DETECTION OF MAIN RENAL-ARTERY STENOSIS USING PHASE-CONTRAST CINE MR-ANGIOGRAPHY

OBJECTIVE. The purpose of our study was to assess the ability of phase -contrast cine MR angiography to detect the presence of main renal art ery stenosis. SUBJECTS AND METHODS, We prospectively evaluated 75 hype rtensive patients for main renal artery stenosis using phase-contrast cine MR angiography. Each main renal artery was evaluated as normal or abnormal, Thirty-seven of the 75 patients underwent conventional arte riography or intraarterial digital subtraction arteriography; these re sults were compared with the MR angiographic interpretations. Only tho se patients who had confirmatory arteriography were included in the st atistical analysis. RESULTS. Thirty-six main renal arteries interprete d as normal by MR angiography were found to be without a focal stenosi s on invasive arteriography. MR angiography suggested 32 main renal ar tery stenoses; invasive arteriography showed 29 of these as stenoses. Three main renal arteries that were interpreted as having focal stenos es by MR angiography were shown to be not stenotic by invasive arterio graphy. Three other patients had diffusely narrowed main renal arterie s bilaterally without a focal stenosis on MR angiography; bilateral pr oximal renal artery stenoses were seen at arteriography in two of thes e patients, and diffusely narrowed main renal arteries were seen in th e third patient. Thus, the sensitivity of phase-contrast cine MR angio graphy for detecting a focal stenosis or abnormal main renal artery wa s 100% (95% confidence interval, 88-100%) and the specificity was 93% (95% confidence interval, 80-99%). The kappa coefficient was 0.85 with a standard error of 0.08. CONCLUSION. Phase-contrast cine MR angiogra phy has a high degree of accuracy and a high negative predictive value in detecting the presence of main renal artery stenoses and may be a good screening technique for renovascular hypertension.