Exploring joint patterns of brain structure and function in inflammatory bowel diseases using multimodal data fusion.

BACKGROUND: A growing number of neuroimaging studies suggest distinct neural changes in inflammatory bowel diseases (IBDs). Whether such changes may show similar spatial patterns across distinct neural features within and between specific IBD is unclear. To address this question, we used multivariate multimodal data fusion analysis to investigate structure/function modulation in remitted patients with Crohn's disease (CD) and ulcerative colitis (UC). METHODS: Patients with IBD (n = 46; n = 31 with CD, n = 15 with UC) in stable remission and 17 healthy controls (HC) underwent structural magnetic resonance imaging (sMRI) and resting-state functional magnetic resonance imaging (rs-fMRI) as well as cognitive testing. Anxiety, depression, and fatigue were assessed using self-rating questionnaires. sMRI data were analyzed via voxel-based morphometry (VBM) and rs-fMRI data via amplitude of low-frequency fluctuations (ALFFs) and regional homogeneity (ReHo). Detection of cross-information between VBM, ALFF, and ReHo was conducted by means of a joint independent component analysis (jICA), followed by group-inference statistics. KEY RESULTS: Joint independent component analysis detected structural alterations in middle frontal and temporal regions (VBM), and functional changes in the superior frontal gyrus (ReHo) and the medial as well as inferior frontal, inferior temporal, rectal, and subcallosal gyrus (ALFF). One joint component of extracted features of the three modalities differed significantly between IBD patients and controls (p = 0.03), and most distinctly between HC and patients with UC. CONCLUSIONS AND INFERENCES: Using a multivariate data fusion technique, this study provides further evidence to brain alterations in IBD. The data suggest distinct neural differences between CD and UC, particularly in frontotemporal regions.

Aberrant brain structural large-scale connectome in Crohn's disease.

BACKGROUND: Disturbed brain-gut interactions and a bidirectional relationship between inflammation and psychiatric symptoms such as anxiety and depression are being discussed in patients with inflammatory bowel diseases (IBD). Alterations of brain structure and function in IBD have been reported with heterogeneous results. Whether these changes reflect independent localized deficits or rather a systematic disruption in the anatomical organization of large-scale brain networks remains unclear. The present study investigated the gray matter structural connectome in patients with Crohn's disease (CD). METHODS: Sixty participants (30 with quiescent CD and 30 matched healthy controls [HC]) underwent high-resolution brain MRI at 3 Tesla. Well-established graph theoretical metrics were analyzed at the global and regional network level and compared between groups. KEY RESULTS: The networks in both groups followed a small-world organization, that is, an architecture that is simultaneously highly segregated and integrated. However, transitivity, a measure of global network segregation, was significantly reduced in patients (P = 0.003). Regionally, patients showed a reduction of nodal betweenness centrality in the right insula and cuneus and the left superior frontal cortex and reduced nodal degree within the left-hemispheric cingulate and the left lateral and right medial orbitofrontal cortex. CONCLUSION AND INFERENCES: These findings lend support to the hypothesis that CD is accompanied by alterations in both global network organization and regional connectivity. A deeper understanding of neural central networks in IBD may facilitate the development of complementary strategies in the treatment of "extraintestinal" comorbid conditions such as depression or anxiety.