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.
Multidetector CT, a very rapid CT scanner can take a picture during a single heartbeat. Such rapid CT scanning (called CT coronary angiography) is sometimes used to evaluate the arteries that supply blood to the heart (coronary arteries). 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.
Electron beam CT, previously called ultrafast or cine CT, is used mainly to detect calcium deposits in the coronary arteries, an early sign of coronary artery disease. Doctors use the test results together with other information to estimate the risk of heart attack or stroke and to recommend preventive measures.
Computed tomography angiography (CTA) is a type of CT that is used to produce three-dimensional images of the major arteries of the body, including the coronary arteries. 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).
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.
