Radionuclide determination of individual kidney function in the treatment of chronic renal obstruction.

Differential radionuclide renal scans can be useful in the management of patients with chronic partial obstruction of 1 kidney. The 99mtechnetium diethylenetriaminepentaacetic acid perfusion scan can be used to assess glomerular blood flow. The 131iodine orthoiodohippurate renal scan provides qualitative functional information from scintigrams and quantitative evaluation of effective renal plasma flow to each kidney, as well as a total excretory index. Sequential 99mtechnetium diethylenetriaminepentaacetic acid and 131iodine orthoiodohippurate renal scans were used to assess individual renal function before and after surgical correction of unilateral chronic renal obstruction in 31 patients. The preservation of cortical perfusion on 99mtechnetium diethylenetriaminepentaacetic acid scans indicated that potential existed for partial recovery of renal function. Effective renal plasma flow and excretory index determined in conjunction with the 131iodine orthoiodohippurate scans provided a quantitative assessment of preoperative renal function, an evaluation of the effect of surgery and a sensitive method for long-term evaluation of differential renal function. Correction of ureteropelvic junction obstruction usually resulted in improvement in unilateral renal function. Neither nephrolithotomy nor extended pyelolithotomy diminished renal function in the kidney subjected to an operation and often improved it. Patients with long-standing distal ureteral obstruction had the least improvement in renal function postoperatively.