False diagnosis of renal transplant urinary leakage on scintigraphy with mercaptoacetyltriglycine

^99mTechnetium-mercaptoacetyltriglycine (^99mTc-MAG-3) has rapidly become the best isotope for transplant renal scintigraphy because of the excellent anatomical resolution. Because ^99mTc-MAG-3 is also sequestered by the liver and excreted into the biliary system, images of the gallbladder and intestinal tract will appear in normal ^99mTc-MAG-3 scans, especially on delayed scintigraphs. We describe the clinical interpretation of normal bowel images as urinary extravasation in a renal transplant recipient with a sudden decrease in renal function.