Influence of neck width on transient flow characteristics in saccular intracranial aneurysm models

Intracranial aneurysm (IA) is a prevalent cerebrovascular disease associated with high mortality and disability rates upon rupture. The hemodynamics of IA, which are significantly influenced by geometric parameters, directly impact its rupture. This study focuses on investigating the transient flow characteristics in saccular IA models fabricated using a water droplet-based method, specifically examining the influence of neck widths. Particle image velocimetry technique and numerical simulation were employed to investigate the dynamic evolution of flow structures within three IA models. The results reveal that neck width (W) has a substantial effect on flow characteristics in the neck region, subsequently impacting the deep flow inside the sac. Three distinct patterns were observed during flow evolution inside the sac: for W = 2 mm, two vortices occur and then disappear with relatively low average flow velocity; for W = 4 mm, enhanced effects of a high-speed jet result in periodic pulsatile flow velocity distribution while maintaining stable vortex core position; for W = 6 mm, significant changes in flow velocity occur due to size expansion and intensity increase of vortices. These findings demonstrate that neck widths play a complex role in influencing transient flow characteristics within IAs. Overall, this research contributes to further understanding transient flow behaviors in IAs.