ABSTRACT
BACKGROUND: Multi-row computed tomography (MDCT) is a promising non-invasive technique and capable of rapid imaging of cardiac structures, including coronary arteries and bypass grafts during a single held breath. In this study, we evaluated coronary artery bypass graft (CABG) patency by comparing 4-slice computed tomography with conventional contrast angiography. One disadvantage of MDCT is the limited diagnostic accuracy with + increased calcification of the grafts. Therefore, the correlation between Ca-grading and diagnostic accuracy was examined. METHODS: We examined 30 patients with 104 bypass grafts with a 4-row MDCT scanner. On the basis of the Ca-score, patients were divided into 3 groups. RESULTS: It was possible to assess the exact degree of stenosis in 25 of 32 > 50% stenoses with 4-row MDCT, 7 stenoses were underestimated. All occlusions in 21 patients were identified correctly, 33 graft segments were underestimated in MDCT, of which 28 were in the group with a Ca-score of > 800. CONCLUSIONS: MDCT allows non-invasive angiographic evaluation of coronary bypass grafts with a high diagnostic accuracy. However, the method strongly depends on the degree of vascular calcification and underrates the degree of stenosis subject to the Ca-score. This is a distinct limitation in distal vascular segments of small calibre which cannot be validly displayed. In patients with low or moderate Ca-score values, MDCT coronary angiography is promising new technique with a high diagnostic accuracy for the detection of graft stenosis or occlusions.
