Evaluation of coronary artery bypass graft. Follow-up with magnetic resonance imaging

This study evaluated the usefulness of magnetic resonance imaging (MRI) for noninvasive follow-up of coronary artery bypass grafting (CABG). Eighty-eight patients who had undergone CABG were evaluated. They had a total of 239 grafts (77 left internal thoracic artery, 12 gastroepiploic artery, 1 radial artery, 149 saphenous vein grafts). All patients underwent graft imaging. Flow measurement within the grafts was also conducted on 15 patients. The accuracy of MRI in the diagnosis of graft patency was confirmed by conventional coronary angiography. The accuracy of MRI was higher in the diagnosis of venous grafts (97%) than in arterial grafts (87%), because the arterial grafts had a smaller caliber and more metallic clips than the venous grafts. Flow measurement within the grafts was possible in 11 of the 15 patients. The graft flow profile showed two peaks in systole and diastole, and the increase of the diastolic component of the flow pattern was considered a demonstration of the graft patency. Flow measurement was impossible in the other 4 patients because of metallic artifact. Recently, we applied the CABG technique without the metallic materials and reduced the metallic artifacts in MRI. We believe this technique will encourage the increased usage of MRI for noninvasive follow-up after CABG. (author)