A Method to Estimate Wall Shear Rate with a Clinical Ultrasound Scanner

A simple technique to estimate the wall shear rate in healthy arteries using a clinical ultrasound scanner has been developed. This method uses the theory of fully developed oscillatory flow together with a spectral Doppler trace and an estimate of mean arterial diameter. A method using color flow imaging was compared with the spectral Doppler method in vascular phantoms and found to have errors that were on average 35% greater. Differences from the theoretic value for the time averaged wall shear rate using the spectral Doppler method varied by artery: brachial −9 (1) %; carotid −7 (1) %; femoral −22 (4) %; and fetal aorta −17 (10) %. Test measurements obtained from one healthy volunteer demonstrated the feasibility of the technique in vivo. E-mail: (james.blake@ed.ac.uk)