Gastric emptying. Comparison of anterior only and geometric mean correction methods employing static and dynamic imaging.

Dynamic (continuous) and static imaging techniques were compared in the analysis of gastric emptying patterns in 16 consecutive adult patients with normal gastric half-emptying times assessed by dynamic imaging for 90 minutes under a dual head camera allowing simultaneous anterior and posterior imaging. Gastric t1/2 values were calculated for each patient based on four different data analysis methods: geometric mean corrected dynamic data (GD), anterior alone dynamic data (AD), geometric mean corrected simulated static data (GS), and anterior alone simulated static data (AS). The mean t1/2 values were: GD = 63.8 minutes, AD = 72.1 minutes, GS = 65.3 minutes, and AS = 73.0 minutes. Both the geometric mean corrected methods had a statistically different t1/2 than either of the anterior methods. Lag phase measurements, defined as a 2% decrease in gastric activity were: GD = 7 minutes, AD = 19 minutes, GS = 6 minutes, and AS = 16 minutes. Dynamic and static geometric mean methods provide similar gastric t1/2 calculations that are statistically different than anterior alone methods, and the lag phase is much shorter using either of the geometric mean methods.