[Evaluating the function of aortocoronary bypasses with magnetic resonance tomography]

Following an aortocoronary bypass operation the differential diagnosis of chest pain of recent onset may be difficult (ischaemia, thoracotomy induced pain). At this point noninvasive methods are preferable to angiography in order to reach exact diagnosis. Magnetic Resonance Imaging (MRI), a new noninvasive imaging method, makes it possible to get anatomical and blood flow information without the use of ionizing radiation or contrast agents. It was the aim of our study to examine the diagnostic impact of MRI for the assessment of aortocoronary bypass graft patency. We compared three different acquisition techniques (a spinecho sequence and two fast-gradient echo sequences). 26 patients were examined, 49 bypass grafts were eligible for comparative evaluation. As compared with the spinecho technique, fast echo gradient sequences had a higher sensitivity (FISP 93%, FLASH 88%) than the spinecho technique 79%, and a higher accuracy (FISP 88%, FLASH 82%) versus 73%, respectively. We conclude that MRI may have a high diagnostic potential in the evaluation of early postoperative aortocoronary bypass graft patency.