Evaluation of pancreatic allografts with sonography.

OBJECTIVES: 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.

METHODS: 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.

RESULTS: 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).

CONCLUSIONS: 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.