Fifty-two consecutive asymptomatic patients with a total of 166 bypass grafts were investigated by 16-slice computed tomography (CT) 15 +/- 5 days before invasive coronary angiography. Overall, 165 grafts (99.4%) were assessable with multislice CT (MSCT). Coronary angiography showed that 111 grafts (67%) were patent and 54 (33%) were occluded. Of the patent grafts, 22 had high-grade stenoses. MSCT correctly classified 111 grafts as patent and 54 as occluded. Of the patent grafts, 16-slice CT correctly detected 21 bypass stenoses (95%). These results yielded 100% sensitivity and specificity of 16-slice CT for detecting bypass grafts occlusion and 96% sensitivity and 100% specificity for detecting high-grade stenoses in patent grafts.