Table 3.

Denver scale: the features of the 5 grades (I-V) of vascular injury are shown, with increasing risk of brain ischemia in relation to higher grades of arterial damage

Grade	Denver grading system	CT-Angiography findings
I	Irregularity of vessel wall Dissection or intramural hematoma with < 25%narrowing	Nonstenotic luminal irregularity Intimal flap or wall thickening with < 25% stenosis
II	Intraluminal thrombus Dissection or intramural hematoma with > 25% narrowing	Luminal hypodensity Intimal flap or wall thickening with > 25% stenosis
III	Pseudoaneurysm	Eccentric contrast-filled outpouching limited by periarterial tissue
IV	Occlusion	Lack of any intraluminal enhancement Carotid occlusions: abrupt or tapered Vertebral occlusion: usually abrupt
V	Transection	Irregular extravascular collection of contrast, not limited by periarterial tissue Increases in density on delayed images, if obtained