What is Carotid Ultrasound Imaging?

Ultrasound scanning, also called ultrasound imaging or sonography, produces pictures of the inside of the body by exposing part of the body to high-frequency sound waves. Ultrasound exams do not use ionizing radiation (as used in x-rays). Because ultrasound images are captured in real-time, they can show the structure and movement of the body's internal organs, as well as blood flowing through blood vessels.

Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. Your body's two carotid arteries, are located on each side of the neck and carry blood from the heart to the brain. Ultrasound imaging provides detailed pictures of these blood vessels.

Doppler ultrasound study may be part of the examination to evaluate blood as it flows through a blood vessel, including the body's major arteries and veins in the abdomen, arms, legs and neck.

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What are some common uses of the procedure?

The carotid ultrasound is most frequently performed to detect narrowing of the carotid artery, a condition that substantially increases the risk of stroke. The major goal of carotid ultrasound is to screen patients for blockage or narrowing of their carotid arteries, which if present may increase their risk of having a stroke. Once the diagnosis is made a comprehensive treatment may be initiated. It may also be performed if a patient has high blood pressure. Other risk factors calling for a carotid ultrasound are:

• advanced age
• diabetes
• elevated blood cholesterol
• a family history of stroke or heart disease

A carotid ultrasound is also performed to:

• locate a hematoma, a collection of clotted blood that may slow and eventually stop blood flow.
• detect dissection of the carotid artery, a split between layers of the artery wall that may lead to obstruction of blood flow or a weakening of the wall of the artery.
• check the state of the carotid artery after surgery to restore normal blood flow.
• verify the position of a metal stent placed to maintain carotid blood flow.

Doppler ultrasound images can help the physician to see and evaluate:

• blockages to blood flow (such as clots).
• narrowing of vessels (which may be caused by plaque).
• tumors and congenital malformation.

In children, Doppler ultrasound is used to:

• evaluate blood flow.
• predict a higher risk of stroke in children with sickle cell disease.
• detect abnormalities in the blood vessels, lymph nodes and lymphatic vessels.

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What are the limitations of Carotid Ultrasound Imaging?

• Carotid ultrasound may be difficult or impossible if a patient has a dressing covering a wound or surgical scar in the neck.
• An occasional patient is difficult to examine because of the size or contour of the neck.
• Calcium deposits in the wall of the carotid artery may make it difficult to evaluate the vessel.
• A small amount of soft plaque that produces low-level echoes may go undetected.
• Ultrasound cannot visualize the entire length of the vessel because the last portion of the carotid artery travels though the bone at the base of the skull. For a complete assessment, patients may need to undergo a CT or MRI of the carotid.

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How should I prepare?

You should wear comfortable, loose-fitting clothing for your ultrasound exam. You may need to remove all clothing and jewelry in the area to be examined.

A loose-fitting, open necked shirt or blouse is ideal.

Ultrasound exams are very sensitive to motion and an active or crying child will slow the exam process. To ensure a smooth experience, it would be beneficial to explain the procedure to the child prior to the exam. You may bring a book to read to the child to ease anxiety. Ultrasound departments often have a television in the examination room and the child's favorite show may be played if there are no other available distractions.

No other preparation is required.

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What are the benefits vs. risks?

Benefits

• Most ultrasound scanning is noninvasive (no needles or injections) and is usually painless.
• Ultrasound is widely available, easy-to-use and less expensive than other imaging methods.
• Ultrasound imaging does not use any ionizing radiation.
• Ultrasound scanning gives a clear picture of soft tissues that do not show up well on x-ray images.
• If a carotid ultrasound exam shows narrowing of one or both carotid arteries, treatment can be taken to restore the free flow of blood to the brain. Many strokes are prevented as a result.

Risks

• For standard diagnostic ultrasound there are no known harmful effects on humans.
• In nearly 50 years of experience, carotid ultrasound has proved to be a risk-free procedure.

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Additional Information and Resources

• American Stroke Association
• National Stroke Association

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