The Added Diagnostic Value of Liquid Gastric Emptying Compared with Solid Emptying Alone

The medical literature states that solid gastric-emptying studies are more sensitive for the detection of gastroparesis than are liquid studies; thus, liquid studies are rarely required. However, we have seen patients with normal solid but delayed liquid emptying. The purpose of this investigation was to determine whether a study of clear liquid gastric empting has added value for the diagnosis of gastroparesis over a study of solid emptying alone. Methods: A total of 101 patients underwent both solid and liquid gastric-emptying studies, acquired sequentially on the same day. A 30-min (1-min frames) liquid study (300 mL of water with 7.4 MBq [0.2 mCi] of In-111-diethylenetriaminepentaacetic acid) was followed by a standardized 4-h solid-meal study (a Tc-99m-sulfur colloid-labeled egg-substitute sandwich meal). Emptying was quantified as a best-fit exponential emptying rate (T1/2) for liquids and percentage emptying at 4 h for solid empting. Thirty healthy volunteers underwent a study of clear liquid emptying to establish normal values. The results of the liquid and solid studies were compared. In-111 liquid downscatter into the subsequent Tc-99m solid meal results was analyzed. Results: The upper range of normal for clear liquid emptying (T1/2) for healthy volunteers was 22 min (mean +/- 3 SDs) and 19 min (mean +/- 2 SDs). Of 101 patients, delayed emptying was found in 36% of liquid and 16% of solid studies. Of all patients with normal solid emptying, 32% had delayed liquid emptying. In-111 downscatter into the Tc-99m window was not generally significant. Conclusion: For the detection of gastroparesis, a 30-min study of clear liquid gastric- emptying has considerable added diagnostic value over a study of solid emptying alone.