Oakes Jessica M, Marsden Alison L, Grandmont Celine, Shadden Shawn C, Darquenne Chantal, Vignon-Clementel Irene E
Mechanical and Aerospace Engineering Department, University of California, San Diego, La Jolla, CA, 92093, USA.
Ann Biomed Eng. 2014 Apr;42(4):899-914. doi: 10.1007/s10439-013-0954-8. Epub 2013 Dec 7.
Image-based in silico modeling tools provide detailed velocity and particle deposition data. However, care must be taken when prescribing boundary conditions to model lung physiology in health or disease, such as in emphysema. In this study, the respiratory resistance and compliance were obtained by solving an inverse problem; a 0D global model based on healthy and emphysematous rat experimental data. Multi-scale CFD simulations were performed by solving the 3D Navier-Stokes equations in an MRI-derived rat geometry coupled to a 0D model. Particles with 0.95 μm diameter were tracked and their distribution in the lung was assessed. Seven 3D-0D simulations were performed: healthy, homogeneous, and five heterogeneous emphysema cases. Compliance (C) was significantly higher (p = 0.04) in the emphysematous rats (C = 0.37 ± 0.14 cm(3)/cmH2O) compared to the healthy rats (C = 0.25 ± 0.04 cm(3)/cmH2O), while the resistance remained unchanged (p = 0.83). There were increases in airflow, particle deposition in the 3D model, and particle delivery to the diseased regions for the heterogeneous cases compared to the homogeneous cases. The results highlight the importance of multi-scale numerical simulations to study airflow and particle distribution in healthy and diseased lungs. The effect of particle size and gravity were studied. Once available, these in silico predictions may be compared to experimental deposition data.
基于图像的计算机模拟工具可提供详细的速度和颗粒沉积数据。然而，在设定边界条件以模拟健康或疾病状态下的肺部生理情况（如肺气肿）时必须谨慎。在本研究中，通过求解一个反问题获得呼吸阻力和顺应性；该反问题是一个基于健康和患肺气肿大鼠实验数据的零维全局模型。通过在与零维模型耦合的MRI衍生大鼠几何模型中求解三维纳维 - 斯托克斯方程进行多尺度计算流体动力学模拟。追踪直径为0.95μm的颗粒，并评估其在肺内的分布。进行了七次三维 - 零维模拟：健康、均匀和五种非均匀肺气肿病例。与健康大鼠（C = 0.25±0.04 cm³/cmH₂O）相比，患肺气肿大鼠的顺应性（C）显著更高（p = 0.04）（C = 0.37±0.14 cm³/cmH₂O），而阻力保持不变（p = 0.83）。与均匀病例相比，非均匀病例的气流增加、三维模型中的颗粒沉积以及颗粒向患病区域的输送均增加。结果突出了多尺度数值模拟对于研究健康和患病肺部气流及颗粒分布的重要性。研究了颗粒大小和重力的影响。一旦可用，这些计算机模拟预测结果可与实验沉积数据进行比较。
