White matter integrity in patients with obsessive-compulsive disorder: a diffusion tensor imaging study

Abstract

Objective To explore white matter abnormalities in obsessive-compulsive disorder (OCD) and the relationship between such abnormalities and clinical features. Methods Forty patients with OCD and 40 healthy controls matched for sex-, age- and education underwent diffusion tensor imaging (DTI) scans. Voxel-based analysis was used to compared fractional anisotropy (FA) map between groups. Correlations between white matter abnormalities, illness duration and clinical symptoms measured by the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) were performed. Results Compared with healthy controls, OCD patients showed overall decreased FA in white matter of the body of the right corpus callosum (MNI(x,y,z): 18,16,16;t=4.00), right thalamus(MNI(x,y,z) : 10,-22,-22;t=5.31) , left anterior cingulate gyrus (MNI(x,y,z): -14,26,24;t=3.95), right posterior cingulate(MNI(x,y,z) : 0,-34,16;t=3.77), bilateral middle and inferior temporal gyri(left middle temporal gyrus MNI(x,y,z) : - 44,- 24,- 8;t=4.45; right middle temporal gyrus MNI(x,y,z) :48,- 34,- 10;t=4.34) , left inferior temporal gyrus MNI(x,y,z): - 46,12,- 30;t=3.91; right inferior temporal gyrus MNI(x,y,z) :46,-20,-12;t=4.11), bilateral parahippocampal gyri(left parahippocampal gyrus MNI(x,y,z): -28,-24,-26;t=4.40; right parahippocampal gyrus MNI(x,y,z) : 20,-32,-20;t=4.21), right precuneus(MNI(x,y,z) : 26,- 42,14;t=4.22), left lingual gyrus (MNI(x,y,z): - 28,- 72,- 2;t=4.30)and bilateral cerebella(left cerebella MNI(x,y,z) : - 6,- 42,- 36;t=4.46; right cerebella MNI(x,y,z) : 10,- 48,- 36;t=4.16). Similar but more extensive abnormailities were observed in drug-naive patients compared to healthy controls (all P<0.001). Correlational analyses revealed that the total score of Y-BOCS was positively correlated with the FA value in white matter of the right frontal lobe, right cingulated, left superior temporal gyrus, right precuneus, left inferior parietal lobe. There was a negative correlation between the right inferior parietal lobe FA and the duration of illness. Conclusions There are extensive microstructural abnormalities in white matter of patients with OCD. Impaired axonal integrity within the white matter may be associated with the pathophysiology of OCD. Similar white matter abnormalities found in drug-naive patients may imply the diathesis of OCD. Key words: Obsessive-compulsive disorder; White matter; Diffusion tensor imaging