Prevalence of perianeurysmal incomplete CoW configurations for each aneurysmal parent artery location
| PC-MR Measurement Location (Aneurysm Location) | Incomplete Configuration | No. |
|---|---|---|
| ICA (ICA/PcomA) | Hypoplastic ipsilateral P1 and/or contralateral A1 | 7/30 (23%) |
| MCA | Hypoplastic ipsilateral P1 and/or contralateral A1 | 6/30 (20%) |
| A1 (AcomA) | Hypoplastic contralateral A1 | 7/28 (25%) |
| A2 (pericallosal artery) | Azygos ACA | 1/4 (25%) |
| VA | Hypoplastic ipsilateral VA | 1/2 (50%) |
| BA | Hypoplastic P1 (1- or 2-sided) | 3/9 (33%) |
| Total | 25/103 (24%) |