Abstract

Existing computational models used for simulating the flow and species transport in the human airways are zero-dimensional (0D) compartmental, three-dimensional (3D) computational fluid dynamics (CFD), or the recently developed quasi-3D (Q3D) models. Unlike compartmental models, the full CFD and Q3D models are physiologically and anatomically consistent in the mouth and the upper airways, since the starting point of these models is the mouth–lung surface geometry, typically created from computed tomography (CT) scans. However, the current resolution of CT scans limits the airway detection between the 3rd–4th and 7th–9th generations. Consequently, CFD and the Q3D models developed using these scans are generally limited to these generations. In this study, we developed a method to extend the conducting airways from the end of the truncated Q3D lung to the tracheobronchial (TB) limit. We grew the lung generations within the closed lung lobes using the modified constrained constructive optimization, creating an aerodynamically optimized network aiming to produce equal pressure at the distal ends of the terminal segments. This resulted in a TB volume and lateral area of ∼165 cc and ∼2000 cm², respectively. We created a “sac–trumpet” model at each of the TB outlets to represent the alveoli. The volumes of the airways and the individual alveolar generations match the anatomical values by design: with the functional residual capacity at 2611 cc. Lateral surface areas were scaled to match the physiological values. These generated Q3D whole lung models can be efficiently used for conducting multiple breathing cycles of drug transport and deposition simulations.

中文翻译：

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整个肺部的准3D模型：使用约束性构造优化和肺泡建模，使用囊-小管模型，将气道延伸至气管支气管极限

摘要

用于模拟人类呼吸道中的流量和物质迁移的现有计算模型是零维（0D）隔室，三维（3D）计算流体动力学（CFD）或最近开发的准3D（Q3D）模型。与隔室模型不同，完整的CFD和Q3D模型在嘴和上呼吸道的生理和解剖学上是一致的，因为这些模型的起点是通常通过计算机断层扫描（CT）扫描创建的嘴-肺表面几何形状。但是，当前CT扫描的分辨率将气道检测限制在第三至第四代和第七至第9代之间。因此，使用这些扫描程序开发的CFD和Q3D模型通常仅限于这些世代。在这项研究中，我们开发了一种方法，可以将导气管从截断的Q3D肺末端延伸到气管支气管（TB）极限。我们使用改良的约束构造优化方法在封闭的肺叶内生长了肺代，创建了一个空气动力学优化的网络，旨在在末端部分的远端产生相等的压力。TB的体积和侧面面积约为165 cc和约为2000 cm²，分别。我们在每个结核病网点创建了一个“囊-喇叭”模型来代表肺泡。气道和各个肺泡的体积通过设计与解剖学值相匹配：功能残余容量为2611 cc。缩放侧面表面积以匹配生理值。这些生成的Q3D全肺模型可以有效地用于进行药物传输和沉积模拟的多个呼吸循环。