The aim of this study was to evaluate the accuracy of 64-slice multidetector row CT (MDCT), as compared with conventional coronary angiography (CCA), for assessing coronary artery bypass grafts (CABG) in the early (< 1 month) postoperative period.

Twenty-four patients underwent both 64-slice MDCT (0.6 mm collimation, 0.37s gantry rotation) and CCA within 15 days after CABG. Sixty-five bypass grafts (20 venous grafts and 45 arterial grafts) and 67 distal runoff arteries in 24 patients were included in the analysis. The bypass grafts and distal runoffs were evaluated for the presence of significant stenosis, including obstruction. The CT findings were compared with the CCA findings.

CCA confirmed that 62 of the 65 grafts were patent and that 3 had significant stenosis or obstruction. Sixty of the 62 patent grafts were correctly identified by MDCT. One of the three grafts that had significant stenosis was misinterpreted on the MDCT images. The sensitivity, specificity and positive and negative predictive values for detecting stenosis were 67%, 97%, 50% and 98%, respectively, with an overall diagnostic accuracy of 95%. MDCT also correctly detected all the stenotic distal runoff arteries (4 of 67).

64-slice MDCT is a promising alternative diagnostic modality for evaluating a CABG in the early postoperative period.