The Value of Renography in the Assessment of Obstruction in the Upper Urinary Tract

Simultaneous renography and intravenous urography have been done to assess the value of renography in detecting the presence of upper urinary tract obstruction. 45 women were treated by Wertheim's operation (radical hysterectomy and pelvic lymph node dissection) and were investigated preoperatively and at 14 days, 2–6 months and 1, 2 and 3 years postoperatively. A total of 193 investigations have been done. Good agreement was found in 33 cases, i.e. 73% (21 had normal flow and 12 had varying degrees of obstruction). A false diagnosis of obstruction was made in 8 cases (i.e. 17%) after renography and in 3 cases after i.v. urography. Renography would appear to be a reliable screening method for detecting ureteric obstruction after Wertheim's operation. A normal renogram excludes obstruction. Abnormal renograms should be followed by urography, not only because the high sensitivity of renography can lead to a false diagnosis of obstruction, but also to delect the site of the lesion.