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International Breast Ultrasound School Course May 2009, Athens Greece

Athina Vourtsis MD, Phd e-mail

Screening mammography remains currently the most sensitive tool in the detection of early breast cancer.


Breast Imaging Reporting And Data System In order to achieve full communication between the radiologists and the referring clinicians members of the American College of Radiology (ACR) cooperated along with other societies to publish this standardized system:

This system is a quality assurance tool designed to standardize the terminology in a mammographic report, to reduce confusion in interpretation of findings and to assist outcome monitoring.

3. edition 1998

4. edition 2003

BI-RADS Breast Imaging Reporting And Data System  BREAST IMAGING LEXICON Description of terms and definitions.  REPORTING SYSTEM Categorization of Lesions – to provide an organized approach to image interpretation.  FOLLOW-UP AND OUTCOME MONITORING Follow up + statistics  GUIDANCE CHAPTER Questions and reports of problems related to the various sections.  DATA COLLECTION CHAPTER  APPENDICES

To perceive and characterize correctly the mammographic findings. To categorize the lesions in the appropriate assessment category in order to avoid unnecessary biopsies!!

Mammography A. Masses B. Calcifications C. Architectural distortion D. Special Cases: Asymmetric tubular structure, solitary dilated duct, intramammary lymph node, global asymmetry, focal asymmetry.

E. Associated Findings:

Skin retraction, nipple retraction, skin thickening, trabecular thickening, skin lesion, axillary adenopathy.

Is a three-dimensional structure demonstrating convex outward borders, usually evident in two different projections. If a potential mass is seen in only one projection it is called “ASSYMETRY”.

1. Shape:

- Round - Oval - Lobular - Irregular

2. Margins:

- Circumscribed - Well defined - Microlobulated - Obscured - Indistinct – (ill-defined) - Spiculated margin

3. Density:

- High density - Equal Density (isodense) - Low density (not fat containing) - Fat-containing Radiolucent


1. Shape:

a. Round b. Oval c. Lobular d. Irregular

BI-RADS Masses - 2. Margin Modifies the Shape of the Mass

Circumscribed, Well defined, Microlobulated, Obscured, Indistinct – (ill-defined), Spiculated

a.Circumscribed mass b.Microlobulated mass

is defined when the margin of is defined when at least 75% of the lesions is associated with the margin is well defined, with the short cycles which produces remainder no worse than obscured small undulations. by overlying tissue and with an abrupt transition between the lesion and the surrounding tissue.

c. Obscured – A margin that is hidden by adjacent normal tissue. d. Indistinct (ill-defined) Margin – Poor definition of the margin or any portion of the margin, raises concern that there may be infiltration. e. Spiculated margin – The lesion is characterized by lines radiating from the margin of a mass.

A. Masses – 3. Density To define the x-ray attenuation of the lesion relative to the expected attenuation of an equal volume of fibroglandular breast tissue. a. High density b. Equal Density (isodense) c. Low density (not fat containing) d. Fat-containing Radiolucent


Discription Shape Size Density – Contour Number

Distribution Modifiers Diffuse/Scattered Regional (>2cc) of tissue. Grouped or Clustered (<1cc) of tissue. Linear - array in a line. Segmental – In duct or ducts.

BI-RADS : Authors of the BI-RADS lexicon also have divided microcalcifications morphologic descriptors into the following designated categories:

1.Typical Benign type of calcifications: Skin, vascular, coarse or popcorn like, large rod-like (>1cm), round (>0.5mm), punctate (<0.5mm), lucent centered, eggshell or rim, milk of calcium, suture and dystrophic ( >0.5mm) calcifications.

2.Intermediate Concern, Suspicious Calcifications: a.Amorphous or Indistinct calcifications. b.Coarse Heterogeneous calcifications (>0.5mm).

3.Higher Probability of Malignancy: a.Fine pleomorphic calcifications (vary in sizes and shapes <0.5mm). b.Fine linear or fine-linear branching calcifications (<0.5mm in width).

2. Intermediate Concern, Suspicious Calcifications

a. Amorphous

Are sufficiently small or hazy in appearance that a more specific morphological classification cannot be determined.

a. Amorphous Calcifications According to scientific evidence this form of calcification, can be associated with probability of malignancy up to 20% of the cases.

2. Intermediate Concern, Suspicious Calcifications b. Coarse Heterogeneous Calcifications (>0.5mm)

Are irregular conspicuous calcifications that are generally larger than 0.5mm and tend to coalesce. As with any calcifications distribution must be considered. An isolated cluster, â&#x20AC;&#x153;coarse heterogeneousâ&#x20AC;? calcifications, have a small but significant likelihood of malignancy and warrants biopsy.

3. Higher Probability Malignancy a. Fine Pleomorphic (I-, V-, Y- configurated)

According to the Guidance Chapter should be used to describe irregular, varying in size calcifications smaller than 0.5mm in diameter.

