title: Oesophago-gastric junction opening function: assessment using ultrasound imaging and the effects of atropine.
abstract: Relaxation and opening of the oesophago-gastric junction (OGJ) is crucial for oesophageal transport. A novel ultrasound technique was used to determine OGJ opening, before and after atropine, in 12 normals. An ultrasound probe, a solid-state pressure transducer and an infusion tube were placed inside a 20-mm diameter bag, which was placed across the OGJ. At various bag pressures ultrasound transducer was pulled across the bag. Acquired B-mode ultrasound images were converted into M-mode image to display the oesophagus, OGJ and stomach. At low bag-pressure (< 20 mmHg), the OGJ but not oesophagus and stomach, is collapsed around the bag. Increasing bag pressure results in gradual opening of the OGJ from distal end. M-mode image identified the narrowest region of OGJ and corresponding cross-sectional area (CSA) was measured. Mean bag pressure to initial OGJ opening was 18 mmHg. Linear relationship between bag-pressure and OGJ-CSA was observed. Atropine reduced opening bag pressure and shifted the OGJ pressure-CSA curve upward without altering slope, i.e. compliance. Our novel ultrasound technique to study the OGJ opening function shows two distinct components; firstly, related to the tonic OGJ contraction and secondly, to passive or viscoelastic properties of the OGJ.
authors.affiliation: Division of Gastroenterology, University of California, San Diego and San Diego VA HealthCare System, San Diego, CA 92161, USA.
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.forename: T
authors.initials: T
authors.lastname: Takeda
authors.forename: I
authors.initials: I
authors.lastname: Dogan
authors.forename: V
authors.initials: V
authors.lastname: Bhargava
authors.forename: R K
authors.initials: RK
authors.lastname: Mittal
mesh_terms: D000328:Adult; D001285:Atropine / Q000494:pharmacology*; D003187:Compliance / Q000187:drug effects; D019160:Endosonography / Q000295:instrumentation / Q000379:methods*; D004943:Esophagogastric Junction / Q000000981:diagnostic imaging* / Q000187:drug effects* / Q000502:physiology*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D018727:Muscarinic Antagonists / Q000494:pharmacology*
chemical_list: D018727:Muscarinic Antagonists; D001285:Atropine