Radionuclide studies in the assessment of the dilated upper urinary tract

The use of radionuclide studies in the functional assessment of upper urinary tract dilation is investigated. The general roles of renography, renal imaging, clearance studies and radionuclide cystography are discussed. Specific, recently introduced investigations including diuresis renography, segmental renography and parenchymal retention functions are assessed in detail. Diuresis renography is is evaluated comprehensively in 256 patients with reference to how clinical management has been influenced. Diuresis renography is compared with other methods of assessment of the presence or absence of obstruction in dilated upper urinary tracts. A good correlation has been found between the results of this test and renal pelvic morphology, pressure-flow studies and parenchymal mean transit time measurements. The relative merits of these investigations are considered. In the evaluation of segmental renography, particular emphasis is placed on the study of duplex kidneys for the determination of the functional contribution of segments and the demonstration of the uretero-ureteric reflux. It is concluded that radionuclide studies, with the merits of safety, convenience and the possibility of serial studies, can be effectively included into a scheme of investigation of upper urinary tract dilatation. (author)