The Study Of Diffusion Tensor Imaging MRI In First-episode Treatment-naive Patients With Major Depressive Disorder And The Relationship Between It And Illness Course And Executive Function Disorder

Objective:To explore the microstructural integrity of whole-brain white matter by diffusion tensor imaging in first-episode,treatment-naive young adults with major depressive disorder and the relationship between the FA values of identified brain regions and illness course,severity of disease as well as cognitive dysfunction.Methods:Eighteen(female 9,male 9)first-episode treatment-naive young adult major depressive subjects and eighteen(female 9,male 9) healthy subjects matched in gender,age and school-life underwent Executive handbook for the structured clinical interview for DSM-ⅣaxisⅠdisorders(SCID-Ⅰ),Hamilton depression scale(HAMD),Self-Rating Depression Scale(SDS),Hamilton Anxiety Scale(HAMA) and Self-RatingAnxiety Scale(SAS).In patients HAMD sorces were requested≥17,HAMAn≤7,SAS≤45 and SDS≥60;but HAMD≤7, HAMA≤7,SAS≤45 and SDS≤45 in controls.Executive function was assessed with Wisconsin Card Sorting Test(WCST),Stroop Color and Word Test(SCWT)and Verbal Fluency Task(VF).Diffusion tensor imaging was employed to examine the white matter integrity in both groups.Diverse clusters between the patients and the healths were obtained by voxel-based analysis(VBA)and the average fractional anisotropy(FA)of the each identified brain regions were obtained by self-developed program.Clinical association of the FA values with illness course,severity of disease and performance of cognitive function tests was examined by using Spearman's correlation analysis(two tail,p＜0.05).Results:1)The MDD exhibited significantly lower FA values than healthy subjects in white matter of bilateral of medial frontal gyrus,the right medial frontal gyrus sub-gyral,the left cingulate gyrus,the left inferior temporal gyrus sub-gyral.;2)The course of the illness,but not HAMD scores,was significantly correlated to FA of the right medial frontal gyral cluster in a manner that lower FA value was found in individuals with longer illness course(r=-0.545,p=0.019);3)White matter FA values of the right medial frontal gyrus sub-gyral are positively related to the correct number of WCST(r=0.587,p=0.045)and inversely related with continuous error numbers(r=-0.593,p=0.042) or error numbers(r=-0.614,p=0.034)of WSCT;4)Significant negtive correlations were found between completion time of SCWT and FA of the right medial frontal gyrus sub-gyral(r=-0.532,p=0.037);5) No significant associations were found between FA values of abnormal brain regions and performance of VF.Results:Changes of the cerebral white matter integrity support the hypothesis that disconnectivity between brain regions contributes to the risk of MDD and progressed with the illness course.These findings suggest that microstructural white matter abnormalities of dorsal lateral prefrontal play an important role in cognitive dysfunction of major depression.