Compartment models of the diffusion MR signal in brain white matter: A taxonomy and comparison
Compartment models of the diffusion MR signal in brain white matter: A taxonomy and comparison
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DOI：
10.1016/j.neuroimage.2011.09.081
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发表时间：
2012-02-01
期刊：
影响因子：
5.7
通讯作者：
Alexander, Daniel C.
中科院分区：
文献类型：
--
作者：
Panagiotaki, Eleftheria;Schneider, Torben;Alexander, Daniel C.
本文的目的是确定一个准确的模型的扩散MR信号在大脑的白色物质的最低要求。我们构建了一个分类的多室模型的白色物质的简单模型的组合内和外轴突空间。我们设计了一种新的扩散MRI协议，提供了广泛的成像参数的扩散敏化平行和垂直于白色物质纤维的测量。我们使用该协议从两个固定的大鼠大脑中获取数据，这使我们能够拟合，研究和比较不同的模型。该研究共检查了47个分析模型，包括文献中的几个常用模型，我们将其置于分类中。结果表明，模型，包括轴突内的限制，如球和棒或CHARMED，一般解释的数据比那些没有，如DT或双指数模型。然而，三房室模型解释限制平行的轴突，并纳入孔径最准确地解释测量。最佳拟合来自于将轴突外空间的全扩散张量（DT）模型与单个半径的圆柱形轴突内组件和非零半径的第三球形隔室相结合。我们还测量了非零半径轴内模型的稳定性，发现单半径轴内模型比伽马分布半径模型更稳定，具有相似的拟合性能。(C)2011 Elsevier Inc. All rights reserved.
This paper aims to identify the minimum requirements for an accurate model of the diffusion MR signal in white matter of the brain. We construct a taxonomy of multi-compartment models of white matter from combinations of simple models for the intra- and the extra-axonal spaces. We devise a new diffusion MRI protocol that provides measurements with a wide range of imaging parameters for diffusion sensitization both parallel and perpendicular to white matter fibres. We use the protocol to acquire data from two fixed rat brains, which allows us to fit, study and compare the different models. The study examines a total of 47 analytic models, including several well-used models from the literature, which we place within the taxonomy. The results show that models that incorporate intra-axonal restriction, such as ball and stick or CHARMED, generally explain the data better than those that do not, such as the DT or the biexponential models. However, three-compartment models which account for restriction parallel to the axons and incorporate pore size explain the measurements most accurately. The best fit comes from combining a full diffusion tensor (DT) model of the extra-axonal space with a cylindrical intra-axonal component of single radius and a third spherical compartment of non-zero radius. We also measure the stability of the non-zero radius intra-axonal models and find that single radius intra-axonal models are more stable than gamma distributed radii models with similar fitting performance. (C) 2011 Elsevier Inc. All rights reserved.