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 T(1/2) ) is useful to assess overall and early GE. AIM: To examine the validity of hourly imaging as a measurement of GE T(1/2) compared with estimates from more detailed imaging.
METHODS: 155 human subjects (99 female, 56 male) underwent scintigraphic GE of a solid-liquid meal. We calculated the GE T(1/2) using linear interpolation based on a full set of abdominal images obtained over 4 h, and the GE T(1/2) based on images at 1, 2, 3, and 4 after the meal with interpolation of data. KEY
RESULTS: Differences in GE T(1/2) 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) = .993 (0.990, 0.995)] and a Bland-Altman plot indicated the variation in the results between the two methods did not change appreciably across the range of GE studied (within ±10 in for all but four subjects). Calculated GE T(1/2) 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: sults of GE T(1/2) solids, using hourly imaging over 4 , are accurate in the range 75-235 n which reflects the typical range of GE of solids in health and disease.