Differences in regional homogeneity between patients with Crohn's disease with and without abdominal pain revealed by resting-state functional magnetic resonance imaging

Abstract

Abnormal pain processing in the central nervous system may be related to abdominal pain in patients with Crohn's disease (CD). The purpose of this study was to investigate changes in resting-state brain activity in patients with CD in remission and its relationship with the presence of abdominal pain. Twenty-five patients with CD and with abdominal pain, 25 patients with CD and without abdominal pain, and 32 healthy subjects were scanned using a 3.0-T functional magnetic resonance imaging scanner. Regional homogeneity (ReHo) was used to assess resting-state brain activity. Daily pain scores were collected 1 week before functional magnetic resonance imaging. We found that patients with abdominal pain exhibited lower ReHo values in the insula, middle cingulate cortex (MCC), and supplementary motor area and higher ReHo values in the temporal pole. In contrast, patients without abdominal pain exhibited lower ReHo values in the hippocampal/parahippocampal cortex and higher ReHo values in the dorsomedial prefrontal cortex (all P < 0.05, corrected). The ReHo values of the insula and MCC were significantly negatively correlated with daily pain scores for patients with abdominal pain (r = -0.53, P = 0.008 and r = -0.61, P = 0.002, respectively). These findings suggest that resting-state brain activities are different between remissive patients with CD with and without abdominal pain and that abnormal activities in insula and MCC are closely related to the severity of abdominal pain.

Fig. 1

Significant differences in ReHo values among the pain CD, non-pain CD, and HC groups with age, gender, weight, anxiety and depression as covariates. (A) The main effect analysis revealed significant differences in ReHo values of the insula, hippocampal/parahippocampal cortex (HIPP/paraHIPP), dorsomedial prefrontal cortex (dmPFC), middle cingulate cortex (MCC), supplementary motor area (SMA) and temporal pole (TP) among the three groups. (B) The post-hoc analysis showed that the ReHo values of the insula, MCC and SMA in the pain CD group were lower and the TP was higher than the ReHo values of the other two groups. The ReHo values of the HIPP/paraHIPP in the non-pain group were lower and those of the dmPFC were higher than the ReHo values of the other two groups. (C) The ReHo values of the insula and MCC in the pain CD group were negatively correlated with the abdominal pain scores. L, left; r, correlation coefficient; VAS, visual analogue scale; *P<0.05, **P<0.01.

Fig. 2

Brain regions with significant correlation between the ReHo values and daily pain scores in CD patients with abdominal pain using whole-brain correlation analysis. The daily pain scores correlated negatively with the left insula and MCC, right dorsolateral prefrontal cortex (dlPFC), bilateral thalamus, and periaqueductal gray (PAG), and positively with the right orbitofrontal cortex (OFC).