Investigating Hemodynamics in Intracranial Aneurysms with Irregular Morphologies: A Multiphase CFD Approach

Unruptured intracranial aneurysms, affecting 2-5% of the population, are characterized by localized wall weakening and irregular morphologies, including features such as blebs, lobulations, or asymmetries, which are significant predictors of rupture risk. Although up to 57% of ruptured intracranial aneurysms exhibit irregular dome geometry, its influence on aneurysm stability remains underexplored. Irregular geometries are associated with adverse hemodynamic forces, such as increased wall shear stress (WSS), amplifying wall stress at specific regions, and promoting flow disturbances, which may increase aneurysm vulnerability. This study investigates the influence of aneurysm dome morphology, particularly in IAs with irregular domes that may include daughter blebs, using Computational Fluid Dynamics (CFD). Unlike prior CFD studies that modeled blood as Newtonian or non-Newtonian, this work employs a three-phase blood flow model, representing plasma and red blood cells (RBCs) as distinct phases. Numerical simulations, conducted via the Finite Volume Method, solve the Navier-Stokes equations to capture complex flow dynamics within cerebral vasculature. Key hemodynamic metrics, such as Wall Shear Stress (WSS), Wall Shear Stress Gradient (WSSG), and Viscous Dissipation Rate, are analyzed to assess the interplay between dome morphology and hemodynamic stressors.