Non-invasive visualization of coronary arteries with and without calcification by electron beam computed tomography

Coronary artery disease (CAD) is one of the leading causes of mortality and morbidity in the western industrialized countries. Recent studies demonstrate the feasability of successful primary and secondary prevention. However, the detection of early stages of coronary artery disease is an unresolved issue. Whereas sensitivity and specificity of traditional risk factor assessment and stress tests are limited, the analysis of coronary calcification allows to obtain a direct sign of coronary atherosclerosis. This concept has been applied using fluoroscopy and conventional computed tomography (CT). However, the exact localization and quantification of coronary calcification only became possible with the advent of electron beam CT (EBCT). This new method showed a high prevalence of coronary calcification in the asymptomatic population. With the definition of a standardized "calcium score" the normal age-specific distribution and amount of coronary calcification was investigated. EBCT proved to be more sensitive in the diagnosis of both non-obstructive and obstructive coronary artery disease than risk factor analysis and stress testing, respectively. Obstructive coronary artery disease, however, cannot yet be predicted with high enough accuracy. A close correlation of EBCT coronary calcification was found to a) the total coronary plaque volume defined by histo-pathology, b) intracoronary ultrasound findings, c) the number of coronary risk factors, d) the coronary prognosis. Using EBCT, a reliable non-invasive identification of persons at risk was obtained for the first time. Guidelines for the use of EBCT in the early diagnosis and treatment of coronary artery disease are being developed.