Grade 0 |
No flow |
|
No canalization |
|
Complete occlusion |
|
No recanalization/reperfusion |
Grade 1 |
Minimal recanalization (<20%) |
|
Minimal flow (very slow) without significant flow distal to the occlusion site |
|
Limited or no reperfusion |
|
Distal movement of thrombus without reperfusion |
|
Perfusion past initial occlusion, but limited distal branch |
|
Filling |
Grade 2 |
Partial recanalization—recanalization of some but not all of the occluded arteries |
|
Incomplete recanalization/reperfusion |
|
Near-normal flow, with flow distal to the occlusion but not filling the distal branches normally |
Grade 2a |
Perfusion of <50% of the MCA distribution |
|
Partial filling of the entire vascular territory |
|
Partial perfusion with incomplete distal filling of <50% of expected territory |
|
Partial filling of the entire vascular territory |
Grade 2b |
Partial perfusion with incomplete distal branch filling of ≥50–99% of the expected territory |
|
Complete filling, but the filling is slower than normal |
|
Perfusion of half or greater of the vascular distribution of the occluded artery |
Grade 2c |
Near-complete perfusion without clearly visible thrombus but with delay in contrast run-off |
Grade 3 |
Full perfusion with filling of all distal branches, including M3, M4 |
|
Normal flow |
|
Partial recanalization with >50% reperfusion |
|
Full perfusion with normal filling of distal branches in a normal hemodynamic fashion |
Grade 4 |
Complete recanalization/reperfusion |