Simulation analysis of airflow alteration in the trachea following the vascular ring surgery based on CT images using the computational fluid dynamics method

Article type: Research Article

Authors: Chen, Fong-Lin^; | Horng, Tzyy-Leng | Shih, Tzu-Ching^;

Affiliations: Institute of Medicine, Chung Shang Medical University, Taichung, Taiwan | Department of Pediatrics, Chung Shan Medical University Hospital, Taichung, Taiwan | Department of Applied Mathematics, Feng Chia University, Taichung, Taiwan | Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan | Department of Biomedical Informatics, Asia University, Taichung, Taiwan

Note: [] Corresponding author: Tzu-Ching Shih, Department of Biomedical Imaging and Radiological Science, College of Health Care, China Medical University, Taichung 40402, 91 Hsueh-Shih Road, Taichung 40402, Taiwan. Tel.: +886 4 2205 3366#7709; Fax: +886 4 2208 1447; E-mail: shih@mail.cmu.edu.tw

Abstract: This study presents a computational fluid dynamics (CFD) model to simulate the three-dimensional airflow in the trachea before and after the vascular ring surgery (VRS). The simulation was based on CT-scan images of the patients with the vascular ring diseases. The surface geometry of the tracheal airway was reconstructed using triangular mesh by the Amira software package. The unstructured tetrahedral volume meshes were generated by the ANSYS ICEM CFD software package. The airflow in the tracheal airway was solved by the ESI CFD-ACE+ software package. Numerical simulation shows that the pressure drops across the tracheal stenosis before and after the surgery were 0.1789 and 0.0967 Pa, respectively, with the inspiratory inlet velocity 0.1 m/s. Meanwhile, the improvement percentage by the surgery was 45.95%. In the expiratory phase, by contrast, the improvement percentage was 40.65%. When the inspiratory velocity reached 1 m/s, the pressure drop became 4.988~Pa and the improvement percentage was 43.32%. Simulation results further show that after treatment the pressure drop in the tracheal airway was significantly decreased, especially for low inspiratory and expiratory velocities. The CFD method can be applied to quantify the airway pressure alteration and to evaluate the treatment outcome of the vascular ring surgery under different respiratory velocities.

Keywords: Complete vascular ring (CVR), vascular ring surgery (VRS), pressure drop, computational fluid dynamics (CFD), tracheal airway resistance

DOI: 10.3233/XST-140420

Journal: Journal of X-Ray Science and Technology, vol. 22, no. 2, pp. 213-225, 2014