Why are renal scans obtained 1 day after renal transplantation?
A renal scan within 1 day of surgical transplantation can be very useful for detecting overall flow in the transplanted kidney to ensure that the transplant renal artery is patent. The renal scan can also be used to help evaluate the extent of acute tubular necrosis (ATN), which occurs in virtually every transplant, although it is much more common and severe in cadaveric transplants compared with living-related transplants. ATN is typically diagnosed on a renal scan when there is normal renal flow but diminished cortical transit of the radiotracer (the normal cortical transit time is usually less than 5 minutes). The degree of ATN can be evaluated based on the delay in cortical transit, with severe ATN showing no significant cortical function. A renal scan can also help with the evaluation of hyperacute rejection, which would appear as near-absent perfusion of the renal transplant. Renal scans can also provide information regarding possible obstruction or leaks of urine (most often occurring within several days after transplantation).