“…CTA can, however, reliably identify type 4 lesions (complete arterial occlusion), which are also the least common and carry the highest risk of stroke [ 22 , 33 , 38 , 39 ]. All pieces of evidence indicate that the risk of stroke with traumatic vessel occlusion (type 4) exceeds the risk of stroke with type 1–3 injuries: unilateral occlusion of the vertebral artery (9–20%) [ 10 , 22 , 33 , 39 ], unilateral occlusion of the ICA (>50%) [ 10 , 22 , 33 , 38 ], and bilateral occlusion of the vertebral arteries (50%) [ 22 , 39 ]. Therefore, in the present era in which CTA is the most commonly used imaging technique for TCVI [ 20 ], the risk of stroke with initially asymptomatic TCVI can be divided into 3 relative categories: low (arterial injury without occlusion), medium (single vertebral artery occlusion), and high (ICA occlusion and bilateral vertebral artery occlusion).…”