Contrast-enhanced magnetic resonance angiography (CE-MRA) is an accurate and noninvasive method used to screen for renal artery stenosis (RAS). Color Doppler ultrasonography (CDUS) and noncontrast enhanced magnetic resonance angiography (NC-MRA) are considered noninvasive imaging modalities, which require no contrast medium injection.
To compare NC-MRA with CDUS for screening for RAS using CE-MRA as a reference standard.
The study was approved by our institutional review board with written informed consent was obtained from all patient participants. We prospectively enrolled 42 consecutive patients who were suspected of having RAS. All patients underwent CDUS, NC-MRA, and CE-MRA of renal arteries. The attending radiologist interpreted the CDUS after scanning the patient. CE-MRA and NC-MRA were separately interpreted by consensus between two radiologists. Data including (1) number of visualized renal arteries, (2) agreement between CDUS and NC-MRA compared with CE-MRA, and (3) time taken for examination, were evaluated.
We included 102 renal arteries and 306 renal artery segments in the study. NC-MRA visualized significantly more renal artery segments (258 segments) than CDUS (286 segments, P = 0.0004). NC-MRA and CDUS were in good agreement with CE-MRA when determining the degree of stenosis (Kw = 0.71 and Kw = 0.66, respectively). NC-MRA took a significantly shorter time for examination (21.2 minutes) than CDUS (47.5 minutes, P <0.0001).
NC-MRA is comparable to CDUS for screening for renal artery stenosis. However, NC-MRA can visualize more renal artery segments and require shorter examination time than CDUS.