BACKGROUND: Qunatitation of blood flow within the cardiac chambers has been tried using digitally recorded velocity information of color Doppler flow mapping (CDFM). However, the accuracy of CDFM has not been systematically assessed. The purpose of the study was to test the accuracy of digitally recorded velocity information obtained through CDFM. Method: Using the American Society of Echocardiography flow phantom, an in vitro steady flow experiment was performed. Eight different flow fields through the phantom (84, 139, 172, 192, 232, 237, 244, 436 mL/sec) were imaged by CDFM using Hewlett Packard Sonos 2500 and all data were stored in the magneto-optical disc. Multiple aliases were visible and 7 different Nyquist limits (17, 23, 27, 37, 42, 53, 58 cm/sec) were used for recording. A fully automatic computer algorithm was used to unwrap the aliases and to convert the CDFM to digital velocity. Among 9 consecutive values at each pixel along the centerline of the phantom, median value was chosen as a representative value, which was compared to the actual value. RESULTS: In the slow velocity region, CDFM tends to overestimate the true velocity, whereas in the fast velocity region, it underestimates. At the aliasing point of 2 times Nyquist limit, there is a marked turbulence and estimation of velocity is impossible;fter aliasing, velocity information of CDFM is totally unreliable. Velocity estimation of CDFM is the most accurate at the velocity region of the Nyquist limit and shows reasonable accuracy between 0.5 x Nyquist limit and 1.5 x Nyquist limit with the error of estimation less than 15%. Conclusion: Velocity information of CDFM is accurate in the limited region and is dependent on the Nyquist limit of each measurement;this can be explained by the effect of wall filter. Baseline-shift of CDFM should be limited to the region between 0.5 x Nyquist limit and 1.5 x Nyquist limit for accurate quantitation using velocity information of CDFM.
Echocardiography

No abstract available.
Mitral Valve Insufficiency

PURPOSE: United States (US) and Canadian citizens attending medical school abroad often desire to return to the US for residency, and therefore must pass US licensing exams. We describe a 2-day United States Medical Licensing Examination (USMLE) step 2 clinical skills (CS) preparation course for students in the Technion American Medical School program (Haifa, Israel) between 2012 and 2016. METHODS: Students completed pre- and post-course questionnaires. The paired t-test was used to measure students' perceptions of knowledge, preparation, confidence, and competence in CS pre- and post-course. To test for differences by gender or country of birth, analysis of variance was used. We compared USMLE step 2 CS pass rates between the 5 years prior to the course and the 5 years during which the course was offered. RESULTS: Ninety students took the course between 2012 and 2016. Course evaluations began in 2013. Seventy-three students agreed to participate in the evaluation, and 64 completed the pre- and post-course surveys. Of the 64 students, 58% were US-born and 53% were male. Students reported statistically significant improvements in confidence and competence in all areas. No differences were found by gender or country of origin. The average pass rate for the 5 years prior to the course was 82%, and the average pass rate for the 5 years of the course was 89%. CONCLUSION: A CS course delivered at an international medical school may help to close the gap between the pass rates of US and international medical graduates on a high-stakes licensing exam. More experience is needed to determine if this model is replicable.
Clinical Competence* ; Curriculum ; Educational Measurement ; Foreign Medical Graduates ; Humans ; Internship and Residency ; Licensure* ; Male ; Mental Competency ; Parturition ; Schools, Medical ; United States*