The radioisotope renogram: an external test for individual kidney function and upper urinary tract patency.

Abstract

Abstract The radioactive Diodrast Renogram test described in this report is an application of external gamma-ray scintillation counting techniques to estimate the vascularity, tubular cell function, and patency of the upper urinary passages in each kidney area separately. The principles, methods, and equipment are basically the same as those used in the radioactive Rose-Bengal liver uptake-excretion test. Experiments in rabbits have revealed that tracer doses of either Diodrast or Urokon, labeled with I 131 , can be employed as test substances. Tracings of renal uptake and excretion in certain specific renal abnormalities have characteristic patterns which reveal the extent and nature of the existing functional impairment. Animal studies also demonstrate that blood clearance rates of I 131 -labeled Diodrast may be detected externally, thus providing a rapid estimate of bilateral renal function. The combined procedure of determining renal uptake and excretion of Diodrast in each kidney plus simultaneous external measurement of blood clearance provides a new tool for further investigations in renal physiology on a dynamic basis. Following successful preliminary trials in rabbits, the methods were adapted for clinical use into a safe, rapid (15 to 30 minutes) procedure which may be performed in the office, clinic, or hospital with little or no discomfort to the patient. The test provides qualitatively reproducible data on the vascularity, tubular cell secretory function, and patency of the upper urinary passages in each kidney area individually which otherwise must be determined by intravenous pyelography and a battery of kidney function tests or, in many instances, by cystoscopy, bilateral ureteral catheterization, and retrograde pyelography. In addition to yielding information of diagnostic value, the test may be repeated at intervals to follow the patient's clinical progress pre- and postoperatively and as influenced by therapeutic measures.