Figure 4: Analysis of gastric contractions (‘contractograms’).

Panels A and B are MR images at baseline and 3 months after ESG. Arrows show a contraction (Panel A) and the ESG (Panel B filled arrows) with liquid nutrient in the gastric fundus above and a contraction (open arrow) below the narrow lumen (filled arrows). Panels C, D, and E are time sequences of gastric cross-sectional diameters along the longitudinal axis of the stomach (y-axis) at baseline, 3 and 12 months after ESG. The vertical scale shows the relative diameter. At each timepoint, gastric diameter is expressed relative to the maximum diameter at that location; maximum diameter is shown in dark red and minimum in dark blue. Compared to baseline (Panel C), the contractions were shorter and weaker at 3 months (Panel D) and not visible at 12 months. The phase shift plot (Panel F) shows a contraction that migrated downstream. Panel F shows that this contraction virtually occluded the stomach. Panels H-M compares gastric emptying and characteristics of contractions at baseline, 3, and 12 months after ESG. Compared to baseline, the upper extent of propagated contractions was lower (i.e., more distal) at 3 and 12 months after ESG (Panel L); hence the distance propagated was shorter (Panel K). However, other features (i.e., periodicity, average relative amplitude change, and propagation velocity) were not different after vs before ESG