Detection of renal artery stenoses using MRI with surface shaded display. Interest in azotemic patients

Forty-three patients with renal artery stenoses were examined with time of flight MR angiography using maximum intensity projection and surface shaded rendering, and with digital substraction angiography. Sensitivity and specificity were 0.83 and 0.78 for main and secondary arteries, 0.87 and 0.84 for main arteries. In azotemic patients, the positive predictive value was estimated at 40 %-70 % and the negative predictive value at 95 %- 98 %, while the prevalence of renal artery stenoses varied from 10 % to 30 %. These results validate MRI for the detection of renal artery stenoses in this population. Surface shaded display was more accurate than maximum intensity projection to reconstruct time of flight sequences and to grade renal artery stenoses. (authors)