1 Introduction Available to Purchase

Non-invasive ultrasonic measurement of mechanical properties is very useful for diagnosis of biological tissues. For example, pathological change of the arterial wall due to atherosclerosis leads to a significant change in its mechanical properties [1, 2]. Most conventional methods for noninvasive measurement of elasticity are based on measurement of the pulse wave velocity (PWV) [3–6] or the change in diameter [7–10]. Although these methods are useful in terms of their ability to assess the vascular elasticity noninvasively, the spatial resolution in elasticity measurement is limited to the propagating distance of the pulse wave or the entire circumference.