Comparison of calculations to estimate gastric emptying half-time of solids in humans

Background Measuring solid gastric emptying (GE) at 4 h is used to identify gastroparesis. GE half-time (GE T1/2) is useful to assess overall and early GE. Aim To examine the validity of hourly imaging as a measurement of GE T1/2 compared with estimates from more detailed imaging. Methods 155 human subjects (99 female, 56 male) underwent scintigraphic GE of a solidliquid meal. We calculated the GE T1/2 using linear interpolation based on a full set of abdominal images obtained over 4 h, and the GE T1/2 based on images at 1, 2, 3, and 4 h after the meal with interpolation of data. Key Results Differences in GE T1/2 values (entire set of scan times compared with just the hourly scans) were small [overall median (5th, 95th percentiles) = -0.2[-7.5, 4.6] min] with slightly greater differences in males compared with females. The agreement between the two methods was very high [concordance correlation coefficient (CCC) (95% CI) = 0.993 (0.990, 0.995)] and a BlandAltman plot indicated the variation in the results between the two methods did not change appreciably across the range of GE studied (within +/- 10 min for all but four subjects). Calculated GE T1/2 values, omitting the 3-h data from the hourly measurements, were associated with similar high accuracy overall and for fast GE, but were less accurate with slow GE. Conclusions & Inferences Results of GE T1/2 solids, using hourly imaging over 4 h, are accurate in the range 75235 min which reflects the typical range of GE of solids in health and disease.