Aortic dissection is a longitudinal partition in the media of the aorta. Intimal tear creates a true and a false lumen. Typically in aortic dissection true lumen is lined by tunica intima, and the false lumen is lined by tunica media. 

Typical CT findings in acute dissection are an intimal flap separating two aortic channels and intramural hematoma. 

In some cases, aortic branch vessel occlusion may cause mesenteric, renal, and in rare cases, limb ischemia to be the initial manifestation of aortic dissection.