title: Abnormal structure and function of the esophagogastric junction and proximal stomach in gastroesophageal reflux disease.
abstract: OBJECTIVE
  This study applies concurrent magnetic resonance imaging (MRI) and high-resolution manometry (HRM) to test the hypothesis that structural factors involved in reflux protection, in particular, the acute insertion angle of the esophagus into the stomach, are impaired in gastroesophageal reflux disease (GERD) patients.
  
  
  METHODS
  A total of 24 healthy volunteers and 24 patients with mild-moderate GERD ingested a test meal. Three-dimensional models of the esophagogastric junction (EGJ) were reconstructed from MRI images. Measurements of the esophagogastric insertion angle, gastric orientation, and volume change were obtained. Esophageal function was assessed by HRM. Number of reflux events and EGJ opening during reflux events were assessed by HRM and cine-MRI. Statistical analysis applied mixed-effects modeling.
  
  
  RESULTS
  The esophagogastric insertion angle was wider in GERD patients than in healthy subjects (+7° ± 3°; P=0.03). EGJ opening during reflux events was greater in GERD patients than in healthy subjects (19.3 mm vs. 16.8 mm; P=0.04). The position of insertion and gastric orientation within the abdomen were also altered (both P<0.05). Median number of reflux events was 3 (95% CI: 2.5-4.6) in GERD and 2 (95% CI: 1.8-3.3) in healthy subjects (P=0.09). Lower esophageal sphincter (LES) pressure was lower (-11 ± 2 mm Hg; P<0.0001) and intra-abdominal LES length was shorter (-1.0 ± 0.3 cm, P<0.0006) in GERD patients.
  
  
  CONCLUSIONS
  GERD patients have a wider esophagogastric insertion angle and have altered gastric morphology; structural changes that could compromise reflux protection by the "flap valve" mechanism. In addition, the EGJ opens wider during reflux in GERD patients than in healthy volunteers: an effect that facilitates volume reflux of gastric contents.
authors.affiliation: 1] Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland [2] Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Jelena
authors.initials: J
authors.lastname: Curcic
authors.affiliation: Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India.
authors.forename: Shammodip
authors.initials: S
authors.lastname: Roy
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Schwizer
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Elad
authors.initials: E
authors.lastname: Kaufman
authors.affiliation: Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Zsofia
authors.initials: Z
authors.lastname: Forras-Kaufman
authors.affiliation: Menne Biomed, Tuebingen, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Menne
authors.affiliation: Division of Gastroenterology, Royal Melbourne Hospital, Melbourne, Australia.
authors.forename: Geoffrey S
authors.initials: GS
authors.lastname: Hebbard
authors.affiliation: Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.
authors.forename: Reto
authors.initials: R
authors.lastname: Treier
authors.affiliation: 1] Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland [2] Zurich Centre for Integrative Human Physiology (ZIHP), Zurich, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Boesiger
authors.affiliation: 1] Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland [2] Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Steingoetter
authors.affiliation: 1] Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland [2] Zurich Centre for Integrative Human Physiology (ZIHP), Zurich, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Fried
authors.affiliation: 1] Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland [2] Zurich Centre for Integrative Human Physiology (ZIHP), Zurich, Switzerland.
authors.forename: Werner
authors.initials: W
authors.lastname: Schwizer
authors.affiliation: Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India.
authors.forename: Anupam
authors.initials: A
authors.lastname: Pal
authors.affiliation: 1] Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland [2] Nottingham Digestive Diseases Centre and Biomedical Research Unit, University Hospital, Nottingham, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Fox
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D004943:Esophagogastric Junction / Q000473:pathology / Q000503:physiopathology; D005260:Female; D005764:Gastroesophageal Reflux / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D021621:Imaging, Three-Dimensional; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D008365:Manometry; D008875:Middle Aged; D015233:Models, Statistical; D011446:Prospective Studies; D013270:Stomach / Q000473:pathology / Q000503:physiopathology