Prospective comparison of MR phase-contrast velocimetry with intravascularDoppler US during infrainguinal artery angioplasty

PURPOSE: To evaluate the accuracy of magnetic resonance (MR) velocimetry fo r quantitative assessment of stenosis in patients undergoing percutaneous t ransluminal angioplasty (PTA). MATERIALS AND METHODS: Thirty patients underwent PTA of the infrainguinal r egion. To assess hemodynamic parameters of lesions, MR phase-contrast veloc imetry with a circular-polarized extremity receiver coil and a cardiac gate d gradient echo sequence was conducted before and 1 day after PTA. Addition ally, all lesions were examined by means of intravascular Doppler flow meas urements (0.018-inch wire, 12 MHz). From these data, the degree of stenosis was calculated and a comparison of MR velocimetry with intravascular Doppl er US was undertaken. RESULTS: Correlation between calculated grade of stenosis for MR velocimetr y and intravascular Doppler US was good and significant (r 0.74; P <.001). Calculated luminal stenosis grade were similar for both methods before PTA (intravascular Doppler US: 0.62 +/- 0.18, MR velocimetry: 0.54 +/- 0.19; P =.17 with paired Student t-test) and after PTA (0.25 +/- 0.23 and 0.3 +/- 0 .2 respectively; P =.56). CONCLUSION: MR velocimetry results in reliable noninvasive in vivo flow mea surements and allows accurate assessment of stenosis in a clinical setting.