The Ability of the CFD Approach to Investigate the Fluid and Wall Hemodynamics of Cerebral Stenosis and Aneurysm

The objective of this chapter is to conduct a computational investigation on cerebral arteries of patients and examine the hemodynamics parameters affected by the presence of a vascular stenosis or aneurysm. The use of CFD simulations involves both idealized and MRI based models of the cerebral arteries. The eight benchmarks are divided into seven straight cylindrical blood vessels featuring idealized stenosis with different d/D ratios (from 0.4 to 1) and one benchmark for the saccular aneurysm. A patient-specific cerebral artery geometry was reconstructed to create a realistic model. To study the hemodynamics parameters, CFD simulations were employed to analyze the recirculation of the flow (flow vortex) and the wall pressure/shear stress. The boundary conditions for the simulation were obtained from ultrasonography measurements taken from the patient. The results of the stenosis analysis indicate that a specific area of vascular contraction critically influences blood flow, leading to a rise in wall shear stress in the stenosis region. This causes a rise in the flow velocity and the formation of vortices after the narrowing zone, potentially leading to blockage of the blood vessel and stroke. Additionally, the computational fluid dynamics results reveal the presence of the flow recirculation in the aneurysm zone. This significantly affects the flow and wall characteristics of the dilation.