Does aging influence pancreatic response in the ultrasound secretin test by impairing hydrokinetic exocrine function or sphincter of Oddi motor function?

Background. Secretin administration induces a brief distinct dilatation of the main pancreatic duct in healthy persons, visible at ultrasonography: Several investigations have indicated that sonographic duct measurements before and after secretin injections are a useful tool in the diagnostic screening for pancreatic disease. Aims. Aim of this study was to evaluate the influence of aging on the test results. Methods. We examined prospectively two groups of patients with distinctly different mean age, measuring the pancreatic duct diameter sonographically before, 2, 4, 6 and 10 minutes after intravenous injection of 1 CU secretin per kilogram body weight. The examination was performed in ail patients on account of abdominal complaints, and pancreatic disease could be excluded by further diagnostic procedures. Group I consisted of PP patients, median age 30.5 years, Group 2: 21 patients, median age 68 years. Results. The younger patients (Group 1) had a mean basal pancreatic duct diameter of 1.6 mm. After secretin injection they showed dilatation reading 3.1 mm, corresponding to 94% of the basal duct diameter. The older patients (Group 2), with a basal diameter of 1.9 mm, showed a duct enlargement of about 84% to 3.5 mm. There was no statistically significant difference between the two groups concerning extent and temporal development of secretin-induced pancreatic duct dilatation. Conclusions. The underlying mechanisms of response to secretin stimulation - hydrokinetic pancreatic function, sphincter of Oddi motor function, and extensibility of Wirsung's duct - do not seem to be impaired by aging. Thus, the ultrasound secretin test should be suitable for application in older patients.