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Definition
Carotid ultrasound is a safe, painless procedure that uses sound waves to examine the structure and function of the carotid arteries in the neck.
You have two carotid (kuh-ROT-id) arteries, one on each side of the neck, which deliver blood from the heart to the brain. Carotid ultrasound can reveal whether an artery has any blockage and how well blood flows through the artery.
Carotid ultrasound is usually used to screen for blockages that 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.
Why it's done
The primary purpose of a carotid ultrasound is to screen for a narrowing of the carotid arteries that indicates an increased risk of stroke. Narrowing is usually caused by plaques — a buildup of fats, cholesterol, calcium and other substances that circulate in the bloodstream. Early detection of narrowing of the carotid arteries enables your doctor to begin treatments that improve blood flow to the 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. These conditions include:
- High blood pressure
- Diabetes
- High cholesterol
- Family history of stroke or heart disease
A carotid ultrasound to screen for stroke risk may be used in combination with other tests, including:
- Abdominal ultrasound to screen for potential abdominal aortic aneurysm, an enlargement or ballooning of the large artery that supplies blood to the abdomen, pelvis and legs
- Ankle-brachial index test, a comparison of your blood pressure measured at an ankle and your blood pressure measured at an arm, which can indicate blockage of blood flow to the 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 and support a weakened artery
- 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
How you prepare
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.
What you can expect
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 and blood cells.
A computer translates the echoed sound waves into a live-action image on a monitor. If a Doppler ultrasound is performed, 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 down 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.
Results
A doctor who specializes in the reading of imaging tests (radiologist) will review and interpret the results of your carotid ultrasound. He or she will prepare a report for the doctor who ordered the exam, such as your primary care doctor, a specialist in heart and blood vessel disorders (cardiologist), or a specialist in brain and nervous system disorders (neurologist).
The radiologist may also discuss the results of the test with you immediately after the procedure.
The doctor who ordered the test will explain to you what the carotid ultrasound revealed and how the results affect your medical care. If the test was ordered to screen for stroke risk, your doctor may recommend the following treatments, depending on the severity of blockage:
- Changes in your diet and exercise routine
- Medication to lower blood cholesterol
- Medication to prevent blood clots
- Surgical procedure to remove carotid artery plaques (carotid endarterectomy)
- Surgical procedure to open up and support your carotid arteries (carotid angioplasty and stenting)
If the test was ordered as a follow-up to a surgical procedure, your doctor can explain whether the treatment is working as planned and whether you'll require additional treatment or follow-up exams.
Additional tests
If the results of the carotid ultrasound are unclear, your doctor may order additional imaging tests:
- Computerized tomography (CT), a specialized X-ray technology that produces thin cross-sectional images of soft tissues
- Magnetic resonance imaging, which uses a magnetic field and radio waves to produce cross-sectional or 3-D images of soft tissues
Last Updated: 2010-06-25
