Diffusion tensor MR imaging of the human brain
Diffusion tensor MR imaging of the human brain
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DOI：
10.1148/radiology.201.3.8939209
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发表时间：
1996-12-01
期刊：
影响因子：
19.7
通讯作者：
DiChiro, G
中科院分区：
文献类型：
--
作者：
Pierpaoli, C;Jezzard, P;DiChiro, G
目的：通过对患者取向不敏感的扩散张量D的定量参数，评估正常人大脑中水扩散的内在特性。材料与方法：对8名健康成人在约25分钟内获得的31张多断面交错回波平面扩散加权图像，计算其主扩散系数D、微量(D)和扩散各向异性指数的分布图。结果：正常脑实质中痕量(D)(约为2,100 x 10（-6) mm(2)/sec）无统计学差异，但皮层中痕量(D)更高。扩散各向异性在不同白质区域之间差异很大，反映了纤维束结构的差异。在胼胝体和锥体束中，平行扩散率与垂直扩散率之比约为先前报道的三倍，扩散呈圆柱对称。然而，在其他白质区域，特别是在半瓣中心，扩散各向异性较低，未观察到圆柱对称。从D导出的参数图也用于根据组织的扩散特性来分割组织。结论：定量表征水在各向异性、异质取向组织中的扩散在临床上是可行的。这将改善各种灰质和白质疾病的神经放射学评估。
PURPOSE: To assess intrinsic properties of water diffusion in normal human brain by using quantitative parameters derived from the diffusion tensor, D, which are insensitive to patient orientation.MATERIALS AND METHODS: Maps of the principal diffusivities of D, of Trace(D), and of diffusion anisotropy indices were calculated in eight healthy adults from 31 multisection, interleaved echo-planar diffusion-weighted images acquired in about 25 minutes.RESULTS: No statistically significant differences in Trace(D) (approximate to 2,100 x 10(-6) mm(2)/sec) were found within normal brain parenchyma, except in the cortex, where Trace(D) was higher. Diffusion anisotropy varied widely among different white matter regions, reflecting differences in fiber-tract architecture. In the corpus callosum and pyramidal tracts, the ratio of parallel to perpendicular diffusivities was approximately threefold higher than previously reported, and diffusion appeared cylindrically symmetric. However, in other white matter regions, particularly in the centrum semiovale, diffusion anisotropy was low, and cylindrical symmetry was not observed. Maps of parameters derived from D were also used to segment tissues based on their diffusion properties.CONCLUSION: A quantitative characterization of water diffusion in anisotropic, heterogeneously oriented tissues is clinically feasible. This should improve the neuroradiologic assessment of a variety of gray and white matter disorders.