A Study On The Prefrontal Cortex, Anterior Cingulate Cortex And Hippocampus In Major Depressive Patients Using Multi Voxel Proton Magnetic Resonance Spectroscopy

Objective:1. To investigate the changes of N-acetylaspartate(NAA), glutamate(Glu), choline(Cho), myo-inositol(mI), creatine(Cr) in the prefrontal cortex, anterior cingulate cortex and hippocampus of major depressive patients.2. To investigate the effect of antidepressant treatment on the metabolites in regions of interest of major depressive patients.3. To study the correlation between the metabolites in regions of interest and the severity of clinical symptoms of major depression.Methods:1 Multi voxel proton magnetic resonance spectroscopy using chemical shift imaging sequence at three dimensional echo (3D-CSI) was performed on 13 unmedicated patients with major depressive disorder and 13 healthy controls at 3.0 T magnetic resonance imaging system. The patients underwent ~1H-MRS repeatedly after six weeks of antidepressant treatment. The compounds measured were NAA, Glu, Cho and mI. Data were acquired from a voxel in left prefrontal cortex, right prefrontal cortex, left anterior cingulate, right anterior cingulate, left hippocampus and right hippocampus respectively.2. Evaluating the symptom of depression using HAMD before and after antidepressant treatment in major depressive patients. To analyze the correlations between the metabolites in regions of interesting and the scores of HAMD before antidepreeant treatment, and to analyze the correlations between the changes of metabolites in regions of interesting and the decreases of HAMD scores after antidepressant treatment in major depressive patients.3. Using SPSS 11.0 statistical package to analyze the date. One-way ANOVA, paired-samples t test and independent-samples t test were used to analyze the differences. Pearson correlation analysis were selected to study the correlation; P<0.05 means a statistical difference.Results:1. Major depressive patients had significantly lower NAA/Cr ratios in bilateral prefrontal cotex and bilateral hippocampus than healthy controls (P<0.05); the Glu/Cr ratios in bilateral anterior cingulate cortex and right prefrontal cortex were significantly lower in major depressive patients than in healthy controls (P<0.05).2. After antidepressant treatment, the NAA/Cr ratios both in bilateral prefrontal cotex and in bilateral hippocampus were increased than before, but only the left prefrontal cortex increased significantly (P<0.05). Comparing to the healthy controls, the NAA/Cr ratios in bilateral prefrontal cotex had no significant difference (P>0.05), the NAA/Cr ratio in right hippocampus and the Glu/Cr ratios in right anterior cingulate cortex was still lower significantly (P<0.05) after treatment. The Cho/Cr ratios was increased significantly (P<0.05) after being treated in left prefrontal cortex and left hippocampus, but there was no significant difference (P>0.05) compared to healthy controls.3. The mI/Cr ratios in right hippocampus and HAMD score had positive correlation in major depressive patients; The changes of NAA/Cr ratio in left prefrontal cortex and the decrease of HAMD score before and after antidepressant treatment had negative correlation.Conclusions:The findings suggest that the metabolites in bilateral prefrontal cortex, anterior cingulate cortex and hippocampus of major depressive patients have changes in varying degrees. These changes may be implicated in the pathogenesis of major depressive disorder, and the functions of neuron and glial cells in the brain are deficient. There is no definitive correlation between the neural biochemistry and clinical symptom in major depressive disorder. Antidepressant treatment can normalize these changes partly.