Fig. 3.
The free-tracing method of gastric antral area measurement. The image was obtained in the epigastric area with the patient in the right lateral decubitus using a curved-array low-frequency probe. Note the presence of clear fluid in the stomach seen as hypoechoic-anechoic content. The yellow dotted line surrounding the gastric antrum represents a manual tracing of the outer layer of the gastric wall (serosa) which allows direct area measurement using the equipment internal caliper. A = antrum; Ao = aorta; L = liver; P = pancreas; SMA = superior mesenteric artery.