MR hydrometry to assess exocrine function of the pancreas: Initial resultsof noninvasive quantification of secretion

PURPOSE: To evaluate magnetic resonance (MR) hydrometry, a method of quanti fying fluid amounts by using MR imaging, for assessing the exocrine functio n of the pancreas after stimulation with secretin. MATERIALS AND METHODS: Images were obtained with a single-shot turbo spin-e cho sequence by using a 1.0-T magnet with a quadrature body coil. Image pos tprocessing and evaluation were performed at an external workstation by usi ng a specially designed histogram algorithm that translates the MR signal i ntensity of duodenal filling into an actual amount of duodenal fluid. This algorithm was tested in vitro and in vivo. Finally, MR hydrometry results i n five patients were correlated with those of the secretin-cerulein test. RESULTS: The phantom measurements showed a high correlation (r = 0.99) betw een the actual amount of fluid in the imaging volume and the calculated res ults. In vivo, the ability of MR hydrometry to enable exact quantification of fluid amounts was demonstrated. In correlating the signal intensity of d uodenal filling with the exact amount of additional fluid in the duodenum i n volunteers, a coefficient of 0.043 gray tones per pixel per milliliter wa s calculated. The correlation (r) between secretin-stimulated duodenal flui d output estimated by using tube aspiration and that estimated by using MR hydrometry was 0.946 (P < .05). CONCLUSION: MR hydrometry is a promising noninvasive method of assessing fl uid output as a measure of exocrine pancreatic function.