Gastric Accommodation Influences Proximal Gastric and Total Gastric Emptying in Concurrent Measurements Conducted in Healthy Volunteers.

Gastric emptying and gastric accommodation play roles in generation of upper gastrointestinal symptoms. Whereas, both functions have been measured simultaneously using MRI or 99m Tc- SPECT methodology, correlation of these two functions has not been evaluated simultaneously using solid and liquid meals. To study relationships of whole or proximal stomach volumes to emptying, we concurrently measured postprandial gastric accommodation and emptying (over 4 hours) of a 111 In-labeled mixed solid and liquid meal. A semi-automated method allowing selection of a segmentation threshold based on greyscale image was used to measure volume of the proximal half of stomach, defined as the top half of axial slices along the vertical length of stomach. A correction factor derived from phantom studies was applied for up-scatter from 99m Tc to 111 In window. Relationships of time to emptying 10, 25 50 and 75% of the meal to fasting and postprandial gastric volumes were evaluated using Spearman correlation. Whole stomach fed and accommodation volumes were significantly correlated with all gastric emptying times 10%, 25%, 50%. Proximal stomach fed volumes were similarly associated with 50% and 75% proximal gastric emptying. Fed proximal gastric volume was associated with 50% and 75% whole gastric emptying. Fed proximal accommodation volume was associated with 50% gastric emptying. Fasting gastric volumes were not significant determinants of emptying rates. In conclusion, postprandial gastric accommodation is significantly associated with the rate of gastric emptying, with higher gastric volumes associated with prolongation of emptying. Novel methods to measure proximal gastric accommodation and correct for radioisotope up-scatter are described.