Evaluation of crossing vessels in patients with ureteropelvic junction obstruction by means of helical CT

Helical computed tomography (CT) was used to demonstrate the distribution o f crossing vessels in patients with ureteropelvic junction (UPJ) obstructio n for planning surgical management. Twenty patients with symptomatic UPJ ob struction were evaluated with dual-phase contrast material-enhanced helical CT. In addition to axial images, coronal, sagittal, and curved paracoronal images along the crossing vessels or the UPJ were obtained by means of mul tiplanar reconstruction. Crossing vessels were evaluated according to type, position, and association with UPJ obstruction. Fifteen vessels in 12 of t he 20 patients were found to cross the UPJ at helical CT. Nine vessels were arteries and six were veins; seven vessels crossed anteriorly and eight cr ossed posteriorly. In 11 patients, crossing vessels were thought to be asso ciated with UPJ obstruction at helical CT; retroperitoneoscopic repair was performed, and the diagnosis was found to have been accurate in all except one. In the eight patients in whom no significant vessels were seen and the one patient in whom the crossing vessel was not associated with UPJ obstru ction at helical CT, endopyelotomy was performed and UPJ obstruction was re lieved, with no complications. Helical CT is useful for evaluation of vesse ls crossing the UPJ and for planning surgical management.