The test is also called a carotid Doppler ultrasound test. Ultrasound uses sound waves to create pictures of structures inside the body. There is no radiation.

Doppler ultrasound is one type of this technique that can also produce a moving picture. In this case, the test creates images of blood in motion. 

A carotid Doppler ultrasound shows the amount of blood flow in the two carotid arteries found on the sides of the neck. These are the major blood vessels that supply oxygen and nutrients to the brain.

With this imaging technique, your doctor can see if your carotid arteries are narrowed due to cholesterol deposits or some other problem. This test is often used to evaluate people who have had a stroke. Or people who might be at high risk for one because of less blood flow in the carotid arteries.

If someone with a major blockage of a carotid artery has symptoms of a stroke — or is at high risk for one — the doctor may advise surgery to open the blockage.