Hemodynamic Fluctuations in Patient-Specific Intracranial Aneurysms: An In-Vitro and In-Silico Study*

Intracranial aneurysms (IAs) are permanent dilatations of brain vessels, posing a rupture risk that leads to subarachnoid hemorrhage. This study focuses on understanding how hemodynamic fluctuations—which are known to exist in IAs—affect risk of rupture of patient-specific IA geometris. We employ in-vitro 4D particle image velocimetry (PIV) and in-silico computational fluid dynamics (CFD) modalities to identify and analyze flow structures in ten IA cases from the University hospital of Magdeburg, Germany. The IA cases maintained varying size, shape, and location along the Circle of Willis; the inflow pulsatile waveform for each geometry was assumed from literature. To minimize errors across modalities, CT scans were performed for all manufactured in vitro models and the measured shape was used for the CFD simulations. Flow structures, hemodynamic metrics of interest such as wall shear stress (WSS) and oscillatory shear index (OSI), as well as fluctuation levels in velocity, WSS, and OSI were evaluated for both modalities. Results were analyzed to qualitatively and quantitatively consider the magnitude of hemodynamic fluctuations across the IA cohort and improve clinical understanding for patient-specific pathological data applications.