BACKGROUND AND OBJECTIVES: The purpose of the present study was to investigate the diagnostic accuracy of coronary stenoses in patients with ischemic heart disease using multidetector CT coronary angiography (MDCT) in the assessment of coronary artery disease. SUBJECTS AND METHODS: Forty-three patients (49-72yrs) undergoing conventional coronary angiography (CCA) were included in this study. All patients were premedicated with oral propranolol, 40-80 mg, to achieve an acceptable heart rate of less than 65 bpm, 1hr before the MDCT. All coronary arteries, including the distal segments and side branches, were assessed with respect to assessability and the presence of significant stenosis (>50%) and the results compared with those of CCA. RESULTS: Of the 645 coronary artery segments scanned, 540 were assessable (84%). A total 44 significant stenoses were detected by CCA and 49 lesions by MDCT. The overall sensitivity and specificity were 77 and 97%, respectively. The overall accuracy for the LAD, RCA and LCX was 94, 98 and 95%, respectively, and there were no differences in the accuracies in each vessel. The sensitivity in the proximal segments was much higher than in the distal segments. A total 15 segments were overestimated by the MDCT due to calcification and the small vessel size. CONCLUSION: MDCT, with improved spatial and temporal resolutions, and pre-treated with oral beta-blocker, permits the detection of coronary artery stenoses with a high degree of accuracy.