Evaluation of obstructive uropathy in children: radionuclide renography vs. the Whitaker test.

Differentiation of obstructed from dilated, nonobstructed urinary systems in the postoperative child is a difficult diagnostic problem. A comparison study was performed in 21 children with hydroureteronephrosis using the Whitaker test in combination with conventional radionuclide renography and/or diuretic (furosemide)-augmented radionuclide renography. The results of each method were correlated with the clinical assessment and surgical findings. Conventional renography was found to be an unreliable study, with a clinical correctness of only 57%. Results were more favorable for both the Whitaker test and diuretic-augmented radionuclide renography, with clinical correctness in 86% and 85%, respectively. Furthermore, when both tests agreed, no false negatives or false positives were obtained. Due to the noninvasive nature of the study, diuretic-augmented renography should be the initial procedure once hydroureteronephrosis is established. A recommended algorithm of the child with postoperative hydroureteronephrosis is suggested.