Brain function in patients with diarrhea type irritable bowel syndrome after rectal balloon distention

Abstract

Objective To investigate the correlation between activated brain regions examined by functional magnetic resonance imaging (fMRI) after rectal balloon distention and intestinal symptoms, psychological status, and quality of life in patients with diarrhea type irritable bowel syndrome (IBS-D) at different stages of disease. Methods According to the symptoms status, patients with IBS-D were divided into onset group (seven patients), remission group (five patients) and persistence group (six patients), and six healthy individuals were selected as healthy controls at the same time. After stimulated with rectal balloon distention at first sensation thresholds, continual defecation thresholds or 80% of maximum tolerable thresholds, patients received fMRI examination. Analysis of variance and two-sample t test were used to compare the difference in activated brain areas between two groups. Pearson analysis was performed to analyze the correlations between activated brain areas and scores of irritable bowel syndrome (IBS) intestinal symptom, Hamilton depression scale (HAMD), Hamilton anxiety scale (HAMA) and irritable bowel syndrome special quality of life scale (IBS-QOL). Results There was no significant difference in first sensation thresholds, continual defecation thresholds or 80% of maximum tolerable thresholds between patients of different groups. After rectal balloon distention, there were differences in such brain areas: bilateral anterior cingulate cortex (ACC), left inferior parietal lobe, and left middle frontal gyrus. Compared with those of control group, the activation of ACC, inferior parietal lobe and middle frontal gyrus lowered in patients of onset group (both P<0.05). There was positive correlation between the activation of middle frontal gyrus and intestinal symptom scores in persistence group(r=0.823, P=0.048). There were negative correlations between the activation of inferior parietal lobe (r =-0.816, P=0.048), middle frontal gyrus(r=-0.860, P=0.028) of persistence group, activation of middle frontal gyrus (r=-0.892, P=0.042) of remission group and HAMD score. There were positive correlations between the activation of inferior parietal lobe (r =0.818, P=0.047), middle frontal gyrus(r = 0.907, P=0.013) of persistence group, activation of midfrontal gyrus (r = 0.914, P=0.030) of remission group and scores of IBS-QOL. Conclusion The brain regions were activated during the rectal balloon distention both in IBS-D patients and healthy controls, and there were differences in activated brain regions among different stages of IBS-D. Key words: Irritable bowel syndrome; diarrhea; Magnetic resonance imaging; Brain region activities; Rectal balloon distention