Sensitivity of blood flow dynamics simulations in the pulmonary arteries to inflow boundary conditions

The Pulmonary Artery (PA) is an important part of the cardiovascular system. The PA drives the oxygenation of blood by transporting it from the Right Ventricle (RV) to the lungs. Blood flow first go through the Main Pulmonary Artery (MPA) and then splits into the Right Pulmonary Artery (RPA) and the Left Pulmonary Artery (LPA), which divides into smaller vessels inside the human lungs. The blood flow in the PA have biological and mechanical characteristics that are sensitive to physiological and anatomical changes. The objective of this study is to understand the sensitivity of the flow patterns to the inflow boundary condition using a combination of in-vivo data and Computational Fluid Dynamics (CFD). A population of N = 35 subjects (reduced to 28 after analysis) composed of healthy adults is considered for this study. Geometries are extracted from magnetic resonance imaging (MRI), and velocity fields from corresponding 4D flow data. Numerical simulations are conducted on an cohort-averaged shape using the software SimVascular. Inlet conditions consist of an average velocity profile (obtained from the mean of the patient-specific in-vivo velocity data); sensitivity is studied superimposing a fraction of the standard deviation. Results were post-processed in the open-source software ParaView. The inlet profile showed significant variations across the cohort. Accordingly, flow patterns demonstrated a non-negligible sensitivity to inflow conditions in terms of flow topology and overall characteristics. The results emphasize the importance of using patient-specific boundary conditions for reliable simulations of blood flow in the pulmonary arteries.Incomin