A Coronary Artery Calcium Scan (CACS) is a specialized, non-invasive imaging procedure using computed tomography (CT) to look inside the heart’s arteries. This examination measures the amount of calcified, or hardened, plaque present within the walls of the coronary arteries. Calcium deposits in this area are a direct marker of atherosclerosis, the buildup of plaque that can restrict blood flow to the heart muscle. By quantifying this calcification, the scan provides a measure of long-term risk for a major cardiovascular event, such as a heart attack.
Practical Preparation Steps
Preparation for a CACS is straightforward but requires adherence to specific instructions to ensure high-quality images. The primary instruction involves restricting substances that can elevate the heart rate, such as caffeine and nicotine. Patients are advised to avoid all products containing these stimulants for four to twelve hours before the scheduled scan.
A slow, steady heart rate is necessary because the CT machine must synchronize image acquisition with the heart’s movement to capture clear pictures. You will also be asked to remove all metal objects, including jewelry, watches, and items like zippers or underwire bras, which can interfere with the X-ray beams. Changing into a hospital gown is often required to eliminate potential image artifacts caused by clothing.
The Scan Itself and Total Time Commitment
The total time commitment for a CACS appointment is short, usually ranging from 15 to 30 minutes. This duration accounts for the administrative process, preparation, the actual procedure, and dressing afterward. The time spent actively acquiring the images is extremely brief.
Upon entering the scanning room, a technologist will have you lie on your back on the CT examination table. To synchronize the imaging with your cardiac cycle, small electrode patches are placed on your chest and connected to an electrocardiogram (EKG) monitor. The table then moves you into the CT scanner’s opening.
The imaging takes only a few seconds of active X-ray exposure, as the CT machine rapidly acquires multiple cross-sectional images of the heart. You will be asked to hold your breath for 5 to 10 seconds to minimize motion blur. Since the scan does not require contrast dye, the process is painless, and you can resume normal activities immediately.
Understanding the Agatston Score
The results of the CACS are quantified using the Agatston score, a standardized value named after Dr. Arthur Agatston. This score is calculated by factoring the total area of detected calcium deposits and the maximum density of the calcification. The final Agatston score represents the overall burden of calcified plaque in the coronary arteries.
The score breakdown correlates directly with cardiac risk:
- A score of zero indicates no detectable calcified plaque and a very low risk of a heart attack.
- Scores between 1 and 100 suggest mild levels of calcification.
- Scores ranging from 101 to 400 denote moderate plaque burden.
- A score greater than 400 represents a significant amount of calcification and a relatively high risk of a future cardiac event.
A radiologist or cardiologist reviews the CT images and calculates the final score, which is compiled into a report. This report is sent to the referring healthcare provider, and patients typically receive results within a few days (often within 72 hours). The Agatston score helps physicians guide decisions about preventive treatments, such as cholesterol-lowering medications, and necessary lifestyle modifications.