New modeling and experimental framework to characterize hindered and restricted water diffusion in brain white matter
New modeling and experimental framework to characterize hindered and restricted water diffusion in brain white matter
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DOI：
10.1002/mrm.20274
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发表时间：
2004-11-01
影响因子：
3.3
通讯作者：
Basser, PJ
中科院分区：
文献类型：
--
作者：
Assaf, Y;Freidlin, RZ;Basser, PJ
为了表征脑白色物质中的各向异性水扩散，提出了一个理论框架，该框架结合了水扩散的受阻和受限模型（CHARMED）和体现扩散张量和q空间MRI特征的实验方法。该模型包含一个受阻的轴突外室，其扩散特性的特点是由一个有效的扩散张量，一个轴突内室，其扩散特性的特点是由一个限制模型的圆柱内扩散。受阻模型主要解释了在低B值下观察到的高斯信号衰减;受限非高斯模型在高B下也是如此。沿沿着不同方向获得的高和低B数据都需要估计复合材料模型的各种微观结构参数，例如神经纤维取向、T-2加权轴突外和轴突内体积分数以及主扩散系数。所提出的模型提供了一个描述的限制扩散在3D中给出的3D概率分布（平均传播），这是通过3D傅立叶变换的估计信号衰减分布。使用合成体模对新模型进行测试，并在切除的脊髓组织上进行验证。该框架显示出比扩散张量成像更精确和准确地确定两个或多个纤维隔室的方向的希望。2004年出版Wiley-Liss，Inc（匕首）。
To characterize anisotropic water diffusion in brain white matter, a theoretical framework is proposed that combines hindered and restricted models of water diffusion (CHARMED) and an experimental methodology that embodies features of diffusion tensor and q-space MRI. This model contains a hindered extra-axonal compartment, whose diffusion properties are characterized by an effective diffusion tensor, an an intra-axonal compartment, whose diffusion properties are characterized by a restricted model of diffusion within cylinders. The hindered model primarily explains the Gaussian signal attenuation observed at low b values; the restricted non-Gaussian model does so at high b. Both high and low b data obtained along different directions are required to estimate various microstructural parameters of the composite model, such as the nerve fiber orientation(s), the T-2-weighted extra- and intra-axonal volume fractions, and principal diffusivities. The proposed model provides a description of restricted diffusion in 3D given by a 3D probability distribution (average propagator), which is obtained by 3D Fourier transformation of the estimated signal attenuation profile. The new model is tested using synthetic phantoms and validated on excised spinal cord tissue. This framework shows promise in determining the orientations of two or more fiber compartments more precisely and accurately than with diffusion tensor imaging. Published 2004 Wiley-Liss, Inc(dagger).