Ureteropelvic junction obstruction: Use of helical CT for preoperative assessment - Comparison with intraarterial angiography

PURPOSE: To evaluate helical computed tomography (CT) in the preoperative a ssessment of crossing arteries in kidneys with ureteropelvic junction (UPJ) obstruction and to compare the results with those obtained by means of ang iography. MATERIALS AND METHODS: Forty-one consecutive patients with symptomatic UPJ obstruction in 42 obstructed kidneys underwent renal helical Ct and renal i ntraarterial digital subtraction angiography (DSA; flush aortography and bi lateral selective renal injections), The helical CT and DSA images were int erpreted in a blinded manner by two readers, and the results were compared. RESULTS: DSA showed 126 renal arteries In the 41 patients; 56% of patients had supernumerary renal arteries. Helical CT depicted 121 (96%) of these 12 6 renal arteries prospectively, Retrospectively 124 (98%) renal arteries we re visible on CT images, Twelve (29%) of the 42 kidneys with UPJ obstruct-i on had identifiable arteries crossing the UPJ on DSA images. If DSA is used as the standard of reference, CT angiography was 100% sensitive and 96.6% specific for depicting these crossing arteries,. CONCLUSION: Renal helical CT seems suitable to replace intraarterial DSA in the preoperative assessment of crossing arteries in kidneys with UPJ obstr uction.