SPIRAL CT OF RENAL-ARTERY STENOSIS - COMPARISON OF 3-DIMENSIONAL RENDERING TECHNIQUES

PURPOSE: To evaluate the accuracy of computed tomographic (CT) angiogr aphy in the detection of renal artery stenosis (RAS). MATERIALS AND ME THODS: CT angiography was performed in 31 patients undergoing conventi onal renal arteriography. CT angiographic data were reconstructed with shaded surface display (SSD) and maximum-intensity projection (MIP). Stenosis was graded with a four-point scale (grades 0-3). The presence of mural calcification, poststenotic dilatation, and nephrographic ab normalities was also noted. RESULTS: CT angiography depicted all main (n = 62) and accessory (n = 11) renal arteries that were seen at conve ntional arteriography. MIP CT angiography was 92% sensitive and 83% sp ecific for the detection of grade 2-3 stenoses (greater than or equal to 70% stenosis). SSD CT angiography was 59% sensitive and 82% specifi c for the detection of grade 2-3 stenoses. The accuracy of stenosis gr ading was 80% with MIP and 55% with SSD CT angiography. Poststenotic d ilatation and the presence of an abnormal nephrogram were 85% and 98% specific, respectively. CONCLUSION: CT angiography shows promise in th e diagnosis of RAS. The accuracy of CT angiography varies with the thr ee-dimensional rendering technique employed.