Comparison of Diagnostic Accuracy between Coronary CT Angiography and Conventional Coronary Angiography

Background: Coronary computed tomography angiography (CCTA) is a noninvasive imaging method with a high diagnostic value and minimal complications for evaluating coronary arteries. Therefore, in cases with low and moderate probabilities of coronary artery disease, CCTA can be a good alternative to conventional coronary angiography (CCA). Previous studies with 64- slice CTA have tried to determine its diagnostic accuracy compared with CCA as the gold standard. In this survey, we compared the results of 256-slice CCTA with CTA. Method: The present cross-sectional descriptive study evaluated 53 patients (36 men) undergoing CCTA and then CCA (except for 4 patients with pervious CCAs). Our primary goal was to compare the 2 imaging methods for the evaluation of coronary lesions and their runoff. Results: In the coronary artery bypass graft group, the diagnostic accuracy of CCTA for the arterial graft lesions (left internal mammary artery to left anterior descending) had 72.73% sensitivity, 100% specificity, 100% positive predictive value, and 84.2% negative predictive value and its diagnostic accuracy for the venous graft lesions had 100% sensitivity, 80% to 100% specificity, 80% to 100% positive predictive value, and 66.4% to 100% negative predictive value. Apropos runoff (adequacy of perfusion), CCTA had 100% sensitivity, 63.64% specificity, 80% positive predictive value, and 100% negative predictive value in the arterial grafts and 54% to 100% sensitivity and 100% specificity in the venous grafts. In the percutaneous coronary intervention group, CCTA had 90% specificity, and 75% positive predictive value, and 0% negative predictive value in the differentiation of significant from nonsignificant in-stent restenoses. Conclusions: The diagnostic accuracy of CCTA in determining the severity of arterial graft stenoses and their runoff was similar to that reported in previous studies with 64-slice CTA. Strikingly, CCTA had low sensitivity for significant in-stent restenosis.