Flow Field Dynamics of a Wide-Neck Intracranial Aneurysm With and Without the Presence of Double-Wall Vascular Stent*

An experimental study is performed to investigate the flow dynamics of a wide-neck intracranial aneurysm with and without the presence of a double-wall vascular stent. A laboratory model of a lateral side-wall aneurysm 3 cm in length and with a 10 mm wide-neck was fabricated using clear plexiglass. The aneurysm model was placed in a circuit driven by a peristaltic pump that delivered water cycling at the rate of one pulse per second. The fluid flow rate was measured using a Honeywell vortex shedding flow meter and was kept constant at 200 mL/min. The flow field was captured by means of stereoscopic Particle Image Velocimetry.  The illumination is provided by a dual-oscillator Nd:YAG laser with 30 mJ/pulse at 532nm wavelength with a maximum repetition rate of 10kHz. A light sheet of 1 mm thickness is created by suitable combination of spherical and cylindrical lenses. The images are recorded by two CMOS cameras (Phantom VEO 410L) with a resolution 1280(H) x 800(V) pixels of a size of 20 microns. A total of 2500 image pairs per second were acquired. The results show that the double-wall vascular stent greatly reduced flow recirculation and wall shear stress. The study provides a basis for the future feasibility of double-wall vascular stents in preventing aneurysm rupture.