A MRI Study On The Volume Changes Of Gray Matter In Patients With Major Depressive Disorder

Objective:Using magnetic resonance imaging(MRI),we examined the volume difference of gray matter (GM) between major depressiove patients and healthy controls,to investigate the disease-specific biological makers,and to provide new clues and evidences for the understanding of the mechanism and diagnosis of depression disorder.Methods:46 cases of major depressive disorder patients (consistent with DSM-IV major depression diagnostic criteria) and 46 healthy controls were studied, divided into two groups:patient group and control groupP. HAMD scores of the patient group must be higher to 17. All subjects must finish their head MRI scans. Voxel-based morphometry method (voxel-based morphometry, VBM) were tested against the two sets of the image of gray matter volume of the brain structure by MRI. The adjusted images represented the brain gray matter volume, white matter volume, cerebral gray matter density and white matter density.The gray matter difference between the patients and controls was examined by analysis of T test. The age,voxel-level,or both of them,were introduced as covariants in the statistic models to examine their effects on VBM results。Results:46 cases of major depressive disorder patients and 46 healthy controls completed the clinical datas and MRI scans. The results showed that:1. The sex and age of two groups were no significant difference. For MDD, the average years of education were 11.83±2.92years (range:2-16). For the healthy controls, the number of years of education was 12.43±3.15 years (range:5-16). There were no significant differences in education between the two groups. But the average score of HAMD for MDD was 24.20±4.30,and that for the control group was 3.22±1.60. There was very significant in HAMD score between the two groups.2 MRI data:Compare to healthy controls, the GM volume reduction was found in two clusters in MDD:Medial Frontal Gyrus(L) and Superior Frontal Gyrus(L). There is one increased GM volume in MDD compared to healthy controls:amygdala (R).Conclusion:Major depression in patients with cerebral gray matter volume changes mainly related to frontal lobe and amygdala brain regions. Many patients with depression has abnormal brain structure and the links between brain areas,leading to "hemispheric disconnection syndrome", especially the connections in the frontal cortex of a dysfunctional amygdala。That may be the pathogenesis key of depression.