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Carotid intima-media thickness (CIMT)
Carotid intima-media thickness, known by its initials CIMT, measures the thickness of the two innermost layers of the carotid artery wall, the intima and the media. It is measured with a Doppler ultrasound, an exam with no pain and no radiation. A thickness greater than expected for your age can be an early sign of atherosclerosis, which is the hardening of the arteries and the buildup of plaque in them. The exam is interpreted together with each person's other risk factors.
In summary
- It measures the thickness of the carotid artery wall, in the neck, with ultrasound.
- It is a painless exam with no radiation and no special preparation.
- It helps detect early signs of atherosclerosis and plaques in the carotid artery.
- It does not give a diagnosis on its own: it is interpreted with age, sex and risk factors.
What is carotid intima-media thickness?
The carotid arteries carry blood to the brain and run along each side of the neck. Their wall has layers. The two innermost are the intima, which is in contact with the blood, and the media, which is muscular. The exam measures the thickness of those two layers together.
With the years, and with factors such as high blood pressure, high cholesterol or smoking, that wall gradually thickens and plaques of fat and calcium can form. This is called atherosclerosis.
What is it for?
- Detecting early changes in the artery wall, before there are symptoms.
- Finding plaques in the carotid arteries and assessing whether there is significant narrowing.
- Complementing the assessment of cardiovascular risk together with the medical history, blood pressure and blood tests.
- Following up people with risk factors or known atherosclerosis.
It is not an exam that is requested routinely for everyone. The doctor decides whether it is indicated in your case.
Who may it be recommended for?
- People with high blood pressure, diabetes, high cholesterol or who smoke.
- People with a family history of heart attack or cerebrovascular disease at an early age.
- People who are overweight, sedentary or have metabolic syndrome.
- People with symptoms such as dizziness, brief loss of vision or temporary weakness, who need a medical assessment.
How it is done
It is a neck Doppler ultrasound. Gel is applied to the skin and a small sensor is moved over the carotid arteries, with the person lying down and the neck slightly turned. The exam lasts a few minutes and does not hurt.
- It requires no fasting or special preparation.
- Both sides are measured and plaques are looked for.
- Doppler also shows the speed of blood flow and can detect narrowing.
How the result is interpreted
Reference values change with age and sex: what is normal at 30 is not the same as at 70. That is why the result is not interpreted from a number alone, but with each person's context.
- A thickness within what is expected for your age is reassuring, but it does not rule out every risk.
- An increased thickness suggests early atherosclerosis and can lead to reinforcing self-care and check-ups.
- A plaque, meaning a localized thickening, is assessed separately and may require more studies and treatment.
What to do with the result
- Control of blood pressure, cholesterol and sugar, as your doctor indicates.
- Quitting smoking.
- A healthy diet, regular physical activity and weight control.
- Medication, when the doctor considers it necessary.
- Regular check-ups according to the case.
What to keep in mind
- A normal result does not guarantee there will be no heart or brain problems in the future.
- An abnormal result does not mean you will have a heart attack or a stroke; it indicates a higher risk that can be reduced.
- The quality of the result depends on the experience of the person who performs and interprets the exam.
When to seek urgent care
These symptoms are not studied with a routine appointment. Go to the emergency department immediately if you have:
- Sudden weakness or numbness in the face, an arm or a leg, especially on one side.
- Sudden difficulty speaking or understanding.
- Sudden loss of vision in one eye, or double vision.
- Sudden severe headache, or loss of balance.
- Chest pain or difficulty breathing.
Frequently asked questions
Does the exam hurt?
No. You only feel the gel and a light pressure of the sensor on the neck. It uses no radiation or needles.
How long does it take?
A few minutes. If it is done together with other Doppler studies, the total time can be longer.
Do I need fasting or preparation?
No. It can be done at any time of day, with comfortable clothing that leaves the neck free.
Does an increased thickness mean I have a serious disease?
Not necessarily. It indicates that the artery wall is thicker than expected for your age and can be an early sign of atherosclerosis. The doctor interprets it with the rest of your risk factors.
Can it be reversed?
Controlling blood pressure, cholesterol and sugar, quitting smoking, exercising and eating healthily help slow its progression. The doctor indicates how often to repeat the exam.
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Book via WhatsAppThe information on this page is general and for guidance only. It does not replace a medical consultation. If you have a warning sign, go to the emergency department. The pages are written for patients in Colombia; consultations are in Spanish.
Last updated: October 16, 2026