Fig. 1

The measurements of US parameters. a, b The transducer was placed a little left-leaning under the xiphoid, to reveal the longitudinal abdominal esophagus and gastro-esophageal junction. c The US image showing the abdominal esophagus and gastro-esophageal junction. The esophagus is delineated as a linear structure (arrows) with the hypoechogenic wall and hyperechogenic lumen. The measurements of abdominal esophagus length (white lines), esophageal wall thickness (red lines), and His angle (yellow lines) are illustrated. C. SWE was obtained by placing the SWE box (trapezoid) on the abdominal esophagus, and the image was frozen after the colored signal was stable. A Q-box region of interest (circle) was positioned within the anterior wall of the abdominal esophagus. The mean elastic modulus within the Q-box was shown on the screen. Each measurement was performed three times. His angle, the gastro-esophageal angle; SWE, shear-wave elastography