Multi-slice computed tomography coronary angiography for ruling out suspected coronary artery disease: what is the prevalence of a normal study in a general clinical population?

AIMS To assess the prevalence of a normal multi-slice computed tomography (MSCT) in patients with suspected coronary artery disease (CAD) and to relate these observations to clinical presentation and pre-test likelihood of CAD. METHODS AND RESULTS In total, 340 consecutive patients (182 men, 55 +/- 12 years) without a history of CAD who were referred for MSCT angiography were included in the study. Based on patient characteristics and the referral reason for MSCT angiography, patients were classified as having a low, intermediate, or high pre-test likelihood of CAD. Patients were evaluated for the presence of coronary artery calcium as well as the presence of atherosclerosis. Overall, 157 (46%) patients did not have coronary artery calcium and 133 (40%) patients had a completely normal MSCT angiogram. In 58% of the patients with low pre-test likelihood, no coronary atherosclerosis was observed when compared with 33 and 17% of the patients with intermediate and high pre-test likelihood, respectively. CONCLUSION MSCT ruled out coronary atherosclerosis in 40-46% of patients without known CAD who were referred for MSCT. Accordingly, in patients with low-to-intermediate pre-test likelihood, MSCT may be an attractive modality to exclude coronary atherosclerosis and may prevent unnecessary additional functional testing or invasive angiography.