Comparison of digital subtraction angiography with gadolinium-enhanced magnetic resonance angiography in the diagnosis of renal artery stenosis

Renal artery stenosis (RAS) is a treatable cause of hypertension and renal failure for which no I ideal screening technique is currently available. We evaluated the use of dynamic gadolinium-enhanced magnetic resonance angiog raphy (MRA) for the diagnosis of RAS. Sixty-two patients with Secondary hyp ertension were enrolled in the study. All patients had conventional renal a ngiography and gadolinium enhanced MRA. The sequence used was a 3D FMP SPGR sequence with the following parameters (TR: 26 ms, TE: 6.9 ms, flip angle 40 degrees, field of view 36 x 36 cm, matrix 246 x 256,1 excitation). Gadol inium 0.3 mmol/kg was administered and 60 1.5-mm-thick partitions were obta ined over a duration of 3.5 min. The MRA images were then compared with con ventional digital subtraction angiography (DSA) images. Conventional DSA de monstrated 138 renal arteries, whereas gadolinium-enhanced MRA demonstrated 129 (93%). Twenty-one renal artery stenoses and four occluded arteries wer e seen at conventional DSA. Gadolinium-enhanced MRA had a sensitivity of 88 %, specificity of 98%, accuracy of 96%, positive predictive value of 92% an d negative predictive value of 97% when compared with conventional DSA, Gad olinium-enhanced MRA is an accurate technique for identifying patients with RAS. It is less sensitive in picking up accessory renal arteries.