Figure 13b. Evaluation of a thoracic aortic aneurysm in an 82-year-old man with a history of prior CABG. (a) Axial MIP image shows aneurysmal dilatation of the ascending aorta (arrow). This dilatation results in a 2-mm separation between the origin of the saphenous vein graft and the inner table of the sternum (arrowhead). (b) Craniocaudal volume-rendered image shows the proximity of the saphenous vein graft (arrow) to the sternum.