Healthcare & Clinical
Modified Fisher CT Scale (0–4) & Hunt-Hess Subarachnoid Hemorrhage (SAH) Grade
Determine the Modified Fisher CT Grade (0 to 4) for delayed cerebral ischemia / vasospasm risk from subarachnoid blood thickness and bilateral intraventricular hemorrhage (IVH), alongside Hunt & Hess SAH clinical severity (Grades 1–5).
Predict cerebral vasospasm (Days 4–14) and SAH mortality after aneurysmal rupture!
Aneurysmal subarachnoid hemorrhage (aSAH) carries two distinct hazards that neurointensivists grade on admission: clinical brain injury severity via William Hunt and Robert Hess's (1968) 1-to-5 clinical scale, and delayed cerebral vasospasm / delayed cerebral ischemia (DCI) risk via Joshua Claassen and F. E. Frontera's (Neurosurgery 2006) Modified Fisher CT Scale (Grades 0 to 4)!
Look at how cleanly the Modified Fisher Scale fixes the original 1980 Fisher scale's famous inversion bug using two binary CT findings—Thick cisternal SAH blood (1 = thick >= 1 mm clot completely filling >= 1 cistern/fissure; 0 = thin focal/diffuse blood, with completely normal CT = Grade 0) and Bilateral Intraventricular Hemorrhage IVH (1 = present in both lateral ventricles, 0 = absent): Thin SAH without IVH = Grade 1 (24% symptomatic vasospasm), Thin SAH WITH IVH = Grade 2 (33%), Thick SAH without IVH = Grade 3 (33%), and Thick SAH WITH IVH = Grade 4 (40% highest DCI risk—monotonically increasing at every step)!
| SAH Cisternal Blood on Head CT | Intraventricular Blood (IVH) | Modified Fisher Grade | Symptomatic Vasospasm / DCI Risk |
|---|---|---|---|
| None (0 = No SAH, 0 = No IVH) | Absent or Isolated IVH | Grade 0 (if no SAH & no IVH) | 0% – Low baseline |
| Thin SAH (1 = Thin) | 0 = No Bilateral IVH | Grade 1 | ~24% Symptomatic Vasospasm |
| Thin SAH (1 = Thin) | 1 = Bilateral IVH Present | Grade 2 | ~33% Symptomatic Vasospasm |
| Thick SAH (2 = Thick Clot) | 0 = No Bilateral IVH | Grade 3 | ~33% Symptomatic Vasospasm |
| Thick SAH (2 = Thick Clot) | 1 = Bilateral IVH Present | Grade 4 (Highest!) | ~40% Symptomatic Vasospasm! |
Modified Fisher CT Scale Grade (0 to 4) from SAH Thickness & Bilateral IVH
Encodes SAH blood B2 (0 = None, 1 = Thin, 2 = Thick) and Bilateral IVH B3 (0 = Absent, 1 = Present) into exact Modified Fisher Grade 0–4.
=IF(OR(B2 < 0, B2 > 2, B3 < 0, B3 > 1), "Invalid CT Inputs", IF(B2 = 0, IF(B3 = 1, 2, 0), IF(B2 = 1, IF(B3 = 0, 1, 2), IF(B3 = 0, 3, 4))))Combined Neuro-ICU Hunt & Hess (1–5) + Vasospasm Surveillance Tier
Classifies Hunt-Hess clinical grade B4 (1–2 Good-Grade vs 3 Intermediate vs 4–5 Poor-Grade Coma/Stupor).
=IF(OR(B4 < 1, B4 > 5), "Invalid Hunt-Hess Grade (1-5)", IF(B4 <= 2, "Good-Grade SAH (HH 1-2: Early Aneurysm Securing + Nimodipine)", IF(B4 = 3, "Intermediate SAH (HH 3: Drowsy/Focal Deficit — Neuro-ICU)", "Poor-Grade High-Mortality SAH (HH 4-5: Stupor/Coma — EVD & ICU)")))Try the example
Use the original values or change them to test your understanding.