Fluid structure interaction of patient specific internal carotid aneurysms: A comparison with solid stress models

Abstract

An intracranial aneurysm (IA) is a pathological dilatation of the cerebral artery wall. In clinical practice it is currently widely accepted that maximum diameter of IA is an indicator for patient whether to treat or not. But studies have demonstrated that maximum diameter is not a reliable determinant of IA rupture. According to the theory of strength, if the stress value exceeds the strength limit of material, it will result in failure. So wall stress may be a better indicator to predict aneurismal rupture (failure). Study about wall stress calculated from solid stress model using static pressure has been performed. But blood flow and pressure inside IA are not steady. The dynamic interaction between the unsteady flow and wall may influence the distribution and magnitude of wall stress. The objective of the present study was to compare static and dynamic wall stress analysis of patient specific IA. Patient-specific model of cerebral aneurysm whose host artery has large bending was created from CT data. Simulations about fluid structure interaction model and static structural model were carried out respectively. Commercial software Ansys 11 was used for simulation. The results demonstrated that FSI can change local wall stresses slightly. However, as far as the peak wall stress is concerned, the change of wall stress is negligible. Therefore static structural simulation can be used to predict rupture risk of aneurysm if wall stress was used as an indicator of aneurismal rupture and computational cost can be reduced greatly. © 2010 International Federation for Medical and Biological Engineering.