Hepatobiliary Excretion of 99mTc-MAG3 on Renal Scintigraphy

A 66-year-old man with end-stage kidney disease status post kidney transplantation underwent 99m Tc-MAG3 renal scintigraphy for evaluation of suspected urine leak. Initial dynamic images demonstrated severely impaired renal function of the graft without evidence of leak. On delayed planar images, radiotracer activity adjacent to the transplanted kidney was seen, which was then identified in the ostomy bag on SPECT/CT, representing hepatic excretion of 99m Tc-MAG3 in the setting of severe renal dysfunction. The findings on planar images may mimic a urinary leak. SPECT/CT is valuable in such cases, as it enables accurate anatomic localization and prevents misinterpretation.