Functional brain imaging in irritable bowel syndrome with rectal balloon-distention by using fMRI.
OBJECTIVE
Irritable bowel syndrome (IBS) is characterized by abdominal pain and changes in stool habits. Visceral hypersensitivity is a key factor in the pathophysiology of IBS. The aim of this study was to examine the effect of rectal balloon-distention stimulus by blood oxygenation level-dependent functional magnetic resonance imaging (BOLD-fMRI) in visceral pain center and to compare the distribution, extent, and intensity of activated areas between IBS patients and normal controls.


METHODS
Twenty-six patients with IBS and eleven normal controls were tested for rectal sensation, and the subjective pain intensity at 90 ml and 120 ml rectal balloon-distention was reported by using Visual Analogue Scale. Then, BOLD-fMRI was performed at 30 ml, 60 ml, 90 ml, and 120 ml rectal balloon-distention in all subjects.


RESULTS
Rectal distention stimulation increased the activity of anterior cingulate cortex (35/37), insular cortex (37/37), prefrontal cortex (37/37), and thalamus (35/37) in most cases. At 120 ml of rectal balloon-distention, the activation area and percentage change in MR signal intensity of the regions of interest (ROI) at IC, PFC, and THAL were significantly greater in patients with IBS than that in controls. Score of pain sensation at 90 ml and 120 ml rectal balloon-distention was significantly higher in patients with IBS than that in controls.


CONCLUSIONS
Using fMRI, some patients with IBS can be detected having visceral hypersensitivity in response to painful rectal balloon-distention. fMRI is an objective brain imaging technique to measure the change in regional cerebral activation more precisely. In this study, IC and PFC of the IBS patients were the major loci of the CNS processing of visceral perception.
Yuan
Yao-Zong
YZ
Department of Gastroenterology, Ruijin Hospital, Shanghai Second Medical University, Shanghai 200025, China. yyz28@hotmail.com
Tao
Ran-Jun
RJ
Xu
Bin
B
Sun
Jing
J
Chen
Ke-Min
KM
Miao
Fei
F
Zhang
Zhong-Wei
ZW
Xu
Jia-Yu
JY
D000328:Adult; D002404:Catheterization; D002560:Cerebrovascular Circulation; D003109:Colonic Diseases, Functional / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D012007:Rectum / Q000503:physiopathology*
D010100:Oxygen