Max Planck Institute for Human Development, Lentzeallee 94, D-14195 Berlin, Germany.
Neuroimage. 2010 Feb 1;49(3):2104-12. doi: 10.1016/j.neuroimage.2009.09.041. Epub 2009 Sep 25.
We collected MRI diffusion tensor imaging data from 80 younger (20-32 years) and 63 older (60-71 years) healthy adults. Tract-based spatial statistics (TBSS) analysis revealed that white matter integrity, as indicated by decreased fractional anisotropy (FA), was disrupted in numerous structures in older compared to younger adults. These regions displayed five distinct region-specific patterns of age-related differences in other diffusivity properties: (1) increases in both radial and mean diffusivity; (2) increases in radial diffusivity; (3) no differences in parameters other than FA; (4) a decrease in axial and an increase in radial diffusivity; and (5) a decrease in axial and mean diffusivity. These patterns suggest different biological underpinnings of age-related decline in FA, such as demyelination, Wallerian degeneration, gliosis, and severe fiber loss, and may represent stages in a cascade of age-related degeneration in white matter microstructure. This first simultaneous description of age-related differences in FA, mean, axial, and radial diffusivity requires histological and functional validation as well as analyses of intermediate age groups and longitudinal samples.
我们从 80 名年轻成年人（20-32 岁）和 63 名老年成年人（60-71 岁）中收集了 MRI 扩散张量成像数据。基于束的空间统计学（TBSS）分析显示，与年轻成年人相比，老年成年人的许多结构中的白质完整性（以各向异性分数（FA）降低表示）受损。这些区域显示了五种不同的、与年龄相关的弥散性能差异的区域特异性模式：（1）径向和平均弥散度均增加；（2）径向弥散度增加；（3）除 FA 外，其他参数无差异；（4）轴向弥散度降低，径向弥散度增加；（5）轴向和平均弥散度降低。这些模式表明，FA 与年龄相关的下降具有不同的生物学基础，例如脱髓鞘、沃勒变性、神经胶质增生和严重的纤维丢失，并且可能代表了白质微观结构中与年龄相关的退行性变级联的不同阶段。这种对 FA、平均、轴向和径向弥散度与年龄相关差异的首次同步描述需要进行组织学和功能验证，以及对中间年龄组和纵向样本进行分析。
