Computed Tomography (CT) of the Heart
Computed tomography(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. Some very rapid CT scanners (multidetector CT) 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 are still trying to determine the best way to use this test within the overall evaluation of whether people have coronary artery disease.
Computed tomography angiography (CTA) is a type of CT that is used to produce three-dimensional images of the major arteries of the body, except 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 is often not done for people who have kidney problems.