Interfaculty Initiative in Information Studies / Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, Japan.
Curr Pharm Biotechnol. 2012 Sep;13(11):2153-65. doi: 10.2174/138920112802502105.
To develop a targeted drug delivery system for cerebrovascular disorders such as stroke, it is important to obtain detailed information on flow rates and hemodynamics of the human cerebrovascular system for individual patients. A patient-specific integrated numerical simulation system has been developed by the authors such that vascular geometry is constructed from medical images such as magnetic resonance imaging (MRI) or computed tomography (CT) data, and computational conditions are modeled mathematically to represent the realistic in vivo environments. In general, the three-dimensional numerical simulation using a patient-specific model is conducted only for a localized diseased region with atherosclerosis or an aneurysm. Although the analysis region is only a part of the circulatory system, the simulation should include the effects from the entire circulatory system. Since the peripheral network determines the flow distributions in the cerebrovascular system, the paper reviews the recent simulation methods to take into account the network by coupling the image-based three-dimensional simulation with a one- and zero-dimensional simulations as an outflow boundary condition The paper shows the mathematical modeling of the multi-scale outflow boundary condition and its applications to patient- specific models of the arterial circle of Willis. The results are compared to those using the conventional, free-stream boundary condition. As a result, the multi-scale outflow boundary condition shows a significant difference in flow rate of each artery and in flow distribution in the arterial circle of Willis.
为了开发针对中风等脑血管疾病的靶向药物输送系统，重要的是要为个体患者获得有关人类脑血管系统流速和血液动力学的详细信息。作者开发了一种特定于患者的集成数值模拟系统，使得血管几何形状可以从磁共振成像（MRI）或计算机断层扫描（CT）等医学图像构建，并且计算条件可以通过数学建模来代表真实的体内环境。通常，仅对具有动脉粥样硬化或动脉瘤的局部病变区域进行基于患者的三维数值模拟。尽管分析区域仅是循环系统的一部分，但模拟应包括整个循环系统的影响。由于外围网络决定了脑血管系统中的流量分布，因此本文综述了最近的模拟方法，通过将基于图像的三维模拟与一维和零维模拟耦合作为流出边界条件来考虑网络。本文展示了多尺度流出边界条件的数学建模及其在Willis 动脉环的特定于患者的模型中的应用。将结果与使用传统的自由流边界条件的结果进行了比较。结果表明，多尺度流出边界条件在每个动脉的流量和Willis 动脉环的流量分布方面存在显著差异。
