Discrimination of Kelvin Materials via ARFI Response

Acoustic Radiation Force Impulse (ARFI) is a noninvasive ultrasound modality that differentiates tissue structure via viscoelastic property. We are interested in using ARFI to discriminate between nonatherosclerotic arterial walls and atherosclerotic plaque. Both of these tissue types can be modeled as Kelvin materials each characterized by its own elasticity and viscosity. These properties define the displacement and recovery of tissue in response to ARFI. In this paper we present algorithms for clustering ARFI-induced displacement curves and we use the Kelvin model as a filter for outlier rejection. We validated these algorithms against a synthetic data set and then obtained preliminary results for an ARFI image of a raised focal atherosclerotic plaque in a porcine iliac artery.