Clinical Research
Copyright ©2006 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Jul 28, 2006; 12(28): 4517-4523
Published online Jul 28, 2006. doi: 10.3748/wjg.v12.i28.4517
Ultrasonographic study of mechanosensory properties in human esophagus during mechanical distension
Ejnar Larsen, Hariprasad Reddy, Asbjørn Mohr Drewes, Lars Arendt-Nielsen, Hans Gregersen
Ejnar Larsen, Department of Radiology, Aalborg Hospital, Aalborg DK-9100, Denmark
Hariprasad Reddy, Asbjørn Mohr Drewes, Hans Gregersen, Center for Visceral Biomechanics and Pain, Aalborg Hospital, Aalborg DK-9100, Denmark t
Lars Arendt-Nielsen, Laboratory for Experimental Pain Research, Center for Sensory-Motor Interaction, Department of Health Technology, Aalborg University, Aalborg Dk-9100, Denmark
Supported by Det Obelske Familiefond, Spar Nord Fonden, Peter Tøfting og Dagmar Tøftings Fund and North Jutland County Research Fund
Correspondence to: Professor Hans Gregersen, Center for Visceral Biomechanics and Pain, the Research Building, Aalborg Hospital, Sdr. Skovvej 15, DK-9100 Aalborg, Denmark. hag@smi.auc.dk
Telephone: +45-9-9326825 Fax: +45-9-9133060
Received: March 8, 2005
Revised: May 12, 2005
Accepted: August 3, 2005
Published online: July 28, 2006
Abstract

AIM: 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.

CONCLUSION: 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.

Keywords: Deformation analysis; Esophagus; Experimental pain; Ultrasonography