Dynamic renal scintigraphy in diagnosis of upper urinary tract obstruction in transplanted kidney

Nuclide renal dynamic imaging was performed on 88 (110 times) transplanted kidney. Two kinds of renal scintigraphic characteristics were identified in recipients with supravesical obstruction of the graft. First, the regular type was characterized by radioactivity defect area in kidney parenchyma during early uptake period followed by ureteropelvic retention. Second, the tubular type was typified by cortical retention and attenuation in collecting system during the whole test period with a special sign of "hollow kidney". Non-obstructive dilated calyces showed similar signs as the regular type. Acute rejection reaction and tubule necrosis demonstrated obstructive time-activity curves. However, the radioactivity retention appeared in cortex. It was suggested that dilated calyces and obstructive renogram might not be reliable evidence for upper urinary tract obstruction. The signs of radioactivity attenuation in kidney parenchyma during early uptake period followed by ureteropelvic retention may be more valuable for the evaluation. As for tubular obstruction, specified "hollow kidney" was the characteristic sign which is helpful for the diagnosis.