Evaluation of coronary artery bypass grafts by magnetic resonance imaging

Magnetic resonance (MR) angiography and now mapping have the potential to b ecome a major noninvasive diagnostic tool for the assessment of coronary ar tery bypass graft morphology and function, Several MR sequences, such as co nventional non-respiratory compensated methods, and phase contrast cine now sequences have been reported for the evaluation of bypass graft patency, H owever the visualization of different graft segments and the detection of g raft stenosis remains difficult. Recent advances in MR coronary angiography and flow mapping are volume coronary angiongraphy with targeted scans, nav igator gated angiography, contrast-enhanced angiography, and breath-hold or navigator gated flow sequences. Future approaches, such as navigator gated fast MR techniques resulting in high-resolution angiography in combination with breath-hold MR flow mapping with high temporal resolution, might allo w a comprehensive evaluation of bypass graft stenosis and function. This re view article will address the major issues concerning the MR evaluation of bypass grafts, (C) 1999 Wiley-Liss, Inc.