Evaluation of elastic property of the arterial wall by measuring small velocity signals using ultrasound

To evaluate the elasticity of the arterial wall more locally, it is necessary to noninvasively measure the local change in thickness of the arterial wall with amplitude of several micrometers. For this purpose, in this paper, small velocity signals on the arterial wall is accurately measured using ultrasound. From this small change in thickness, the systolic blood pressure, and the diastolic blood pressure, the average elastic modulus of the arterial wall is noninvasively evaluated. The elastic modulus of the arterial wall depends upon the arterial inner pressure because of the hysteresis property between the inner pressure and the strain of the artery. Therefore, we obtain the change in the Young's modulus in one cardiac cycle from the local pulse wave velocity (PWV) measured in each short period. From the resultant PWV in each short period, the hysteresis property of the arterial wall is estimated.