CT Calcium Score: Measuring Coronary Artery Calcification to Indicate the Risk of Acute Ischemic Heart Disease and Stroke
Currently, cardiovascular diseases remain one of the leading causes of death worldwide, including in Thailand. A major issue is that these diseases often show no symptoms until an emergency occurs, such as a heart attack or a stroke caused by blocked or ruptured blood vessels. Early risk screening is therefore extremely important.
One of the popular and highly effective screening methods today is the CT Calcium Score, which measures the amount of calcified plaque in the coronary arteries. This test can accurately assess the risk of cardiovascular disease before any symptoms appear. What is CT Calcium Score? How is it performed? What are its advantages? We provide detailed information to help you confidently take care of your heart health.
CT Calcium Score: Measuring Coronary Artery Calcification
CT Calcium Score, or Coronary Artery Calcium (CAC) Score, is a test using a high-speed computed tomography (CT Scan) to measure the amount of calcium (calcified plaque) accumulated in the walls of the coronary arteries.
This calcium buildup is part of the atherosclerosis process, which is a major cause of ischemic heart disease.
How is the CT Calcium Score Test Performed?
The CT Calcium Score test is safe and non-invasive but provides clear information about heart disease risk.
The CT Scan machine takes hundreds of images of the heart within just a few seconds. Specialized software analyzes these images to identify and measure the amount of calcium present in the walls of the four main coronary arteries: Left Main (LM), Left Anterior Descending (LAD), Left Circumflex (LCX), and Right Coronary Artery (RCA).
Calcium in the arteries appears as bright spots on the CT images, and the software calculates a score called the Agatston Score, which is a global standard used by doctors worldwide to assess risk.
What Score Indicates Risk of Ischemic Heart Disease?
The CT Calcium Score results are categorized into risk levels as follows:
- Score 0: No calcium detected in the coronary arteries; very low risk, considered safe.
- Score 1-99: Small amount of calcium detected; low to moderate risk. Lifestyle adjustments and regular monitoring are recommended.
- Score 100-299: Moderate to high risk. Doctors may consider prescribing medication and serious lifestyle changes.
- Score 300-999: Very high risk, with a greater than 20% chance of heart disease within the next 10 years. Intensive care and treatment are necessary.
Note: Scores above 400 to over 1,000 indicate very high risk, comparable to multiple disease flare-ups, and usually require further in-depth cardiac evaluation.
Advantages of Coronary Artery Calcium Scoring (Calcium Score)
The CT Calcium Score test has several advantages that make it popular for preventive health care:
- Detects risk before symptoms appear, identifying individuals likely to develop heart disease early, before chest pain or heart attack occurs.
- Simple and convenient, non-invasive, no contrast dye injection, no catheterization, safe and painless.
- Short examination time, typically only 10–15 minutes, suitable for busy individuals.
- Helps doctors plan effective treatment based on the score, deciding on cholesterol-lowering drugs, aspirin, or lifestyle modifications.
- Encourages patients to be aware and adjust their behavior by seeing clear scores, enabling better health management.
How Does CT Calcium Score Differ from Other Cardiac Function Tests?
There are many methods to assess cardiovascular risk, each with its own strengths and suitability. CT Calcium Score differs from other heart tests as follows:
- Electrocardiogram (EKG/ECG) measures heart rhythm and acute ischemia, suitable for detecting arrhythmias but cannot quantify calcium in arteries.
- Exercise Stress Test evaluates heart response to exercise, suitable for those with chest pain but less accurate in asymptomatic individuals.
- Coronary Angiography provides the clearest images of coronary arteries but is invasive, risky, and costly.
- CT Calcium Score is non-invasive, fast, accurate, ideal for screening asymptomatic individuals, and provides quantitative data.
Therefore, CT Calcium Score is best suited for preventive screening before symptoms appear, helping to decide whether to start treatment or lifestyle changes.
Who Should Get a Coronary Artery Calcium Score Test?
International medical guidelines recommend the following groups consider CT Calcium Score testing:
- Individuals aged 40–75 years, especially men over 45 and women over 55.
- Those with a family history of premature heart disease (father or brother with symptoms before age 55, or mother/sister before age 65).
- Current or former smokers.
- Individuals with hypertension (treated or untreated).
- Those with high blood lipid levels, especially high LDL or low HDL.
- People with diabetes, especially type 2 diabetes.
- Individuals with high body mass index (BMI) or central obesity.
- Patients whose doctors are uncertain about starting cholesterol-lowering medication (statins), especially those with moderate cardiovascular risk.
If you have more than one risk factor, you should consult a doctor to consider CT Calcium Score testing promptly.
How Quickly Are CT Calcium Score Results Available?
CT Calcium Score is a convenient test with a short examination time and quick results. After scanning, a radiologist typically analyzes and reports the results within 1–2 hours. The report includes official documentation with CT images and the Agatston Score. Your doctor will review these alongside your medical history and other risk factors to plan appropriate care.
Is CT Calcium Score Dangerous?
CT Calcium Score is considered very safe because:
- No contrast dye is used, so there is no risk of allergic reaction or kidney damage.
- Low radiation dose, equivalent to about 1–2 chest X-rays or approximately 1–3 mSv, much lower than typical CT scans.
- Non-invasive procedure: no blood draws, injections, or catheterization required.
- No anesthesia needed; can be performed on normal patients without special preparation.
However, as with all radiological tests, it is not recommended to undergo frequent scans unnecessarily and is not suitable for pregnant women.
How Long Does the CT Calcium Score Test Take?
The CT Calcium Score test takes very little time compared to other cardiac tests:
- Preparation time: about 10–15 minutes.
- Actual CT scan: about 5–10 minutes.
- Waiting for results: about 1–2 hours for evaluation and treatment planning with your doctor.
Overall, patients can complete the entire process within 1–2 hours and immediately return to daily activities without recovery time, making it ideal for busy modern lifestyles.
Preparation Before the CT Calcium Score Test
The CT Calcium Score test is straightforward, but proper preparation helps ensure the most accurate results:
- Avoid tea, coffee, and caffeinated drinks for at least 4–6 hours before the test, as caffeine can increase heart rate and affect image quality.
- Refrain from smoking for at least 4–6 hours before the test.
- Inform your doctor about any medications you are taking, especially heart rate controlling drugs like beta-blockers. Your doctor may advise taking them before the test to slow your heart rate and improve image clarity.
- Wear easily removable clothing without metal; you may need to change into a hospital gown.
- No need to fast unless specifically instructed by your doctor.
- Inform if you are pregnant or suspect pregnancy, as radiation tests are not suitable for pregnant women.
- If you have had previous tests, bring the results for comparison.
CT Calcium Score Accurately Indicates Risk of Ischemic Heart Disease
CT Calcium Score, or coronary artery calcification measurement, is an effective screening test to assess cardiovascular risk. It is easy, safe, non-invasive, and provides accurate results. This test has become one of the top choices for those seeking preventive heart health care.
If you are over 40 years old or have risk factors such as diabetes, hypertension, high cholesterol, or a family history of heart disease, it is recommended to consult your doctor about CT Calcium Score testing. Early detection and timely management are key to heart health in today’s world. Don’t let accumulated risk go unnoticed.
Dr. Suchai Kanjanatharayanont
Cardiologist, Heart Center
Phyathai 3 Hospital
