Table 1.

Arterial occlusive lesion (AOL) categories and criteria

AOL Category	Criteria based on CT angiography
ICA	Occlusion of the internal carotid artery (ICA) at (a) origin (b) cervical; (c) petrous; (d) lacerum; (e) cavernous; (f) clinoidal; (g) ophthalmic artery to posterior communicating artery; or (h) posterior communicating artery to terminus. Subjects with single ICA occlusions as well as subjects with tandem occlusions involving the ICA and a more distal cerebral vessel were included in the ICA category.
MCA-M1	Occlusion of the first segment of the middle cerebral artery (MCA-M1) (a) proximal to the striate or (b) distal to the striate vessels.
MCA-M2+	Occlusion of (a) a single secondary branch of the middle cerebral artery (MCA-M2); (b) multiple M2s; (c) a single M3; (d) multiple M3s; (e) a single M4; or (f) multiple M4 branches.