基于脑白质纤维密度成像研究胼胝体神经纤维密度随年龄变化的规律

Study on the Change of Nerve Fiber Density in Corpus Callosum with Age Based on White Matter Fiber Density Imaging

目的:利用脑白质纤维密度成像(TDI)研究不同年龄段胼胝体(CC)内纤维数目的分布规律,分析CC随年龄增长变化的复杂性和差异性;对照研究TDI是否能在CC体积变化之前检测到其内纤维数目的变化,以及FA值、胼胝体体积的变化。方法:纳入131名健康志愿者,根据年龄分为6组。通过球面反卷积方法来重建轨道密度图。将CC分割成5个子区域,并使用T1W-3D图像测量所有组中每个子区域的TDI,体积和分数各向异性(FA)并进行比较。结果:CC2、CC3和CC4的TDI值增加到40岁时最高,随后降低。CC2、CC3和CC4的体积在30~50年时增加,在50~60年减少。CC2、CC3和CC4的FA在40~60岁之间下降。结论:胼胝体的TDI,体积和FA值存在年龄相关差异。TDI对检测年龄相关的胼胝体差异具有高度敏感性。

Purpose: To study the distribution of fibers in corpus callosum(CC) of different ages by trackdensity imaging(TDI) and analyse the complexity and difference of CC with age. Furtherly, to figure out whether TDI can detect the change of fibers number before the CC volume being changed by comparing the age-related changes with fractional anisotropy(FA) value and CC volume.Methods: The study included 131 healthy volunteers,who were divided into six groups according to their ages. The spherical deconvolution method was used to reconstruct the orbit density map. The CC was divided into five sub-regions. TDI, volume and FA of each sub region in all groups were measured and compared using T1W-3D images.Results: The TDI values of CC2, CC3, and CC4 increased to the maximum at the age of 40, and then decreased. The volume of CC2, CC3 and CC4 increased between 30 and 50 years, and decreased between 50 and 60 years. The FA of CC2, CC3 and CC4 decreased between40 and 60 years old. Conclusion: There exist the age-related differences in TDI, volume, and FA of the corpus callosum. TDI is highly sensitive to detect age-related differences in the corpus callosum.