PIV-measured versus CFD-predicted flow dynamics in anatomically realistic cerebral aneurysm models

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Medical Imaging

Background:

• Computational fluid dynamics (CFD) is increasingly used to study brain aneurysms.
• Previous work validated CFD indirectly using virtual angiography.
• Direct validation of CFD velocity fields against experimental data is needed.

Purpose of the Study:

• To directly validate detailed CFD-predicted velocity fields against particle imaging velocimetry (PIV) measurements.
• To assess the accuracy of CFD in modeling intra-aneurysmal hemodynamics in patient-specific phantom models.
• To compare CFD and PIV in capturing complex flow dynamics, including vortices and cycle-to-cycle fluctuations.

Main Methods:

• Constructed two anatomically realistic flow-through phantoms (internal carotid artery and basilar artery aneurysms) from silicone elastomer.
• Acquired PIV images on multiple planes within the phantoms under controlled flow conditions.
• Performed CFD simulations using a validated solver, incorporating micro-CT geometry reconstructions and PIV-derived boundary conditions.

Main Results:

• Good overall agreement between CFD and PIV velocity vector fields was observed for both aneurysm models.
• CFD and PIV accurately captured complex vortex dynamics in the internal carotid artery aneurysm.
• CFD and PIV compellingly resolved counter-rotating vortices in the basilar artery aneurysm, including cycle-to-cycle fluctuations.

Conclusions:

• CFD modeling demonstrates reliable prediction of intra-aneurysmal flow dynamics in realistic in vitro models.
• The strong agreement between CFD and PIV supports the use of CFD for studying brain aneurysm hemodynamics.
• Further validation against in vivo data is recommended to confirm the simulation of actual in vivo hemodynamics.