|Depending on your condition, your cardiologist may want to obtain image of your heart arteries to help determine the severity of your condition and how likely you are to suffer a heart attack in the next five years. This image was obtained from a special type of CT scan that provides information about how much calcium is in the arteries. This is called a Coronary Calcium Score. The areas highlighted in yellow are calcium, which indicates how much plaque has accumulated in the heart artery. (Thanks to Dr. John P. Reilly and James O'Meara for supplying this image.)
A coronary calcium score is a test result that can give your physician information about your risk for heart disease. A coronary calcium scan is performed through a CT scan, which uses x-rays and a computer to create three-dimensional images of your coronary arteries – the arteries that supply the heart with blood. The CT scan detects calcium deposits in the arteries, which show up as white specks on the image.
Calcium - along with fat, cholesterol, and other substances – is a component of plaque, a material that can build up in the artery walls. This build up of plaque is called atherosclerosis, or “hardening of the arteries,” and is the cause of coronary artery disease. The more plaque one has, the higher the coronary calcium score. A coronary calcium score can help predict a patient’s likelihood of suffering a heart attack from coronary artery disease within the next five years or so.
A coronary calcium score can augment a patient’s Framingham Risk Score - a common method for assessing cardiovascular disease risk that can be calculated by a physician. The Framingham Risk Score looks at risk factors, such as cholesterol levels, smoking, and blood pressure, to estimate a person’s 10-year risk for cardiovascular disease. It is based on findings from the Framingham Heart Study, a research study that has been ongoing for more than 60 years.
A Framingham Risk Score can accurately identify a low or high risk of heart disease, and a coronary calcium score does not further aid prediction in those cases. However, patients who are identified as at moderate risk by the Framingham Risk Score may be able to have their risk more accurately measured by the addition of a coronary calcium score.
Coronary calcium scoring is a test that is performed on people without symptoms to assess their future risk. It is not generally used for patients with symptoms. Also, it is not a test that is generally repeated, the first coronary calcium score tells your doctor what your risk is for the next five or 10 years.
How Does It Work?
Radiation is beamed at the heart, and detectors opposite the source of the radiation beam translate the radiation into images. These images are taken of different views of the coronary arteries and compiled by a computer into three-dimensional (3-D) images.
A physician will analyze the information from the scan to determine a score that indicates the patient’s risk for heart disease. A score of zero indicates no calcium deposits in the coronary arteries, with almost no risk of having a heart attack in the next five years. A score above 80 typically indicates an increased risk of heart attack, and scores of 400 or more are indicative of extensive heart disease.
How Is It Performed?
Be sure to follow any instructions your physician or a nurse provides to you about food and drink guidelines for the day of the test, as well as appropriate clothing to wear and any jewelry that should be removed.
You will be asked to lie down on a table that will pass through the doughnut-shaped scanner. During the test, you will have to remain very still and you may be asked to hold your breath for short intervals to reduce the risk of blurred images from breathing. No IV is needed, and you will be ready to leave immediately after the test. In many cases you may receive the results before you leave.
An electrocardiogram (EKG or ECG) will be performed at the same time as the CT scan to monitor the electrical activity of your heart. (Your heartbeat is a result of natural electrical impulses in your heart muscle.) Electrodes – small, sticky patches – will be attached to your chest for the EKG.
Is It Safe?
A coronary calcium scan is a very safe procedure; however, it does involve radiation and should be used only when it can provide valuable information about heart attack risk, such as patients at intermediate risk according to their Framingham Risk Score. It requires significantly less radiation than a coronary angiogram, or a nuclear stress test.
Because a coronary calcium scan uses radiation, it is not recommended during pregnancy. Please be sure to notify your physician if you are, or may be, pregnant. Also, if you have undergone many tests or procedures that involve radiation in the past, please inform your physician.
For more on radiation in diagnostic testing, please see the SecondsCount Guide to Radiation Safety in Medical Testing.
Questions to Ask Your Doctor
The following questions can help you talk to your physician about undergoing a coronary calcium scan. Consider printing out or writing down these questions and taking them with you to your appointment. Taking notes can help you remember your physician’s response when you get home.
- Am I a good candidate for a coronary calcium score? That is, am I at moderate risk of a heart attack based on risk factors?
- What will the coronary calcium score tell us about my risk for a heart attack?
- How much radiation will I be exposed to during the test?
- What happens next if the coronary calcium scan shows something that needs further examination?
- How often is a coronary calcium score incorrect, and what are common reasons for it being incorrect?
Please print this list of questions here. Take them with you to the doctor and share them with friends and loved ones when you are encouraging them to see their doctors.