The evaluation of coronary artery bypass graft patency with ultrafast CT

Twenty-four patients with 36 saphenous vein (SVG) and 22 internal mammary artery (IMAG) bypass grafts were evaluated to establish the sensitivity of ultrafast computed tomography (UFCT) for determining graft patency compared with IVDSA. All patients underwent dynamic flow mode scanning after the administration of 25 ml of non-ionic contrast medium (6 ml/second for 4 sec) into an arm vein. Electrocardiographically triggered flow mode scanning was acquired at single or multi-tomographic level. Criteria for graft patency was contrast density-time curve morphologically similar to that of the aorta. UFCT correctly diagnosed 35 patent SVGs and 14 of 21 patent IMAGs (sensitivity for SVG and IMAG, 100% and 66.7%). The overall sensitivity of detecting open graft by reference to intravenous digital subtraction angiography (IVDSA) was 87.5%. This study suggests that 1) UFCT is a useful non-invasive technique for evaluating coronary artery bypass graft patency, and 2) the single-slice flow mode, which had better spatial resolution (0.75 mm) than the multi-slice flow mode, should be selected for determining the smaller IMAG patency with UFCT. (author)