Spontaneous progression of ascending aortic intramural hematoma to Stanford type A dissection fortuitously witnessed during an MR examination.

Aortic intramural hematoma may occur as a primary event (spontaneous dissection without intimal flap) or secondary to a penetrating atherosclerotic ulcer. The management of intramural hematoma of the ascending aorta is somewhat controversial because of limited published data, but some centers advocate early surgical intervention. We describe a patient with an intramural hematoma of the ascending aorta that progressed to a classic communicating dissection during an MR examination. This case graphically demonstrates the potential instability of patients with intramural hematoma of the ascending aorta.