MSM simulation of gas flow distribution in human lung

描述（由申请人提供）：该项目的最终目标是开发一个全面的肺气流计算流体动力学（CFD）模型，该模型利用受试者特定的气道几何形状，跨越从最大的支气管气道到肺泡囊的空间尺度，并采用计算机断层扫描（CT）数据驱动的多阶段方法，通过整个移动气道树提供区域通风和气体输送的准确预测。该方法通过数值优化，将三维（3D）和一维（1D）流体动力学模型与CT动态数据相结合，实现真实的多尺度呼吸肺模拟。该模型将带来对空气流动、气体输送和气溶胶颗粒在肺部沉积的新认识。该项目的具体目标是：(1)建立有效的技术，为CFD分析生成特定主题的计算网格；(2)通过开发高效的算法，将定制的三维CFD模型集成到一维气体输运模型中，实现三维到一维耦合（大到小气道）或一维到三维耦合（细支气管到肺泡管）的多尺度模拟；(3)通过一维流动模型，将三维CFD模型与通风动态成像相结合，建立新的通风分布预测模型并进行实验验证；(4)提供耦合算法，并与研究和临床社区共享数据库。我们将使用定制开发的分割软件从CT数据集中提取气道几何形状。然后使用体积填充技术和Voronoi网格方案补充基于ct图像的几何图形。3D-1D耦合CFD模拟将使用上述气道几何形状进行。耦合CFD解将通过CT实验进行验证，并与一维模型进行对比。耦合软件和数据库将通过医学图像档案系统提供给研究和临床社区。该模型的应用包括但不限于改善药物气溶胶给药，预测受试者特定区域通气，以诊断与气道几何形状和实质破坏病理变化相关的模式，以及预测环境污染物对肺功能的长期影响，其中环境暴露已被证明会改变早期气道结构。

DESCRIPTION (provided by applicant): The ultimate goal of the project is to develop a comprehensive computational fluid dynamics (CFD) model for pulmonary air flow that utilizes subject-specific airway geometries, spans spatial scales from the largest bronchial airways to alveolar sac, and employs a Computed Tomography (CT) data-driven, multistage approach to provide accurate predictions of regional ventilation and gas transport through the entire moving airway tree. The approach integrates three-dimensional (3D) and one-dimensional (1D) fluid dynamic models supplemented with dynamic CT data through numerical optimization to achieve realistic multi-scale breathing lung simulations. The model will bring about new understanding of air flow, gas transport, and aerosol particle deposition in the lungs. The specific aims of the project are: (1) Establish efficient techniques for generating subject-specific computational meshes for CFD analysis; (2) Integrate the custom developed 3D CFD model to the 1D gas transport model by developing an efficient algorithm to facilitate 3D to 1D coupling (large to small airways) or 1D to 3D coupling (bronchioles to alveolar ducts) for multi-scale simulation; (3) Develop and experimentally validate a new predictive model of ventilation distribution by linking 3D CFD models to dynamic imaging of ventilation, via 1D flow models; (4) Make available the coupling algorithms and share the databases with the research and clinical communities. We will use the custom developed segmentation software to extract airway geometries from the CT data sets. The CT-image based geometries will then be supplemented with synthetic geometries using the volume filling technique and Voronoi meshing scheme. The 3D-1D coupled CFD simulations will be performed using the above airway geometries. The coupled CFD solutions will be validated through CT experiments and compared with those of the 1D model. The coupling software and databases will be made available to both research and clinical communities through the medical image file archive system. The applications of the model include, but are not limited to, improving pharmaceutical aerosol drug delivery, predicting subject-specific regional ventilation for diagnosis of patterns related to pathologic changes in airway geometry and parenchyma destruction, and predicting long-term effects of environmental pollutants on lung function where environmental exposure has been shown to alter airway structure in early development.