Further observations in the ultrasound evaluation of renal allograft rejection

In order to determine whether sonographic parenchymal changes and volume changes are reliable predictors of acute transplant rejection, 36 recipients of renal allografts were studied. The significance of graft volume changes was evaluated, since most previous studies have not utilized routine immediate postoperative baseline scans for comparison to follow-up scans. All patients had baseline scans within 24 hours of the transplant. All 24 acute rejection patients had biopsy proof of rejection within three days of the follow-up scans. Seven clinically normal and five clinically designated acute tubular necrosis (ATN) patients were studied for comparison. A retrospective blind review utilizing three sonologists and previously described criteria combined with calculated volume changes demonstrated an overall sensitivity of 85 per cent and specificity of 94 per cent for the detection of acute rejection. The kidneys with acute rejection had an average volume increase of 73 per cent vs. 27 per cent for ATN patients and 24 per cent for normal patients, a statistically significant difference.