Relation of electron beam computed tomography screening for coronary calcium to cardiovascular risk and disease: A review

Electron beam computed tomography has become an increasingly popular technology to noninvasively screen for coronary artery calcium as a marker of atherosclerotic burden. Coronary artery calcium is invariably associated with atherosclerosis, and the amount (volume, mass, or calculated 'score') of calcium is directly associated with age, male gender, and other cardiovascular risk factors. Coronary artery calcium is highly sensitive and moderately specific for the identification of angiographically significant disease. Recent reports also show a direct association between the amount of coronary calcium and the risk of combined new coronary events and revascularization in previously asymptomatic individuals, and hard coronary events among symptomatic patients. Coronary artery screening by electron beam computed tomography is a cost-effective tool compared with other diagnostic modalities when the pre-test likelihood of disease is low to moderate. Although some reports have shown significant retest variability in calcium scores obtained from repeated scans, and in the individual relationship between angiographic disease and coronary calcium quantity, such variability may be minimized by averaging results from two or more consecutive scans, techniques to minimize respiratory motion artifact, and possibly the use of thicker scan slice thicknesses. Serial scanning by electron beam computed tomography is also being investigated as a noninvasive tool for following the effects of medical or lifestyle intervention for controlling cardiovascular risk factors or disease. At present, coronary artery scanning by electron beam computed tomography may be most appropriately utilized in screen patients with established coronary risk factors or known or suspected coronary disease, and in combination with established diagnostic testing to confirm the presence of suspected coronary disease.