Doppler color flow analysis of normal flow patterns in the carotid bifurcation

One hundred normal carotid bifurcations were examined with Doppler color flow imaging. Areas of flow reversal were identified in all but one vessel. Before the bifurcation, flow reversal was typically located peripherally, opposite the origin of the external carotid artery. Beyond the bifurcation, flow reversal typically assumed a linear configuration in the center of the vessel, extending from the superficial to the deep wall. On the average, flow reversal occupied 33% of the lumen of the carotid bulb and extended for a distance of 14 mm. The average duration of flow reversal was 22% of the total cardiac cycle, with reversal typically occurring at peak systole and being replaced by static blood during diastole