Carotid (kuh-ROT-id) ultrasound is a safe, painless procedure that uses sound waves to examine the structure and function of the carotid arteries in your neck.Your two carotid arteries are located on each side of your neck. Carotid arteries deliver blood from your heart to your brain.Carotid ultrasound is usually used to test for blocked or narrowed carotid arteries, which can indicate an increased risk of stroke. Results from a carotid ultrasound can help your doctor determine what kind of treatment you may need to lower your risk of stroke.