Grades of increasing severity of arterial occlusion
| Grade | Type of Occlusion | ||
|---|---|---|---|
| 0 | No occlusion | ||
| 1 | MCA occlusion (M3 segment) | ACA occlusion (A2 or distal segments) | 1 BA and/or VA branch occlusion |
| 2 | MCA occlusion (M2 segment) | ACA occlusion (A1 and A2 segments) | ≥2 BA and/or VA branch occlusions |
| 3 | MCA occlusion (M1 segment) | ||
| 3A | Lenticulostriate arteries spared and/or leptomeningeal collaterals visualized | ||
| 3B | No sparing of lenticulostriate arteries and no leptomeningeal collaterals visualized | ||
| 4 | ICA occlusion (collaterals present) | BA occlusion (partial filling, direct or via collaterals) | |
| 4A | Collaterals fill MCA | Anterograde filling* | |
| 4B | Collaterals fill ACA | Retrograde filling* | |
| 5 | ICA occlusion (no collaterals) | BA occlusion (complete) |
Note.—Grading system is from Qureshi AI: New grading scheme for angiographic evaluation of arterial occlusions and recanalization response to intra-arterial thrombolysis in acute ischemic stroke.
Neurosurgery 2002;50:1405–1415 (7). MCA indicates middle cerebral artery; ACA, anterior cerebral artery; BA, basilar artery; VA, vertebral artery; ICA, internal carotid artery.
* Predominant pattern of filling.