Comparative hemodynamic remodeling induced by coil embolization in intracranial aneurysms: Computational study

This study evaluates the hemodynamic influence of endovascular coiling on four intracranial aneurysm types — ACA, MCA, BAS and ICA — using patient-specific CFD models with matched sac volumes. The analysis focuses on key biomechanical markers associated with aneurysm growth and rupture, including wall shear stress (WSS), oscillatory shear index (OSI), pressure and intra-saccular velocity structure. Unsteady, incompressible, non-Newtonian blood flow was simulated using the Casson model and rigid-wall assumptions. Coiling was represented through a porous-medium formulation, with permeability derived from coil geometry and Kozeny-based relations. Boundary conditions employed physiological inlet waveforms and zero-pressure outlets. The simulations were performed using a finite-volume computational fluid dynamics framework implemented in ANSYS Fluent, solving the unsteady incompressible Navier–Stokes equations with a non-Newtonian Casson blood rheology. Endovascular coiling was modeled through a porous-medium formulation to account for coil-induced hydraulic resistance within the aneurysm sac. The simulations were performed using a finite-volume computational fluid dynamics framework implemented in ANSYS Fluent, solving the unsteady incompressible Navier–Stokes equations with a non-Newtonian Casson blood rheology. Endovascular coiling was modeled through a porous-medium formulation to account for coil-induced hydraulic resistance within the aneurysm sac. Flow patterns, WSS, pressure, AWSS, OSI, iso-velocity surfaces and streamline structures were examined before and after coiling across three simulated cardiac cycles. In untreated aneurysms, strong inflow jets, elevated WSS and high OSI were observed, with substantial variability among ACA, MCA, BAS and ICA geometries. Coiling treatment significantly reduced intra-saccular velocity magnitudes, suppressed vortex formation and limited inflow penetration at the neck. WSS and AWSS decreased by more than 60–75% in all cases, while OSI was broadly reduced, indicating improved temporal shear stability. Pressure distributions became smoother and more uniform, reflecting coil-induced flow damping. The differences between aneurysm locations diminished considerably after coiling, demonstrating the homogenizing effect of porous resistance on hemodynamic behavior. Endovascular coiling consistently attenuates harmful hemodynamic conditions across four major aneurysm locations, producing lower shear stress, reduced oscillatory flow and stabilized intra-saccular pressure. These findings highlight the effectiveness of coiling in promoting a low-velocity, low-shear environment conducive to thrombosis and aneurysm healing, while emphasizing the value of CFD-based comparative analysis for understanding location-specific treatment responses.