Reconstruction of the Gastro-esophageal Junction Based on Ultramill Imaging for Biomechanical Analysis

The gastro-esophageal junction (GEJ) regulates the entry of food into the stomach and prevents reflux of acidic gastric contents into the lower esophagus. This is achieved through multiple mechanisms and the maintenance of a localized high-pressure zone. Diseases of the GEJ typically involve impairments to its muscular functions and often are accompanied by symptoms of reflux, heartburn, and dysphagia. This study aimed to develop a finite element-based model from a unique human cadaver GEJ data reconstructed from an ultramill imaging setup. A pipeline was developed to generate a mesh from an input stack of images. The anatomy of the model was compared to an existing Visible Human finite element GEJ model. Biomechanical simulations were also performed on both models using loading steps of differing levels of calcium to model different levels of contraction. It was found that the ultramill GEJ model is shorter than the Visible Human model (31 vs 48.3 mm), as well as producing lower pressure (1.35 vs 4.36 kPa). The model will be used to investigate detailed pressure development in the GEJ during swallowing under realistic loading conditions. Clinical Relevance - The modeling of the GEJ would allow further insights into pressure influencing factors and aid in the development and testing of treatments.