What is a carotid ultrasound study?
Ultrasound studies use high frequency sound waves to produce images of various parts of the body. Carotid ultrasound captures images of the carotid arteries located on both sides of the neck. The carotid arteries carry blood from the heart to the brain. It is a painless exam with no restrictions or special instructions before or after the test.
Who needs carotid ultrasound?
Carotid ultrasound studies are often performed to detect narrowing in the carotid arteries. Carotid ultrasound is often performed if a doctor hears a high pitched sound called a bruit through the stethoscope. Patients with strokes or mini-strokes may be referred for a carotid ultrasound. Patients who have undergone carotid stenting or carotid surgery may also be sent to have follow-up carotid ultrasound studies.
How is a carotid ultrasound study performed?
The patient will be lying face up on an examination table. A clear gel is applied to the neck area which allows the ultrasound waves to travel through the body. A small wand-like instrument called a transducer is placed firmly against the skin and images are recorded by the technologist.
You may hear noise during the exam, which is the sound of blood flowing through the arteries. For carotid ultrasound studies, wear comfortable clothing with a loose fitting collar. The exam takes approximately 30 minutes.
The carotid arteries are a pair of blood vessels located on both sides of your neck that deliver blood to your brain and head.
The primary purpose of a carotid ultrasound is to test for narrowed carotid arteries that indicate an increased risk of stroke.
Narrowing of carotid arteries is usually caused by plaque — a buildup of fat, cholesterol, calcium and other substances that circulate in the bloodstream. Early detection of narrowed carotid arteries enables your doctor to begin treatments to improve blood flow to your brain and decrease your risk of stroke.
Your doctor may recommend a carotid ultrasound if you have medical conditions that increase the risk of stroke, including:
- High blood pressure
- 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
You’ll have a Doppler ultrasound that evaluates the blood flow through your carotid arteries.
A carotid ultrasound may be used in combination with other tests to screen for narrowed or blocked blood vessels in other areas of your body, including:
- Abdominal ultrasound. You may have an abdominal ultrasound to test for conditions affecting the blood vessels or organs in your abdominal area.
- Ankle-brachial index test. This test measures and compares your ankle’s blood pressure and your arm’s blood pressure. The test can indicate reduced or blocked blood flow to your legs.
Other uses of carotid ultrasound
Your doctor also may order a carotid ultrasound to:
- Evaluate the structure and function of the artery after surgery to remove plaques (carotid endarterectomy)
- Evaluate the placement and treatment effect of a stent, a mesh tube used to improve blood flow through an artery by mechanically decreasing the narrowing
- Locate a collection of clotted blood (hematoma) that may inhibit blood flow
- Detect other abnormalities in the structure of a carotid artery that may disrupt blood flow
You can take the following steps to prepare for your appointment:
- Call the day before the exam to confirm the time and location of the exam.
- Wear a comfortable shirt with no collar or an open collar.
- Don’t wear a necklace or dangling earrings.
- Unless your doctor or the radiology lab provides special instructions, you shouldn’t need to make any other preparations.
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. In a Doppler ultrasound, the information about 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 procedure. The ultrasound technician (sonographer) may gently adjust the position of your head to improve access to 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 eliminate the formation of air pockets between your skin and the transducer. The sonographer then gently presses the transducer against the side of your neck in order for the instrument to send and receive sound waves.
You shouldn’t feel any discomfort during the procedure. If you do, tell the sonographer.