Magnetic resonance angiography has a high reliability in the detection of renal artery stenosis

In this prospective study we examined the value of magnetic resonance angiography (MRA) in the imaging of the proximal renal arteries, with the main aim of detecting renal arterial stenosis, as compared with intraarterial digital subtraction angiography. The study was done among a group of 38 hypertensive patients seen in the outpatient department of the department of medicine of our university hospital. In all patients a magnetic resonance angiography and an intraarterial subtraction angiography of the renal arteries was made, and the outcomes of the investigations were compared. Clinical and biochemical data of the patients also were analyzed in relation to the presence or absence of a stenosis. In one patient, MRA resulted in technical failure because of unsuspected claustrophobia. Of the remaining 37 patients, 14 had renal artery stenosis. Of 12 patients in whom the stenoses were >50% of luminal surface on intraarterial digital subtraction angiography, eight were unilateral and four bilateral. All these stenoses were recognized by magnetic resonance angiography. There was also one false positive result by magnetic resonance. Thus, for the identification of stenoses >50%, magnetic resonance has a sensitivity of 100% and a specificity of 96%. Of the 12 accessory renal arteries seen on digital subtraction angiography, only three were identified by magnetic resonance angiography. We conclude that magnetic resonance angiography has great accuracy in depicting the main renal arteries and detecting clinically significant renal artery stenosis; however, the identification of accessory renal arteries is suboptimal and should be improved. (C) 1997 American Journal of Hypertension, Ltd.