Delineating white matter structure in diffusion tensor MRI with anisotropy creases
Delineating white matter structure in diffusion tensor MRI with anisotropy creases
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DOI：
10.1016/j.media.2007.07.005
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发表时间：
2007-10-01
影响因子：
10.9
通讯作者：
Westin, Carl-Fredrik
中科院分区：
文献类型：
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作者：
Kindlmann, Gordon;Tricoche, Xavier;Westin, Carl-Fredrik
白质结构的几何模型在弥散张量成像的神经科学应用中发挥着越来越重要的作用，最常用的方法是纤维束成像。然而，对于某些分析任务，可以在扩散各向异性的一阶导数和二阶导数中找到令人信服的替代方法。我们将经典计算机视觉中的脊谷概念扩展到张量场，并将各向异性折痕定义为局部极值张量各向异性的特征。在数学上，这些是各向异性梯度与其黑森矩阵的一个或多个特征向量正交的位点。我们提出，各向异性折痕为提取主要白质通路的骨架提供了基础，因为各向异性的脊与纤维束的内部重合，各向异性的谷与相邻但取向明显的纤维束之间的界面重合。我们提出的折痕提取算法生成高质量的折痕曲面多边形模型，并通过连通分量分析进一步简化该模型。我们在测量的扩散MRI数据上展示了各向异性折痕，并将其与神经束造影相结合，以确认其解剖学相关性。(C) 2007 Elsevier B.V.版权所有
Geometric models of white matter architecture play an increasing role in neuroscientific applications of diffusion tensor imaging, and the most popular method for building them is fiber tractography. For some analysis tasks, however, a compelling alternative may be found in the first and second derivatives of diffusion anisotropy. We extend to tensor fields the notion from classical computer vision of ridges and valleys, and define anisotropy creases as features of locally extremal tensor anisotropy. Mathematically, these are the loci where the gradient of anisotropy is orthogonal to one or more eigenvectors of its Hessian. We propose that anisotropy creases provide a basis for extracting a skeleton of the major white matter pathways, in that ridges of anisotropy coincide with interiors of fiber tracts, and valleys of anisotropy coincide with the interfaces between adjacent but distinctly oriented tracts. The crease extraction algorithm we present generates high-quality polygonal models of crease surfaces, which are further simplified by connected-component analysis. We demonstrate anisotropy creases on measured diffusion MRI data, and visualize them in combination with tractography to confirm their anatomic relevance. (C) 2007 Elsevier B.V. All rights reserved.