WALL SHEAR STRESS IN AN MRI-BASED SUBJECT-SPECIFIC HUMAN AORTA USING FLUID-STRUCTURE INTERACTION

摘要

Wall shear stress (WSS) is well established as an indicator of increased risk for development of atherosclerotic plaques, platelet activation and thrombus formation [1]. Prediction and simulation of the sites of wall shear stresses that are deemed dangerous before intervention would be of great aid to the surgeon. However, the geometries used for these types of simulations are often approximated to be rigid. To more accurately capture the flow and arterial wall response of a realistic human aorta, fluid-structure interaction (FSI) which allows movement of the wall, is needed. Hence, the pressure wave and its effect on the wall motion are resolved and enables a more physiological model as compared to a rigid wall case. FSI is an iterative process where the fluid pressure is taken as an input to the solid solver that calculates a displacement which is then fed back to the fluid solver as an updated geometry. With a sufficiently fine computational mesh, the WSS can be calculated in an accurate way allowing characterization of the mechanical signals relevant to the endothelium [2]. Compared to idealized cases, subject-specific models are very important to analyze due to the complexity of both geometry and flow-field. In this paper the influence of the rigid wall assumption is investigated. The long-term scope is to develop deformable wall-models that can be used clinically to capture the cardio-vascular flow in a more physiological way.