首次发病未用药老年抑郁症患者脑白质完整性的弥散张量成像研究

目的 使用弥散张量成像探讨首次发病未用药老年抑郁症患者的脑白质完整性.方法 15例首次发病未用药的老年抑郁症患者和15例正常对照组接受脑弥散张量成像扫描,用基于体素的分析方法对脑内所有体素的各向异性分数(FA)逐一进行组间比较.结果 与正常对照组相比,首次发病未用药老年抑郁症患者左侧前扣带(丛集体积=106体素,t=3.21)、右侧前扣带(丛集体积=60体素,t=2.71)、右侧膝下扣带(丛集体积=63体素,t=3.37)、左侧脑干(丛集体积=62体素,t=3.25)白质FA值显著降低(检验水准为未校正的单侧P＜0.01,体素集阈值＞50体素).结论 老年抑郁症发病早期存在双侧前扣带及右侧膝下扣带白质完整性下降,经由该脑区的神经通路损害可能与老年抑郁症的病理机制有关.

Abnormalities of white matter integrity detected by diffusion tensor imaging in first-episode, medication-naive geriatric depression

Objective To explore the white matter integrity by using diffusion tensor imaging (DTI) in first-episode, medication-naive geriatric patients with major depressive disorder.Methods Fifteen first-episode, medication-naive depressive patients and fifteen healthy controls underwent DTI scan.Fractional anisotropy (FA) of white matter was compared between the two groups using voxel-based approach.Results Compared with healthy controls, geriatric depressive patients showed significantly lower FA in left anterior cingulate (cluster size = 106 voxels, t = 3.21 ), right anterior cingulate ( cluster size =60 voxels, t = 2.71 ), right subgenual cingulate ( cluster size = 63 voxels, t = 3.37 ) and left brainstem ( cluster size = 62 voxels, t = 3.25 ) ( level of significance was uncorrected single-tailed P ＜ 0.01, threshold of cluster size ＞ 50 voxels).Conclusion Decrease of white matter integrity in bilateral anterior cingulate and right subgenual cingulate are present in the early stage of geriatric depression.Lesions of neural pathways by way of these regions may be involved in the pathophysiology of geriatric depression.