Focal acute tubular necrosis in a renal allograft

Nuclear imaging is used to evaluate renal allografts demonstrating delayed function after transplantation. Interpretation of the nuclear scan in the context of clinical data, provides helpful information in the management of the transplant recipient. The better quality of images obtained with technetium-99m mercaptoacetyltriglycine (Tc-99m MAG3) has made it the radiotracer of choice compared to technetium-99m diethylenetriamine pentaacetic acid (Tc-99m DTPA) for imaging of the renal allograft. Tc-99m MAG3 is cleared from the kidney by tubular secretion, whereas Tc-99m DTPA is cleared by glomerular filtration. In this report, we discuss a unique abnormality found on nuclear imaging of a renal allograft. Utilizing our understanding of the characteristic handling of various radiotracers by the kidney, we were able to demonstrate that the renal scan was consistent with an area of focal acute tubular necrosis in the newly transplanted kidney.