Diagnosis of obstruction in experimental hydroureteronephrosis.

A canine model with partial ureteral obstruction and progressive hydroureteronephrosis was utilized to validate and compare the accuracy of several diagnostic methods currently used to assess urinary tract obstruction. Tests of renal function and measurements of intrapelvic pressure were not helpful in following the progress of hydroureteronephrosis but did provide insight into the mechanisms by which incomplete ureteral occlusion impairs renal function. Serial intravenous pyelography, diuretic radionuclide urography, and perfusion pressure flow studies were frequently accurate in assessing obstruction, but each was subject to potential and, at times, regular misinterpretation. In applying the results of these laboratory studies to the problems of evaluating human hydroureteronephrosis, the clinician must recognize the pitfalls and limitations of these methods in order to ensure an accurate diagnosis of partial urinary obstruction.