Visualization of Blood Flow in AAA Patient-Specific Geometry: 3-D Reconstruction and Simulation Procedures

Abstract

Abdominal aortic aneurysm (AAA) is a life-threatening disease when the diameter exceeds its safety margin or the aortic wall reaches its mechanical strength. Both of these potential problems need to be clinically assessed. The geometrical influence on blood flow behavior and hemodynamic changes of AAA are not fully clinically understood. The study aimed to explore creating comprehensive and detailed models for use in reconstruction, modeling, and simulating three-dimensional (3D) patient-specific geometry based on two-dimensional (2D) computed tomography images. The patient information was extracted from computed tomography images and the AAA patient’s database. The 3D geometrical models were created using MIMICS software segmentation tools and exported in STL files to ANSYS Workbench. Computational fluid dynamics (CFD) and finite volume methods were used to solve Navier-Stokes equations for fluid flow in the 3D domain. Blood was treated as incompressible and Newtonian fluid, and a transient flow with a time-dependent velocity waveform assigned at the inlet boundary. The computational results were visualized using ANSYS Fluent post-processing. The CFD transient simulation results are presented using the hemodynamic parameters, including velocity vectors, flow patterns (streamlines), pressure distribution, and wall shear stress. The demonstrated results are part of the study aims and methods in order to provide detailed approaches of computational analysis. The procedures used in this study would be useful for understanding the biomechanical influence on blood flow and hemodynamics.