Elasticity imaging of atheroma with transcutaneous ultrasound both in longitudinal-axis and short-axis planes

This paper describes a noninvasive method for evaluating regional viscoelasticity of the arterial wall in which a novel method is applied to measure minute changes in wall thickness caused by the change in internal pressure. (1) By comparing the pathological findings with the elasticity distribution, statistical parameters for lipid and a mixture of smooth muscle and collagen fibers can be determined. By applying the method to the common carotid arteries, thin collagen fiber was clarified and soft inclusion of lipid in plaque was detected. (2) A new beam steering method was proposed to apply the above method to the plane, which is perpendicular to the axis of the artery. (3) For improvement of classification of tissue, a method was proposed to measure viscosity by generating the change in internal pressure using the external actuation from the skin surface, namely remote actuation. These methods offer the potential for detection of plaque vulnerability in a clinical setting.