| Grade 0 |
Grade 0 |
|
|
No collaterals visible to the ischemic site |
| Grade 1 |
Grade 1 |
|
|
Slow collaterals to the periphery of the ischemic site with persistence of some of the defect |
| Grade 2 |
Grade 2 |
|
|
Rapid collaterals to the periphery of ischemic site with persistence of some of the defect and to only a portion of the ischemic territory |
| Grade 3 |
Grade 3 |
|
|
Collaterals with slow but complete angiographic blood flow of the ischemic bed by the late venous phase |
| Grade 4 |
Grade 4 |
|
|
Complete and rapid collateral blood flow to the vascular bed in the entire ischemic territory by retrograde perfusion. |