We report the case of a 40-year-old man with known Marfan syndrome who presented with severe aortic valve regurgitation secondary to significant aortic root dilatation. To rule out coronary artery disease and to evaluate the rest of the thoracic aorta before surgery, cardiac computed tomography (CT) was performed. A brief review of the literature shows how cardiac CT can, in selected cases, rule out coronary artery disease before non-coronary cardiothoracic surgery. (c) 2012 Sociedade Portuguesa de Cardiologia Published by Elsevier Espana, S.L. All rights reserved.