Sonographic evaluation of acute pancreatic transplant rejection: morphology-Doppler analysis versus guided percutaneous biopsy.

OBJECTIVE

Despite the increasing success of pancreatic transplantation for diabetes, rejection remains the most common cause of graft loss. The purpose of this study was to correlate gray-scale sonographic morphology and Doppler resistive index (RI) with acute pancreatic transplant rejection as determined by percutaneous, sonographically guided biopsy of the pancreas.

SUBJECTS AND METHODS

Fifty-one sonograms of 36 patients were correlated with sonographically guided biopsies performed for clinically suspected acute rejection. Sonographic studies consisted of gray-scale morphologic assessment of gland size, texture, marginal definition, peripancreatic fluid, and duct dilatation as well as measurement of the average Doppler RI. Biopsies were performed within 48 hr of sonography. After localization by sonography, we performed percutaneous biopsy with an 18-gauge automated biopsy device.

RESULTS

Biopsy findings were acute rejection (n = 40, 78%), chronic rejection (n = 2, 4%), and no evidence of rejection (n = 9, 18%). Procedure-related hemorrhage occurred in one patient and resolved spontaneously. Gray-scale sonographic abnormalities were present in 37 studies (73%). The most common abnormality was pancreatic enlargement (n = 23) with a sensitivity and specificity of 58% and 100%, respectively, for acute rejection. Loss of marginal definition occurred in nine studies with a sensitivity and specificity of 15% and 73%, respectively, for acute rejection. An RI > or = 0.7 was found in 11 studies (22%) with a sensitivity of 20% and a specificity of 73% for acute rejection.

CONCLUSION

For the diagnosis of acute pancreatic rejection, sonographically guided percutaneous biopsy is superior to gray-scale and spectral Doppler sonography. Sonographically guided percutaneous biopsy is a safe technique with a high success rate. Gray-scale and spectral Doppler sonography lack sensitivity, and a normal RI should not delay biopsy.