Heart disease remains the leading cause of death worldwide, making early detection and prevention critical to saving lives. One effective tool for assessing heart health is the Computed Tomography (CT) Calcium Score scan. This simple, non-invasive scan helps detect early signs of Coronary Artery Disease (CAD) by measuring calcium deposits in the coronary arteries. But like any medical test, it comes with both risks and benefits. This blog post will walk you through what a CT calcium score is, how it works, and the pros and cons of getting this scan.

What is a CT Calcium Score?

A CT calcium score, also known as a coronary artery calcium (CAC) scan, is a specialised type of CT scan that measures the amount of calcium in the walls of the coronary arteries—the vessels that supply blood to the heart. Calcium deposits in these arteries are a sign of atherosclerosis or “hardening of the arteries,” which can lead to CAD.

The test calculates a calcium score based on the amount of calcium found. The higher the score, the greater the likelihood that a person has CAD or is at risk of future heart problems, such as a heart attack. A score of 0 indicates no detectable calcium and a low risk of heart disease, while a high score suggests the presence of significant plaque build-up and increased risk:

• A score of zero means no calcium is seen in the heart. It suggests a low chance of developing a heart attack in the future.
• When calcium is present, the higher the score, the higher the risk of heart disease.
• A score of 100 to 300 means moderate plaque deposits. It’s associated with a relatively high risk of a heart attack or other heart disease over the next 3 to 5 years.
• A score greater than 300 is a sign of more extensive disease and a higher heart attack risk

How Does the Test Work?

The CT calcium score test is quick and painless. It involves lying on a table that slides into a CT scanner—a machine that uses X-rays to take detailed images of your heart and its arteries. You may be asked to hold your breath briefly during the scan to ensure clear images. The test usually takes about 10 to 15 minutes.

No special preparation is needed, and there’s no need for contrast dye, making it simpler than other types of scans. After the test, a radiologist will review the images and calculate your calcium score, which your doctor will then interpret to assess your heart health.

Benefits of a CT Calcium Score

1. Early Detection of Coronary Artery Disease (CAD)

• One of the primary benefits of a CT calcium score is its ability to detect early signs of CAD before symptoms develop. Even if you feel healthy, plaque build-up in your coronary arteries could be silently progressing. The test allows for early intervention, helping doctors recommend lifestyle changes, medications, or other treatments to reduce your risk of a heart attack or other serious cardiovascular events.

2. Non-Invasive and Quick

• The CT calcium score test is non-invasive, meaning there are no needles, incisions, or invasive procedures. It is also relatively quick, taking less than 15 minutes, and causes no discomfort during or after the scan.

3. Guides Preventative Treatment

• If your calcium score indicates a moderate or high risk of CAD, your doctor may suggest preventive measures like medications (e.g., statins) or lifestyle changes (e.g., diet, exercise, and smoking cessation). This proactive approach can significantly reduce your risk of a heart attack or stroke. Knowing your score empowers you and your healthcare team to create a heart-healthy strategy tailored to your individual risk.

4. Motivates Lifestyle Changes

• Sometimes seeing a high calcium score can be the wake-up call people need to take their heart health more seriously. The test results can motivate patients to adopt healthier habits, such as exercising more, eating a balanced diet, quitting smoking, and managing stress.

5. Improves Risk Stratification

• The CT calcium score helps doctors more accurately assess a patient’s risk of heart disease, especially when used alongside traditional risk factors such as age, blood pressure, cholesterol levels, smoking status, and family history. This additional data can refine treatment plans and ensure that those at higher risk get appropriate care sooner.

6. No Need for Contrast Dye

• Unlike many CT scans, the calcium score test does not require contrast dye, which is especially beneficial for people with kidney problems or allergies to the dye used in other imaging procedures.

Risks of a CT Calcium Score

While the CT calcium score test is widely considered safe, there are some risks and limitations to keep in mind:

1. Radiation Exposure

• One of the primary risks associated with the CT calcium score is exposure to ionizing radiation. Although the amount of radiation is low (similar to a mammogram or X-ray), any exposure to radiation carries a slight risk, particularly with repeated scans over time. For most individuals, however, the benefits of the test far outweigh the minimal radiation risk.

2. Not Suitable for Everyone

• The test is most beneficial for individuals at intermediate risk of heart disease—those who have some risk factors but are not yet showing symptoms. It is generally not recommended for people at low risk (no risk factors) or very high risk (those with known CAD). For high-risk individuals, other tests, such as stress tests or angiography, may be more appropriate.

3. Incidental Findings

• While the focus of the scan is on calcium in the coronary arteries, sometimes other abnormalities in the chest are detected incidentally. While this can occasionally be helpful, it can also lead to additional tests, anxiety, and follow-up procedures that may not be necessary.

4. No Information on Soft Plaque

• The CT calcium score only measures hard, calcified plaque in the arteries. It does not detect soft plaque, which can also cause heart attacks. As a result, a person with a low calcium score could still have soft plaque that contributes to heart disease risk. This is why the test is typically used in combination with other risk assessments.

5. May Not Change Management for Some

• For individuals already on a comprehensive treatment plan for heart disease—such as those taking statins or managing multiple risk factors—the results of the calcium score may not significantly change the course of treatment. In these cases, the test may not provide much added benefit.

Who Should Consider a CT Calcium Score?

The CT calcium score is particularly useful for individuals who are at risk (see below) of heart disease but do not yet have symptoms. It may be recommended for:

• People over the age of 40 with multiple risk factors, such as high cholesterol, hypertension, diabetes, or a family history of heart disease.
• Current or former smokers.
• Individuals with borderline risk factors who are unsure if they need aggressive treatment, such as starting statins.

It is less useful for people at low risk, as a score of 0 will likely not change the need for lifestyle modifications, or for people at high risk who already need medical intervention.

How to Prepare for a CT Calcium Score Test

In most cases, no special preparation is needed for a CT calcium score test. You will likely be asked to avoid caffeine and smoking before the scan, as these can affect heart rate and imaging quality. Be sure to inform your healthcare provider if you are pregnant, as radiation exposure should be avoided during pregnancy.

Conclusion: Balancing Risks and Benefits

The CT calcium score test is a valuable tool for detecting early signs of coronary artery disease and helping individuals take proactive steps to protect their heart health. By offering detailed insights into calcium deposits in the arteries, the scan enables doctors to assess heart disease risk more accurately and tailor preventive treatments.

While the test carries minimal risks, including radiation exposure and limited information about soft plaque, the benefits—particularly for those at intermediate risk—often outweigh these concerns. If you’re unsure whether this test is right for you, speak with your healthcare provider. Together, you can decide if a CT calcium score will provide meaningful information about your heart health and help guide your future care.