Nakata Yasuhiro, Sato Noriko, Abe Osamu, Shikakura Shoko, Arima Kunimasa, Furuta Nobuo, Uno Masatake, Hirai Shigeo, Masutani Yoshitaka, Ohtomo Kuni, Aoki Shigeki
Department of Radiology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
Radiat Med. 2008 Oct;26(8):466-73. doi: 10.1007/s11604-008-0258-3. Epub 2008 Oct 31.
The aim of this study was to determine diffusion abnormalities in the posterior cingulate fiber tracts (PCFTs) in patients with Alzheimer's disease (AD) by diffusion tensor tractography (DTT).
We studied 23 AD patients and 18 age-matched normal controls who underwent magnetic resonance imaging using diffusion tensor imaging (DTI). DTT of PCFTs was generated from DTI. Mean diffusivity (MD) and fractional anisotropy (FA) were measured in co-registered voxels along with DTT of PCFTs. Student's t-test was used to compare results between the AD patients and normal controls.
The MD in PCFTs was significantly higher in AD patients than in normal controls (P = 0.019). The FA in PCFTs was significantly lower in AD patients than in normal controls (P = 0.007).
The abnormal MD increase and FA decrease, which is considered to indicate a net loss of barriers that restrict water molecular motion and tissue anisotropy of white matter, is consistent with neuropathological data that demonstrate partial loss of myelin, axons, and oligodendrial cells in white matter of AD brains. Our results suggest that MD and FA reflect progression of AD-related histopathological changes in the PCFTs and may represent a useful biological index for monitoring AD.
本研究旨在通过扩散张量纤维束成像（DTT）确定阿尔茨海默病（AD）患者后扣带回纤维束（PCFTs）的扩散异常。
我们研究了23例AD患者和18例年龄匹配的正常对照者，他们均接受了使用扩散张量成像（DTI）的磁共振成像检查。PCFTs的DTT由DTI生成。在与PCFTs的DTT共同配准的体素中测量平均扩散率（MD）和分数各向异性（FA）。采用学生t检验比较AD患者和正常对照者的结果。
AD患者PCFTs中的MD显著高于正常对照者（P = 0.019）。AD患者PCFTs中的FA显著低于正常对照者（P = 0.007）。
MD异常增加和FA异常降低，这被认为表明限制水分子运动的屏障和白质组织各向异性的净损失，与神经病理学数据一致，该数据表明AD脑白质中髓磷脂、轴突和少突胶质细胞部分丢失。我们的结果表明，MD和FA反映了PCFTs中与AD相关的组织病理学变化的进展，可能代表了监测AD的有用生物学指标。
