EVALUATION OF RENAL-ARTERY STENOSIS BY MAGNETIC-RESONANCE ANGIOGRAPHY

BACKGROUND: Accurate identification of patients with surgically correc table renovascular hypertension has been difficult by noninvasive mean s. Advances in the technique of magnetic resonance angiography (MRA) h ave begun to provide detailed, accurate imaging of the vascular system . This study reports our recent experience in the evaluation of the re nal arteries by this technique. METHODS: MRA and contrast arteriograph y were performed in 32 arteries (16 adult patients) for evaluation of hypertension, abdominal aortic aneurysm, mesenteric vascular disease, and aorto-iliac occlusive disease. Luminal diameter reduction (%) was determined from two-dimensional time-of-flight (TOF) axial images. Con trast arteriography served as the gold standard for comparison. RESULT S: Contrast arteriography revealed a 50% or greater stenosis in 11 of 32 vessels studied (34%). As a screening test for detection of greater than 50% diameter reduction, MRA had a sensitivity of 91%, a negative predictive value of 94%, and an overall accuracy of 81%. Linear regre ssion analysis demonstrated significant correlation between MRA and ar teriographic measurements (r = 0.8; P <0.001). CONCLUSIONS: This study demonstrates the ability of MRA to accurately assess the main renal a rteries for the presence of critical stenosis. This noninvasive evalua tion compares well with conventional angiography and may have increasi ng application in the screening of patients with suspected renovascula r disease.