Background:Hemodynamic factors are considered to play an important role in the initiation and recurrence of cerebral aneurysms.However,hemodynamic characteristics leading to the recurrence of aneurysms is not well recognized.This study analyzes the hemodynamics of simple-coiling and remnant-neck aneurysms,and discusses the impact of hemodynamic factors on the recurrence of cerebral aneurysms.Methods:This study selected three simple-coiled and remnant-neck aneurysms with at least once angiographic follow-up.The follow-up was conducted by 3D rotational DSA and the 3D reconstruction of the vessel.The aneurysms located on ophthalmic segment of ICA,including one recurrent case and two stable cases.We used a porous medium model to simulate and analyze the hemodynamics of aneurysms.Results:For the recanalized aneurysm,in the immediate post-operative period,the WSS at the remnant neck decreased,low blood flow velocity and stagnant regions were found in the aneurysm sac.In the first follow-up,compared to immediately post-operative,at the residual neck,the WSS was higher,the flow impingement was stronger.In the sac,the stagnation area decreased and its contour limit shrank into the aneurysm.However,in the second follow-up,compared to the previous follow-up,at the remnant neck,the WSS was lower,the flow impingement weaker,while in the sac the stagnant region expanded.Conclusions:Aneurysm recurrence could occur in two phases:early coil compaction resulting from blood flow impingement and later vessel remodeling due to hemodynamic effects.