Comprehensive Flow Structures and Hemodynamic Analysis of Patient-Specific Cerebral Aneurysms using Volumetric PIV*

Cerebrovascular hemodynamic factors are believed to play a role in progression and rupture of intracranial aneurysms (ICA). Computational fluid dynamics (CFD) has overwhelmingly been the modality used for hemodynamic ICA studies. Velocity fields obtained from 4D Flow MRI have been used but are limited by low resolution and dynamic range, hindering accurate hemodynamic analysis. Experimental particle image velocimetry (PIV) studies in this domain have been noticeably limited, and to-date only two-velocity component PIV studies have been reported. In this work, we present volumetric (3D-3 component) PIV results using two patient-specific cerebral aneurysm models. Subsequently, 3D hemodynamic metrics including wall shear stress (WSS), oscillatory shear index, residence times, pressure, and coherent and frequency structures were computed. Resulting flow metrics were compared to those obtained from CFD and MRI. Preliminary comparisons across modalities have revealed subtle differences between CFD and PIV data, e.g. in areas of low WSS, which may have high impact on aneurysm stability. The results demonstrate a need for more volumetric PIV studies in this domain.