Figure 17a. Preoperative assessment for aortic aneurysm repair in a 52-year-old man who had previously undergone repair of a type A aortic dissection. (a) Axial ECG-gated CT image obtained during diastole shows the relationship of the right coronary artery to the sternum (arrow.) Note the distance from the native right coronary artery to the sternum. (b) Axial ECG-gated CT image obtained during systole shows close approximation of the right coronary artery to the sternum (arrow). Because of this close anatomic relationship, a "keyhole" sternal incision was performed to avoid injury to the native coronary artery.