Turbulence in Artery. A carotid bruit is a "swishing" sound heard when listening to the neck with a stethoscope. The noise is turbulence caused by blood flowing past a blockage in the artery. These blockages are most often formed by plaque build-up / atherosclerosis. Interestingly this finding correlates with mild to moderate blockages not blockages near or greater than 90%. An ultrasound is the next best test.
Blood flow . A bruit is just a sound heard in a blood vessel that represents turbulent blood flow. In the carotid it could possibly represent a narrowing in the artery. Hearing a bruit does not automatically mean that there is something wrong though. .