  The clinical and economic burden of cardiovascular diseases (CVDs) poses a
global challenge. Growing evidence suggests an early assessment of arterial
stiffness can provide insights into the pathogenesis of CVDs. However, it
remains difficult to quantitatively characterize the arterial stiffness in
vivo. Here we utilize the guided elastic waves continuously excited and
detected by ultrasound as a tool to probe the blood pressure (BP) and
mechanical properties of the common carotid artery (CCA) simultaneously. In a
pilot study of 17 healthy volunteers, we obverse a ~20% variation in the group
velocity (5.16 m/s in systole and 4.31 m/s in diastole) induced by variation of
the BP. A linear relationship between the square of the group velocity and the
BP is revealed by our experimental data and finite element analysis, which
enables us to measure the waveform of the BP. Furthermore, we propose to use
the wavelet analysis to extract the dispersion relation of the guided waves,
which provides a quantitative measurement of the arterial stiffness. The
results and methods reported in this study show the group velocity and
dispersion relation of the guided waves can be adopted to probe BP and arterial
stiffness noninvasively and thus promising for early diagnosis of the CVDs.
