Quantification of coronary artery stenosis with 16-slice MSCT in patients before CABG surgery: comparison to standard invasive coronary angiography.

OBJECTIVE Invasive, selective coronary angiography is the gold standard for evaluation of coronary artery disease (CAD) and degree of stenosis. The purpose of this study was to compare 3-dimensional (3D) reconstructed 16-slice multislice computed tomographic (MSCT) angiography and selective coronary angiography in patients before elective coronary artery bypass graft (CABG) procedure. METHODS Sixteen-slice MSCT scans (Philips Mx8000 IDT) were performed in 50 patients (42 male/8 female; mean age, 64.44 +/- 8.66 years) scheduled for elective CABG procedure. Scans were retrospectively electrocardiogram-gated 3D reconstructed. The images of the coronary arteries were evaluated for stenosis by 2 independent radiologists. The results were compared with the coronary angiography findings using the American Heart Association segmental classification for coronary arteries. RESULTS Four patients (8%) were excluded for technical reasons. Thirty-eight patients (82.6%) had 3-vessel disease, 4 (8.7 %) had 2-vessel disease, and 4 (8.7%) had an isolated left anterior descending artery stenosis. In the proximal segments all stenoses >50% (56/56) were detected by MSCT; medial segment sensitivity was 97% (73/75), specificity 90.3%; distal segment sensitivity was 90.7% (59/65), specificity 77%. CONCLUSION Accurate quantification of coronary stenosis greater than 50% in the proximal and medial segments is possible with high sensitivity and specificity using the new generation of 16-slice MSCTs. There is still a tendency to overestimate stenosis in the distal segments. MSCT seems to be an excellent diagnostic tool for screening patients with possible CAD.