaging studies or as part of evaluations for infertility. Ultrasound is the primary imaging technique used to assess testicular lesions. Additionally, multiparametric MRI can help differentiate LCTs from other benign conditions and germ cell tumours.

LCTs account for approximately 22% of non-palpable testicular nodules.2 They exhibit a dual frequency peak, with one peak occurring in childhood (between the ages of 5–10 years) and another in adults (beyond the third decade).2,3 In children, the most common presentation is precocious puberty, which is caused by the androgen production from these tumours.3 In adults, however, androgen production is less readily detected and is often discovered incidentally or during infertility evaluations.

Many patients with LCTs also experience gynaecomastia. Although there is no specific biomarker for LCT, serum markers such as alpha-fetoprotein, beta-human chorionic gonadotropin, and lactate dehydrogenase are typically measured to rule out germ cell tumours, which usually present with elevated tumour marker levels. In contrast, levels in LCTs are generally negative.2 While most cases are unilateral, bilateral occurrences have been reported in about 3% of cases.4 The majority of these tumours are benign, and metastasis is the only reliable criterion for diagnosing malignancy.

Additionally, there is a strong association between LCTs and Klinefelter syndrome.2,5

CASE PRESENTATION A 19-year-old male with short stature presented with complaints of small testes.

There was no significant past medical or surgical history. On examination, there were no palpable lesions in the scrotum.

Apart from raised 17-alpha-hydroxyprogesterone (6 ng/mL), the rest of the hormonal and tumour marker workup was normal. On ultrasound, there were multiple non-grouped microliths in the right testis.

There was a 7x4 mm heterogeneously hypoechoic lesion in the right testis with a hyperechoic rim. It had predominantly peripheral vascularity (Figure 1). The lesion was hard on ultrasound elastography (Figure 2). On MRI, it was hypointense on T2-weighted and short tau inversion recovery (STIR) sequences. It was isohyperintense on T1-weighted sequences.

There was no diffusion restriction (Figure 3). The patient underwent right orchidectomy. Histopathology showed features of LCT. The patient encountered no complications during the surgery or in the ward course. He was discharged after a few weeks and asked to follow up on an outpatient basis regularly.

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LCTs are usually smaller than 1 cm, with a median size of about 7 mm.

Macroscopically, these tumours exhibit a golden–brown colour.2 Due to the ease of access, ultrasound is typically the preferred initial imaging modality; it is also less expensive than other cross-sectional imaging techniques, such as MRI. On ultrasound, LCTs appear as homogeneously hypoechoic lesions with a well-defined interface with the surrounding testicular tissue.2 In some cases, a hyperechoic rim may be observed.3 Although microlithiasis is rare in LCTs, if present, it tends to be non-grouped. Colour Doppler imaging reveals peripheral vascularity, often with a prominent feeding vessel. In contrastenhanced ultrasound (CEUS), there is centripetal filling with homogeneous enhancement. This enhancement pattern distinguishes LCTs from seminomas, which typically exhibit radial or trans-lesional

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Figure 1: Ultrasound of the testis shows a hypoechoic lesion with hyperechoic rim and peripheral vascularity.

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Ultrasound of the right testis (A) with a linear probe, in a longitudinal section, shows a well-defined, heterogeneously hypoechoic lesion with a hyperechoic rim (arrowheads). There are multiple non-grouped microliths (red arrow). On colour Doppler (B), the vascularity is predominantly peripheral (arrowheads).

Figure 2: The lesion is stiff on elastography.

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B

Ultrasound of the right testis in B mode (A) and elastography (B) shows that the lesion (white arrowheads) is stiff on elastography (white arrows), depicted by blue colour, which corresponds to ‘hard’ on the scale.

vascularity.2 It is important to note that this differentiation may be challenging in smaller lesions. In paediatric cases, central vascularisation may be observed.3 On elastography, LCTs appear stiff.2,6 Multiparametric MRI is valuable for further characterisation of these tumours. On T2-weighted MRI, LCTs are usually hypointense compared to the surrounding parenchyma, which is hyperintense.2,6,7 They tend to be iso-hypointense on T1weighted sequences. The fibrous capsule 106

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may appear hyperintense on T2-weighted images. Additionally, areas of hyperintensity within the lesion may indicate the presence of a central scar.4,6 Haemorrhage, necrosis, and fat are not typically associated with LCTs. While the testis has inherent diffusion restriction, LCTs themselves do not exhibit this restriction. The enhancement pattern often shows rapid wash-in and prolonged washout, indicating significant and sustained enhancement, which can be attributed to the abundant vascularisation surrounding and within the LCTs.2,4,6,8

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Figure 3: The lesion is hypointense on T2 and short tau inversion recovery, iso-hyperintense on T1 without diffusion restriction.

A

B

C

D

E

Axial (A) and coronal (C) T2, and coronal STIR (D) sequences of the MRI of the testes show a well-defined hypointense lesion in the right testis (arrowhead). On the axial T1 (B) sequence, the lesion is iso-hyperintense (arrowhead).

The lesion (arrowheads) shows no diffusion restriction (E).

This vascularisation is linked to a high expression of vascular endothelial growth factor derived from endocrine glands.8 The primary differential diagnosis for an LCT is a germ cell tumour, such as seminoma. In cases of germ cell tumours, serum markers are typically elevated. Seminomas usually exhibit blurred margins with the surrounding tissue and are not significantly hypointense on T2-weighted imaging. Additionally, seminomas are characterised by grouped microlithiasis. Their vascularity is often CC BY-NC 4.0 Licence

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radial and translesional, and they display heterogeneous kinetics on CEUS.2 The key differences between LCT and seminomas have been listed in Table 1.

