Fibrosis in the Hiatus of Esophagus in Patients With Primary Esophageal Motor Disorders: Radiomic Analysis

In normal subjects, the esophagus and crus of the diaphragm slide relative to each other during esophageal peristalsis, which is not the case in patients with achalasia esophagus.

To examine the tissue characteristics of the esophageal hiatus in patients with achalasia esophagus, high amplitude esophageal contractions (HAEC), esophagogastric junction outflow obstruction (EGJOO), and normal subjects using radiomics analysis of the CT images.

A large number of medical records (1221 controls, 409 achalasia, 562 EGJOO, and 349 HAEC) were screened to identify subjects with a CT scan of the abdomen/chest in their record that met the pre-determined criteria. Using multiplanar rotation of CT images, the esophageal hiatus was visualized in a 2D plane. The grayscale intensity distributions (GSID) of the three regions of interest, i.e., (1) subcutaneous adipose tissue, (2) a posterior spine muscle (marker of fibro-connective tissue), and (3) esophageal hiatus were determined.

No differences in the mean GSID of subcutaneous adipose tissue and muscle were found among the four groups. On the other hand, the esophageal hiatus mean GSID was significantly higher in the three patient groups compared to controls. The GSIDs were higher in achalasia patients than in HAEC and EGJOO patients. The mean GSI of the hiatus was closer to that of the muscle with greater overlap between the hiatus and muscle in the three patient groups; the overlap was greater in achalasia as compared to HAEC and EGJOO patients.

A higher GSI of the hiatus with greater overlap between the hiatus and muscle suggests an increase in fibro-connective tissue in the esophageal hiatus of patients with primary esophageal motility disorders (EMD). We propose that fibrosis in the esophageal hiatus restricts axial separation between the LES and crural diaphragm, which may be important in the pathogenesis of esophageal motor disorders.