The aorta is the main artery in the human body. It runs from the top of the heart, through the chest and into the abdomen, where it divides into two arteries. The wall of the aorta is made of several layers consisting of an inner (intima), middle (media) and outer (adventitia) layer.
Acute aortic dissection is a serious, potentially life-threatening condition, in which the inner layer of the aorta (the intima) tears. Blood gushes through the tear and causes separation of the inner from the middle layers along a variable length of the aorta. This gives the aorta a typical double barrel appearance on imaging with blood flowing in the original (true) lumen and also in the newly formed (false) lumen (Figure 1). The blood-filled false channel may rupture through the outer layer, invariably causing fatal internal bleeding.
Aortic dissection is a rare phenomenon; it occurs in less than 10 people per 100,000 per yea, and usually affects men in their 60 and 70s.