Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia; Thompson Institute, University of The Sunshine Coast, Birtinya, Queensland, Australia.
School of Psychology and Counselling and IHBI, Queensland University of Technology, Brisbane, Queensland, Australia; Department of Nuclear Medicine, University of Bern, Inselspital, Bern, Switzerland.
Biol Psychiatry Cogn Neurosci Neuroimaging. 2021 Nov;6(11):1100-1109. doi: 10.1016/j.bpsc.2021.04.014. Epub 2021 May 4.
Possible white matter (WM) alterations following moderate-to-severe traumatic brain injury (TBI) and posttraumatic stress disorder (PTSD) and their relationship to clinical outcome have yet to be investigated decades after trauma. We utilized structural magnetic resonance imaging and diffusion tensor images to investigate brain volume and WM alterations in Vietnam War veterans with moderate-to-severe TBI and/or PTSD examined 5 decades after trauma.
Data from 160 veterans-history of moderate-to-severe TBI (n = 23), history of TBI+PTSD (n = 36), history of PTSD (n = 53), and control veterans (n = 48)-were obtained from the Department of Defense Alzheimer's Disease Neuroimaging Initiative database. Voxel-based morphometry and tract-based spatial statistics were used to investigate ongoing brain morphometry and WM abnormalities. The fractional anisotropy (FA) and mean diffusivity were then correlated with neuropsychological scores and amyloid deposition in the trauma groups.
Compared with control subjects, the three trauma groups showed gray matter atrophy, lower FA, and distinctly higher diffusivity in the major WM tracts, including the corpus callosum, external and internal capsules, cingulum, and inferior and superior longitudinal fasciculi. The FA and mean diffusivity correlated with cognitive deficits in the trauma groups. Furthermore, the FA in the cingulum correlated negatively with amyloid deposition in the posterior cingulate cortex of all three trauma groups.
Diffusion tensor imaging detected WM abnormalities that correlated with the severity of present cognitive dysfunction and the degree of cortical amyloid deposition decades after moderate-to-severe TBI and/or PTSD. These results may hint that PTSD secondary to TBI may incur late cognitive sequalae and persistence of brain microstructure alterations.
中度至重度创伤性脑损伤（TBI）和创伤后应激障碍（PTSD）后可能出现的白质（WM）改变及其与临床结果的关系，在创伤后几十年仍有待研究。我们利用结构磁共振成像和弥散张量成像来研究 50 年前创伤后患有中度至重度 TBI 和/或 PTSD 的越南战争退伍军人的脑容量和 WM 改变。
从国防部阿尔茨海默病神经影像学倡议数据库中获得了 160 名退伍军人的数据-中度至重度 TBI 病史（n=23）、TBI+PTSD 病史（n=36）、PTSD 病史（n=53）和对照退伍军人（n=48）。基于体素的形态测量学和基于束流的空间统计学用于研究持续的脑形态测量和 WM 异常。然后将各向异性分数（FA）和平均扩散系数与创伤组的神经心理学评分和淀粉样蛋白沉积相关联。
与对照组相比，三个创伤组的大脑灰质萎缩，主要 WM 束的 FA 降低，弥散度明显升高，包括胼胝体、外囊和内囊、扣带束以及下和上纵束。FA 和平均扩散系数与创伤组的认知缺陷相关。此外，扣带束的 FA 与所有三个创伤组的后扣带皮层的淀粉样蛋白沉积呈负相关。
弥散张量成像检测到的 WM 异常与中度至重度 TBI 和/或 PTSD 后当前认知功能障碍的严重程度和皮质淀粉样蛋白沉积程度相关。这些结果可能表明，TBI 继发的 PTSD 可能会导致迟发性认知后遗症和脑微观结构改变的持续存在。
