Carotid ultrasound is a test that shows the carotid arteries (vessels in the neck that provide blood flow to the brain), as well as how much blood flows and how fast it travels through them. Ultrasound waves -- the same ones used in imaging the fetus in a pregnant woman -- are used to make an image of the arteries. This image can be used to find out if there is an abnormality or blockage of the carotid arteries that could lead to stroke. This test can be used to investigate the carotid arteries for several reasons, but the information here applies only to stroke evaluation.

Why do doctors use carotid ultrasound?
Doctors often use carotid ultrasound on patients who have had a stroke or who might be at high risk for a stroke. Narrowing of the carotid arteries -- often caused by cholesterol deposits -- and blood clots can be detected using this procedure. These conditions can cause problems with the blood flow to the brain and lead to a stroke. The actual blood flow through the carotid arteries can also be imaged by this test.