Biexponential diffusion tensor analysis of human brain diffusion data
Biexponential diffusion tensor analysis of human brain diffusion data
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DOI：
10.1002/mrm.10685
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发表时间：
2004-02-01
影响因子：
3.3
通讯作者：
Mulkern, RV
中科院分区：
文献类型：
--
作者：
Maier, SE;Vajapeyam, S;Mulkern, RV
几项研究表明，在b因子扩展范围内的组织中，信号衰减显著偏离基本单指数模型。迄今尚未查明这一离开的真正性质。对于目前的研究，线扫描扩散图像的大脑适合双指数扩散张量分析，在临床MR系统上获得正常受试者。对于6个非共线方向的每一个，收集了32个b因子范围为5至5000 s/mm（2）的图像。双指数拟合产生了快速和缓慢扩散组件的参数图。扩散数据的一个子集（由在5至972 s/mm（2）之间的常规b因子范围内获得的图像组成）用于单指数扩散张量分析。分数各向异性（FA）的快速扩散组件和单指数拟合没有表现出显着差异。FA的慢扩散双指数组件是显着较高的，特别是在较低的纤维密度的地区。的两个双指数组件和单指数的解决方案的主要扩散方向在很大程度上是相同的，并在协议与已知的纤维束。第二和第三，扩散特征向量方向也似乎是对齐的，但它们在局部区域表现出显着的偏差。(C)2004 Wiley-Liss，Inc.
Several studies have shown that in tissues over an extended range of b-factors, the signal decay deviates significantly from the basic monoexponential model. The true nature of this departure has to date not been identified. For the current study, line scan diffusion images of brain suitable for biexponential diffusion tensor analysis were acquired in normal subjects on a clinical MR system. For each of six noncollinear directions, 32 images with b-factors ranging from 5 to 5000 s/mm(2) were collected. Biexponential fits yielded parameter maps for a fast and a slow diffusion component. A subset of the diffusion data, consisting of the images obtained at the conventional range of b-factors between 5 and 972 s/mm(2), was used for monoexponential diffusion tensor analysis. Fractional anisotropy (FA) of the fast-diffusion component and the monoexponential fit exhibited no significant difference. FA of the slow-diffusion biexponential component was significantly higher, particularly in areas of lower fiber density. The principal diffusion directions for the two biexponential components and the monoexponential solution were largely the same and in agreement with known fiber tracts. The second and third, diffusion eigenvector directions also appeared to be aligned, but they exhibited significant deviations in localized areas. (C) 2004 Wiley-Liss, Inc.