A cardiac calcium scoring CT scan (often called a coronary calcium scan) is a quick, non-contrast scan that checks for calcified plaque build-up in your heart’s arteries. Over time, fat and calcium can build up in the coronary arteries, forming hard plaques that restrict blood flow and increase the risk of a heart attack.
By measuring the amount of calcium in these plaques, the scan produces a "calcium score." This score helps your referring doctor assess your heart health and estimate your risk of a future heart attack.
Common Indications for a Cardiac Calcium Scoring CT Scan
- Assessing heart attack risk in individuals with risk factors like high cholesterol, high blood pressure, or diabetes.
- Screening patients with a family history of early heart disease.
- Evaluating individuals with borderline risk factors to decide if they need cholesterol-lowering medications (statins).
- Supporting preventive decisions in selected adults whose cardiovascular risk remains uncertain after standard risk assessment.
What exactly does a cardiac calcium scoring CT scan show?
The scan shows the location and amount of calcified plaque inside the arteries that supply blood to your heart. It does not show soft, non-calcified plaques; it calculates a numerical score (Agatston score) based on the hard calcium deposits.
How should I prepare for a cardiac calcium scoring CT scan?
Preparation varies by centre. Fasting is often unnecessary, but you may be asked to avoid caffeine, nicotine, or exercise for a stated period. Follow the appointment instructions rather than assuming a universal four-hour rule.
Do I need to stop taking medication?
Do not stop prescribed medication unless the clinical team tells you to. Ask the centre about any heart-rate medicines and preparation specific to its scanner and protocol.
What happens when I arrive for my scan?
You will change into a hospital gown. The technician will clean three small areas on your chest and place sticky patches (ECG electrodes) there. These electrodes are connected to a monitor that tracks your heart rhythm, allowing the CT scanner to take images between heartbeats.
How is the procedure performed?
You will lie flat on your back on the scanner table. The table will slide into the scanner. The radiographer will ask you to hold your breath for about 10 seconds while the images are taken. The scanner does not use any contrast dye or injections.
How long does a cardiac calcium scoring CT scan take?
The actual scan takes only about 10 to 15 seconds. The entire appointment takes about 15 to 20 minutes.
Is there any discomfort?
The scan itself does not usually hurt, although ECG sticker preparation, positioning, or breath-holding may be mildly uncomfortable.
Are there risks?
The scan uses ionising radiation; dose varies by scanner, patient, and protocol, so comparison with another examination can be misleading. It does not normally use iodinated contrast, so contrast-reaction and contrast-associated kidney considerations do not apply.
Can children have this scan?
This scan is performed on adults to assess cardiovascular disease risk. It is not performed on children.
Can I have this scan if I am pregnant?
Pregnancy Precaution
Tell the clinician and CT team if you are pregnant or could be pregnant. Calcium scoring is usually a preventive examination rather than an urgent test, so it will generally be deferred unless there is an unusual, clearly justified reason.
When will I get my results?
A radiologist will calculate an Agatston calcium score and send a report to the referring clinician; timing varies by centre. A score of zero means no calcified coronary plaque was detected, but it does not exclude non-calcified plaque or every cause of chest symptoms. Interpretation depends on age, sex, symptoms, and overall cardiovascular risk rather than a single universal threshold.
What if the scan finds something?
If the score is elevated, the referring clinician will combine it with your overall cardiovascular risk to discuss lifestyle measures, lipid-lowering treatment, or whether another assessment is needed. Do not start aspirin or other medication solely from the score without individual clinical advice.
Questions to ask your team
- Is calcium scoring appropriate for my age and overall cardiovascular risk?
- How will the result change prevention decisions such as statin treatment?
- Could current chest pain require a different urgent test?
Sources and further reading
Conclusion
Cardiac calcium scoring is a quick, noncontrast test that can refine preventive cardiovascular-risk discussions in selected adults. It is not an emergency test for active chest pain and does not show non-calcified plaque; follow the preparation instructions from your centre.