A heart CT scan is a non-invasive imaging test that identifies blockages and narrowing within the heart’s arteries. It provides detailed images of the heart and its blood vessels, assessing coronary artery disease (CAD), which involves the buildup of plaque.
How Heart CT Scans Visualize Arteries
A heart CT scan uses X-rays to generate detailed cross-sectional images of the heart and its blood vessels. The CT scanner rotates around the body, capturing multiple images from various angles. A computer then processes these images to create comprehensive three-dimensional (3D) views of the heart’s anatomy.
Many heart CT scans, particularly Coronary CT Angiography (CCTA), involve the injection of an iodine-based contrast dye into a vein. This dye travels through the bloodstream and highlights the blood vessels, making them more visible and distinct on the CT images.
Identifying Blockages and Plaque
Heart CT scans employ different techniques to detect blockages and plaque. One method is Coronary Artery Calcium (CAC) scoring, which is a CT scan designed to detect and quantify calcified plaque in the arteries. Calcium deposits are a marker for atherosclerosis, the hardening of the arteries, and their presence indicates the extent of plaque buildup. The Agatston score measures the total area and density of these calcium deposits, with a higher score indicating more extensive calcification and a greater risk of heart disease.
Coronary CT Angiography (CCTA) uses contrast dye to visualize the inside of the arteries. CCTA can detect both calcified and non-calcified (soft) plaque within the arterial walls. This scan provides detailed images that show any narrowing, also known as stenosis, caused by plaque buildup, and can assess the degree of such narrowing. CCTA detects coronary plaques and their characteristics, providing insight into the atherosclerotic burden.
Interpreting Results and Next Steps
After a heart CT scan, a radiologist analyzes the images and generates a report for the healthcare provider. A normal result indicates clear, well-defined arteries with no significant blockages or plaque buildup. For a CAC score, a score of zero signifies a low chance of developing a heart attack in the near future.
When blockages or plaque are detected, the results are assessed to determine their severity and potential implications. For example, a CAC score between 100 and 300 suggests moderate plaque deposits and a higher risk of a heart attack. Depending on the findings, healthcare providers may recommend lifestyle modifications, such as dietary changes or increased exercise, or prescribe medications to manage risk factors like high cholesterol. In cases of significant narrowing or other concerning findings, further diagnostic tests, such as a stress test or traditional angiography, may be considered to evaluate blood flow or guide treatment decisions.
Understanding the Scan’s Role in Diagnosis
A heart CT scan is a valuable diagnostic tool for heart conditions. Its non-invasive nature is an advantage, as it avoids surgical incisions or catheter insertion, unlike traditional invasive angiography. The scan provides high-resolution images that offer precise details of the heart’s structures and coronary arteries, aiding in early detection of coronary artery disease.
Despite its benefits, heart CT scans have considerations. It involves exposure to X-ray radiation, although modern machines use lower doses to minimize this risk. While CCTA can show anatomical narrowing, it does not directly assess blood flow, which may require other tests. In some instances, such as with heavily calcified arteries, the images may be challenging to interpret, potentially leading to inconclusive results that necessitate further evaluation. Doctors recommend this scan for individuals with suspected coronary artery disease, unexplained chest pain, or for risk assessment.