The Coronary Artery Calcium (CAC) scan, commonly known as the Calcium Score Test, is a non-invasive imaging procedure used to evaluate an individual’s risk of future heart problems. This test provides a direct measurement of calcified plaque in the arteries supplying the heart muscle. While the process involves several steps, the actual scanning time is extremely short.
What the Calcium Score Test Measures
The Calcium Score Test uses specialized Computed Tomography (CT) technology to create detailed cross-sectional images of the heart. The primary purpose of this scan is to detect and quantify the amount of calcified plaque inside the coronary arteries. This calcification is a strong indicator of atherosclerosis, which is the hardening and narrowing of the arteries.
The presence of calcium in the coronary arteries signals the early stages of coronary artery disease, even in people who have not yet developed symptoms. The test calculates a numerical value, known as the Agatston score, which reflects the overall burden of atherosclerotic plaque. This score is then used by healthcare providers to estimate an individual’s long-term risk of a heart attack or stroke.
Preparing for the Scan
Preparation is necessary to ensure the clearest possible images are captured during the scan. Patients are often instructed to avoid stimulants like caffeine or nicotine for about four hours before the test, as these can raise the heart rate. An elevated heart rate can cause motion artifacts in the images, making it difficult for the CT scanner to accurately capture the fine details of the coronary arteries.
Additionally, since metal interferes with the CT imaging process, patients should remove all jewelry and wear comfortable clothing free of metallic components like zippers or underwire.
The Full Time Commitment of the Procedure
The total time commitment for a Calcium Score Test is significantly longer than the actual scan, but the entire appointment is still brief, typically requiring 30 to 45 minutes from arrival to departure. This duration accounts for necessary preparation and post-scan steps.
Upon arrival, the first 10 to 15 minutes are dedicated to administrative tasks and pre-scan preparation, including check-in, paperwork, changing into a hospital gown, and recording vital signs. Next, the technician places small electrode patches on the patient’s chest. These electrodes connect to an electrocardiogram (ECG) machine, which monitors the heart’s rhythm and synchronizes the CT scan to the precise moment the heart is at rest.
Once positioned on the CT table, the actual scanning time is exceedingly fast, often taking only a few minutes. The patient is asked to hold their breath for a very short period, usually less than 20 seconds, while the machine captures the images. After the images are acquired, the electrodes are removed, and the patient may change back into their clothes. Many facilities estimate the total time spent in the room is about 10 to 15 minutes.
Interpreting Your Calcium Score
The final result of the Coronary Artery Calcium scan is expressed as an Agatston score, which quantifies the total area and density of the detected calcification. A score of zero is considered the most favorable outcome, indicating no measurable calcified plaque and a very low risk of a heart attack over the next several years. This finding often helps to reclassify an individual into a lower risk category.
Scores ranging from 1 to 99 suggest minimal or mild plaque burden. While this confirms the presence of early-stage coronary artery disease, the risk remains relatively low, and a physician may recommend lifestyle adjustments. A moderate score, typically between 100 and 400, indicates a more significant plaque presence, which corresponds to a moderately increased risk of a cardiac event.
A score exceeding 400 signifies an extensive amount of calcified plaque and places the individual in a high-risk category for a heart attack. For these scores, healthcare providers often recommend more aggressive management, which may include additional testing and the initiation of medication to reduce cardiovascular risk. The final calcium score is always evaluated in conjunction with other traditional risk factors, such as age, cholesterol levels, and blood pressure, to determine the most appropriate personalized prevention strategy.