Performance characteristics of the measurement of gastric volume using single photon emission computed tomography

Background A non-invasive single photon emission computed tomography (SPECT) method was developed and validated to measure gastric volumes (GV). The natural variation in gastric volume responses and performance characteristics of SPECT imaging are unclear. Methods The primary aim of this study was to assess the performance characteristics of SPECT imaging by estimating the inter-individual coefficients of variation (COV) in fasting and postprandial GV in 433 participants in prior research studies over the last decade, and the intra-individual COV in all volunteers who had undergone at least two studies. The secondary aim was to assess the relationship of gender, BMI and age on GV. Key Results The COV_INTER for all subjects in the study (n=433) was 32.6% fasting, 16.0% fed, and 19.0%Δ fed - fasting. The COV_INTRA for 47 subjects with repeat estimates of gastric volume was 37.0% fasting, 17.6% fed, and 22.0%Δ fed - fasting. COV_INTRA was stable over time interval from 2 to 60months. There were no significant differences by gender or subgroups. Mean fed and gastric accommodation volumes were associated with age and BMI but the magnitude of variation attributable was <5%. Conclusions & Inferences COV_INTRA and COV_INTER of GV by SPECT are very similar, and there is a small effect of age and BMI. These data are important for planning future studies of GV and further validate SPECT for studies of gastric motility disorders and obesity.