Prediction of Insulin Secretion Ability with Microcirculation Evaluated by Contrast-enhanced Ultrasonography in Pancreas Transplantation

Objectives: Contrast-enhanced ultrasonography can evaluate microcirculation. Thus, we used contrast-enhanced ultrasonography in evaluating pancreas graft perfusion and examined the relationship between graft circulation and function. Methods: Contrast-enhanced ultrasonography was performed in 17 cases within 24 hours and at 1, 3, 5, 7, 14, 21, and 28 days after transplantation (Tx). The time between the time to peak intensity in the parenchyma and that in the vein was defined as delta-Tp(P-V). Graft function was evaluated with oral glucose tolerance test (OGTT) at 1 and 3 months after Tx, and glucagon stimulation test at 1 month after Tx. Results: Differences in delta-Tp(P-V) between individual cases were more significant early after Tx, and delta-Tp(P-V) within 24 hours (delta-Tp[P-V]_24h) was used in the subsequent analysis. Delta-Tp(P-V)24 hours showed a negative correlation with C-peptide increment in the glucagon stimulation test and the area under the curve of insulin level in oral glucose tolerance test. The cases were divided into the following 2 groups: the standard group (delta-Tp[P-V]_24h ≤6.10 seconds) and the delayed group (>6.10 seconds). The area under the curve of insulin level increased significantly from 1 to 3 months after Tx in the standard group only. Conclusions: These results suggest that delta-Tp(P-V)24 hours affects insulin secretion after Tx. Contrast-enhanced ultrasonography is useful in predicting endocrine function of the graft.