Table 6 Modified Fisher Scale [29]
| Grade | Criteria on CT head | Incidence of Symptomatic Vasospasm |
|---|---|---|
| 0 | No SAH; no IVH | 0% |
| 1 | Focal or diffuse, thin SAH; no IVH | 24% |
| 2 | Thin, focal, or diffuse SAH; IVH | 33% |
| 3 | Thick, focal, or diffuse SAH; no IVH | 33% |
| 4 | Thick, focal, or diffuse SAH; IVH | 40% |