Blood flow simulations in a cerebral aneurysm secured by a Flow Diverter stent

Objective: The objective of this research was to show a potential use of computational fluid dynamics tools in supporting the medical personnel by offering objective data regarding the hemodynamic changes in the aneurysm caused by implanting different models of the stent. Methods: The authors reconstructed patient-specific model of the cerebral arteries with diagnosed aneurysm. Then, four virtual models of the Flow Diverter stent (with varied nominal diameters) were prepared. During the numerical analyses, the Immersed Solid Method was used to model the presence of the stent wirebraid. After performing steady state and transient simulations of non-Newtonian blood flow in pre- and post-treatment models, changes in numerous hemodynamic parameters were analysed. Results: The results confirmed that stent porosity influences hemodynamic changes inside the aneurysm (for presented case studies). The less porous the stent, the more it promotes the possible intrasaccular thrombosis. This could be concluded by observing larger regions of stagnant blood with higher viscosity. Additionally, the denser the stent, the lower and more uniform the stress exerted on the aneurysm wall. Conclusions: Numerical simulations can provide valuable insight into phenomena occurring inside the blood flow after implanting the stent. This can support selecting optimal stent configuration for the particular patient and, consequently, can help in planning the endovascular procedure.