The Study Of MRI In First-onset Major Depressive Disorder By Antidepressant Treatment

PARTⅠCortical abnormalities in first-onset major depressive disorder investigated with MRI and voxel-based morphometryObjective To study the structural changes of the whole brains in first onset major depressive disorder(MDD).Material and Methods Thirty-two patients with first onset MDD and 32 the age- and sex-matched control subjects were enrolled in the study.Gray volume differences of the whole brain were assessed using SPM2 to make voxel-based morphometry comparison between patients and the control subjects.Results The volume of the right hippocampus,amygdala and right medial occipital lobule was significantly smaller in the patient group than controls(P＜.05 FDR corrected).Conclusion Tendency of the reduced volume of the right hippocampus,amygdala and right medial occipital lobule was a characteristic of first onset major depressive disorder.PARTⅡWhite matter abnormalities and changes in first-onset major depressive disorder by antidepressant treatment investigated with voxel-based diffusion tensor imagingObjective To detect white matter abnormalities in patients with in first-onset major depressive disorder(MDD) and identify changes by antidepressant treatment.Material and Methods Thirteen patients with first onset MDD and 14 normal age-matched volunteers underwent diffusion tensor imaging(DTI) and patients underwent scanning twice during an 8-week period.Fractional anisotropy(FA) maps were processed using SPM2 to make voxel-wise comparison of anisotropy in whole brain between the two groups.Results Significant reductions in anisotropy were found in the white matter of genu of corpus callosum,genu of the right internal capsule and right inferior longitudinal fasciculus in patients(P＜.001 corrected).Symptomatic improvement after antidepressant was associated with reversion of the FA reductive areas (P＜.001 corrected).Conclusion Changes in FA maps of genu of corpus callosum, genu of the right internal capsule and right inferior longitudinal fasciculus associated with symptomatic improvement indicate that DTI may be a useful surrogate marker of antidepressant treatment response.PARTⅢNeural responses with emotional processing in first-onset major depressive disorder by antidepressant treatment investigated with functional MRIObjective To detect Changes of neural response toward sad and happy facial expressions in first-onset major depressive disorder(MDD) by antidepressant treatment investigated with functional magnetic resonance imaging(fMRI).Material and Methods Thirteen patients with with first onset MDD and 14 normal age-matched volunteers underwent fMRI and patients underwent scanning twice during an 8-week period.Blood oxygenation level dependent(BOLD) were processed using SPM2 to compare of function in whole brain between the two groups during exposure to neutral, positive and negative pictures.Results Incresesd activation of anterior cingulate cortex (ACC) during exposure to sad pictures and decreased activation of left laterial superior frontal cortex during exposure happy pictures were found in patients compared with control grougs(P＜.001,uncorrected).Symptomatic improvement after antidepressant was associated with reversion of ACC and left laterial superior frontal cortex(P＜.001, uncorrected).Conclusion Changes in BOLD of fMRI associated with symptomatic improvement indicate that fMRI may be a useful surrogate marker of antidepressant treatment response.PARTⅣAmplitude of low frequency fluctuation in first-onset major depressive disorder by antidepressant treatment investigated with resting-state functional MRIObjective To detect amplitude of low frequency fluctuation(ALFF) in patients with in first-onset major depressive disorder and identify changes by antidepressant treatment.Material and Methods Thirteen patients with with first onset major depressive disorder(MDD) and 14 normal age-matched volunteers underwent resting-state functional MRI and patients underwent scanning twice during an 8-week period.ALFF were processed using REST and SPM2 to compare resting-state function in whole brain between the two groups.Results Patients with MDD had decreased ALFF in "default-mode" network compared with control grougs(P＜.001,uncorrected). Symptomatic improvement after antidepressant was associated with reversion of the ALFF decreased areas in the right anterior cingulated cortex,right laterial inferior frontal cortex,right orbital frontal cortex,right temporal lobe,and bilateral posterior cingulated cortex(P＜.05,uncorrected).Conclusion Changes in ALFF maps of resting-state function associated with symptomatic improvement indicate that ALFF may be a useful surrogate marker of antidepressant treatment response.