Evaluation of the stimulating effect of a low dose of secretin compared to the standard dose on the exocrine pancreas with MRCP: preliminary results in normal subjects (MRCP quantification of secretin stimulation).

BACKGROUND: Secretin administration during MRCP improves depiction of pancreatic ducts and allows assessment of pancreatic exocrine secretions. However, secretin increases the cost of secretin-enhanced MRCP (S-MRCP). The aim of this study was to quantify using MRCP the stimulating effect of 0.3 CU/kg of secretin and to compare it to the standard dose (1 CU/kg).
METHODS: Ten healthy volunteers underwent four S-MRCP (two for each dose). Pancreatic exocrine secretions were quantified by pancreatic flow output (PFO) and total excreted volume (TEV), derived from a linear regression between MR calculated pancreatic exocrine volumes and time. Two readers analysed individually all sets of images.
RESULTS: A linear increase of pancreatic exocrine volumes was observed after administration of both doses of secretin. Intra-individual and inter-observer differences were not statistically significant (P > 0.05). The mean PFO and TEV, given for reader 1 only, were, respectively, 6.9 +/- 1.5 mL/min and 103 +/- 26 mL for the standard dose and 6.1 +/- 1.2 mL/min and 84 +/- 19 mL for the dose of 0.3 CU/kg. Differences between PFO and TEV obtained with the two doses of secretin were statistically significant for both readers (P < 0.05).
CONCLUSIONS: MRCP is a non-invasive, reproducible tool that allows quantification of pancreatic exocrine secretions during secretin stimulation. PFO and TEV calculated with the low dose were still in the range of previously reported reference values. The administration of 0.3 CU/kg of secretin can reduce significantly the cost of S-MRCP.