Mechanical Engineering Department, Northern Arizona University, Flagstaff, AZ, USA.
Mechanical Engineering Department, Northern Arizona University, Flagstaff, AZ, USA.
J Biomech. 2019 May 9;88:122-129. doi: 10.1016/j.jbiomech.2019.03.028. Epub 2019 Mar 27.
Flow stagnation and residence time (RT) are important features of diseased arterial flows that influence biochemical transport processes and thrombosis. RT calculation methods are classified into Eulerian and Lagrangian approaches where several measures have been proposed to quantify RT. Each of these methods has a different definition of RT, and it is not clear how they are related. In this study, image-based computational models of blood flow in an abdominal aortic aneurysm and a cerebral aneurysm were considered and RT was calculated using different methods. In the Lagrangian methods, discrete particle tracking of massless tracers was used to calculate particle residence time and mean exposure time. In the Eulerian methods, continuum transport models were used to quantify RT using Eulerian RT and virtual ink approaches. Point-wise RT and Eulerian indicator RT were also computed based on measures derived from velocity. A comparison of these methods is presented and the implications of each method are discussed. Our results highlight that most RT methods have a conceptually distinct definition of RT and therefore should be utilized depending on the specific application of interest.
血流停滞和停留时间（RT）是病变动脉血流的重要特征，会影响生化传输过程和血栓形成。RT 计算方法分为欧拉方法和拉格朗日方法，其中已经提出了几种用于量化 RT 的方法。这些方法中的每一种都对 RT 有不同的定义，目前尚不清楚它们之间的关系。在这项研究中，考虑了腹主动脉瘤和脑动脉瘤的血流基于图像的计算模型，并使用不同的方法计算 RT。在拉格朗日方法中，使用无质量示踪剂的离散粒子跟踪来计算粒子停留时间和平均暴露时间。在欧拉方法中，使用连续体输运模型通过欧拉 RT 和虚拟墨汁方法来量化 RT。还基于速度导出的度量值计算了逐点 RT 和欧拉指示剂 RT。对这些方法进行了比较，并讨论了每种方法的意义。我们的结果强调，大多数 RT 方法对 RT 有概念上不同的定义，因此应根据特定的应用领域进行选择。
