ABSTRACT
Acute aortic dissection can be an emergency event characterized by the splitting of tunica media of the aortic wall by high pressure arterial blood throught an intimomedial tear: The CT imaging is a currently emerging technique for dianosis and evaluation of aortic dissection and has sensitivity and specificity of nearly 100%. The differentiation between true and false lumens of aortic dissection is important for percutaneous treatment with endovascular grafts or surgical repair: Previous studies described CT criteria to distinguish true from false lumens. The most reliable sings in this study are outer wall calcification, intraluminal thrombus, eccentric flap calcification, a larger area at one-quarter distance, and a larger area at one-half distance.