Crossing vessels at the ureteropelvic junction: Detection with contrast-enhanced color Doppler imaging

PURPOSE: To investigate the feasibility of imaging crossing vessels at the ureteropelvic junction (UPI) preoperatively by means of contrast agent-enhanced color Doppler imaging (CDI). MATERIALS AND METHODS: Twenty-nine patients (13 female patients, 16 male patients; age range, 17-76 years; mean age, 45 years) with symptomatic UPJ obstruction were examined with CDI before and after intravenous infusion of the contrast agent. The type tie, arterial or venous) and position of the vessel relative to the UPJ tie, anterior or posterior) were assessed. The CDI findings were correlated with the surgical findings at laparoscopic pyeloplasty. RESULTS: Among the 29 patients, crossing vessels were detected with nonenhanced CDI in 15 patients, with enhanced CDI in 22 patients, and with laparoscopy in 23 patients. Enhanced CDI depicted crossing vessels in 22 (96%) of the 23 laparoscopically confirmed cases compared with nonenhanced CDI, which depicted 15 (65%) of the 23 cases. The rate of detecting crossing vessels increased significantly with use of the contrast agent (P < .016, McNemar test). CONCLUSION: Compared with nonenhanced CDI, contrast-enhanced CDI significantly improves the detection of crossing vessels at the UPJ and is useful in the presurgical evaluation of UPJ obstruction.