Sino-Dutch Biomedical and Information Engineering School, Northeastern University, Shenyang, China.
Key Laboratory of Medical Image Computing of Northeastern University (Ministry of Education), Shenyang, China.
J Med Syst. 2018 Mar 1;42(4):65. doi: 10.1007/s10916-017-0879-0.
Tracheal Bronchus (TB) is a rare congenital anomaly characterized by the presence of an abnormal bronchus originating from the trachea or main bronchi and directed toward the upper lobe. The airflow pattern in tracheobronchial trees of TB subjects is critical, but has not been systemically studied. This study proposes to simulate the airflow using CT image based models and the computational fluid dynamics (CFD) method. Six TB subjects and three health controls (HC) are included. After the geometric model of tracheobronchial tree is extracted from CT images, the spatial distribution of velocity, wall pressure, wall shear stress (WSS) is obtained through CFD simulation, and the lobar distribution of air, flow pattern and global pressure drop are investigated. Compared with HC subjects, the main bronchus angle of TB subjects and the variation of volume are large, while the cross-sectional growth rate is small. High airflow velocity, wall pressure, and WSS are observed locally at the tracheal bronchus, but the global patterns of these measures are still similar to those of HC. The ratio of airflow into the tracheal bronchus accounts for 6.6-15.6% of the inhaled airflow, decreasing the ratio to the right upper lobe from 15.7-21.4% (HC) to 4.9-13.6%. The air into tracheal bronchus originates from the right dorsal near-wall region of the trachea. Tracheal bronchus does not change the global pressure drop which is dependent on multiple variables. Though the tracheobronchial trees of TB subjects present individualized features, several commonalities on the structural and airflow characteristics can be revealed. The observed local alternations might provide new insight into the reason of recurrent local infections, cough and acute respiratory distress related to TB.
气管支气管（TB）是一种罕见的先天性异常，其特征为异常支气管起源于气管或主支气管，并指向肺上叶。TB 患者的气管支气管树中的气流模式很关键，但尚未进行系统研究。本研究拟采用 CT 图像建立模型和计算流体动力学（CFD）方法来模拟气流。共纳入 6 名 TB 患者和 3 名健康对照（HC）。从 CT 图像中提取气管支气管树的几何模型后，通过 CFD 模拟得到速度、壁压和壁面剪切应力（WSS）的空间分布，并研究了各叶段的空气分布、气流模式和整体压降。与 HC 相比，TB 患者的主支气管角度和容积变化较大，而横截面积增长率较小。气管支气管局部观察到高速气流、壁压和 WSS，但这些测量值的整体模式仍与 HC 相似。进入气管支气管的气流占吸入气流的 6.6-15.6%，使右肺上叶的气流比（HC 中的 15.7-21.4%）降至 4.9-13.6%。进入气管支气管的空气来源于气管近背侧壁的右侧区域。气管支气管不会改变依赖于多个变量的整体压降。尽管 TB 患者的气管支气管树呈现出个体特征，但仍可以揭示出一些结构和气流特征的共性。观察到的局部变化可能为反复发生的局部感染、咳嗽和与 TB 相关的急性呼吸窘迫提供新的见解。
