Statistical analysis of hemodynamic contributions to intracranial aneurysm rupture with daughter sac symptoms*

Intracranial aneurysms (IAs) with daughter sacs/secondary IAs (SIAs) tend to increase IA rupture risks, while the hemodynamic factors contributing to IA rupture are still under-investigated. This study aimed to investigate hemodynamic characteristics of IAs with SIA symptoms using computational fluid dynamics (CFD) modeling and statistical analysis. 43 patients with well-defined 67 SIA scenarios were built using 3D rotational angiographical images, according to benchmarked model reconstruction procedures that were developed in our previous study. The mesh independence test was conducted to decide the final mesh for CFD modeling. Using physiological pulsatile flow boundary conditions, in-vitro validated CFD simulations were conducted to secure hemodynamics in the IAs of 43 patients. Statistical significance was evaluated for each wall shear stress-associated parameter on the entire IA region and SIA region accounting for IA rupture according to IA locations, i.e., internal carotid artery (ICA), anterior communicating artery (ACA), and middle cerebral artery (MCA). Statistical significance was assigned when p £ 0.05. When conducting a general analysis without the consideration of IA location, no significant difference was found in the investigated hemodynamic parameters between ruptured IAs (RIAs) and unruptured IAs (UIAs). When comparing the hemodynamics between RIAs and UIAs at ACA, statistical significance was found, revealing high wall shear stress (WSS) which could lead to IA rupture at ACA bifurcation. Meanwhile, relatively low maximum WSS and high oscillatory shear index (OSI) could be critical indicators that could lead to IA rupture at ICA. Also, when comparing hemodynamics between RIAs and UIAs on the regional SIA location only, a significant difference was found in MWSS (p = 0.047), MWSSG (p =0.034), and MTAWSS (p = 0.047) for the IAs at ACA, respectively. For IAs on ICAs, the significance was found in MWSS (p =0.042), MTAWSS (p = 0.034), and MTAWSSG (p = 0.027). No significant hemodynamic difference was found for IAs at MCA, possibly due to the corresponding recruited 10 cases being too few to secure reliable statistical results.