EFSUMB EUROPEAN FEDERATION OF SOCIETIES FOR ULTRASOUND IN MEDICINE AND BIOLOGY ‘Building a European Ultrasound Community’ Young Investigator’s Award WFUMB 2011 VIENNA AUSTRIA 28 August 2011 13.50 – 15.45 10 minutes each for presentation plus 3 minutes discussion
Do dead elements affect the accuracy of spectral Doppler measurements? Jaromir Vachutka1, Ladislav Dolezal2, Christian Kollmann3 1
Department of Medical Biophysics, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic 2
Medical Ultrasound Research Laboratory, Palacky University, Olomouc, Czech Republic
Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria
ABSTRACT Purpose The aim of this work is to contribute to the safe use of ultrasound in medical diagnosis which includes safe application as well as accurate diagnosis. It is not possible to obtain quality diagnostic information with an ultrasound imaging system that does not perform properly. Dead elements belong to the common ultrasound probe failures. We are trying to find out how an exactly defined ultrasound probe failure affects the quality of diagnostic information. This work describes the effect of dead elements on the accuracy of spectral Doppler measurements. Materials and Methods We used a specially designed ultrasound imaging system Sonix RP that enables to turn off the elements in the probe. Using a faultless convex, linear and phased array probe we measured parameters of a steady parabolic flow profile which was generated by a flow test object (IEC 61685). The same measurements were repeated using a probe with 1 – 10 dead elements. Acquired velocity spectra were analysed – we determined overall Doppler power, maximum, minimum and average velocity. Statistical parameters were calculated. Results Our results indicate that in the vast majority of cases overall Doppler power as well as maximum and average velocity decrease with increasing number of dead elements. Decrease of maximum and average detected velocity higher than 20 % was registered. Significant differences were found between the results obtained with different types of probes. Conclusion We can conclude that dead elements undoubtedly affect the accuracy of spectral Doppler measurements. Our goal is to find a threshold probe defect which would determine that a given device cannot be henceforward used in medical practice. To determine such a threshold there it is a need of further research (for example we have to determine how probe failures affect the measurements of pulsatile flow). This work was supported by a project LF_2011_009.