Conformal initialization for shape analysis applications in SlicerSALT.
Conformal initialization for shape analysis applications in SlicerSALT.
复制标题
SlicerSALT 中形状分析应用的保形初始化。
DOI：
10.1117/12.2503894
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Styner,Martin
中科院分区：
文献类型：
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作者：
Fang,Zhengyang;Mostapha,Mahmoud;Prieto,Juan;Styner,Martin
形状分析是神经影像学研究界使用的一种重要方法，因为它具有精确定位健康结构和病理结构之间形态变化的潜力。神经影像学界流行的形状分析框架基于将表面位置编码为球谐函数，用于称为 SPHARM-PDM 的表示。1 SPHARM-PDM 管道将单个大脑结构（例如海马体）的一组大脑分割作为输入，并将其转换为相应的球谐描述 (SPHARM)，然后将其采样到三角表面 (SPHARM-PDM)。目前，SPHARM-PDM 管道利用基于表面网格到单位球体的基于初始热方程的映射的球形映射的面积保留优化。对于具有复杂形状的物体，这种初始球形映射会遭受高度映射失真，并且始终不能通过以下优化过程来纠正。在这里，我们提出使用基于共形平坦化的替代初始化。2该方法采用双射角保持共形平坦化方案来代替热方程映射方案作为SPHARM-PDM管道中使用的初始化。在根据各种复杂结构计算出形状的定量测量结果后，我们得出的结论是，在大多数情况下，新管道比旧管道产生的结果要好得多。本文的主要贡献是基于切片器执行模型的命令行工具，它将共形展平合并到 SPHARM-PDM 管道中，以在 SALT 形状分析工具箱中使用。
Shape analysis is an important method used in neuroimaging research community due to its potential to precisely locate morphological changes between healthy and pathological structures. A popular shape analysis framework in the neuroimaging community is based on the encoding surface locations as spherical harmonics for a representation called SPHARM-PDM.1 The SPHARM-PDM pipeline takes a set of brain segmentation of a single brain structure (for example, hippocampus) as input and converts them into a corresponding spherical harmonic description (SPHARM), which is then sampled into triangulated surface (SPHARM-PDM). At present, the SPHARM-PDM pipeline utilizes an area-preserving optimization of the spherical mapping based on an initial heat-equation based mapping of the surface mesh to the unit sphere. In the case of objects with complex shape, this initial spherical mapping suffers from a high degree of mapping distortion that cannot always be corrected by the following optimization procedure. Here we proposed the use of an alternative initialization based on a conformal flattening.2 This method adopts a bijective angle preserving conformal flattening scheme to replace the heat equation mapping scheme as initialization for use in the SPHARM-PDM pipeline. After quantitative measures of shape calculated from various complex structures, we concluded that in most cases, the new pipeline produced dramatically better results than the old pipeline. The main contribution of this paper is a command line tool based on the Slicer Execution Model, which merges the conformal flattening into the SPHARM-PDM pipeline for use in the SALT shape analysis toolbox.