Ureteropelvic junction obstruction: use of helical CT for preoperative assessment--comparison with intraarterial angiography

PURPOSE: To evaluate helical computed tomography (CT) in the preoperative assessment of crossing arteries in kidneys with ureteropelvic junction (UPJ) obstruction and to compare the results with those obtained by means of angiography. MATERIALS AND METHODS: Forty-one consecutive patients with symptomatic UPJ obstruction in 42 obstructed kidneys underwent renal helical CT and renal intraarterial digital subtraction angiography (DSA; flush aortography and bilateral selective renal injections). The helical CT and DSA images were interpreted 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 126 renal arteries prospectively. Retrospectively, 124 (98%) renal arteries were visible on CT images. Twelve (29%) of the 42 kidneys with UPJ obstruction 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 obstruction.