Diffusion Tensor Imaging of the Hippocampus in MCI and Early Alzheimer's Disease
Diffusion Tensor Imaging of the Hippocampus in MCI and Early Alzheimer's Disease
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DOI：
10.3233/jad-2011-0001
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发表时间：
2011-01-01
影响因子：
4
通讯作者：
Yakushev, Igor
中科院分区：
文献类型：
--
作者：
Fellgiebel, Andreas;Yakushev, Igor
海马体是最先受到阿尔茨海默病（AD）病理影响的脑结构之一。在这个区域内的微观结构的变化已经量化在体内使用扩散张量成像（DTI），一个相对新颖的基于MRI的技术映射水的扩散特性。现有的证据表明，DTI衍生的平均扩散率（MD）的前海马比普通体积指数的早期AD患者的情节记忆障碍的程度更具有预测性。因此，（前）海马的MD改变可能高度指示海马功能障碍，从而潜在地使该测量作为监测AD进展的候选标记物合格。需要纵向研究来证实这一概念。基于DTI的海马微结构评估也可能对早期AD诊断和预测阿尔茨海默病痴呆风险受试者的认知能力下降过程具有价值。平均扩散率作为海马完整性的微观结构和宏观结构指数的体积似乎反映了不同的，虽然重叠，神经退行性过程的方面。相比之下，分数各向异性是不太有效的量化在临床背景下的病变海马的微结构完整性。自动算法的开发，提供常规使用的海马体的MD测量，是未来研究的任务。
The hippocampus is among the first brain structures to be affected by Alzheimer's disease (AD) pathology. Microstructural alterations within this region have been quantified in vivo using diffusion tensor imaging (DTI), a relatively novel MRI-based technique for mapping diffusion properties of water. Existing evidence indicates that DTI-derived mean diffusivity (MD) of the anterior hippocampus is more predictive than ordinary volumetric indices of the degree of episodic memory impairment in patients with early AD. Thus, altered MD of the (anterior) hippocampus might be highly indicative of hippocampal dysfunction, thereby potentially qualifying this measure as a candidate marker for monitoring progression of AD. Longitudinal studies are needed to confirm this concept. DTI-based assessment of hippocampal microstructure might be also of value for early AD diagnosis and for predicting the course of cognitive decline in subjects at risk for Alzheimer's dementia. Mean diffusivity as microstructural and volume as macrostructural index of hippocampal integrity seem to reflect different, albeit overlapping, aspects of the neurodegenerative process. In contrast, fractional anisotropy is less efficient for quantifying microstructural integrity of the diseased hippocampus in the clinical context. Development of automatic algorithms, providing MD measurements of the hippocampus for routine use, is a task for future studies.