Carotid Ultrasound

Intima Media Thickness (IMT) and Plaque Assessment

What is a carotid ultrasound IMT?

Carotid ultrasound is a safe, noninvasive, and painless procedure that uses ultrasound waves to examine for early signs of atherosclerosis (plaque) in carotid arteries. Your carotid arteries are the main arteries in your neck that deliver blood from the heart to the brain.  

This test evaluates for early signs of atherosclerosis, such as an increased thickness of the carotid artery wall (intima media thickness, IMT) as well as plaque, both soft and calcified. It also can provide you with your vascular age.

This information can be helpful to better understand the current status of your vascular health, and make adjustments in lifestyle and medical therapy in order to decrease your risk of stroke and heart attack. It is also a window into what might also be happening in the other arteries of your body, such as those in your heart (coronary arteries).


Why get a carotid IMT and plaque assessment?

Traditional risk algorithms may miss 50% of patients who experience a heart attack or stroke. 

Carotid IMT represents a combination of intimal (atherosclerosis) and medial (vascular hypertrophy) in the artery wall. It is an early sign of atherosclerosis, and there is high correlation between the disease found in this test and the disease found through pathology samples. The amount of disease found in the common carotid artery correlates highly to the amount of atherosclerotic disease found elsewhere in the body.

Studies in asymptomatic individuals demonstrate that an increased carotid IMT indicates a higher risk of stroke, heart attack, or death from cardiovascular disease. The identification of carotid plaque increases risk further, and is recommended by the American Society of Echocardiography. 

Screening for carotid arterial disease, particularly in younger and middle aged adults, increases detection rates - atherosclerosis sometimes emerges first in one vascular bed before others. Carotid IMT and plaque thickness are associated with risk of future cardiovascular events in both primary (without known cardiovascular disease) and secondary (with cardiovascular disease) prevention populations. Additionally, given multi-site occlusive disease (ie severe atherosclerosis in multiple vascular beds) is associated with worse clinical outcomes, this test compliments vascular assessment in other territories such as coronary artery calcium scans or CT angiograms. 

Research has also demonstrated that showing individuals signs of atherosclerosis in their carotid arteries can prompt healthy lifestyle changes that reduce their risk of cardiovascular disease. As such, it can be a powerful tool to impact healthy change.

Who should have a carotid ultrasound IMT?

The test is available to anyone who would like to screen for early signs of atherosclerosis or know their vascular age. Individuals who should consider this test in particular are those with

  • High blood pressure

  • Diabetes,  insulin resistance, or metabolic syndrome 

  • High cholesterol

  • Elevated Lp(a)

  • Family history of stroke or heart disease

  • Rheumatoid arthritis, psoriasis, or other autoimmune conditions

  • Coronary artery disease

  • Elevated coronary artery calcium score

What to Expect

A carotid ultrasound uses ultrasound technology to image your carotid arteries. There is no radiation involved nor should it be painful. A transducer will be placed on your neck and gel is used to improve ultrasound wave transmission. The test takes about 20-30 minutes. 

Please wear a comfortable shirt ideally with no tight collar. No special preparation is required

Dr Harkin will review the preliminary results with you, including showing you the images,  at the time of the appointment. You’ll receive a formal report in about 5-7 business days maximum. If she feels you would benefit from a carotid duplex ultrasound to determine if plaque that is seen might benefit from surgery, she will also let you know.