Hong Qingqi, Li Qingde, Wang Beizhan, Tian Jie, Xu Fei, Liu Kunhong, Cheng Xuan
School of Informatics, Xiamen University, Xiamen, China.
School of Engineering and Computer Science, University of Hull, UK.
Comput Methods Programs Biomed. 2020 Nov;196:105598. doi: 10.1016/j.cmpb.2020.105598. Epub 2020 Jun 18.
High-quality vascular modeling is crucial for blood flow simulations, i.e., computational fluid dynamics (CFD). As without an accurate geometric representation of the smooth vascular surface, it is impossible to make meaningful blood flow simulations. The purpose of this work is to develop high-quality vascular modeling and modification method for blood flow computations.
We develop a new technique for the accurate geometric modeling and modification of vasculatures using implicit extrusion surfaces (IES). In the proposed method, the skeleton of the vascular structure is subdivided into short curve segments, each of which is then represented implicitly locally as the intersection of two mutually orthogonal implicit surfaces defined by distance functions. A set of contour points is extracted and fitted with an implicit curve for accurately specifying the vessel cross-section profile, which is then extruded locally along the skeleton to fill the gaps between two vascular tube cross sections. We also present a new implicit geometric editing technique to modify the constructed vascular model with pathology for virtual stenting.
Experimental results and validations show that accurate vascular models with highly smooth surfaces can be generated by the proposed method. In addition, we conduct some blood flow simulations to indicate the effectiveness of proposed method for hemodynamic simulations.
The proposed technique can achieve precise geometric models of vasculatures with any required degree of smoothness for reliable blood flow simulations.
高质量的血管建模对于血流模拟，即计算流体动力学（CFD）而言至关重要。因为若没有光滑血管表面的精确几何表示，就无法进行有意义的血流模拟。本研究的目的是开发用于血流计算的高质量血管建模与修改方法。
我们开发了一种利用隐式挤压曲面（IES）对血管进行精确几何建模与修改的新技术。在所提出的方法中，血管结构的骨架被细分为短曲线段，然后每个短曲线段在局部被隐式表示为两个由距离函数定义的相互正交隐式曲面的交线。提取一组轮廓点并用隐式曲线进行拟合，以精确指定血管横截面轮廓，然后沿骨架在局部进行挤压，以填充两个血管管横截面之间的间隙。我们还提出了一种新的隐式几何编辑技术，用于对构建的带有病变的血管模型进行修改以用于虚拟支架置入。
实验结果与验证表明，所提出的方法能够生成具有高度光滑表面的精确血管模型。此外，我们进行了一些血流模拟，以表明所提出的方法在血流动力学模拟方面的有效性。
所提出的技术能够实现具有任何所需光滑度的精确血管几何模型，以进行可靠的血流模拟。
