Measurement of regional pulse-wave velocity using spatial compound imaging of the common carotid artery in vivo

• The high temporal imaging is achieved by the spatial compound with plane waves.
• The 2D vector of the artery motions induced by heartbeat is measured.
• The pulse wave velocity at four phases in common carotid artery is investigated.
• The lateral motions of the artery is investigated.
• The pulse wave velocity is compared at each phase.

Pulse-wave velocity (PWV) is an important index for diagnosing cardiovascular diseases. The pulse wave is volumetric change induced by heartbeat or inflowing blood, and significantly depends on the propagating path and stiffness of the artery. In this study, PWV of the propagating wave was visualized using spatial compound imaging with high temporal resolution. The frame rate was 1000 Hz, or a time interval of 1 ms. Subjects were four young healthy males and one young healthy female (n = 5, age: 23.8 ± 1.17 years old), and the measurement area was the right common carotid artery. PWVs in four phases (the four phases of heart valve opening and closing) were investigated during a cardiac cycle. In phase I, the heart pulsates. In phase II, the tricuspid and mitral valves close, and the aortic and pulmonic valves open. In phase III, the tricuspid and mitral valves open, and the aortic and pulmonic valves close. In phase IV, the propagating wave is reflected. PWVs in phases II and III were easily observed. PWVs were 3.52 ± 1.11 m/s in phase I, 5.62 ± 0.30 m/s in phase II, 7.94 ± 0.85 m/s in phase III, and −4.60 ± 0.99 m/s for the reflective wave. PWV was measured using Spatial Compound Imaging with high temporal resolution, and the PWV in each phase may be used as the index for diagnosing stages of arteriosclerosis progression.