Coronary CT calcium scan | |
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Purpose | assessment of severity of coronary artery disease |
A coronary CT calcium scan is a computed tomography (CT) scan of the heart for the assessment of severity of coronary artery disease. Specifically, it looks for calcium deposits in atherosclerotic plaques in the coronary arteries that can narrow arteries and increase the risk of heart attack.[1] These plaques are the cause of most heart attacks, and become calcified as they develop.
These calcifications can be detected by CT imaging because of their opacity to x-rays. This severity can be presented as an Agatston score or coronary artery calcium (CAC) score. The CAC score is an independent marker of risk for cardiac events, cardiac mortality, and all-cause mortality.[2] In addition, it provides additional prognostic information to other cardiovascular risk markers.[2]
Obstructions may be present even with an Agatston score of zero, especially in younger patients.[3] A typical coronary CT calcium scan is done without the use of radiocontrast agent but it can also be performed using contrast-enhanced images as well, such as in coronary CT angiography.[4] The exam is best performed with cardiac gating to eliminate motion but can also be estimated in the presence of motion.