Diffusion Tensor Imaging Of White Matter In Patients With First Episode Obsessive-compulsive Disorder

BackgroundObsessive-compulsive disorder(OCD)is a complex and serious chronic disabled mental disease with obsessive ideas and compulsive behaviors as the core performance,affecting about 2%-3%of the general population.It has a high rate of disability,which seriously impair the occupational and social functions of patients,but its etiology and pathophysiological mechanism are still unclear.Diffusion tensor imaging(DTI)is a noninvasive imaging technique that can be used to observe the microstructure of white matter fibers in vivo,and can sensitively display the integrity and directional changes of intracranial white matter fiber bundles.Fractional anisotropy(FA)is the most commonly used index,which is considered as a sensitive marker to detect the changes of tissue microstructure,which has been widely used in the study of OCD.Many previous studies on obsessive-compulsive disorder DTI studies at home and abroad have reported extensive white matter changes in frontal lobe,cingulate gyrus,insular lobe,occipital lobe and other brain regions in patients with OCD,but the current results lack consistency,and the exploration of potential white matter abnormalities is still insufficient.Therefore,it is necessary to further explore the structural integrity of white matter fibers in patients with OCD,in order to clarify the potential neurobiological mechanism of OCD,and provide the basis for early identification and intervention.Objective1.DTI and Voxel-based Analysis(VBA)were used to investigate the integrity of white matter fibrous tracts in first-episode of untreated OCD patients.2.To explore the correlation between the FA values in brain regions with significant white matter changes and clinical symptoms and course of disease in patients with OCD,in order to provide imaging basis for the etiological research and clinical diagnosis of OCD patients.MethodsAccording to the Diagnostic and Statistical Manual of Mental Disorders Edition 5(DSM-5)diagnostic criteria for OCD,49 first-episode of untreated patients with OCD met the inclusion criteria,all completed the Yale-Brown Obsessive-Compulsive Scale(Y-BOCS).Only 38 patients with OCD and 40 healthy volunteers matched in gender,age and years of education at the same time completed the whole brain MRI scan and general data collection.Based on Linux operating system and MATLAB platform,SPM8 software and FSL are used to process all the data,the DTI parameter diagram is analyzed by VBA.SPSS 22.0 software was used to compare the age of two groups by Mann Whitney U test.The course of disease and years of education were compared by two independent-sample t test,and the gender difference between the two groups is tested by χ2 test.Pearson correlation analysis was used to explore the correlation between FA value of significantly changed brain areas and total score of Y-BOCS and compulsive behavior score in patients with OCD.Spearman correlation analysis was used to explore the correlation between FA value of significantly changed brain areas and obsessive thinking score and course of disease in patients with OCD.Results1.There were no significant differences in gender(χ2=0.000,P=0.991),age(Z=0.987,P=0.324)and years of education(t=0.345,P=0.731)between the OCD group and the healthy control group.2.There were significant statistically differences in the FA values of right frontal lobe/right precentral gyrus,left frontal lobe/left insular/left inferior frontal gyrus and right occipital/right inferior occipital gyrus in the OCD group and healthy control group(P<0.05).Compared with the healthy control group,the FA values of the above brain regions were significantly decreased in the OCD group,and no brain regions with increased white matter FA values were found.3.There was no correlation between the FA value of abnormal brain region and the total score of Y-BOCS,the score of obsessive thinking,the score of obsessive behavior and the course of disease in patients with OCD(P>0.05).Conclusions1.The first-episode of untreated OCD patients have abnormal integrity of white matter fiber tracts in several brain regions,mainly involving the frontal lobe,occipital lobe and insular lobe,and the changes of white matter fiber tracts in these brain regions may be involved in the pathophysiological mechanism of OCD.2.This study further proves that white matter abnormalities in the cortical-striatalthalamic-cortical circuitry may play an important role in the pathogenesis of OCD,and the changes of large-scale brain regions may participate in the pathophysiological process of OCD.