3. Higher Probability Malignancy b. Fine Linear or Fine-Linear Branching (Casting) Calcifications

These are thin, linear or curvilinear with irregular shape; suggesting filling of a lumen of a duct involved irregularly by breast cancer.


- diffuse - regional - clustered (<1cc) - linear - segmental

The normal architecture is distorted with no definite mass visible. This includes thin lines or spiculations radiating from a point and focal retraction or distortion of the edge of the parenchyma. Architectural distortion can also be associated with a mass, asymmetry or calcifications. In the absence of appropriate history of trauma or surgery architectural distortion is suspicious for malignancy or radial scar and biopsy is appropriate.

Global Asymmetry

Focal Asymmetry

Was introduced in the 4th edition to underscore the difference between generalized and focal asymmetry. Global asymmetry involves a large portion of the breast (at least a quadrant) and has replaced the “Asymmetric breast tissue”.

Focal asymmetry has replaced the “focal asymmetric density”. Differs from a mass since it lacks convex outward borders. It differs from “global asymmetry” only in the size of the area of the breast involved. It seen as a confined asymmetry.

A focal asymmetry is of more concern. Comparison to prior films is critical. A developing asymmetry needs further evaluation in the absence of trauma, infection or history of surgery. Further evaluation with spot compression views and/or ultrasound.

Paget Disease


0: Additional imaging is necessary


1: Negative - nothing to describe


2: Benign


3: Probably benign


4: Suspicious abnormality


5: Highly suggestive for malignancy


6: Histologically verified carcinoma

THE BI-RADS CATEGORIZATION Category 0 - Incomplete.

Needs additional imaging evaluation by spot compression, magnification, special mammographic views, ultrasound. In this category are placed examinations after a screening mammogram.

Category 1 - Negative. Normal interval follow-up. There are no findings to comment on.

Category 2 -Benign findings. The mammogram is negative, but the interpreter chooses to describe a benign finding in the mammographic report. A calcified fibroadenoma, multiple secretory calcifications, 348


fat-containing lesions such


oil cysts, lipomas, galactoceles, and mixed density hamartomas. Other typical benign findings described in this category are




intramammary lymph nodes, vascular calcifications, implants or architectural distortion clearly related to prior surgery.



PPV = < 2%

Probably benign - Short interval follow-up.

Is reserved for lesions that are most certainly benign and which have less than 2% chance of malignancy.

1. A non-palpable circumscribed solid mass. 2. A focal asymmetry. 3. A cluster of round â&#x20AC;&#x201C; punctate calcifications (if fine detail images portray the calcific particles to be round or oval).



THE BI-RADS CATEGORIZATION Category 4 (4A, 4B, 4C ) Suspicious abnormality. A biopsy should be considered without having a typical appearance of malignancy. Findings in this category prompt interventional procedures ranging from aspiration of complicated cysts to biopsy of pleomorphic calcifications. Many institutions have, on an individual basis, subdivided Category 4 to account for the vast range of lesions subjected to interventional procedures and corresponding broad range of risk of malignancy. According to the likelihood of malignancy Category 4 is divided into 3 subcategories. This stratification is helpful in communicating the level of suspicion to pathologists and referring physicians. Moreover, this allows a more meaningful practice audit and is useful in research involving receiver-operating characteristics curve analysis.

Category 4 A : May be used for a finding needing intervention but with a low suspicion for malignancy. A malignant pathology report not expected and a 6month or routine follow-up after a benign biopsy or cytology is appropriate. Examples of findings placed in this category may be a palpable, partially circumscribed solid mass with ultrasound features suggestive of a


fibroadenoma, a palpable complicated cyst or probable abscess. Category 4 B : Includes lesions with an intermediate suspicion of malignancy. Findings in this category warrant close radiologic and pathologic correlation. Follow-up with a benign result, depends on concordance. A partially indistinctly marginated mass yielding fibroadenoma or fat necrosis is acceptable, but a result of papilloma might warrant excisional biopsy. Category 4 C: Includes findings of moderate concern, but not typical for malignancy. Examples of findings placed in this category are an ill-defined, irregular mass or a new cluster of fine pleomorphic calcifications. A malignant result in this category is expected.

THE BI-RADS CATEGORIZATION Category 5 Highly suggestive for malignancy. Appropriate action should be taken (generally biopsy). This category must be reserved for findings that are classic breast cancers, with a >95% likelihood of malignancy. This category contains lesions for which one-stage surgical treatment could be considered without preliminary biopsy. However current oncologic may require percutaneous tissue sampling.

THE BI-RADS CATEGORIZATION Category 6 This category has been added for breast findings confirmed to be malignant by biopsy but prior to definitive therapies such as surgical excision, radiation therapy, chemotherapy or mastectomy. This category is appropriate for second opinions on findings previously biopsy and shown to be malignant or for the monitoring of responses to neoadjuvant chemotherapy prior to surgical excision. Use of category 6 is not appropriate following excision of a malignancy (lumpectomy). After surgery, there may be no residual evidence of tumor, with final assessment of Category 3 or Category 2.

