Reproducibility and normal ranges for gastric emptying in normal volunteers using a test meal designed for post-operative patients†

Scintigraphy is the current gold standard for the quantification of gastric emptying; however, results vary with meal composition. We modified a dual phase meal for administration to patients in the early post-operative period and aimed to test the reproducibility of the method, to obtain normal ranges and to compare these with previous data. Twenty healthy volunteers (10 male, 10 female), studied prospectively, were compared with 10 historical male volunteers. Each volunteer was studied twice (Test 1 at day 0 and Test 2 at day 7-10). After an overnight fast, subjects had Meal A consisting of a 60 g pancake labelled with 3 MBq of non-absorbable 99mTc-ion exchange resin and 100 ml of water labelled with 0.5 MBq of non-absorbable 111In-diethylenetriamine pentaacetic acid (111In-DTPA). Anterior and posterior gamma camera images of the stomach were obtained every 20 min for 3 h. The time for 50% emptying (T50) was derived from time-activity curves. Data obtained for males were compared with historical data using a similar technique with Meal B, consisting of two pancakes and a 200 ml milkshake labelled with identical amounts of radioisotopes. The mean (95% CI) T50 values for solid phase emptying for males and females using Meal A, and for historical males using Meal B, were 51.1 min (44.1-58.1), 58.6 min (52.7-64.5) and 128.9 min (112.8-145.1), respectively. Corresponding figures for the liquid phase were 33.2 min (26.1-40.3), 50.2 min (38.4-62.1) and 30.7 min (21.4-39.9). Bland-Altman plots for each phase showed good agreement between Tests 1 and 2 for Meal A. The modified test meal gave reproducible results in healthy volunteers; however, solid phase emptying was significantly faster than that of the bulkier test meal in historical subjects.