Internal Pressure Dependence on Viscoelasticity of Arterial Wall by Ultrasonic Measurement

Previously, we proposed an ultrasonic measurement method of arterial wall elasticity for the early detection of arteriosclerosis. Since vascular wall elasticity depends on blood pressure, in this study, the elasticity and viscosity were estimated using the hysteresis loop determined between the incremental strain in the wall and internal pressure by altering the internal pressure in the phantom and in vivo experiments. Consequently, both the estimated elasticity and viscosity increased with the internal pressure. Moreover, the slope of each hysteresis loop was larger than that of the approximated curve for the lowest blood pressures of the hysteresis loops with different internal pressures, as the blood pressure changed in the order of several hertz within a single heartbeat. Hence, we conclude that measuring both the blood pressure and the elastic and viscous moduli would be beneficial in comprehensively investigating more vessel wall properties that change with the progression of arteriosclerosis.