Grades of increasing severity of arterial occlusion

GradeType of Occlusion
0No occlusion
1MCA occlusion (M3 segment)ACA occlusion (A2 or distal segments)1 BA and/or VA branch occlusion
2MCA occlusion (M2 segment)ACA occlusion (A1 and A2 segments)≥2 BA and/or VA branch occlusions
3MCA occlusion (M1 segment)
3ALenticulostriate arteries spared and/or leptomeningeal collaterals visualized
3BNo sparing of lenticulostriate arteries and no leptomeningeal collaterals visualized
4ICA occlusion (collaterals present)BA occlusion (partial filling, direct or via collaterals)
4ACollaterals fill MCAAnterograde filling*
4BCollaterals fill ACARetrograde filling*
5ICA 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.