  Rapid and accurate simulation of cerebral aneurysm flow modifications by flow
diverters (FDs) can help improving patient-specific intervention and predicting
treatment outcome. However, with explicit FD devices being placed in
patient-specific aneurysm model, the computational domain must be resolved
around the thin stent wires, leading to high computational cost in
computational fluid dynamics (CFD). Classic homogeneous porous medium (PM)
methods cannot accurately predict the post-stenting aneurysmal flow field due
to the inhomogeneous FD wire distributions on anatomic arteries. We propose a
novel approach that models the FD flow modification as a thin inhomogeneous
porous medium (iPM). It improves over classic PM approaches in that, first, FD
is treated as a screen, which is more accurate than the classic
Darcy-Forchheimer relation based on 3D PM. second, the pressure drop is
calculated using local FD geometric parameters across an inhomogeneous PM,
which is more realistic. To test its accuracy and speed, we applied the iPM
technique to simulate the post stenting flow field in three patient-specific
aneurysms and compared the results against CFD simulations with explicit FD
devices. The iPM CFD ran 500% faster than the explicit CFD while achieving
94%-99% accuracy. Thus iPM is a promising clinical bedside modeling tool to
assist endovascular interventions with FD and stents.
