Endoluminal sonography in evaluation of the obstructed ureteropelvic junction.

Endoluminal sonography is a technique well suited to imaging structures beyond the lumen of the hollow viscus. The development of small-diameter (6.2F), catheter-enclosed ultrasound probes has made this technique available for use within the urinary tract. It is capable of defining adjacent vessels, calculi, and masses. Ureteropelvic junction (UPJ) obstruction has been increasingly treated by incisional techniques, either nephroscopic, ureteroscopic, or radiographically controlled, with each incision at risk for causing damage to any adjacent vessel. Endoluminal sonography of the obstructed UPJ was attempted in 46 patients and completed in 45 patients, 41 with primary and 4 with secondary obstruction. Adjacent vessels could be seen in 24 patients. Twelve were located anterior or medial to the UPJ or both. Nine patients had vessels at the UPJ located laterally or anterolaterally, posterolaterally, or medially and laterally. Sonographic localization guided the choice of incision site in all patients and changed therapy in five patients. This technique also allows recognition of high insertion of the ureter into the renal pelvis. Endoluminal sonography of the obstructed UPJ is a valuable technique to determine the location and nature of associated vessels and, therefore, to guide decisions in treatment.