Study on Human Brain Responses to Acid Exposure of Esophageal Mucosa by Functional Magnetic Resonance Imaging Technique

Background:Recently blood oxygen level dependent(BOLD)-functional magnetic resonance imaging(fMRI)technique was extensively used in human visceral perception research study.It has been accepted that visceral hypersensitivity is closely related with the pathogenesis of non-erosive reflux disease(NERD).Aims:To investigate the human brain responses to esophageal acid perfusion using BOLD-fMRI technique and to explore the central mechanism of visceral hypersensitivity in NERD.Methods:Thirty-one NERD patients,13 with reflux esophagitis(RE)and 12 volunteers were enrolled in this study.The NERD patients were divided into two groups:the sensation normal(NERD-N)group and visceral hypersensitivity(NERD-H)group,according to the results of esophageal balloon dilatation and Bernstein test.MRI scanning was performed in each subject.Cortical response to acid perfusion was determined and compared between these groups.Results:The main centers affected in NERD-H patients were secondary somatosensory cortex,primary somatosensory cortex,right orbitofrontal cortex,insular cortex,amygdala,striatum,motor cortex and supplementary and cerebellum cortices.The areas were wider than those in the other groups.The average percent of signal intensity increased in the region of secondary somatosensory cortex,right prefrontal cortex,motor cortex and supplementary,insular cortex,amygdala,striatum and cerebellum cortices were significantly higher than those in the NERD-N group and the control group(P0.01).The initial and peak fMRI signal occurred earlier in the NERD-H group compared with the NERD-N and the control groups(P0.01).Conclusions:The pattern of fMRI activated by esophageal acid perfusion in NERD-H patients provides the evidence for revealing the functional abnormalities of integration of central nerves system and process of esophageal perception of afferent signals in these patients.