Frequently asked questions about Carotid Intima Media Thickness Testing (CIMT)
What is CIMT?
CIMT stands for Carotid intima media thickness and refers to the thickness of the inner layers of the artery.
What does the thickness of the vascular lining indicate ?
Genetics and environmental factors (including diet, exposure to carcinogens such as cigarette smoke, and exercise - or the lack of exercise, etc) combine over time to cause inflammation of the inner layers of the artery and the formation of plaque on the inner lining of the arterial wall. This thickening can be measured using ultrasound and sophisticated edge-detection software to quantify the amount of disease present. The measurement of the thickness of the intima and media layers of the common carotid artery is predictive of future events (i.e. stroke, myocardial infarction, and heart attack).
What is an IMT test?
It is a painless noninvasive test utilizing digital ultrasound technology and digital sophisticated edge detection software. The test can be performed easily in the physician's office.
The CIMT scan is brief (approximately 10 minutes), does not require the patient to disrobe, is noninvasive (no needles), and does not expose the patient to radiation. It is relatively inexpensive and provides valuable information about an individual's risk of experiencing a heart attract, stroke, or MI.
What information does the CIMT test provide?
Multiple studies indicate that CIMT measurement detects the presence or absence of atherosclerotic disease and also allows for assessment of the degree of atherosclerotic burden better than other noninvasive cardiovascular tests available. It is recommended by both the American Heart Association and the American College of Cardiology. The procedure:
- Can predict future cardiac and cerebrovascular events.
- Allows earlier detection and intervention
- Allows more accurate risk stratification in asymptomatic patients than do traditional risk factors
- Can distinguish between different types of plaque providing further information about stable and unstable plaque
How long does it take to complete CIMT testing of one patient?
The test has two parts. A sononographer takes sonographic images and sends them to the CardioRisk IMT Technical Center where they are measured or read by a Registered Vascular Technician (RVT). In general it will take about 10 minutes of the patient's time to complete the test. The patient is not required to disrobe and the procedure is well tolerated.
Are there any special requirements for a patient prior to the test?
There are no special requirements.
As many as 50% of those who died from heart attacks or strokes had no previous signs or symptoms. This test allows early intervention and prevention of disease which has the potential to catch more of these patients so they can be treated before they experience an event.
As many as 50% of those who died from heart attacks or strokes had normal "lipid" profiles. Carotid IMT will catch more people with disease who may have been shown to be normal on other tests like stress echo, standard lipid panels, and other blood/urine screens.
It is a cost effective diagnostic tool which provides health value and saves lives.
How accurate is CIMT as a predictive tool?
CIMT is more accurate in predicting disease than any other risk factor alone. CIMT measurement is an independent risk factor even in the absence of any other identifiable risk factors.
Progression of disease over time is another independent risk factor.
Studies have shown a 96% correlation between the disease found in the common carotid and the disease found elsewhere in the body. There is a very high correlation between the thickness of the intima media and other risk factors. Perhaps most important is CIMT's correlation and ability to predict coronary and cerebral events. CIMT was more accurate at predicting CAD than was an Angiogram.