Computed tomography (CT) is a type of medical imaging that combines a series of x-rays to create cross-sectional, detailed images of internal structures, including the heart.
CT may be used to detect structural abnormalities of the heart, the sac that envelops the heart (pericardium), major blood vessels, lungs, and supporting structures in the chest. A CT scan uses multiple x-ray beams, obtained rapidly and from different positions around the body, to create a series of cross-sections (slices) or a 3-dimensional image. Many CT scans are timed to an electrocardiogram so they take pictures at a specific time during the heartbeat.
This contrast CT scan shows a cross section of the chest and heart. In this image one of the coronary arteries, in this case the left coronary artery, comes off of the aorta (red arrow).
© 2017 Elliot K. Fishman, MD.
Computed tomography angiography (CTA) is a type of CT that is used to produce images of the major arteries of the body, including the coronary arteries (in coronary CTA or CCTA). Typically, a contrast agent (a substance that can be seen on x-rays) is injected into the person's vein. The person is asked not to breathe during a scan so that the image will not be blurred. The images are similar in quality to those produced by conventional angiography. CTA can be used to detect narrowing of the arteries supplying organs and aneurysms and tears in major arteries. CTA can also detect clots that have broken off within a vein, traveled through the venous bloodstream, and lodged in the small arteries of the lungs (pulmonary emboli). CCTA can be used to diagnose coronary artery diseases, in some cases avoiding the need for a cardiac catheterization.
Unlike conventional angiography, CTA is not an invasive procedure. The radiopaque contrast agent is injected into a vein rather than into an artery as in angiography. CTA usually takes less than 1 to 2 minutes. Since the contrast agent can cause damage to the kidneys, this test must be done cautiously or avoided in people who have kidney problems.
Coronary calcium scoring, uses CT to detect the amount of calcium present in the coronary arteries. The amount of calcium, together with other information, can help doctors determine a person's risk of a heart attack or stroke and to recommend preventive measures.
