title: Ultrasonographic study of mechanosensory properties in human esophagus during mechanical distension.
abstract: OBJECTIVE
  To study the esophageal geometry and mechanosensation using endoscopic ultrasonography during volume-controlled ramp distensions in the distal esophagus.
  
  
  METHODS
  Twelve healthy volunteers underwent distension of a bag. During distension up to moderate pain the sensory intensity was assessed on a visual analogue scale (VAS). The esophageal deformation in terms of multidimensional stretch ratios and strains was calculated at different volumes and VAS levels. Distensions were done before and during administration of the anti-cholinergic drug butylscopolamine.
  
  
  RESULTS
  The stimulus-response (volume-VAS) curve did not differ without or with the administration of butylscopolamine. Analysis of stretch ratios demonstrated tensile stretch in circumferential direction, compression in radial direction and a small tensile stretch in longitudinal direction. A strain gradient existed throughout the esophageal wall with the largest circumferential deformation at the mucosal surface. The sensation intensity increased exponentially as function of the strains.
  
  
  CONCLUSIONS
  The method provides information of esophageal deformation gradients that correlate to the sensation intensity. Hence, it can be used to study mechanosensation in the human esophagus. Further studies are needed to determine the exact deformation stimulus for the esophageal mechanoreceptors.
authors.affiliation: Department of Radiology, Aalborg Hospital, Aalborg DK-9100, Denmark.
authors.forename: Ejnar
authors.initials: E
authors.lastname: Larsen
authors.forename: Hariprasad
authors.initials: H
authors.lastname: Reddy
authors.forename: Asbjorn Mohr
authors.initials: AM
authors.lastname: Drewes
authors.forename: Lars
authors.initials: L
authors.lastname: Arendt-Nielsen
authors.forename: Hans
authors.initials: H
authors.lastname: Gregersen
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D002086:Butylscopolammonium Bromide / Q000627:therapeutic use; D002404:Catheterization; D004108:Dilatation, Pathologic; D019160:Endosonography / Q000295:instrumentation; D004947:Esophagus / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008465:Mechanoreceptors / Q000503:physiopathology*; D008875:Middle Aged; D010146:Pain / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology; D010276:Parasympatholytics / Q000627:therapeutic use; D012026:Reflex, Stretch / Q000502:physiology
chemical_list: D010276:Parasympatholytics; D002086:Butylscopolammonium Bromide