Is excretory urography still a valuable test in diagnosing ureteropelvic junction obstruction in adults? A prospective comparison of excretory urography and diuretic renography

Objectives. The aim of the study is to compare excretory urography (IVU) and diuretic renography (DR) in terms of their ability to provide objective data for discerning whether or not clinically significant ureteropelvic junction obstruction (UPJO) is present. Material and Methods. IVU and DR were performed on 42 patients who had been diagnosed with UPJO on the basis of ultrasound examination (US). Clinically significant obstruction on IVU was defined as a ureteropelvic junction that was narrowed or not visible and dilatation of the pelvicalyceal system on the affected side. On DR a curve showing a plateau-like, gradually increasing or gradually decreasing third phase with no or little furosemide effect was assumed abnormal. The upper limit of the half-time to tracer clearance (T1/2) for nonobstructed systems was 12 minutes. Results. IVU confirmed the diagnosis of UPJO based on US in 40 out of 42 patients (95.2%), whereas DR confirmed it in 35 out of 42 (83.3%). IVU and DR yielded unanimous results in 37 out of 42 cases (88%): Both tests indicated the presence of obstruction in 35 cases and excluded obstruction in two cases. False positive IVU results were observed in four patients (all of them asymptomatic). In one patient a false negative DR was noted. Conclusions. Excretory urography still remains a valuable test in diagnosing UPJO in symptomatic patients. In asymptomatic patients a diagnosis of UPJO on IVU should be confirmed by DR. (authors)