CFD and FSI Face-Off: Revealing Hemodynamic Differences in Cerebral Aneurysms

Accurately modeling the hemodynamics of intracranial aneurysms is crucial for understanding theirbehavior and potential progression. While computational fluid dynamics (CFD) simulations are commonly used to assess blood flow patterns, their rigid-wall assumption may overlook important biomechanical interactions within the vessel. In contrast, fluid-structure interaction (FSI) simulations incorporate vessel wall deformation, providing a more realistic representation of vascular dynamics.This study investigated aneurysm rupture risk by correlating von Mises stress distribution and walldisplacement with rupture status. In the first phase, we aimed to highlight the importance of accounting for vessel wall mechanics in aneurysm stability assessments. For this purpose, we analyzed an additional aneurysm case with knowledge of its rupture status. We compared hemodynamic variables between CFD and FSI simulations to assess the impact of wall deformation. Results revealed that ignoring vessel wall mechanics may lead to insufficient evaluation of aneurysm stability, as critical flow features were less accurately captured in CFD models. In the second part of the study, we analyzed six female patients to minimize gender bias, three with stable aneurysms and three with confirmed rupture status. By solving the FSI problem for these cases, we examined the relationship between mechanical wall behavior and aneurysm stability. Our analysis demonstrated distinct patterns in von Mises stress and wall displacement, underscoring their potential as predictive indicators. All simulations were performed using our massively parallel, in-house developed C++ code tailored for high-performance computing of coupled fluid and structural dynamics.These findings emphasize the need for improved modeling approaches that integrate wall deformation to enhance the accuracy of hemodynamic assessments. Incorporating such refinements is essential for advancing aneurysm research and improving clinical insights into their development and management.