Full diffusion characterization implicates regionally disparate neuropathology in Mild Cognitive Impairment
Full diffusion characterization implicates regionally disparate neuropathology in Mild Cognitive Impairment
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DOI：
10.1007/s00429-013-0506-x
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发表时间：
2014-01-01
影响因子：
3.1
通讯作者：
Krikorian, Robert
中科院分区：
文献类型：
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作者：
Boespflug, Erin L.;Storrs, Judd;Krikorian, Robert
扩散张量成像（DTI）用于检测组织病理。在阿尔茨海默病（AD）研究中，DTI已被用于阐明疾病阶段的差异，并跟踪随时间和临床严重程度的进展。这些研究中的许多已经确定穹窿在与前驱AD的记忆衰退相关的病理学的早期阶段特别脆弱。新兴的研究表明，主张量分量，轴向（DA）和径向（DR）扩散率，是更敏感的基础组织病理比平均扩散率（MD）和各向异性分数（FA）。鉴于MCI中已建立的区域特异性组织下降，我们检查了全扩散张量（MD，FA，DR和DA）的组成部分对18名MCI患者中与特定记忆缺陷相关的区域病理学的敏感性。我们研究了多个感兴趣的区域，包括穹窿，颞干和控制区域与多种记忆指标受损严重程度的相关性，包括一种对MCI早期记忆下降特别敏感的神经心理学任务。较好的配对联想学习选择性地与较低的DA相关（β =-0.663，p = 0.003），但与颞干的DR、MD或FA无关。相反，更好的配对联想学习与较低的DR（β =-0.523，p = 0.026）、较高的FA（β = 0.498，p = 0.036）和较低的MD（β =-0.513，p = 0.030）相关，但与穹窿中的DA无关。没有关联被发现的控制区域，或控制认知措施。这些发现表明颞干和穹窿白色物质的不同病理与MCI的早期记忆障碍有关。此外，他们强调了评估完整张量的方法学重要性，而不仅仅是使用DTI进行研究的总结性指标。
Diffusion tensor imaging (DTI) is used to detect tissue pathology. In Alzheimer's disease (AD) research, DTI has been used to elucidate differences in disease stages and to track progression over time and clinical severity. Many of these studies have identified the fornix as particularly vulnerable in the early stages of pathology associated with memory decline in prodromal AD. Emerging research suggests principal tensor components, axial (DA) and radial (DR) diffusivity, are more sensitive to underlying tissue pathology than are mean diffusivity (MD) and fractional anisotropy (FA). Given the established regionally specific tissue decline in MCI, we examined components of the full diffusion tensor (MD, FA, DR, and DA) for sensitivity to regional pathology associated with specific memory deficits in 18 individuals with MCI. We investigated multiple regions of interest, including fornix, temporal stem, and control regions for association with severity of impairment on multiple memory measures, including a type of neuropsychological task shown to be particularly sensitive to early memory decline in MCI. Better paired associate learning was selectively associated with lower DA (beta = -0.663, p = 0.003), but not with DR, MD, or FA of the temporal stems. Conversely, better paired associate learning was associated with lower DR (beta = -0.523, p = 0.026), higher FA (beta = 0.498, p = 0.036), and lower MD (beta = -0.513, p = 0.030), but not DA in the fornix. No association was found for control regions, or for control cognitive measures. These findings suggest disparate pathology of temporal stems and fornix white matter in association with early memory impairment in MCI. Further, they highlight the methodological importance of evaluating the full tensor, rather than only summative metrics in research using DTI.