MR DIFFUSION TENSOR SPECTROSCOPY AND IMAGING
MR DIFFUSION TENSOR SPECTROSCOPY AND IMAGING
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DOI：
10.1016/s0006-3495(94)80775-1
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发表时间：
1994-01-01
影响因子：
3.4
通讯作者：
LEBIHAN, D
中科院分区：
文献类型：
--
作者：
BASSER, PJ;MATTIELLO, J;LEBIHAN, D
本文描述了一种新的核磁共振成像方式--磁共振扩散张量成像。它包括估计体素内的有效扩散张量D-Eff，然后显示从中得出的有用的量。我们展示了如何利用水(或代谢物)在各向异性组织中的各向异性扩散现象，通过这些核磁共振方法非侵入性地测量，来确定纤维束方向和平均颗粒位移。一旦从一系列核磁共振脉冲梯度自旋回波实验中估算出D-ef，就可以确定组织的三个正交各向异性轴。它们与D-Eff的特征向量重合，而沿这些正交各向异性方向的有效扩散系数是D-Eff的本征值。在每个体素中构造的扩散椭球体描述了这些正交各向异性轴和这些方向上的平均扩散距离。此外，D-Eff的三个标量不变量与组织在实验室参照系中的取向无关，揭示了反映局部微结构和解剖结构的分子流动性的有用信息。本质上，描述各向异性介质中输运过程的张量(如D-ef)在宏观体素内包含标量(如表观扩散系数、质子密度、T-1和T-2)所不包含的新信息。
This paper describes a new NMR imaging modality-MR diffusion tensor imaging. It consists of estimating an effective diffusion tensor, D-eff, within a voxel, and then displaying useful quantities derived from it. We show how the phenomenon of anisotropic diffusion of water (or metabolites) in anisotropic tissues, measured noninvasively by these NMR methods, is exploited to determine fiber tract orientation and mean particle displacements. Once D-eff is estimated from a series of NMR pulsed-gradient, spin-echo experiments, a tissue's three orthotropic axes can be determined. They coincide with the eigenvectors of D-eff while the effective diffusivities along these orthotropic directions are the eigenvalues of D-eff. Diffusion ellipsoids, constructed in each voxel from D-eff depict both these orthotropic axes and the mean diffusion distances in these directions. Moreover, the three scalar invariants of D-eff, which are independent of the tissue's orientation in the laboratory frame of reference, reveal useful information about molecular mobility reflective of local microstructure and anatomy. Inherently, tensors (like D-eff) describing transport processes in anisotropic media contain new information within a macroscopic voxel that scalars (such as the apparent diffusivity, proton density, T-1, and T-2) do not.