OBJECTIVE The purpose of this study was to delineate the course and determine the patency of venous and arterial conduits in the early postoperative period following minimally invasive bypass grafting. A less invasive magnetic resonance angiogram was evaluated as alternative to standard contrast angiography and cardiac catheterization. METHODS Twelve patients (8 males and 4 females) with a mean age of 65.3 (+/- 7.4 ) years were evaluated four to seven days following minimally invasive direct coronary artery bypass surgery (MIDCAB) or off-pump multivessel revascularization with the Octopus stabilizer on the beating heart. Altogether 17 coronary bypass grafts were investigated: 12 left-sided mammary artery grafts to the LAD and five aortocoronary venous bypass grafts. The examination was performed with a 1.5 Tesla Magnetom Vision (Siemens AG, Erlangen) with phased array coil technology. Data acquisition was done with an ultrafast 3D gradient-echosequence in single breathhold and sagittal and coronal views. Contrast enhancement of the vessels was performed with automatic intravenous bolus injection of Gadolinium-DTPA after determination of the individual contrast transit time. Traditional contrast angiography was obtained in all patients during the same time period as a comparison to assess the sensitivity and specificity of the magnetic resonance imaging. RESULTS All five venous grafts and 11 of the 12 IMA grafts were detected and shown to be patent with the MRA technique. Contrast angiography demonstrated complete patency for all 17 bypass grafts with adequate anastomoses and no evidence of stenosis. The calculated sensitivity for the visualization with MRA was therefore 92% for IMA grafts and 100% for venous grafts. CONCLUSIONS The contrast-enhanced ultrafast MRA in single breathhold technique is a reliable, noninvasive method for visualization and determination of the patency of arterial and venous coronary grafts.