Leydig cell hyperplasia is a condition characterised by bilateral and multifocal lesions, where patients typically remain asymptomatic. This contrasts with LCTs, which may present with endocrine abnormalities such as gynecomastia.9 Notably, lesions associated with Leydig cell hyperplasia do not exhibit vascularity.

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Table 1: Differences between Leydig cell tumour and seminoma.

Feature

Leydig cell tumour

Seminoma

Serum markers

Normal

Raised

Margins

Sharp

Blurred

Vascularity on Doppler

Peripheral with a prominent feeding artery

Radial and translesional

Microliths

Non grouped

Grouped

Very rapid wash-in with prolonged washout

Less marked and rapid

Homogenous

Heterogenous

T2 signal

Markedly hypointense

Moderate hypointensity

Diffusion restriction

Less

More

Enhancement characteristics

In children, one of the most common differential diagnoses is testicular adrenal rest tumours (TART), which are often associated with congenital adrenal hyperplasia and tend to be bilateral.

On ultrasound, TART lesions can appear either hyper- or hypoechoic and do not have a hyperechoic rim.3 It is also crucial to screen the adrenal glands in these cases.

For small LCTs, testis-sparing surgery (TSS) is recommended. Prompt diagnosis is essential to prevent the need for orchidectomy.10,11 Despite the variety of imaging findings, the specificity of imaging modalities is low, especially for small tumours; therefore, an intraoperative frozen section examination is essential before proceeding with TSS.8,12 Microsurgery is particularly important for cases with bilateral tumours and in patients with solitary testis, as it is more cosmetically appealing. The success of microsurgery can be attributed to the presence of a pseudocapsule, which helps ensure negative tumour margins.12 Metastatic LCT generally shows a poor response to adjuvant chemoradiotherapy. Follow-up imaging is recommended to monitor for recurrence or metastasis. Studies indicate that long-term follow-up shows a diseasefree status in all patients, supporting the idea that conservative management is safe for LCTs. However, there is no significant 108

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improvement in fertility potential for patients treated for LCT.5 This article serves as a comprehensive repository, meticulously illuminating the imaging characteristics of LCT. Beyond detailing the diagnostic insights offered by ultrasound and MRI, it further accentuates the emerging role of elastography, enriching the discourse with advanced perspectives on its application.

The limitation of this article is that it only describes a single case report.

CONCLUSION LCTs are solitary, subcentimetric, homogeneous hypoechoic lesions seen incidentally or in patients with gynaecomastia and Klinefelter syndrome with negative tumour markers. There can be a hyperechoic rim with a peripheral vascularity. On MRI, it is hypointense on T2 sequences with no diffusion restriction.

There is homogeneous enhancement with a rapid wash-in and prolonged washout.

Although these imaging features may favour the diagnosis of LCT, a frozen section is mandatory prior to microsurgery.

Patient Perspective

I was really scared when I was told about cancer in my testis and how it would affect my life. However, I was reassured by the

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hospital team, and I feel perfectly alright post-surgery. Although it was a rough patch in my life, I am glad, as it could have been something worse. I am thankful to the doctors for diagnosing the condition and surgically removing it.

References 1.

2.

3.

4.

Aladamat N, Tadi P, Histology, Leydig Cells. [Internet] (2022) Treasure Island: StatPearls. Available at: https://www.ncbi.nlm.nih.gov/ books/NBK556007/. Last accessed: 14 November 2022.

Maxwell F et al. Leydig cell tumors of the testis: an update of the imaging characteristics of a not-so-rare lesion.

Cancers (Basel). 2022;14(15):3652.

Grand T et al. Precocious puberty related to Leydig cell testicular tumor: the diagnostic imaging keys.

Eur J Med Res. 2022;27(1):67.

Fernández GC et al. MRI in the diagnosis of testicular Leydig cell tumour. Br J Radiol. 2004;77(918):521-4.

Informed Consent

Written informed consent has been obtained from the patient for writing the manuscript. There is no identifiable information in the manuscript that could reveal the identity of the patient.

5.

Pozza C et al. Clinical presentation, management and follow-up of 83 patients with Leydig cell tumors of the testis: a prospective case-cohort study.

Hum Reprod. 2019;34(8):1389-403.

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Tsili AC et al. Leydig cell tumor of the testis. Eurorad. 2018;DOI:10.1594/ EURORAD/CASE.15233.

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Yamamoto Y et al. Leydig cell tumor of the testis with characteristic contrast patterns of tumor and non-tumorous testicular parenchyma on MRI: a case report. Abdom Radiol (NY).

2023;48(8):2477-82.

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Carucci LR et al. Testicular Leydig’s cell hyperplasia: MR imaging and sonographic findings. Am J Roentgenol. 2003;180(2):501-3.

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Zhu J et al. Management of testicular Leydig cell tumor: a case report. Medicine (Baltimore).

2018;97(25):e11158.

10. De Stefani S et al. Microsurgical testissparing surgery in small testicular masses: seven years retrospective management and results. Urology.

2012;79(4):858-62.

11. Dupeux M et al. Testicular lesions in infertile men: the challenges of frozen section examination. Am J Clin Pathol.

2022;157(6):936-41.

12. Leonhartsberger N et al. Increased incidence of Leydig cell tumours of the testis in the era of improved imaging techniques. BJU Int. 2011;108(10):1603-7.

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