Secretin provocation ultrasonography in the diagnosis of papillary obstruction in pancreas divisum.

The diagnostic value of secretin provoked abdominal ultrasound was studied on 34 patients with pancreas divisum and on 20 control subjects. The patients received a 1.0 unit/kg body weight dose of secretin. The degree of ductal expansion and the time required to return to the initial state were registered and these values were compared to the clinical diagnosis. The control subject's ductal diameters prior to secretin administration were 1 mm in all cases (maximum expansion 2 mm, return to the initial value within 10 minutes). The pancreas divisum patients could be placed in two groups based on their initial ductal diameter. Fourteen patients had initial ductal diameters of 2 mm or greater (A group mean +/- SD: 2.4 +/- 0.3) while 21 patients had an initial value of less than 2 mm (B group; 1.7 +/- 0.3). Following secretin administration the ductal diameter of the A group's patients increased on average +/- SD to 1.3 +/- 0.5 times the initial value and in the B group 3.2 +/- 1.1 times the initial value (p less than 0.01). In the A group the ductal diameter returned to it's initial value within 10 minutes while it took 35 minutes for the same to occur in the B group. A relationship can be observed between the clinical diagnosis, the initial ductal diameter, the degree of expansion following secretin administration and the time required to return to the initial state.