Solution: Abdominal aortic aneurysms are common, up to 6% of patients > 80 years old, and can be associated with catastrophic complications including: Rupture (as in this case), peripheral embolization, infection, and spontaneous occlusion with associated ischemia. Surgery is generally recommended when the aneurysm reaches 5 cm in diameter, but surgery can be associated with significant morbidity and mortality (up to 5% in unruptured patients and up to 75% in ruptured patients). One sign to be very aware is the "crescent sign". This is a peripheral high-attenuating crescent within an aneurysm wall that is best seen on non-contrast CT. This represents an acute intramural hematoma and is a sign of impending rupture. Endovascular stenting is becoming more common as a treatment for abdominal aortic aneurysm.