Simultaneous imaging of bidirectional guided waves probes arterial mechanical anisotropy, blood pressure, and stress synchronously.

Abstract

Arterial biomechanical indicators have long been recognized as fundamental contributors to the physiology and pathology of cardiovascular systems. Probing multiple biomechanical parameters of arteries simultaneously throughout the cardiac cycle is highly important but remains challenging. Here, we report a method to quantify arterial anisotropic stiffness, arterial wall stresses, and local blood pressure in a single measurement. With programmed ultrasound excitation and imaging, arterial axial and circumferential guided waves were simultaneously induced and measured in the longitudinal view. Then, a mechanical model was proposed to quantitatively predict the correlation of arterial guided waves with arterial biomechanical parameters. Our experimental design and biomechanical model enable an elastography method to assess temporal variations in blood pressure, bidirectional stiffness, and mechanical stresses in arterial walls. In vivo experiments were performed on healthy young, normotensive older, and hypertensive older volunteers. The results demonstrate that our method can find applications in understanding aging of cardiovascular system and diagnosis of cardiovascular diseases.