Figure 12b. Penetrating ulcer. (a) Lateral digital subtraction angiogram obtained with a pigtail catheter in the proximal descending aorta shows a large penetrating ulcer involving the ventral aspect of the descending aorta (arrow). (b, c) Sagittal contrast-enhanced 3D partition (b) and sagittal MIP image (c) also show this finding (arrow). The subintimal penetration is best seen on the 3D partition (b). The diagnosis of penetrating ulcer was confirmed at surgery.