A CT Calcium Score is a quick, non-invasive cardiac CT examination performed without contrast. It measures the amount of calcium in the walls of the coronary arteries, helping to identify signs of atherosclerosis and provide a more personalised assessment of cardiovascular risk, even before symptoms develop.
In certain cases, this exam is complemented with a Cardiac CT Angiography (performed with intravenous iodinated contrast), which provides a detailed view of the entire coronary tree, heart chambers, valves, and the aorta, ensuring highly accurate diagnoses.
What is a CT Calcium Score and what is it used for?
A Calcium Score, also known as a Coronary Calcium Score or Cardiac CT Calcium Score, uses X-rays to obtain high-resolution images of the arteries that supply blood to the heart muscle.
The examination looks for calcium deposits within atherosclerotic plaques in the walls of the coronary arteries. Specialised software identifies and quantifies these calcifications, producing a numerical value that is usually calculated using the Agatston method.
This result helps estimate the amount of calcified coronary atherosclerosis and refine the assessment of cardiovascular disease risk. It should be interpreted alongside the patient’s age, family history, blood pressure, cholesterol levels, diabetes, smoking status and other clinical risk factors.
A Calcium Score is particularly useful when a conventional assessment does not clearly establish the level of risk, or when there is uncertainty about whether preventive measures should be started or adjusted, including cholesterol-lowering medication.
What is the price of a CT Calcium Score?
The price of a Calcium Score when performed privately is €120.
However, the examination may also be performed through several agreements, including:
- SNS / ARS: When a CT Calcium Score is performed through the Portuguese National Health Service, the patient does not pay any amount. A referral from the Health Centre must be presented;
- Protocols: NRD has protocols with several clinics and institutions that allow patients to undergo the examination at highly competitive prices. Under these protocols, the price of a Calcium Score is €100.
How is it performed?
The patient lies on their back on a table that moves through the opening of the CT scanner. Small electrodes connected to an electrocardiogram are placed on the chest so that image acquisition can be synchronised with the heart rhythm.
For a few seconds, you will need to remain still and hold your breath when instructed. The scanner obtains cross-sectional images of the heart, which are then analysed by a radiologist. NRD’s equipment processes 128 slices simultaneously, allowing rapid and detailed imaging of the cardiac anatomy.
A Calcium Score does not require the insertion of an intravenous cannula, does not use iodinated contrast and does not usually require medication. Image acquisition takes only a few seconds, although the complete procedure, including preparation and positioning, may take approximately 10 minutes.
What can it detect?
A Calcium Score detects and quantifies calcified deposits in the walls of the coronary arteries. The presence of calcium indicates that some degree of coronary atherosclerosis is already present, even when the patient has no symptoms.
The examination can assess:
- The presence of calcified atherosclerotic plaques in the coronary arteries;
- The location of the calcifications and their distribution across the different vessels;
- The overall amount of coronary calcium, expressed as a numerical result;
- Signs of subclinical atherosclerosis, meaning disease that has not yet caused symptoms such as chest pain;
- Whether cardiovascular risk may have been underestimated or overestimated by a conventional clinical assessment.
The higher the result, the greater the amount of calcified coronary atherosclerosis is likely to be and, in general, the higher the future risk of cardiovascular disease. However, the result should not be interpreted in isolation.
How are CT Calcium Score values usually interpreted?
The ranges shown in the table below provide general guidance. The clinical conclusion also depends on age, sex, risk factors and, where applicable, comparison with people who have similar characteristics.
| Result | General interpretation |
| 0 | No coronary calcification was identified |
| 1 to 10 | Minimal amount of calcium |
| 11 to 100 | Mild calcification |
| 101 to 400 | Moderate calcification |
| Over 400 | Extensive coronary calcification |
A result of zero is associated with a lower risk, but it does not completely rule out coronary artery disease, as non-calcified plaques may still be present. This limitation is particularly relevant in younger people.
Likewise, a high result does not necessarily mean that there is a severe blockage in a particular artery. A Calcium Score quantifies the calcium burden but does not allow direct visualisation of the inside of the coronary arteries or precise measurement of a stenosis. A Coronary CT Angiography or another examination recommended by the doctor may be required for this purpose.
When is it recommended?
The indication should be determined by the referring physician after assessing the patient’s cardiovascular risk and the potential clinical value of the result. A Calcium Score should not be used as an indiscriminate screening examination for the entire population.
It may be recommended in situations such as:
- People without symptoms who have an intermediate cardiovascular risk or whose risk classification remains uncertain;
- The presence of factors such as high cholesterol, high blood pressure, diabetes, smoking, excess weight or a sedentary lifestyle;
- A family history of coronary artery disease or heart attack at a young age, particularly when the other clinical parameters do not fully explain the risk;
- Uncertainty about the potential benefit of starting preventive cholesterol-lowering treatment;
- The need to tailor preventive measures more accurately, including lifestyle changes and management of cardiovascular risk factors.
Preparation for a Calcium Score
Please arrive at the clinic approximately 30 minutes before your scheduled appointment. You should bring the following:
| Topic | Instructions |
| Medical History and Previous Examinations | Bring recent clinical reports and cardiac imaging examinations, such as echocardiograms, electrocardiograms, magnetic resonance imaging scans, previous CT scans or cardiac catheterisation records. If you have previously undergone heart surgery, please also bring the relevant discharge summaries or surgical reports. |
| Metal Objects | We recommend wearing comfortable clothing without metal components, such as zips, metal buttons or accessories. Jewellery, watches and piercings must be removed before entering the examination room, as they may cause artefacts and reduce image quality. |
| Fasting | Fasting is not required. |
| Heart Rate Control — 6 to 12 hours before the examination | Avoid smoking and consuming stimulants, including coffee, black or green tea, caffeinated soft drinks and energy drinks, as your heart rate should remain as low and stable as possible. |
| Usual Medication | On the day of the examination, take your usual medicines with water at the normal times. |
| Mandatory Medical Warnings | Inform the clinical team immediately if you have asthma, a history of arrhythmias, kidney failure or raised urea or creatinine levels, or any type of allergy. |
Instructions during the examination
Your cooperation helps reduce the effects of cardiac and respiratory motion and allows images of sufficient quality to be obtained for accurate coronary calcium quantification.
During the procedure, you may be instructed to:
- Remain lying down and still while the images are being acquired;
- Keep your arms in the position indicated by the clinical team, usually above your head;
- Breathe in and hold your breath for a few seconds when instructed by the radiographer;
- Avoid speaking or changing position during image acquisition;
- Report any discomfort or difficulty following the breathing instructions.
The radiographer will maintain visual contact with you at all times and will be able to communicate with you through the scanner’s intercom system.
When and how will you receive the results?
You will receive the CT Calcium Score results within seven days of the examination, either by email or as a printed copy at the clinic. On the day of the examination, you will be given a CD containing the images.
Where can a Calcium Score be performed?
A Calcium Score can be performed at NRD at the following address: Avenida Columbano Bordalo Pinheiro, no. 11-B, ground floor, 1070–060 Lisbon (Next to Praça de Espanha)