Multimodal imaging evidence for axonal and myelin deterioration in amnestic mild cognitive impairment.
Multimodal imaging evidence for axonal and myelin deterioration in amnestic mild cognitive impairment.
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DOI：
10.3233/jad-2012-112165
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Smith CD
中科院分区：
文献类型：
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作者：
Gold BT;Jiang Y;Powell DK;Smith CD
白色物质（WM）的微结构下降已被证明在阿尔茨海默病和遗忘型轻度认知障碍（aMCI）。然而，控制WM萎缩后aMCI中WM显微结构变化的模式尚不清楚。在这里，我们解决这个问题，通过联合考虑aMCI改变分数各向异性，平均扩散率，轴向扩散率和径向扩散率，以及宏观结构体积在WM和灰质室。参与者包括18名aMCI患者和24名健康老年人。使用基于束的空间统计（TBSS）和体素分析的高分辨率结构数据进行了体素分析的扩散张量成像数据进行。在控制WM萎缩后，TBSS结果的主要模式表明各向异性分数降低，平均扩散率/径向扩散率/轴向扩散率仅发生微小变化。这些WM微结构下降接壤和/或连接到显示体积下降的灰质结构。然而，在连接的灰质结构中，WM完整性和体积之间的潜在关系都不显著，并且与单独使用海马萎缩相比，添加分数各向异性信息提高了aMCI的分类准确性。这些结果表明，WM微结构下降提供了萎缩测量未捕获的独特信息，这可能有助于磁共振成像对aMCI检测的贡献。
White matter (WM) microstructural declines have been demonstrated in Alzheimer’s disease and amnestic mild cognitive impairment (aMCI). However, the pattern of WM microstructural changes in aMCI after controlling for WM atrophy is unknown. Here, we address this issue through joint consideration of aMCI alterations in fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity, as well as macrostructural volume in WM and gray matter compartments. Participants were 18 individuals with aMCI and 24 healthy seniors. Voxelwise analyses of diffusion tensor imaging data was carried out using tract-based spatial statistics (TBSS) and voxelwise analyses of high-resolution structural data was conducted using voxel based morphometry. After controlling for WM atrophy, the main pattern of TBSS findings indicated reduced fractional anisotropy with only small alterations in mean diffusivity/radial diffusivity/axial diffusivity. These WM microstructural declines bordered and/or were connected to gray matter structures showing volumetric declines. However, none of the potential relationships between WM integrity and volume in connected gray matter structures was significant, and adding fractional anisotropy information improved the classificatory accuracy of aMCI compared to the use of hippocampal atrophy alone. These results suggest that WM microstructural declines provide unique information not captured by atrophy measures that may aid the magnetic resonance imaging contribution to aMCI detection.