Fisher Grading Scale (SAH)

Select the CT pattern grade (1–4) that best matches subarachnoid blood distribution.

Choose one Fisher grade:

Grade 1 — No blood detected on CT (or diffuse thin SAH without clots). Grade 2 — Diffuse vertical layers <1 mm thick without localized clot or intraventricular blood. Grade 3 — Localized clot and/or thicker layer of blood (≥1 mm) in the subarachnoid space. Grade 4 — Intraventricular blood or parenchymal extension of hemorrhage.