Angiographic Suzuki grade and presence of collaterals
| Cerebral Hemispheres Studied | n = 74 |
|---|---|
| Suzuki stage | |
| 0 | 9 (12.2%) |
| I | 10 (13.5%) |
| II | 10 (13.5%) |
| III | 14 (18.9%) |
| IV | 15 (20.3%) |
| V | 5 (6.8%) |
| VI | 11 (14.9%) |
| OA–intracranial artery collaterals | 35 (47.3%) |
| Rete mirabile of the OA | 17 (23%) |
| Anterior ethmoidal artery–ACA branch direct collaterals | 15 (20.3%) |
| Anterior ethmoidal artery–ACA branch collaterals via anterior falcine artery | 23 (31.1%) |
| Posterior ethmoidal artery–orbitofrontal artery | 16 (21.6%) |
| Recurrent meningeal artery–MMA–Sylvian branch | 1 (1.4%) |
| Collaterals | |
| Leptomeningeal collaterals to ACA territory | 51 (68.9%) |
| Duro-pial collaterals to ACA territory | 5 (6.8%) |
| Posterior callosal artery collateral | 22 (29.7%) |
| Periventricular collaterals | 47 (63.5%) |
Note:—MMA indicates middle meningeal artery.