The final assessment categories of BI-RADS lexicon are useful predictors of malignancy.







BI-RADS 4 A,B,C 2-30%,30-60%,60-95% BI-RADS 5



Probably Benign Finding- Initial Short-Interval Follow-up Suggested

Well-studied, documented criteria in Surveillance of Cases • Baseline Screening or screening follow-up without prior exam available. • Complete diagnostic imaging evaluation before making a probably benign assessment. • Exclude palpable lesions.

BI-RADS 3 Category is based Three Principles 1. Since these lesions have a low probability of malignancy (<2%) a short interval follow-up is recommended rather than immediate biopsy to avoid unnecessary invasive procedures, patient anxiety, and medical costs. 2. The small percentage of lesions assigned to the probably benign group that are actually malignant are rapidly identified â&#x20AC;&#x201C; usually within 6-12 months- by a change in appearance at subsequent imaging. 3. The small numbers of cases ultimately identified as malignant are of early stage and maintain prognosis similar to that of other cancers identified at routine screening mammography. Two large prospective trials, from the university of California at San Francisco and the Hospital Pereira Rossell in Montevideo, Uruguay. Lit. Varas et al. Non-palpable probably benign lesions: role of follow-up mammography. Radiology 1992;184:409-414. Sickles EA. Periodic mammographic follow-up of probably benign lesions: results in 3,184 consecutive cases. Radiology 1991;179:463-468. Sickles EA. Probably benign breast lesions: when should follow-up be recommended and what is the optimal follow-up protocol? Radiology 1999;213:11-14. Sickles EA. Non-palpable, circumscribed non-calcified solid breast masses: likelihood of malignancy based on lesion size and age of patient. Radiology 1994;192:439-442.

BI-RADS 3 - Lesions almost certainly benign with <2% of malignancy â&#x20AC;&#x201C; Guidance Chapter Typically, a repeat diagnostic mammography examination is suggested after 6 months to determine whether the lesion has remained stable. Lesions that have progressed require immediate biopsy! Whereas those that remain stable, the recommendation is a bilateral follow-up examination after 6 months. If after, one year of observation, the lesion has not progressed, the mammogram is again coded as BI-RADS 3 with one year surveillance for the next 1 or 2 years. According to the literature, after 2 to 3 years of stability, the final assessment category may change to Category 2 benign, although diagnostic rather than screening followup may be appropriate.

CATEGORIZATION Category 3 - Probably benign - Short interval follow-up.




It is possible that findings in this category are biopsied as a result of patient and /or clinician concern, or lack of confidence in the probably benign follow-up assessement. In such instances the final assessment category should be based on risk of malignancy.


Category BI-RADS 3 The false negative rate of BI-RADS 3 mammograms accounts to 4.5%. 4.5% Is a category associated with uncertainty. It has the higher probability of leading to a wrong diagnosis. The mammographic appearance of

a non-palpable circumscribed solid mass are not

reliable. Therefore fibroadenoma, pappilomas, phyllodes tumor cannot












pappilary carcinoma) leading to a false negative mammogram. The distinction of a focal asymmetry from a poorly marginated mass and the correct categorization of microcalcifications according to their morphologic descriptors may vary.

Variability in mammographic interpretation among experienced radiologistâ&#x20AC;&#x2122;s.

BI-RADS Breast Imaging Reporting And Data System  Indication for Examination (screening or diagnostic).  A description of the overall breast composition.  Clear Description of any significant findings (lesion type, size, associated calcifications, associated findings.  Location of the abnormality based on the face of a clock and / or quadrant.  Comparison to prior examinations. Assumes importance if the feature of concern is new or when there is a feature requiring the evaluation of change.  Assessment Categories with any recommendations.

ACR density type I â&#x20AC;&#x201C; IV: Information about the reliability of the mammogram to detect a tumor within the normal tissue. Protection for the radiologist !!!

According to the results of publish studies there is not a fully agreement regarding the efficiency of clinical examination.

However, in the fourth edition the committee considers that clinical examination is an





Therefore in a case of a negative mammogram management decisions should be made based on the clinical evaluation.

BI-RADS is a useful tool, since it helps the radiologists to have a common and adequate language to discribe and define the imaging signs, leading to the correct interpretation. There is a direct link between the caterogorization and the action to be taken.


Another advantage is the collection of data for monitoring the radiologist overall interpretation outcomes. Inconsistency in assessement and recommendation still persists. Category 3 has the highest variability in mammographic reports.

The use of the probably benign category should be based solely on well-studied, documented criteria rather than on the individual radiologistsâ&#x20AC;&#x2122;s instinct. Continued efforts to educate radiologists and referring clinicians in the use and classification of BI-RADS terms promotes a higher consistency in reporting terminology. A flawless technique, a good deal of interpretation skill, and adequate time to exercise both are the basic fundamentals which all experts practicing in the field of mammography are required to preserve.

bi-rads mammography