Figure 34A: Axial noncontrast CT image shows near-circumferential high attenuation soft tissue (blue arrows) in the wall of a dilated ascending aorta; note that the blood in the lumen of the aorta is lower in attenuation than in the wall. Axial contrast-enhanced CT image at the same level shows contrast in the aortic lumen, and persistence of the abnormal soft tissue in the aortic wall (yellow arrows).

Acute intramural hematoma, atheromatous plaque, penetrating ulcer, chronic thrombus.