Acute Pancreatic Transplant Rejection: Evaluation with Dynamic Contrast-enhanced MR Imaging Compared with Histopathologic Analysis

Abstract

Dynamic contrast-enhanced MR imaging is highly sensitive for the detection of acute pancreatic transplant rejection. Because of overlap of cases in the normal and rejection groups, percutaneous biopsy may be needed in some cases. Pancreatic allografts with infarction can be clearly identified.

Value of magnetic resonance imaging in evaluating the pancreatic allograft transplant complications

“…In our study, the percentage of enhancement in the normal allografts was greater, 120%, compared with 9% in the necrotic allografts. These results are similar to those of Fernandez et al [15] and Krebs et al [11].…”

“…Small cohort studies have shown that MRI has become valuable in detecting pancreatic allograft complications [7][8][9][10][11][12][13]. Currently, in our institution, MRI is used as a second-line imaging modality for post- allograft patients who could not be adequately evaluated by CT or US.…”

“…Prior studies [14][15][16][17][18] demonstrated that the unenhanced MRI had variable results and limitations in evaluating dysfunctional pancreatic allograft. The allograft edema and heterogeneity that occurs in rejection can be identified by conventional sequence including T1-and T2-weighted imaging [10,11,[13][14][15][16][17][18][19], parenchymal edema alone is not a specific finding of allograft rejection, and it is difficult to differentiate rejection from acute pancreatitis or ischemia using the finding of edema. Fernandez et al [15] demonstrated that the percentage of post-contrast enhancement in normal allograft was greater than that in dysfunctional allograft.…”

“…In their study, the mean percentage of enhancement at 1 min was 98% in 6 normal allografts as compared with 42% in 6 dysfunctional allografts. Krebs et al [11] compared the results of MRI with histopathologic analysis in 25 patients and found that the percentage of enhancement (at 1 min) in the normal group was greater, 106%, compared with 50% enhancement in the dysfunctional group. In our study, the percentage of enhancement in the normal allografts was greater, 120%, compared with 9% in the necrotic allografts.…”

“…It can occur secondary to a vascular graft anastomotic abnormality or microvascular disease [11]. Another reason for thrombosis usually due to severe rejection with alloimmune arteritis and occlusion of small vessels.…”