A carotid ultrasound test is a diagnostic test that determines whether plaque is present in the carotid arteries, which are arteries that supply oxygen-rich blood to the brain, neck, scalp and face, according to the National Heart, Lung, and Blood Institute. The test is painless and harmless.
During a carotid ultrasound, a technician uses the high-frequency sound waves of an ultrasound to create pictures of the two carotid arteries, which are located on each side of the neck, explains the National Heart, Lung, and Blood Institute. These pictures can confirm or rule out the presence of plaque, which is a waxy substance that builds up in the arteries, causing carotid artery disease. If built-up plaque hardens, it narrows the bloodﾒs path to the brain. If the plaque ruptures or breaks off, it can cause the formation of a blood clot that blocks or nearly blocks blood flow from the carotid artery to the brain, resulting in a stroke.
A Doppler ultrasound goes beyond the standard carotid ultrasound test and shows the flow of blood through the vessels. Doctors use carotid ultrasound and Doppler ultrasound test results to determine if carotid artery disease is present and to what extent the disease affects the flow of blood to the brain, notes the National Heart, Lung, and Blood Institute.