How does DWI correlate with white matter structures?
How does DWI correlate with white matter structures?
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DOI：
10.1002/mrm.20542
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发表时间：
2005-08-01
影响因子：
3.3
通讯作者：
Kim, DS
中科院分区：
文献类型：
--
作者：
Ronen, I;Ugurbil, K;Kim, DS
弥散加权磁共振成像（DWI）被广泛用于表征脑白色物质（WM），特别是通过使用扩散张量成像（DTI）。本研究在9.4T高分辨率条件下研究了猫视皮层WM的DWI空间特性。结果表明，从DWI图像测量的WM道的空间范围高度依赖于b值。特别是，当垂直于纤维束的主方向施加扩散梯度时，在常用的b值1000 S/mm（2）下估计的纤维束厚度超过T-2加权图像上显示的厚度的50%。只有当b值大于6000 s/mm（2）时，纤维束的厚度才接近于T2加权图像和相同区域组织切片上观察到的厚度。对这些结果的进一步分析表明，选择1000 s/mm（2）的b值对于各向异性WM结构的划分可能不是最佳的。高b值DWI可能包含更特异于WM束的空间信息。
Diffusion-weighted MRI (DWI) is widely used to characterize brain white matter (WM), particularly through the use of diffusion tensor imaging (DTI). In this study the spatial characteristics of DWI in WM of cat visual cortex were investigated at 9.4T at very high resolution. It is shown that the spatial extent of the WM tract as measured from the DWI images depends highly on the b-value. In particular, when the diffusion gradient is applied perpendicular to the main direction of the fiber tract, the estimated thickness of the tract at the commonly used b-value of 1000 S/mm(2) exceeds by 50% the thickness as it appears on a T-2-weighted image. Only at b-values greater than 6000 s/mm(2) does the thickness of the tract approach the thickness characterized by the T-2-weighted image and that observed on histological slices of the same area. Further analysis of these results indicates that the choice of b-value of 1000 s/mm(2) may not be optimal for the demarcation of anisotropic WM structures. DWI at high b-value may contain spatial information that is more specific to WM tracts.