Helical computed tomography for identification of crossing vessels in ureteropelvic junction obstruction-comparison with operative findings.

Objectives: To evaluate the use of contrast-enhanced helical computed tomography (HCT) scanning with three-dimensional reconstructions as a possible identifier of crossing vessels in ureteropelvic junction (UPJ) obstruction. Endoscopic treatment of UPJ obstruction has a success rate that approaches 90%. These results drop to 40% in the presence of crossing vessels. Unrecognized crossing vessels can also result in significant hemorrhage during endopyelotomy. The presence of crossing vessels is, for many, an indication for open or laparoscopic UPJ repair. Therefore, accurate preoperative imaging is crucial for appropriate treatment planning.

Methods: Our study population consisted of 18 patients evaluated and treated for UPJ obstruction at the University of Michigan Health System. These patients underwent routine contrast-enhanced preoperative HCT scanning before UPJ repair. A prior history of failed endoscopic treatment, patient preference, and HCT findings of crossing vessels were indications for open or laparoscopic repair. The imaging findings were compared with open findings during laparoscopic or open pyeloplasty.

Results: An HCT finding of the presence of crossing vessels was a significant positive predictor, with a value of 100%. The sensitivity in this population was 91% and the specificity was 100%. No difference was noted between the detection of arterial or venous crossing vessels. The positive predictive value was 100%, and the negative predictive value was 88%.

Conclusions: HCT is an accurate predictor of the presence of crossing vessels in UPJ obstruction. Because crossing vessels may have a profound impact on treatment outcome, HCT can serve as an effective, noninvasive, preoperative screening tool.