The latest on the calcium story.

Coronary calcium scanning is no longer restricted to specialized centers but has become widely available as a test that can easily be performed in clinical practice. There have been parallel developments in scientific evaluation of coronary calcium scanning in numerous research studies and the practical use of this test. A number of reports have clarified the relation between the unstable coronary plaque and coronary calcium. Whereas calcium is a frequent feature of plaque rupture, there is too much overlap with more stable plaques to be specific. However, data are accumulating to indicate that calcium is associated with coronary atherosclerotic disease activity. Indeed, reports presented within the past year have demonstrated that very high calcium scores, in particular those >1,000, indicate a significantly increased cardiovascular risk. The advent of cardiac spiral computed tomography (CT) has made coronary calcium scanning widely available. As this methodology is continuously evolving, a number of challenges regarding standardization of test ordering, performance, and interpretation have arisen. Currently, 4-slice spiral CT scanners are most widely used. Protocols with prospective or retrospective electrocardiographic triggering are used, which appear to yield results similar to the Agatston coronary calcium score compared with electron-beam CT, despite the technical differences. New scoring algorithms are being evaluated. With electron-beam and spiral CT we have, for the first time, a readily available test for direct diagnostic visualization of the coronary arteries in clinical practice. This represents the opportunity and the challenge of a proof of principle.