Particle Tracking Velocimetry as a Tool to Quantify Platelet Residence Times in Intracranial Aneurysms Treated with Flow Diverting Stents*

Rupture of an Intracranial Aneurysm (IA) causes hemorrhagic stroke, with high mortality and morbidity. Success of endovascular stent treatment of IA relies on changes in hemodynamics, and specifically in the platelet biomechanical environment to form a stable thrombus in the IA sac post-treatment. PTV experiments are performed on in vitro models with patient-specific data, and Lagrangian analysis of platelet trajectories quantify residence times and hemodynamics. The particles are tracked in 3D for various cardiac cycles, in a novel experimental technique applied to neurovascular flows, and this data is used to characterize the platelet residence time and thrombotic shear exposure along their trajectories in the whole IA sac.

In order to find new insight on a successful thrombus formation, the velocity field was computed from the 3D time-resolved PTV image sets. This enables the analysis of hundreds of platelet trajectories. The residence time (RT) and shear exposure results were compared against pre- and post-stent CFD simulations, where platelet Lagrangian tracking over long times was performed.

The goal of this study is better understanding of thrombus formation in IA to predict clinical outcomes.