Estimation of Pulse Wave Velocity Using Arterial Parameters Extracted by Carotid Ultrasound Images

Several indices have been introduced to estimate arterial stiffness that based on changes in brachial blood pressure. But because of the error resulted by the substitution of brachial blood pressure instead of the other central arteries, such as carotid, it will be very important to present elastic parameter based on the mechanical models without any emphasis on brachial blood pressure. In this study, estimation of pulse wave velocity of large arteries is used as an index for arterial stiffness. At first a suitable dynamic model is introduced for pulsatile blood flow in arteries based on Navier-Stokes equations in fluid mechanics. Then, according to the theory of elasticity, equations governing arterial wall is described and coupled to the equations of fluid flow. Attained system of equations is completed by clinical information that obtained from Doppler ultrasound images from carotid artery of healthy male subject. For this purpose Doppler ultrasound images were recorded and saved in computer and then center-line blood velocity, arterial wall thickness, the period of a cardiac cycle and arterial radius measured by offline processing. The results from analytic solution of completed equations showed that the PWV for this healthy subject is 2 m/s. By applying this method, non-invasive and clinical evaluation of arterial stiffness by Doppler ultrasound measurement of common carotid artery without any measurement of local blood pressure will be possible.