Atherosclerosis is the leading cause of morbidity and mortality in industrialised nations, and its prevalence in developing countries is rising. In up to 70% of patients the initial manifestation of coronary artery disease is either myocardial infarction or sudden death.1 Studies comparing coronary angiography with intravascular ultrasound, the reference standard for detection of atherosclerotic disease, have shown that vascular remodelling accompanies the early stages of the development of atherosclerotic plaque, and luminal narrowing therefore often does not occur until a clinically significant amount of intimal plaque has been formed.2 About 70% of acute coronary syndromes occur from rupture of haemodynamically insignificant or non-obstructive coronary artery plaques^w1 in previously asymptomatic individuals. The need is growing to identify accurately asymptomatic patients with a sizeable burden of coronary atherosclerotic plaque for intensive treatment.

The inflammatory response, which also contributes to atherogenesis, results in calcium being deposited in the atherosclerotic plaque. Histopathological studies confirm the close correlation between the extent of coronary artery calcification and the total burden of atherosclerotic plaque.3 Electron beam computed tomography (G E Imatron, South San Francisco, California) is an evolving, non-invasive technique for the detection of calcium in the coronary …