A novel exocrine pancreas stress test with 11C-acetate PET and secretin stimulation

Objectives To develop a noninvasive test of pancreatic exocrine function.

Methods In this pilot study, 5 healthy volunteers without known pancreatic pathology underwent 45 minute dynamic 11C-acetate PET studies before and after administration of intravenous secretin. Kinetic analysis was done using a one compartment model with a blood volume term and an image-derived input function. Standard uptake value in a 1 cm3 sphere corrected for lean body mass (SULpeak) was measured from the pancreas, and in a 3 cm3 sphere from the liver. Pancreas-to-liver SULpeak ratio (P/L) from the 0-45 minute summed image was computed for baseline and after secretin stimulation.

Results The baseline data for all 5 patients were consistent (table 1). Following secretin stimulation, both the k1 and k2 increased in all 5 cases, and the P/L ratio was decreased in all cases. The difference between baseline and after secretin k2 values were significant (paired t-test p=0.023). The average P/L reduction from all patients was 32.4%. Increased 11C-acetate uptake was noted within the duodenum after secretin stimulation in the summed PET images.

Conclusions 11C-acetate PET studies with and without secretin stimulation are a noninvasive method for assessing basal and stimulated pancreas exocrine function.