Regional changes of cortical mean diffusivities with aging after correction of partial volume effects.
Regional changes of cortical mean diffusivities with aging after correction of partial volume effects.
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DOI：
10.1016/j.neuroimage.2012.05.082
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发表时间：
2012-09
期刊：
影响因子：
5.7
通讯作者：
Huang, Hao
中科院分区：
文献类型：
--
作者：
Jeon, Tina;Mishra, Virendra;Uh, Jinsoo;Weiner, Myron;Hatanpaa, Kimmo J.;White, Charles L., III;Zhao, Yan D.;Lu, Hanzhang;Diaz-Arrastia, Ramon;Huang, Hao
准确测量年轻、老年健康大脑和阿尔茨海默病（AD）患者的大脑皮层平均扩散率（MD），可以为研究由衰老和AD引起的异质性皮层微结构变化提供依据。由于部分容积效应（PVE），测量皮质MD被高估的脑脊液（CSF）的污染。对于衰老和AD大脑，这种偏差尤其严重，因为这些大脑的皮质显著变薄。在这项研究中，我们的目的是定量描述无偏的区域皮质MD的变化，由于老龄化和AD和描绘老年健康和AD组的皮质变薄MD测量的影响。对14例青年、15例老年健康人和17例AD患者进行DTI和T1加权成像。将T1加权像的脑回和脑叶离散化后转换为DTI，测量PVE矫正前后的局部皮质MD。CSF污染模型用于校正PVE引起的MD偏倚。与青年组相比，老年健康组和AD组的校正MD仅在额叶和边缘区显著增加，而未校正MD在整个皮层均显著增加。AD组边缘回和颞叶回的未校正MD显著高于老年健康组，但PVE校正后MD仅保留在边缘回。还测量了所有组的皮质厚度。PVE矫正后，老年健康组和AD组皮质MD与厚度的相关斜率较矫正前显著降低，而青年组相关斜率无显著变化。这表明，在老年健康和AD组的皮质变薄是一个显着的贡献者的偏差未经校正的皮质MD测量。所建立的年轻、老年健康受试者和AD患者在脑叶、脑回和体素水平上的全面无偏皮质MD轮廓可作为皮质微结构的临床参考。
Accurately measuring the cortical mean diffusivity (MD) derived from diffusion tensor imaging (DTI) at the comprehensive lobe, gyral and voxel level of young, elderly healthy brains and those with Alzheimer's disease (AD) may provide insights on heterogeneous cortical microstructural changes caused by aging and AD. Due to partial volume effects (PVE), the measurement of cortical MD is overestimated with contamination of cerebrospinal fluid (CSF). The bias is especially severe for aging and AD brains because of significant cortical thinning of these brains. In this study, we aimed to quantitatively characterize the unbiased regional cortical MD changes due to aging and AD and delineate the effects of cortical thinning of elderly healthy and AD groups on MD measurements. DTI and T1-weighted images of 14 young, 15 elderly healthy subjects and 17 AD patients were acquired. With the parcellated cortical gyri and lobes from T1 weighted image transformed to DTI, regional cortical MD of all subjects before and after PVE correction were measured. CSF contamination model was used to correct bias of MD caused by PVE. Compared to cortical MD of young group, significant increases of corrected MD for elderly healthy and AD groups were found only in frontal and limbic regions, respectively, while there were significant increases of uncorrected MD all over the cortex. Uncorrected MD are significantly higher in limbic and temporal gyri in AD group, compared to those in elderly healthy group but higher MD only remained in limbic gyri after PVE correction. Cortical thickness was also measured for all groups. The correlation slopes between cortical MD and thickness for elderly healthy and AD groups were significantly decreased after PVE correction compared to before correction while no significant change of correlation slope was detected for young group. It suggests that the cortical thinning in elderly healthy and AD groups is a significant contributor to the bias of uncorrected cortical MD measurement. The established comprehensive unbiased cortical MD profiles of young, elderly healthy subjects and AD patients at the lobe, gyral and voxel level may serve as clinical references for cortical microstructure.
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影响因子：
5.7
作者：
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通讯作者：
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