Accuracy evaluation in the measurement of a small change in the thickness of arterial walls and the measurement of elasticity of the human carotid artery

For the diagnosis of the early stages of atherosclerosis, it is important to evaluate the local acoustic characteristics of the arterial wall. For this purpose, it is necessary to increase the spatial resolution in the axial direction to several millimeters, which corresponds to the size of the macular lesion on the surface of the wall. We have proposed a method for measuring small velocity signals on the intima and adventitia of the arterial wall from the skin surface using pulsive ultrasonic waves. The small change in thickness of the arterial wall is obtained by integrating the difference between the two velocity signals on the intima and adventitia. The elastic property of the arterial wall is noninvasively evaluated from the change in thickness and the arterial inner pressure. In this paper, we evaluate the accuracy of the proposed method for measuring the small displacement. Moreover, we applied this method to evaluate the elastic properly of the arterial wall of 50 patients and 8 healthy subjects.