Fast and optimized T1 mapping technique for the noninvasive quantification of gastric secretion

PURPOSE: To evaluate the noninvasive quantification of gastric secretion volume after administration of a labeled viscous glucose solution by fast T(1) mapping. MATERIALS AND METHODS: T(1) values of a series of labeled and diluted glucose solutions were measured in vitro to characterize the interrelationship between T(1) and contrast agent concentration (C(Gd)) as well as the dependency of relaxivity and reference T(1) (T(10)) on the macromolecular concentration. Abdominal T(1) mapping in five healthy volunteers of different body mass index was performed after filling an intragastric balloon with a labeled and diluted glucose solution. In additional ex vivo experiments, T(1) values of gastric (GJ) and duodenal juice (DJ) and 0.1 N HCl solution were determined. RESULTS: A linear relationship between relaxivity and macromolecular concentration and between T(10) and macromolecular concentration was found. The in vitro T(1)-C(Gd) calibration curve was successfully validated in all volunteers. T(1) values of GJ, DJ, and HCl (2939 msec vs. 2858 msec vs. 2760 msec) were close to the T(1) of water ( approximately 3000 msec). CONCLUSION: The presented method allows one to noninvasively quantify the spatial distribution of gastric secretory products in the human stomach and provides a valuable tool for evaluating the efficacy of drugs to stimulate/inhibit gastric secretion.