Comparison of gastric volumes in response to isocaloric liquid and mixed meals in humans

Aims: To compare gastric volume responses to ingestion of isocaloric liquid or mixed (solid-liquid) meals and document the intra- and interindividual reproducibility of gastric volume measurement using single photon emission computed tomography (SPECT) imaging after i.v. ^99mTc-pertechnetate. Methods: Eight healthy volunteers performed two studies at least 9 months apart. Gastric volumes were measured after a 317 kcal liquid nutrient meal. Within 2 weeks of the second liquid meal study, participants performed a third study, ingesting an isocaloric mixed meal. The order of the mixed and second liquid meals was randomized; Bland-Altman plot displayed data on repeated studies with liquid meal and paired t-test compared gastric volumes after mixed or liquid isocaloric meals. Results: Fasting and postprandial gastric volumes associated with the two liquid meals were not significantly different; inter- and intra-individual coefficients of variation were 13 and 13.8%. In response to the mixed meal, there was a lower absolute post-prandial volume and lower change in gastric volume over fasting volume compared with the response to the liquid meal (P = 0.0001). Conclusion: The SPECT measurement of gastric volumes in response to a nutrient liquid meal is reproducible. The magnitude of the volume response is greater after the liquid meal compared with the isocaloric mixed meal.