Human carotid artery diameter and flow by a noninvasive technique.

This paper presents a technique tested in vitro and in dogs and used in humans to measure carotid artery blood flow continuously by placing a transducer on the skin over the artery. The tranducer consists of a pulse echo crystal used to locate the carotid artery and measure its diameter and wall velocity. It also has a pair of Doppler shift crystals used to measure the velocity of the artery wall and blood flow in the vessel. It was found that the pulsatile artery wall distension was between 8 and 13 percent of the diastolic diameter. The peak blood flow varied inversely with pulse rate. Occlusion of one carotid resulted in an increase in diastolic but not systolic flow in the other.