Background: Contrast-enhanced multi-detector row spiral computed tomography(MDCT) has been introduced as a promising noninvasive method for dynamic vascular imaging. We investigated the accuracy of this technique in the detection of significant coronary artery stenoses(> 50% luminal narrowing). Method: Both MDCT(Sensation 16, Siemens, Germany, 12x0.75mm collimation and 0.42s rotation speed, 120kV, 500 effective mA, and 2.7 mm/rotation table-feed) and coronary angiography(CAG) were performed in 61 consecutive patients (mean age 59.2짹10, 44 men ) who were suspected to have coronary artery disease. All patients were treated with atenolol(25-50mg) 4 hours prior to imaging and heart rate was maintained below 65 beats per minutes during image acquisition. Images were reconstructed in diastole around TI -400ms with 0.5mm increment and 1.0mm thickness. Density was measured with multiple ROIs under setting of window width of 5000 HU and level of 200 HU. All coronary arteries with a diameter of 2.0mm or more were assessed for the presence of stenoses. MDCT data were evaluated by two independent radiologists in unaware of the results of CAG and were compared with the results of CAG (interval 1-33 mean 7.4days). Result: Evaluation of MDCT was possible in 58 of 61 patients (95%). Image acquisition of major coronary arteries including the left main trunk was available in 175 out of 180 arteries. Thirty-six of 58 patients had significant coronary artery stenoses by CAG. By patient analysis, MDCT correctly classified 31 of 36 patients as having at least 1 coronary stenosis(sensitivity 86.1%, specificity 90.9%) and correctily detected 65 of 82 coronary lesion(79.3%). By vascular territory analysis, MDCT correctly detected 50 of 62 coronary artery stenoses and absence of stenoses was correctly identified in 156 of 167 normal coronary arteries (sensitivity 80.6%, specificity 93.4%). Conclusion: The non-invasive technique of MDCT for coronary artery appears to be a useful method for detection of coronary artery stenoses with high accuracy.