A method for evaluation of regional elasticity of arterial wall with non-uniform wall thickness by measurement of its change in thickness during an entire heartbeat

The average elastic modulus of the artery has been evaluated previously by measurement of the pulse wave velocity and the change in arterial diameter during one heartbeat. On the other hand, we aim to measure the regional elastic modulus of the arterial wall by measurement of its small change in thickness during an entire heartbeat. In this paper, a method is proposed for measurement of the regional elastic modulus even if the artery has non-uniform wall thickness such as an atherosclerotic plaque. In a basic experiment, the proposed method is validated using a silicone rubber tube as a model of the artery. In in vivo experiments, the spatial distribution of the elastic modulus is measured around the human carotid atherosclerotic plaque. From this result, the difference in the regional elasticity around the atherosclerotic plaque can be observed and the soft region is found in the plaque. Such information seems to be useful for diagnosis whether the plaque easily ruptures or not.