Alterations of brain gray matter volume in untreated patients with obsessive-compulsive disorders: a high resolution MRI and voxel-based morphometry study

Objective To investigate the correlations between the gray matter (GM) volume changes and the clinical characteristics manifestations in untreated obsessive-compulsive disorder (OCD)patients using high resolution MRI and voxel-based morphometry (VBM) method.Methods Forty-six untreated patients with OCD,admitted to our hospital from January 2012 to December 2013 and fulfilled our inclusion criteria,and 31 age-,gender-,and education-matched healthy controls were chosen in our study; they were scanned with magnetic resonance imaging (MRI) for VBM by using SPM8,VBM8 and REST software tools.The Yale-Brown Obsessive Compulsive Scale (Y-BOCS),Hamilton Rating Scale for Depression 17-Item (HAMD-17) and Hamilton Anxiety Rating Scale (HAMA) were used to assess the clinical symptoms.The relationship between the average gray matter volume and the severity of clinical symptoms in patients with OCD was analyzed while such elements as gender,age,and the years of education were controlled.Results As compared with the controls,the studied patients with OCD showed significantly reduced gray matter volume in the left calcarine (BA18; MNI coordinate:x=-17,y=-77,z=-5; connected voxels:673; t=-4.426; P＜0.01 uncorrected),left precuneus (BA7; MNI coordinate:x=-2,y=-51,z=44; connected voxels:1420; t=-4.222; P＜0.01 uncorrected) andright cingulate gyrus(BA32; MNI coordinate:x=12,y=20,z=44; connected voxels:618; t=-4.716; P＜0.01 uncorrected).Significant positive correlation was observed between the decreased volume in left calcarine and total YBOCS scores (r=0.380,P=0.009).Conclusion The gray matter volume changes of left calcarine,left precuneus and right cingnlate gyrus underlie the pathophysiology of OCD; the gray matter volume change of left calcarine can objectively reflect the severity of OCD. Key words: Obsessive-compulsive disorder;  Voxel-based morphometry;  Magnetic resonance imaging;  Cingulate gyrus;  Precuneus;  Occipital lobe