Noninvasive assessment of renal artery stenosis. A comparison of MR angiography, color Doppler sonography, and intraarterial angiography.

The purpose of this study was to evaluate MR angiography (MRA) and color Doppler sonography as noninvasive screening methods in suspected renovascular hypertension. Fifty-five consecutive patients with arterial hypertension were examined prospectively using high resolution 3-D TOF MRA and color Doppler sonography. Intraarterial angiography was the standard of reference. Stenoses of 60% or more were regarded as significant. MR angiograms were evaluated by 3 independent observers who studied 110 main renal arteries. All 8 significant stenoses and 2 occlusions were correctly classified with MRA while one 60% stenosis was underestimated by color Doppler sonography. Mild stenoses were overestimated by MRA in 4 and by color Doppler sonography in 6 cases. A drawback of both methods was the large number of not evaluable arteries (6 in MRA, 11 in color Doppler sonography). These arteries were regarded as pathologic because stenosis could not be excluded. Due to this fact specificities of MRA and color Doppler sonography were 90% and 85% respectively. Accessory vessels were detected in 47% (8/17) by MRA and in 0% (0/17) by color Doppler sonography.