The radiological size of renal transplants—a retrospective study

The size of renal transplants is discussed and related to the size of the same kidney in the donor. In our series of 31 related donor and 23 cadaver transplants we found a renal length of more than 16·5 cm using a 40 in. focus film distance, likely to indicate rejection, as long as there were no other factors enlarging or magnifying the kidney. Relating the radiological size of the donor kidney to the radiological size of the same kidney in the recipient was more accurate and rejecting pelvic transplanted kidneys were more than 20 per cent longer or 40 per cent wider than in the donor. The actual increase in renal length of over 15 per cent indicates acute or intermediate rejection, but slow chronic rejection may not produce sufficient enlargement to be detected by renal size alone. A control film at the time of the transplant, the use of metallic clips on the kidney and frequent follow-up films with unvarying radiological factors are recommended.