Biomechanics of aneurysms

Determining the stiffness of artery walls is a difficult task due to their dynamic behaviour and presence in the human body. Knowledge of artery wall stiffness would prove invaluable in predicting when an aneurysm is at high risk of rupture. Aneurysm rupture is a failure of the artery wall and hence is directly related to its mechanical properties.Medical imaging techniques such as magnetic resonance imaging (MRI) are able to provide information on a number of mechanical characteristics that are critical to aneurysm behaviour. However, they cannot determine the artery wall stiffness or Young's modulus (E) which is needed to perform a failure analysis. Multiple silicon rubber models of aneurysms will be produced and will vary in stiffness. The models will be placed into a flow circuit to simulate the flow of blood through them. The velocity through the models will then be measured and used to create a velocity stiffness relationship. The process will be repeated for different sized aneurysm models. The velocity stiffness relationship for each sized aneurysm will then be combined into one graph. The size of, and velocity through an aneurysm can then be used to estimate the artery wall stiffness and hence predict the risk of rupture.