Background Intrasaccular devices such as SEAL™ and WEB™-SL are designed to disrupt aneurysmal flow. We present a new in vitro method for estimating neurointerventional devices’ flow dynamics. Methods Particle image velocimetry (PIV) method was used in a patient-specific middle cerebral artery (MCA) wide-neck bifurcation aneurysm (WNBA) model to measure velocity, residence time (RT), and vorticity strength (VS). Tested devices included 3 each of SEAL-BASE (6 × 2 mm), SEAL-ARC (6 × 5 mm), and WEB-