Pancreatic transplants: evaluation with MR imaging.

Eighty-eight magnetic resonance (MR) imaging studies of 31 pancreas transplants in 30 patients were performed. The postoperative graft usually appears enlarged and inhomogeneous, with patchy areas of increased signal intensity on T2-weighted images that may last 3-4 weeks. During acute rejection, T1-weighted images of graft abnormalities show a decrease in signal intensity, similar to that of muscle, and T2-weighted images show an increase in signal intensity, equal to or higher than that of the bladder. The pattern of abnormal signal is most frequently multifocal but can be diffuse, and the graft may be enlarged. During recovery from rejection, the graft parenchyma shows a decrease in signal intensity (less than that of the bladder) on T2-weighted images when compared with that of acute rejection. During chronic rejection the graft is small and shows low signal intensity, slightly higher than or similar to that of muscle, on both T1- and T2-weighted images. MR imaging appears to be useful for detection of early pancreas allograft rejection and complications in conjunction with clinical findings, laboratory data, and other radiologic procedures.