Diagnosis of urinoma by MAG3 scintigraphy in a renal transplant patient

Technetium-99m MAG3 is a new renal tracer that has been proposed to replace combination of I-131 orthoiodohippurate and Tc-99m DTPA in the evaluation of patients with renal transplants. One concern raised in the literature is that diagnosing urine leaks may be hampered by the fact that MAG3 may be excreted in the gut, simulating a urine leak. Attention should be directed to the fact that a minimal amount of MAG3 is excreted with bile and appears first in the upper small bowel-a pattern distinctly different from a transplant urine leak or urinoma. The authors present a typical example of urinoma appearance on MAG3 scintigraphy. The high urinary concentration of the tracer facilitated prompt and facile identification of the urinoma.