Diagnosis of hydronephrosis: comparison of radionuclide scanning and sonography.

Diagnostic sonographic and radioisotope scanning techniques have been shown to be useful in the diagnosis of obstructive uropathy. The accuracy of both methods was compared and sonography was found to provide the more accurate data (sensitivity, 90%; specificity, 98%; accuracy, 97%). Sonography provides excellent anatomic information and enables one to grade the degree of dilatation. Renal radionuclide studies were less sensitive in detecting obstruction, particularly in the presence of chronic renal disease, but offered additional information regarding relative renal blood flow, total effective renal plasma flow, and interval change in renal parenchymal function.