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.