To detect atherosclerotic vascular changes in a timely manner, sonography (ultrasound) is used to determine the intima-media thickness (synonyms: IMD; intima-media-thickness – IMT) of the common carotid artery bilaterally (carotid intima-media thickness test (CIMT)).
The intima refers to the tunica interna (layer of endothelial cells; inner layer) and the media refers to the tunica media (layer of smooth muscle cells; middle layer) of the vessel wall of an artery. In young vascularly healthy individuals, the thickness of these two layers is 0.5-0.7 mm. After the age of 40, the thickness of this layer increases by an additional 0.1 mm approximately every decade.
Indications (areas of application)
- Obesity (overweight)
- Smokers
- Physical inactivity
- Apoplexy (stroke) or transient ischemic attack (sudden onset neurological disorder that resolves within 24 hours)
- Diabetes mellitus
- Atherosclerosis
- Cardiac arrhythmias (atrial fibrillation)
- Hypercholesterolemia (lipid metabolism disorder)
- Hypertension (high blood pressure)
- Coronary artery disease (disease of the coronary arteries).
- Peripheral arterial occlusive disease (pAVK)
- Myocardial infarction (heart attack) risk or condition after myocardial infarction.
- Hyperhomocysteinemia
- Periodontitis (disease of the periodontium).
- Increased CRP (C-reactive protein)
The procedure
Intima-media thickness is measured with the help of high-resolution sonography (ultrasound). This involves imaging the common carotid artery (carotid artery) and measuring the intima-media thickness (IMD). This examination method can detect vessel wall changes such as plaques (deposits) as thin as 1.0 mm. The procedure should be used when atherosclerosis (hardening of the arteries) is suspected. An early sign of subclinical atherosclerosis is an increase in wall thickness (as increased intima-media thickness), especially if the 75th percentile (> 0.9 mm) is exceeded as a statistical measure.
Intima-media thickness measurement results are assessed as follows:
| Measured value | Interpretation |
| 0.7-1.0 mm | “Gray zone” in need of observation |
| > 1.0 mm | pathological |
| > 1.5 mm | Indication of severe changes in the vessel wall |
Intima-media thickness measurement can be performed quickly, easily, and painlessly by an experienced physician. It does not require any special preparation and/or follow-up.
Further notes
- A meta-analysis demonstrated that therapeutic interventions that had a beneficial effect on the progression of intima-media thickness were also associated with a decrease in cardiovascular events: Each 10 μm/year slowing of IMD progression in the common carotid artery was associated with a relative risk of cardiovascular events of 0.91, that is, a 9 percent lower risk.
Benefits
Measurement of intima-media thickness allows rapid and uncomplicated detection of vascular changes. Timely detection of atherosclerotic vascular changes allows the use of preventive measures to prevent secondary diseases of atherosclerosis, such as myocardial infarction (heart attack) and apoplexy (stroke).