Table I.

Definitions used in this study regarding aortic injury grade and aortic injury evolution.

Aortic injury grades

Grade I aortic injury – aortic intimal tear or flap

Grade II aortic injury – aortic intramural hematoma without change in external contour of aorta

Grade III aortic injury – contained aortic pseudoaneurysm with concurrent increase in external contour of the   aorta but without extravasation of intravenous contrast

Grade IV aortic injury – full-thickness aortic injury resulting in rupture with extravasation of intravenous   contrast on imaging

Aortic injury evolution

Injury resolution – interval injury resolution with aorta of normal diameter; absence of external contour   abnormality or intraluminal filling defect; no identifiable aortic injury

Stable injury – no interval change in aortic injury

Injury progression – interval enlargement of injury, either by increase in injury grade, or by increase in size of   injury with no change of injury grade