Numerical aspects of modeling flow through the cerebral artery system with multiple small perforators

This study investigates the flow and hemodynamics of small perforator blood vessels that branch from the basilar artery (BA) in the brain. Using advanced imaging techniques and computational fluid dynamics (CFD) simulations, detailed 3D geometries of the perforators were acquired through barium contrast injection, micro-CT scans, and data processing. The hybrid geometry, combining micro-CT scans and mesh extraction algorithms, provided accurate vessel models. The influence of different types of finite volume on the analysis was examined, with polyhedral elements showing the most efficient ratio of the analysis time to convergence level. Additionally, the effect of boundary conditions on hemodynamic parameters was studied. Simulations using 0.0 mmHg pressure conditions at the outlets directed flow mainly through the BA, neglecting the perforator branches. In contrast, non-zero outlet pressure conditions significantly increased the flow in the perforators, leading to non-physiological flow velocities and overestimation of hemodynamic parameters. The assumption of pressure conditions of 0 mmHg at outlets was found to be valid for simple single vessel geometries, but not for more complex vascular systems. This research contributes valuable information on the complex flow patterns and hemodynamics of small perforator blood vessels in the brain and emphasizes the importance of accurately modeling geometry and boundary conditions in such studies.