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空气流动计算流体动力学(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腔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来提供对整个移动的气道树的区域通风和气体运输的准确预测。该方法通过数值优化将三维(3D)和一维(1D)流体动力学模型与动态CT数据相结合，实现了逼真的多尺度呼吸肺模拟。该模型将带来对空气流动、气体传输和肺部气溶胶粒子沉积的新理解。该项目的具体目标是：(1)建立用于CFD分析的特定对象的高效计算网格生成技术；(2)通过开发高效的算法，将定制开发的3D CFD模型与1D气体传输模型集成，以便于进行多尺度模拟的3D-1D耦合(大到小气道)或1D-3D耦合(细支气管到肺泡管)；(3)开发并实验验证新的通风分布预测模型，通过1D流动模型将3D CFD模型与通风的动态成像联系起来；(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网格方案对基于CT图像的几何形状进行补充。3D-1D耦合CFD模拟将使用上述通道几何形状进行。耦合的CFD解将通过CT实验进行验证，并与一维模型的结果进行比较。将通过医学影像档案系统向研究界和临床界提供连接软件和数据库。该模型的应用包括但不限于，改善药物气雾剂的药物输送，预测特定对象的区域通气量以诊断与呼吸道几何形状和实质破坏相关的病理变化模式，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在发育早期改变了呼吸道结构。

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.