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The cases
Published in Chris Schelvan, Annabel Copeman, Jacky Davis, Annmarie Jeanes, Jane Young, Paediatric Radiology for MRCPCH and FRCR, 2020
Chris Schelvan, Annabel Copeman, Jacky Davis, Annmarie Jeanes, Jane Young
There is an anomalous origin of the left pulmonary artery from the posterior aspect of the right pulmonary artery, rather than the main pulmonary trunk. It loops around the trachea to reach the hilum of the left lung, creating a pulmonary artery sling.
Computational modelling of airflow in distal airways using hybrid lung model
Published in Mathematical and Computer Modelling of Dynamical Systems, 2023
Olusegun J. Ilegbusi, Adnan Islam, Anand P. Santhanam
The advancement of medical imaging technology has made it feasible for image-derived lung geometries to be used for patient-specific modelling. CT image-derived lung model has demonstrated complex flow patterns compared to idealized Weibel model in a previous study [14]. This study has also shown that ideal airway model is insufficient to accurately predict deposition patterns in the actual airways. Qi et al. [15] and Islam et al. [16] studied flow in patients with left pulmonary artery sling and reported increased pressure drop in image-derived model compared to healthy condition. Ilegbusi et al. [17] used a lung model derived from four-dimensional CT (4DCT) to predict and validate local deformation of lung tissue and tumour motion. Gemci et al. [18] analysed steady flow in a 17-generation anatomical model although simulation on fully converged mesh was not possible due to the large domain of the model. Image-based geometries are often limited to few generations beyond the trachea due to the small scale of the distal airways and tissue structure [19,20]. Different approached have thus been proposed to incorporate distal airways. Walters et al. [21] simulated flow from the oronasal opening to terminal bronchioles by utilizing stochastically coupled boundary conditions at the truncated branch. Velocity boundary condition was imposed at the terminal and truncated boundaries based on flow fraction obtained from preliminary steady-state solution in which truncated boundaries were set to have the same pressure distribution as a randomly selected interior face zone within the same generation. This method can resolve pressure and velocity distribution in the truncated model of healthy lung but spatial distribution of flow in the distal parts cannot be analysed due to truncation. A 1D network model has been proposed by Choi et al [22] where 1D energy balance equation is solved in an iterative manner for an airway structure generation based on stochastic population data by volume-filling method [23]. The effect of middle airways cannot be incorporated in 1D computations where there is significant secondary flow, and 3D analysis with this method in distal airways is not possible due to the reduced dimensionality.