The incidence of coronary artery calcification on standard thoracic CT scans

Coronary artery calcification indicates the presence of atheromatous disease and can represent an area of severe stenosis. The absence of calcification does not correlate with the absence of coronary artery disease, but an incidental finding of calcification has important prognostic implications. The best method available at present is electron beam computed tomography (EBCT) but these are often dedicated units in specialist centres and currently this modality is not widely available in the UK. This is the first study to establish the age/sex frequency with which incidental coronary artery calcification is detected using standard CT scanning in a large population. The methods used are simple, reproducible and based on standard thoracic protocols. The presence of calcification is easily detected using readily available equipment. The reported incidence of calcification using EBCT, the most sensitive method available, was compared with standard CT detection rates. While standard CT underestimates the presence of calcification, the age/sex trends are very similar. Standard CT probably detects the most dense lesions, missing areas of mild calcification, recent studies having shown that these lesions are most likely to represent areas of stenosis. This study shows that, with very little change in current practice and on readily available equipment, it is possible to obtain important diagnostic information suggesting the presence of severe coronary artery disease.