Carotid ultrasound is a safe and painless procedure that uses sound waves to examine the blood flow through the carotid arteries. Your two carotid arteries are located on each side of your neck. They deliver blood from your heart to your brain.

A carotid ultrasound is performed to test for narrowed carotid arteries, which increase the risk of stroke.

Carotid arteries are usually narrowed by a buildup of plaque — made up of fat, cholesterol, calcium and other substances that circulate in the bloodstream. Early diagnosis and treatment of a narrowed carotid artery can decrease stroke risk.

Your doctor will recommend a carotid ultrasound if you have transient ischemic attacks (TIAs) or certain types of stroke and may recommend a carotid ultrasound if you have medical conditions that increase the risk of stroke, including:

• High blood pressure.
• Diabetes.
• High cholesterol.
• Family history of stroke or heart disease.
• Recent transient ischemic attack (TIA) or stroke.
• Abnormal sound in carotid arteries (bruit), detected by your doctor using a stethoscope.
• Coronary artery disease.

How it works

A technician (sonographer) conducts the test with a small, hand-held device called a transducer. The transducer emits sound waves and records the echo as the waves bounce off tissues, organs and blood cells.

A computer translates the echoed sound waves into a live-action image on a monitor. The radiologist may use a Doppler ultrasound, which shows blood flowing through the arteries. In a Doppler ultrasound, the rate of blood flow is translated into a graph.

A carotid ultrasound usually takes about 30 minutes.

During the procedure

You'll likely lie on your back during the ultrasound. The ultrasound technician (sonographer) may position your head to better access the side of your neck.

The sonographer will apply a warm gel to your skin above the site of each carotid artery. The gel helps transmit the ultrasound waves back and forth. The sonographer then gently presses the transducer against the side of your neck.

You shouldn't feel any discomfort during the procedure. If you do, tell the sonographer.