Endoureteral sonography to define the anatomy of the obstructed ureteropelvic junction.

Endoluminal ultrasound of the obstructed ureteropelvic junction (UPJ) provides accurate anatomic information not available through other studies. Endoluminal ultrasonography in the evaluation of the obstructed UPJ can be extremely valuable and its use can be expected to expand with increasing experience with the techniques. The anatomy demonstrated through the fine resolution of this technique may ultimately provide the key to the selection of optimal therapy for the obstructed UPJ.