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Last reviewed on May 01, 2023

Carotid Intima-Media Thickness Test

A carotid intima-media thickness test (CIMT) is used to determine the extent of plaque buildup in the walls of the arteries supplying blood to the head. If a CIMT shows increased thickness in the inner layers of the carotid artery, you may be at risk for cardiovascular disease. CIMT uses ultrasound imaging to measure the thickness of the two inner layers of the carotid artery—called the intima and media.

Little or no special preparation is required for this procedure. Leave jewelry at home and wear loose, comfortable clothing. A loose-fitting, open necked shirt or blouse is ideal.

What is a Carotid Intima-Media Thickness Test?

A carotid intima-media thickness test (CIMT), also known as a carotid artery IMT ultrasound scan, uses ultrasound to measure the thickness of the intima and media, the two inner layers of the carotid artery. These measurements can help physicians assess the health of the carotid arteries and the risk of cardiovascular disease-related events like heart attacks and strokes, even in asymptomatic patients. Risk factors for increased carotid intima-media thickness include:

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What are some common uses of the procedure?

CIMT is used to diagnose and determine the extent of plaque buildup in the walls of the vessels supplying oxygenated blood to the head. Increased thickness in the intima and media is associated with an increasingly diseased artery. Because there is a link between intimal medial thickness and cardiovascular events, CIMT is an important test for detecting disease in its earliest stage, when interventions such as diet, lifestyle, and medications can have the greatest impact.

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Who interprets the results and how do I get them?

A radiologist, a doctor trained to supervise and interpret radiology exams, will analyze the images. The radiologist will send a signed report to the doctor who requested the exam. Your doctor will then share the results with you. In some cases, the radiologist may discuss results with you after the exam.

Follow-up examinations may be necessary, and your doctor will explain the exact reason why another exam is requested. Sometimes a follow-up exam is done because a suspicious or questionable finding needs clarification with additional views or a special imaging technique. A follow-up examination may also be necessary so that any change in a known abnormality can be monitored over time. Follow-up examinations are sometimes the best way to see if treatment is working or if an abnormality is stable or changes over time.

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What are the benefits vs. risks?

Benefits

  • Most ultrasound scanning is noninvasive (no needles or injections).
  • Occasionally, an ultrasound exam may be temporarily uncomfortable, but it should not be painful.
  • Ultrasound is widely available, easy to use, and less expensive than most other imaging methods.
  • Ultrasound imaging is extremely safe and does not use radiation.
  • Ultrasound scanning gives a clear picture of soft tissues that do not show up well on x-ray images.
  • If CIMT shows thickening in the carotid artery, treatment can be initiated to reduce the risks associated with the development of atherosclerosis.
  • CIMT can be used repeatedly with no adverse effects.
  • CIMT scanning protocol can detect atherosclerotic diseases in their early stage, before symptoms appear.
  • CIMT allows for observation of the arterial wall, the actual site of the atherosclerotic disease, rather than the lumen.
  • CIMT is not dependent on calcification of the plaque like other assessment tools such as cardiac CT for calcium scoring.

Risks

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What are the limitations of a Carotid Intima-Media Thickness Test?

  • Occasionally, imaging a patient is difficult 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.
  • CIMT is only an indirect assessment of the possible atherosclerotic burden in the coronary arteries.

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Images

Radiologist performing an ultrasound exam. View full size with caption

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