Hanyu H, Shindo H, Kakizaki D, Abe K, Takasaki M
Department of Geriatric Medicine, Tokyo Medical College.
Rinsho Shinkeigaku. 1996 Jul;36(7):909-11.
To investigate changes in water diffusion in the cerebral white matter in Alzheimer-type dementia (AD), diffusion MRI studies were performed on 11 patients with AD without hyperintensity lesions on T2-weighted images, and 10 age-matched controls. In the anterior and posterior white matter around the lateral ventricule, and the splenium of the corpus callosum, the apparent diffusion coefficients (ADCs), in which the diffusion gradient was applied perpendicular to the predominant fiber direction, were significantly higher in patients with AD than in the controls. However, those in which the diffusion gradient was applied parallel to the predominant fiber direction, there were no significant difference in ADCs between patients and controls. Therefore, diffusional anisotropy was lost in the white matter. These results suggest that demyelination occurs in patients with AD even in apparently normal white matter (without signal abnormalitis). Degeneration related to grey matter encephalopathy may be a possible explanation of the demyelinating process in the white matter.
为研究阿尔茨海默型痴呆（AD）患者脑白质水扩散的变化，对11例T2加权图像上无高信号病变的AD患者及10例年龄匹配的对照者进行了扩散磁共振成像研究。在侧脑室周围的前后白质以及胼胝体压部，扩散梯度垂直于主要纤维方向时的表观扩散系数（ADC），AD患者显著高于对照者。然而，扩散梯度平行于主要纤维方向时，患者与对照者的ADC无显著差异。因此，白质中扩散各向异性丧失。这些结果表明，AD患者即使在看似正常的白质（无信号异常）中也会发生脱髓鞘。与灰质脑病相关的变性可能是白质脱髓鞘过程的一种可能解释。
