Renal transplant rejection: sonographic evaluation in children

The ability to detect renal rejection sonographically was studied in 42 pediatric renal transplant patients over a 33-month period. Sonography was not helpful in detecting rejection when the donor was less than five years of age. When the donor was over five years of age, a combination of sonographic findings allowed detection of rejection with a greater specificity than has been reported previously. The combination of three or more of the sonographic findings (increased renal volume 30% over the baseline value; enlarged, broadened, rectangular medullary pyramids [rays]; a reduction or absence of the central sinus echoes, and altered echogenicity in the renal parenchyma) indicated rejection with 97% specificity and 58% sensitivity. Radionuclide imaging with Tc-99m DTPA gave approximately the same sensitivity (60%) but was less specific (88%). By excluding rejection with the absence of the sonographic findings, it was possible to suggest acute tubular necrosis in some patients. It was also possible to detect the complications of renal transplantation, but sonography did not detect small ruptures of the kidney as a part of the rejection phenomenon.