抑郁症与双相抑郁患者脑白质微结构标志物探索

The white matter imaging markers focusing on hippocampus in unipolar depression and bipolar depression

目的 探讨抑郁症（major depressive disorder）和双相抑郁（bipolar depression）患者以海马为种子点的大脑白质纤维的特异性.方法 共纳入符合DSM-Ⅳ诊断标准的33例抑郁症患者（抑郁症组）和33例双相抑郁患者（双相抑郁组）,同时纳入年龄、性别及教育程度匹配的33名健康对照者（对照组）.所有受试者均行头颅MRI扫描,采集弥散张量成像（diffusion tensor imaging,DTI）数据.以海马为种子点,应用DSI studio软件对DTI数据进行可视化弥散张量纤维束追踪,计算并比较3组受试者海马DTI的基本指标;进一步分析海马与其他脑区之间连接强度的纤维连接数目（fiber number,FN）值;采用Pearson相关分析分析上述差异性影像学指标与临床特征之间的关系.结果 与对照组相比,双相抑郁组左侧海马径向弥散率（radial diffusivity,RD）2组间差异有统计学意义（P=0.014）;抑郁症组与对照组差异无统计学意义;抑郁症组与双相抑郁组之间差异无统计学意义.与对照组相比,抑郁症组左侧额下回三角部FN值[0（0,25）与0（0,1）,P=0.018]和左侧枕中回FN值（38.6±6.7与26.9±25.6,P=0.015）降低;双相抑郁组左侧海马旁回FN值（47.2±24.0与65.8±30.1,P=0.007）及舌回FN值（50.4±33.2与74.2±35.9,P=0.012）升高.双相抑郁组左侧海马RD与病程呈正相关（r=0.418,P=0.016）.结论 双相抑郁患者左侧海马髓鞘退化,与左侧海马旁回、舌回的纤维结构连接异常;抑郁症患者左侧海马与额叶以及右侧海马与枕叶纤维连接异常.

Objective Taking the hippocampus as seed,to investigate the characteristics of white matter in patients with major depressive disorder （MDD） and bipolar depression （BD）.Methods 33 MDD and BD according with the Fourth Edition of Diagnostic and Statistical Manual of Mental Disorders diagnostic criteria,accompanying with 33 healthy controls （HC） matching with age,sex and education years were analyzed.All subjects underwent MRI scanning,acquiring diffusion tensor imaging （DTI）data.Taking the hippocampus as seed,to adopt diffusion tensor fiber tracing by DSIstudio to obtain and calculate basic index of DTI,then find the differences among three groups;furthermore,calculating the fiber number （FN） evaluating the connective strength between areas between hippocampus and other areas.Additionally,Pearson correlation analysis was used to analyses the relationship between the difference index and clinical characteristics.Results Compared with HC,radial diffusivity （RD） in the left hippocampus had significant difference （P=0.014）in BD group.While no significance parameter was found between MDD group and the other two groups.Compared with HC group,the reduction of FN value in MDD patients mainly exists in left inferior frontal gyrus（0（0,25）vs.0（0,1）,P=0.018）and left middle occipital gyrus （38.6±6.7 vs.26.9±25.6,P=0.015）.Compared with HC,FN value of BD increase in the left parahippocampal gyms （47.2± 24.0 vs.65.8 ± 30.1,P=0.007） and tongue gyrus （50.4 ± 33.2 vs.74.2 ± 35.9） in BD （P=0.012）.Pearson correlation analysis found that RD mean of left hippocampus remain positively correlated with the duration of disease in BD group （r=0.418,P=0.016）.Conclusions BD has some changes mainly in the left hippocampus,which exists myelin sheath degeneration and the alteration of white matter fiber connected with left parahippocampal gyrus and tongue gyrus,while MDD shows some differences of connectivity between left hippocampus and frontal lobe,and between right hippocampus and occipital lobe as well.