Acute pancreatic transplant rejection: Evaluation with dynamic contrast-enhanced MR imaging compared with histopathologic analysis

PURPOSE: To evaluate the use of dynamic contrast material-enhanced gradient -recalled-echo MR imaging for the diagnosis of acute pancreatic transplant rejection, as confirmed at histopathologic analysis. MATERIALS AND METHODS: Thirty MR imaging studies were performed in 25 patie nts within 3 days of percutaneous biopsy or pancreatectomy. The mean percen tage of parenchymal enhancement (MPPE) at dynamic contrast-enhanced MR imag ing was calculated. RESULTS: Biopsy findings were no evidence of rejection (n = 7 [23%]), mild rejection (n = 10 [33%]), moderate (n = 6 [20%]) and severe (n = 2 [7%]) ac ute rejection, and infarction (n = 5 [17%]). The corresponding MPPEs at 1 m inute were 106%, 66%, 62%, 57%, and 3%, respectively. Overlap of cases in t he normal and rejection groups occurred; however, using an MPPE cutoff of 1 00% resulted in a sensitivity of 96%. An MPPE over 120% was seen in the nor mal group only. The MPPE was significantly greater in the normal group than in the rejection or infarction group (P < .05). CONCLUSION: Dynamic contrast-enhanced MR imaging is highly sensitive for th e detection of acute pancreatic transplant rejection. Because of overlap of cases in the normal and rejection groups, percutaneous biopsy may be neede d in some cases. Pancreatic allografts with infarction can be clearly ident ified.