Age-related microstructural differences quantified using myelin water imaging and advanced diffusion MRI
Age-related microstructural differences quantified using myelin water imaging and advanced diffusion MRI
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DOI：
10.1016/j.neurobiolaging.2015.02.029
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发表时间：
2015-06-01
影响因子：
4.2
通讯作者：
Emsell, Louise
中科院分区：
文献类型：
--
作者：
Billiet, Thibo;Vandenbulcke, Mathieu;Emsell, Louise
使用扩散张量成像（DTI）检测年龄相关的显微结构差异。虽然DTI对衰老的影响很敏感，但它并不特定于任何潜在的生物学机制，包括脱髓鞘。结合多指数T2弛豫（MET2）和多壳层扩散MRI （dMRI）技术可以阐明这一过程。从59名17-70岁的健康参与者中获得多壳dMRI和MET2数据。评估与多种dMRI模型（DTI、弥散峰度成像[DKI]、神经突取向弥散和密度成像[NODDI]）和髓鞘敏感MET2指标相关的全脑和区域年龄相关性。随着年龄的增长，DTI和NODDI的各向同性扩散系数普遍增加。在额叶白质中，分数各向异性随着年龄的增长而线性下降，与“神经突”弥散增加平行，髓鞘水分数无差异。DKI测量和神经突密度与髓鞘水分数、细胞内和细胞外水分数有良好的相关性。DTI估计仍然是白质中与年龄相关的变化最敏感的标志之一。NODDI、DKI和MET2表明，额叶分数各向异性的最初下降可能是由于轴突弥散增加而不是脱髓鞘。(C) 2015爱思唯尔公司版权所有。
Age-related microstructural differences have been detected using diffusion tensor imaging (DTI). Although DTI is sensitive to the effects of aging, it is not specific to any underlying biological mechanism, including demyelination. Combining multiexponential T2 relaxation (MET2) and multishell diffusion MRI (dMRI) techniques may elucidate such processes. Multishell dMRI and MET2 data were acquired from 59 healthy participants aged 17-70 years. Whole-brain and regional age-associated correlations of measures related to multiple dMRI models (DTI, diffusion kurtosis imaging [DKI], neurite orientation dispersion and density imaging [NODDI]) and myelin-sensitive MET2 metrics were assessed. DTI and NODDI revealed widespread increases in isotropic diffusivity with increasing age. In frontal white matter, fractional anisotropy linearly decreased with age, paralleled by increased "neurite" dispersion and no difference in myelin water fraction. DKI measures and neurite density correlated well with myelin water fraction and intracellular and extracellular water fraction. DTI estimates remain among the most sensitive markers for age-related alterations in white matter. NODDI, DKI, and MET2 indicate that the initial decrease in frontal fractional anisotropy may be due to increased axonal dispersion rather than demyelination. (C) 2015 Elsevier Inc. All rights reserved.