WCE 2011 Camera Ready L Thomas-Seale

Assessment of the rupture risk of plaque is commonly made via imaging of the lumen reduction. However it is known that this is an imperfect criterion and that other features, such as plaque stiffness, may be more relevant. Magnetic Resonance Elastography (MRE) estimates the stiffness of tissues using inversion algorithms applied to the displacement of the tissue, measured in response to the induction of a shear wave from an external actuator. An idealised diseased vessel, embedded in an arbitrary tissue, was created to simulate the application of MRE to atherosclerotic plaque. The behaviour of shear waves propagating through an atherosclerotic plaque with development of the stenosis and lipid pool size was investigated. There is a local increase in wave displacement and decrease in wavelength, through a plaque containing a lipid pool compared to a purely fibrotic plaque. The amplitude of the wave through the lipid increases with lipid pool volume. This suggests that shear waves used in MRE may be able to differentiate between lipid pool sizes within an atherosclerotic plaque. The behaviour of shear waves through relatively large and small lipid pools needs further investigation. Experimental validation of the technique is required.