Cortical thickness and white matter integrity abnormalities in obsessive-compulsive disorder: A combined multimodal surface-based morphometry and tract-based spatial statistics study.

BACKGROUND: Cerebral morphological abnormalities may play a key role in pathogenesis of obsessive-compulsive disorder (OCD). However, few studies have used multimodal imaging strategies to investigate alterations of cortical morphometry and white matter (WM) integrity. This study aimed to evaluate cortical thickness, cortical and subcortical volume, and WM integrity characteristics in OCD patients comprehensively.

METHODS: We acquired magnetic resonance imaging (MRI) scans from 52 OCD patients and 46 well-matched healthy controls (HCs). Cortical thickness and cortical and subcortical volume were measured using the surface-based morphometry (SBM) approach. We also evaluated fractional anisotropy (FA) and mean diffusivity (MD) derived from diffusion tensor imaging (DTI) using tract-based spatial statistics (TBSS). The disease severity was evaluated by score of the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). For those brain regions exhibiting altered structure, correlations between alterations and clinical symptoms severity were analyzed in all patients and medication-naïve patients, respectively.

RESULTS: Compared with controls, OCD patients exhibited cortical thinning in right posterior cingulate cortex (PCC), as well as significantly decreased FA values in the genu and body of corpus callosum (CC). In medication-naïve patients group, the total Y-BOCS score and obsession score were significantly negative correlated with right PCC cortical thickness.

CONCLUSIONS: OCD patients demonstrated symptom-related reduced cortical thickness structural alteration of the right PCC, and altered WM integrity in the genu and body of CC. Medication seems could alleviate the alteration of cortical thickness but not WM integrity. Combined multimodal neuroimaging methods may provide a more comprehensive perspective to clarify the pathological mechanism of OCD.