Hanyu H, Shindo H, Kakizaki D, Abe K, Iwamoto T, Takasaki M
Department of Geriatric Medicine, Tokyo Medical College, Japan.
Gerontology. 1997;43(6):343-51. doi: 10.1159/000213874.
We investigated the changes in water diffusion in the cerebral white matter in 19 patients with Alzheimer's disease (AD), including 11 without and 8 with periventricular hyperintensity (PVH) lesions, using diffusion-weighted magnetic resonance imaging (MRI). The apparent diffusion coefficients in the anterior and posterior white matter were significantly higher in the 19 AD patients than in the 10 age-matched controls. The apparent diffusion coefficients were higher in patients with PVH than in those without. The anisotropic ratios, defined as diffusion restricted perpendicular to the direction of the nerve fibers, were significantly higher in AD patients, even in those without PVH, than in the controls. Our results suggest that mild myelin loss occurs in AD patients even in the apparently normal white matter. A definite loss of myelin and axons, including incomplete infarction, occurs in the white matter, as seen on T2-weighted images as PVH. Studies with diffusion-weighted MRI may allow the characterization of different pathological processes and enable the demonstration of underlying white matter lesions in AD that cannot be visualized by conventional MRI.
我们使用扩散加权磁共振成像（MRI）研究了19例阿尔茨海默病（AD）患者脑白质中水扩散的变化，其中11例无脑室周围高信号（PVH）病变，8例有PVH病变。19例AD患者前、后白质的表观扩散系数显著高于10例年龄匹配的对照组。有PVH的患者的表观扩散系数高于无PVH的患者。定义为垂直于神经纤维方向的扩散受限的各向异性比率，在AD患者中显著高于对照组，即使在无PVH的患者中也是如此。我们的结果表明，即使在外观正常的白质中，AD患者也会发生轻度髓鞘丢失。如T2加权图像上所见，白质中发生了明确的髓鞘和轴突丢失，包括不完全梗死，表现为PVH。扩散加权MRI研究可能有助于表征不同的病理过程，并能够显示常规MRI无法显示的AD潜在白质病变。
