A Computational Framework to Explore the Role of Pulsatile Haemodynamics on Cerebral Aneurysm Development for Patient-Specific Arterial Geometries

A patient-specific cerebral aneurysm case was identified from clinical imaging data, and then segmented to create a geometrical representation of the aneurysm and surrounding vasculature. Using ANSYS ICEM CFD, the geometry was manipulated to remove the aneurysm and replace it with a short (initially cylindrical) section, which reconnected to the upstream and downstream arterial sections so that the surface gradients were continuous. This section is modelled using a realistic constitutive model of the arterial wall and is the location where the computational model of the aneurysm evolves. The aneurysm evolution FEA model is combined with detailed 3D haemodynamic solutions using ANSYS CFX. A rigid-wall approach is adopted to solve the flow, to derive the haemodynamic stimuli that act on the endothelial cell layer of the tissue. Additionally, the geometry of the aneurysm is obtained at systolic and diastolic pressures (using a quasi-static approach) to obtain the cyclic stretch experienced by the cells within the arterial wall. This is the first patient-specific model of cerebral aneurysm evolution to explicitly link growth and remodelling of arterial tissue to the local mechanical environment. It will provide the basis for investigating the role and importance of various mechanical stimuli on the progression of the disease and will yield improved understanding of the aetiology of cerebral aneurysm formation