Experimental study on transient flow patterns in simplified saccular intracranial aneurysm models using particle image velocimetry.

The hemodynamics of intracranial aneurysm (IA) comprises complex transient flow patterns that affect its growth and rupture. Owing to the combined effects of geometrical factors and pulsatile flow conditions, the transient flow patterns in the IA are still unclear. The purpose of this work is to reveal the effect of the aspect ratio (AR, sac height/neck width) on the evolution of the internal flow patterns and the hemodynamics of the IA. We proposed an easy method to fabricate three simplified elastic IA models and measured the transient flow characteristics by using particle image velocimetry (PIV). Transient vortex structures in the IA modes during a cardiac cycle were systemically measured and many new flow phenomena were found, including the vortex morphology (size, structure, and core location), a high-speed jet, wall compliance effects, and three flow modes during retrograde flow phase. The results show that the AR of the IA affects the transient flow patterns as well as the wall shear stress (WSS) in complex ways. The results could deepen our understanding of the transient flow behaviors in IA and guide related clinical studies. [ABSTRACT FROM AUTHOR]