Free Water Elimination and Mapping from Diffusion MRI
Free Water Elimination and Mapping from Diffusion MRI
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DOI：
10.1002/mrm.22055
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发表时间：
2009-09-01
影响因子：
3.3
通讯作者：
Assaf, Yaniv
中科院分区：
文献类型：
--
作者：
Pasternak, Ofer;Sochen, Nir;Assaf, Yaniv
当图像体素包含具有自由水的部分脑组织体积（诸如脑脊液或水肿）时，将脑组织特性与扩散张量成像（DTI）相关联是有限的，使得DTI指数不再用于描述潜在的组织特性。我们在这里提出了一种方法，用于分离周围的自由水的脑组织的扩散特性，同时映射的自由水的体积。这是通过拟合双张量模型来实现的，其中引入了数学框架来稳定拟合。将该方法应用于来自健康受试者和水肿患者的数据集，得到了校正的DTI指数和更完整的通道重建，该重建靠近心室并通过水肿。我们能够根据底层组织的情况将水肿分割成不同的区域。此外，自由水体积被建议作为一个新的定量对比扩散MRI。研究结果表明，自由水不限于脑实质的边界，因此，它有助于周围的神经束的架构，并可能表明特定的解剖过程。分析需要常规的DTI采集，并且可以很容易地与现有的DTI管道合并。Magn Reson Med 62：717-730，2009。(C)2009威利-利斯公司
Relating brain tissue properties to diffusion tensor imaging (DTI) is limited when an image voxel contains partial volume of brain tissue with free water, such as cerebrospinal fluid or edema, rendering the DTI indices no longer useful for describing the underlying tissue properties. We propose here a method for separating diffusion properties of brain tissue from surrounding free water while mapping the free water volume. This is achieved by fitting a bi-tensor model for which a mathematical framework is introduced to stabilize the fitting. Applying the method on datasets from a healthy subject and a patient with edema yielded corrected DTI indices and a more complete tract reconstruction that passed next to the ventricles and through the edema. We were able to segment the edema into areas according to the condition of the underlying tissue. In addition, the volume of free water is suggested as a new quantitative contrast of diffusion MRI. The findings suggest that free water is not limited to the borders of the brain parenchyma; it therefore contributes to the architecture surrounding neuronal bundles and may indicate specific anatomical processes. The analysis requires a conventional DTI acquisition and can be easily merged with existing DTI pipelines. Magn Reson Med 62: 717-730, 2009. (C) 2009 Wiley-Liss, Inc.