Evaluation of pancreatic allografts with sonography

The purposes of this study were to develop a protocol for evaluating pancreas allografts, to describe a method for successfully studying pancreatic transplants, and to determine whether the resistive index (RI) of the splenic artery is a useful differentiator between complications.

We retrospectively analyzed clinical, surgical, procedural, and radiologic reports in 51 consecutive patients undergoing 182 sonographic examinations during a 4.5-year period. Complications included splenic vein thrombosis, rejection, and pancreatitis. We obtained RIs in normal and complication groups and performed mixed model regression methods and receiver operating characteristic analysis.

The mean RI ± SD for normal transplants was 0.65 ± 0.09; for splenic vein thrombosis, 0.76 ± 0.09; after resolution of splenic vein thrombosis, 0.73 ± 0.09; during rejection, 0.94 ± 0.09; after successful treatment of rejection, 0.74 ± 0.09; for pancreatitis, 0.83 ± 0.09; and for fluid collections, 0.66 ± 0.09. There was a statistically significant difference (P < .05) between normal transplants and splenic vein thrombosis (P = .0003), rejection (P < .0001), and pancreatitis (P = .04). A significant difference was also seen between rejection and successful treatment thereof (P < .0001).

We developed a protocol that allowed us to successfully evaluate 96% of the pancreatic allografts studied. Furthermore, our data show that the RI can be used as a therapeutic guide. When the RI is less than 0.65, the risk of vascular abnormalities is very low; however, fluid collections may be present. When greater than 0.75, splenic vein thrombosis, pancreatitis, or rejection should be suspected. When greater than 0.9, rejection must be seriously considered.