The effect of wall roughness on velocity distribution in a model of the carotid sinus bifurcation--analysis of laser and ultrasound Doppler velocity data.

The purpose of this work was to find out whether a rough surface in the sinus of a carotid model affects the flow velocity distribution and the properties of the corresponding ultrasonic Doppler spectrum, in view of potential application to the evaluation of risk of cerebral embolism. True-to-scale elastic models of carotid artery were used in the experiments. Experiments were performed in three models with varying severity of roughness and a normal (physiological healthy) model. The different degrees of roughness in the three models were created by melting graded holes in the wax cast used to make the model. Velocity data were collected using 4 Mhz pulsed ultrasonic and single component laser Doppler velocimeters. The roughness resulted in modified velocity distribution, affecting to various extent ultrasonic Doppler spectral parameters, in particular the measure of symmetry of spectral distribution.