Renal MR angiography at 1.0 T: Three-dimensional (3D) phase-contrast techniques versus gadolinium-enhanced 3D fast low-angle shot breath-hold imaging

OBJECTIVE, The purpose of this study was to evaluate the diagnostic usefuln ess of three different MR angiographic techniques at 1.0 T. SUBJECTS AND METHODS. In 22 patients with renal artery stenosis confirmed a t intraarterial catheter angiography, we also performed unenhanced and gado linium-enhanced three-dimensional phase-contrast MR angiography and gadolin ium-enhanced single breath hold three-dimensional fast low-angle shot MR an giography. We determined circulation time to optimize signal acquisition in gadolinium-enhanced breath-hold MR angiography after bolus injection of co ntrast material. RESULTS. Sensitivity, defined as the detection of a hemodynamically signifi cant stenosis (>50% luminal narrowing), was 85% for enhanced phase-contrast MR angiography, 91% for gadolinium-enhanced MR angiography, and 95% for un enhanced phase-contrast MR angiography. The combination of unenhanced phase -contrast MR angiography and gadolinium-enhanced MR angiography yielded 100 % sensitivity for hilar artery stenoses. There were 13 false-positive findi ngs with unenhanced phase-contrast MR angiography, 10 with enhanced phase-c ontrast MR angiography, and four with gadolinium-enhanced MR angiography (s pecificity: 38%, 52%, and 79%, respectively). Accessory renal arteries were not seen on unenhanced or enhanced phase-contrast MR angiography (0/8 pati ents) but were detected with gadolinium-enhanced MR angiography in five of the eight patients. Interobserver agreement (kappa = .62) was best with gad olinium-enhanced MR angiography. The quality of the images was unsatisfacto ry for adequate evaluation of segmental renal arteries with all three MR an giographic techniques. CONCLUSION. A combination of unenhanced phase-contrast MR angiography and g adolinium-enhanced MR angiography at 1.0 T proved useful as a screening pro tocol for renal artery stenosis.