Dynamic magnetic resonance imaging evaluation of stomach geometry modifications after endoscopic sleeve gastroplasty

Sleeve gastrectomy (SG) induces weight loss through tubulization of the stomach. Up to 35% of SG patients develop Gastroesophageal Reflux Disease (GERD). The pathophysiological mechanism for GERD development has been associated to changes in the geometry and mechanics of the Esophago-Gastric junction (EGJ). Endoscopic sleeve gastroplasty (ESG) is an endoscopic bariatric procedure leading to weight loss and obesity-related comorbidities resolution through gastric restriction and shortening. Unlike SG, ESG preserves the gastric fundus, potentially resulting in lesser impact on EGJ geometry. This study aimed to identify and quantify the geometric changes of the EGJ following ESG using dynamic magnetic resonance imaging (Dy-MRI).

ESG patients were enrolled to undergo Dy-MRI. Dy-MRI performed before and 6 months after ESG consisted in ingestion of a 400 mL liquid meal and images acquisition every 20 min, up to 120 min post-ingestion. 3D-segmentations of the stomach were generated through the 3D Slicer software. The His angle (HA) was calculated by identifying anatomical landmarks, on sagittal, coronal, and transverse planes for precise comparison between pre- and postoperative images. Clinical data were collected over a 12 months period.

Of the 25 patients who underwent pre- and postoperative Dy-MRI, 3 were excluded due image abnormality. 12 (54.5%) patients reported preoperative GERD symptoms and PPI use. Over 12 months follow-up 6/12 patients (50%) reported resolution of GERD symptoms and stopped PPI use. No de-novo GERD was reported. Computation of gastric geometry modifications revealed a significant (p-value 0.05) difference between mean pre-procedure HA degree 62.2° (SD 10.3°), and mean post-procedure (6 months) degree 59.6° (SD 10.2°).

ESG reduces the HA degree which may serve as a protective factor against GERD development. Future steps will include developing automatic segmentation algorithms and leveraging software such as VTK to minimize measurement variability and enhance reproducibility in a larger patients cohort.