A heart CT scan is a non-invasive imaging test that creates detailed pictures of the heart and its surrounding blood vessels. It provides comprehensive views of the heart’s anatomy, valuable for diagnosing various heart conditions.
What a Heart CT Scan Is
A heart CT scan, or cardiac Computed Tomography, uses X-rays and computer processing to generate cross-sectional images of the heart. Unlike a standard X-ray, a CT scanner rotates around the body, capturing multiple images from different angles. These images are then compiled by a computer to create detailed, three-dimensional views of the heart.
This advanced imaging technique allows doctors to examine the heart’s structure, blood vessels, and surrounding tissues with high resolution. It provides a clearer picture of internal organs and soft tissues compared to traditional X-rays, helping identify abnormalities.
Reasons for a Heart CT Scan
Doctors recommend a heart CT scan for various diagnostic purposes. One common reason is to detect coronary artery disease (CAD), where the scan looks for plaque buildup, often quantified through a calcium scoring test. This test measures calcified plaque in the coronary arteries, indicating the extent of atherosclerosis.
The scan also helps in evaluating heart valves, assessing the aorta for issues like aneurysms or dissections, and planning for complex heart procedures. It can also investigate symptoms such as unexplained chest pain or shortness of breath when other tests are inconclusive.
What to Expect During a Heart CT Scan
Preparation for a heart CT scan involves specific instructions. Patients are advised to avoid caffeine for 12 hours before the scan and to fast from food for a few hours prior to the appointment. Inform medical staff about any allergies, especially to iodine or contrast dyes, and discuss current medications.
During the scan, you will lie on a narrow table that slides into a large, donut-shaped CT machine. Electrodes are placed on your chest to monitor your heart’s electrical activity, which helps synchronize the images with your heartbeat. If a contrast dye is needed, it will be injected intravenously, often causing a warm sensation or a metallic taste in your mouth. You will be asked to remain very still and hold your breath for short periods to prevent blurred images. The entire process usually takes less than an hour, with the actual scanning time often completed within 10 to 15 minutes. After the scan, you can typically return to your normal activities.
Understanding Potential Risks
A heart CT scan involves potential risks related to radiation exposure and contrast dye. The procedure uses X-rays, meaning there is a small amount of radiation exposure. While the dose is generally considered low, the benefits of diagnosis typically outweigh these risks. For example, a cardiac CT for calcium scoring might involve about 3 mSv of radiation, while a CT angiogram (CTA) can range from 3 to 20 mSv.
Contrast dye can sometimes cause side effects. Mild reactions, such as flushing, nausea, itching, or a mild rash, occur in up to 1% of patients. More severe allergic reactions, though rare, can include difficulty breathing or anaphylaxis. Pregnant individuals, or those who might be pregnant, should inform their doctor, as radiation exposure can pose a risk to the fetus.
Interpreting Your Scan Results
After your heart CT scan, a radiologist will analyze the images and send a detailed report to the referring doctor. The scan can reveal various types of information, including the presence and extent of plaque buildup in the coronary arteries, blockages, or structural abnormalities within the heart and major blood vessels.
If a coronary artery calcium (CAC) scan was performed, your results will include a calcium score, also known as an Agatston score. A score of zero typically indicates no calcified plaque and a low risk of a heart attack in the next few years. Higher scores suggest a greater amount of calcified plaque and an increased risk of heart disease. Your doctor will discuss these results with you, explaining what they mean for your specific health situation and guiding you on any necessary next steps.