Definition
A Coronary CT Calcium Scoring is a simple, non-invasive test that takes only a few seconds to perform on an outpatient basis. Using state-of-the-art computerized tomography (CT) methods, it can detect calcium deposits in atherosclerotic plaques in the arteries of the heart. These calcium deposits appears years before development of heart disease symptoms like chest pain and shortness of breath.
It is a very useful tool used by your cardiologist to determine if there is coronary artery disease and assess if there is an increased risk of a cardiac event in the future.
What are the benefits of this test?
This test is used to:
- 1Diagnose asymptomatic coronary artery disease
- Presence of calcium deposits indicate the presence of plaques in the coronary arteries, which increases the risk of angina (chest pain) and cardiac events (eg heart attack)
- 2Assess the risk of future cardiovascular events
- The greater the amount of calcium deposited in the heart arteries, indicating more coronary artherosclerosis, portends a greater likelihood of significant narrowing somewhere in the heart arteries and a higher risk of future cardiovascular events.
- 3Guide medical therapy for coronary artery disease
- The higher the calcium score, the greater the need for medical therapy (eg aspirin, statin therapy) and aggressive treatment of the risk factors that lead to the development of the heart blockages.
- Your physician will use the calcium score to guide the lifestyle changes and medications needed to retard the progression of disease and development of symptomatic coronary artery disease.
Who will benefit from this test?
Those at increased risk includes individuals with the following risk factors:
- Family or personal history of coronary artery disease
- Male over 45 years of age
- Females over 55 years of age
- Past or present smoker
- History of high cholesterol, diabetes or high blood pressure
- Elevated body mass index (BMI)
- Inactive lifestyle
What are the limitations of this test?
- 1It picks up only calcified plaques
- There are 2 types of plaques (blockages) in the heart arteries – soft plaques and calcified plaques
- Soft plaques are blockages that can cause narrowings of the heart arteries and do not contain calcium. These will not be picked up by this test and an injection of dye through the arm will be needed for detection of soft plaques (via a CT Coronary Angiogram)
- Your physician will guide you as to whether this test or a CT coronary angiogram will be more suitable for you.
- 2It does not correspond directly to the percentage of narrowing in the heart arteries
- Though the higher the calcium score, the greater is the likelihood of significant narrowing of the heart arteries and risk of a future cardiac events like a heart attack over the next 3 years, it will not give information on the percentage of narrowing of the heart arteries.
How to prepare for the test
- Wear a shirt that can be easily removed so as to facilitate the exam.
- You may eat and drink as you normally would the day of the test.
- Take all of your medications at the usual times as prescribed by your doctor.
- CT scanners use X-rays and the amount of radiation exposure is kept to the minimum for your safety. Because X-rays can harm a developing fetus, please inform your doctor and the technologist if you are pregnant.
How is the test performed?
- This exam will take place in a radiology center chosen by your physician.
- 1Before the test
- You will change into a hospital gown.
- The nurse will record your height, weight and blood pressure.
- You will lie on a special scanning table.
- Three electrodes (small flat sticky patches) will be placed on your chest wall and attached to an ECG monitor that charts your heart’s electrical activity during the test.
- 2During the test
- You will feel the table move inside a donut-shaped scanner.
- The high-speed CT scanner will capture multiple images, synchronised with your heart beat to detect the presence of calcification within the coronary arteries.
- Absence of calcium – considered a “negative” exam but it does not exclude the presence of soft non-calcified plaques.
- If calcium is present, a sophisticated computer program will generate a calcium score that estimated the extent of coronary artery disease.
- 3After the test
- You may resume your normal daily activities after the exam.
- You calcium score with be reviewed by our doctor and a summarized report will be provided and explained to you during your review.
How does the doctor use this test to treat me?
Calcium Score | Implication | Risk of coronary Artery Disease |
|---|---|---|
0 | No identifiable plaque | Very low, generally less than 5 percent |
1 - 10 | Minimal identifiable plaque | Very unlikely, less than 10 percent |
11 - 100 | Definite, at least mild atherosclerotic plaque | Mild or minimal coronary narrowings likely |
101 - 400 | Definite, at least moderate atherosclerotic plaque | Mild coronary artery disease highly likely, significant narrowings possible |
401 or Higher | Extensive atherosclerotic plaque | High likelihood of at least one significant coronary narrowing |
CAC score – Coronary Artery Calcium score
- 1Normal exam
- No further testing may be needed
- 2Abnormal exam
- Further investigations such as a stress test or a CT coronary angiogram may be needed.
Lifestyle changes and treatment with cardiac medications to optimize your condition will be given by your physician.
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