Secretin-stimulated MRCP in volunteers: assessment of safety, duct visualization, and pancreatic exocrine function

The objective of our study was to investigate secretin-stimulated MRCP in terms of the safety of secretin, improvement of duct visualization, and assessment of pancreatic exocrine function.

Eight hundred sixteen volunteers (370 women and 446 men; mean age, 49.7 ± 13.1 [SD] years) underwent 3D MRCP before and after secretin stimulation (1 U/kg of body weight) at 1.5 T. For the first 2 hours after secretin injection, subjects were evaluated for adverse reactions. Improvement of duct visualization after secretin stimulation was subjectively evaluated by two readers and was quantified by duct diameter measurements. Pancreatic exocrine function was evaluated subjectively by two readers according to the duodenal filling and was quantified using calibrated volumetric measurements of total excreted volume and pancreatic flow output.

Two subjects (0.2%) showed flushing (minor adverse reaction). Duct visualization after secretin injection was improved for reader 1 in 468 (57.4%) and for reader 2 in 478 (58.6%) subjects, was unchanged for reader 1 in 324 (39.7%) and for reader 2 in 315 (38.6%) subjects, and was worse for reader 1 in 24 (2.9%) and reader 2 in 23 (2.8%) subjects (interrater agreement, κ = 0.925). Main pancreatic duct diameters increased significantly after secretin stimulation: pancreatic head, 10.5% (mean); body, 12.5%; and tail, 7.7%. Pancreatic exocrine function evaluated according to assessment of duodenal filling was as follows: grade 0 (restricted function) in 0.7% of subjects by both readers, grade 1 (reduced function) in 4.8% of subjects by reader 1 and 4.5% of subjects by reader 2, grade 2 (low-grade reduced function) in 31.1% of subjects by reader 1 and 26.5% of subjects by reader 2, and grade 3 (physiologic function) in 63.4% of subjects by reader 1 and 68.3% of subjects by reader 2 (interrater agreement, κ = 0.838). The mean total excreted volume was 111.8 ± 49.8 (SD) mL, and the mean pancreatic flow output was 9.6 ± 4.2 mL/min.

Secretin-stimulated MRCP moderately improves main pancreatic duct visualization and allows noninvasive quantification of pancreatic exocrine function with a negligible risk of side effects.