OBJECTIVETo assess the diagnostic accuracy of 64-slice computed tomography coronary angiography (64-SCTCA) in individuals with suspected coronary artery disease (CAD).

METHODSThe study enrolled 285 individuals undergoing 64-SCTCA with calcium scoring and thereafter invasive coronary angiography (CAG) within 4 weeks for suspected CAD. Pretest probability of having obstructive CAD was determined using the Duke clinical score, which was estimated by type of chest discomfort, age, gender, and traditional risk factors and stratified into 3 levels of probability: low (≤ 30%, n = 80), intermediate (31% to 70%, n = 92), and high (≥ 71%, n = 113). CAD was defined as the presence of at least one vessel of ≥ 50% coronary stenosis on CAG.

RESULTSThe patient-based diagnostic accuracy of 64-SCTCA for detecting CAD according to CAG revealed a sensitivity of 81.2%, a specificity of 93.3%, a positive predictive value of 68.0% and negative predictive value of 96.6%. The CAD prevalence in the low, intermediate and high risk groups according to Duke probability was 46.3%, 72.8% and 82.3%, respectively. The sensitivity and positive predictive value were lower in the low probability group than those in the intermediate and high probability groups. For those with coronary artery Agatston calcium score > 400, the diagnostic accuracy was linked with a higher sensitivity but lower specificity. The diagnostic value of 64-SCTCA for proximal and mid-segment of coronary artery was superior to that for distal segment.

CONCLUSIONS64-SCTCA is mainly indicated in individuals with an intermediate probability of having CAD. The diagnostic value of 64-SCTCA could be affected by coronary artery calcium, lesion location and vessel diameter.