Distribution of severe (≥70%) stenosis
| Location | No. of Lesions |
|---|---|
| Intracranial arteries | 203 (52) |
| Anterior circulation | 114 |
| M1 | 58 |
| A1 | 24 |
| ICA | 15 |
| M2 | 10 |
| A2 | 6 |
| ACHA | 1 |
| Posterior circulation | 89 |
| VA | 27 |
| P1–3 | 23 |
| PICA | 14 |
| BA | 12 |
| VBJ | 7 |
| AICA | 4 |
| P4 | 1 |
| SCA | 1 |
| Extracranial arteries | 186 (48) |
| Anterior circulation | 117 |
| ICA | 116 |
| CCA | 1 |
| Posterior circulation | 69 |
| VA | 61 |
| SA | 8 |
| Total | 389 |
Note.—Data in parentheses are percentages. M1 indicates the horizontal segment of middle cerebral artery; A1, horizontal segment of anterior cerebral artery; ICA, internal carotid artery; M2, vertical segment of middle cerebral artery; A2, vertical segment of anterior cerebral artery; ACHA, anterior choroidal artery; VA, vertebral artery; P1–3, area from precommunicating segment to the quadrigeminal segment of posterior cerebral artery; PICA, posterior inferior cerebellar artery; BA = basilar artery; VBJ, vertebrobasilar junction; AICA, anterior inferior cerebellar artery; P4 = cortical branch of posterior cerebral artery; SCA, superior cerebellar artery; CCA, common carotid artery; SA, subclavian artery.