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Modified Fisher Scale

Estimates symptomatic vasospasm risk in aneurysmal subarachnoid hemorrhage from admission CT.

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Method · Limits of application

Modified Fisher — Frontera et al., 2006, Table 1: absent, thin or thick SAH and intraventricular hemorrhage; grades 0–4

A CT grading system studied to predict symptomatic vasospasm after subarachnoid hemorrhage. The consulted study pooled patients from the placebo arms of four trials. It does not by itself establish a vasospasm diagnosis, predict all outcomes or indicate treatment.

Conditions of use

Check the population, units, inclusion and exclusion criteria, and version in the original source. A result alone does not establish a diagnosis, discharge decision or prescription.

Documented parameters

Finding on the admission CT scan

3/3 reference cases checked. Numerical tests are not clinical validation.

Sources and documentation

Documented formula

Transcribed from the source or a recorded revision; this is not a clinical recommendation.

Classifies the admission CT by the presence and thickness of subarachnoid blood (SAH) and the presence of intraventricular hemorrhage (IVH). Grade 0: no SAH and no IVH; grade 1: thin SAH without IVH; grade 2: IVH with either no SAH or thin SAH; grade 3: thick SAH without IVH; grade 4: thick SAH with IVH. In Frontera et al. (2006), local investigators classified blood as thin or thick by global impression, without explicit thickness criteria. The tool records the grade selected by the examiner; it does not interpret images.

References

Frontera JA et al. Prediction of symptomatic vasospasm after subarachnoid hemorrhage: the modified Fisher scale. Neurosurgery, 2006.

Identifier: escala-de-fisher-modificada

Original clinical content: Brazilian Portuguese.

Method version

Modified Fisher — Frontera et al., 2006, Table 1: absent, thin or thick SAH and intraventricular hemorrhage; grades 0–4

escala-de-fisher-modificada@native-2026-10-03+08afeac1ce50

Source for the active edition

The bibliographic edition identifies the source. By itself, it proves neither full conformity of the formula nor clinical approval.

Synthetic cases checked (3)

Synthetic cases for checking the implementation, with no patient data.

Case 1

reference-001

Inputs

Finding on the admission CT scan: 0 – No SAH and no intraventricular hemorrhage

{
  "grau": "0"
}

Expected result

{
  "score": 0,
  "level": "low"
}

Actual result

{
  "score": 0
}

Case 2

reference-002

Inputs

Finding on the admission CT scan: 2 – Intraventricular hemorrhage with no SAH or thin SAH (focal or diffuse)

{
  "grau": "2"
}

Expected result

{
  "score": 2,
  "level": "mid",
  "verdict": "33%"
}

Actual result

{
  "score": 2
}

Case 3

reference-003

Inputs

Finding on the admission CT scan: 4 – Thick SAH with intraventricular hemorrhage

{
  "grau": "4"
}

Expected result

{
  "score": 4,
  "level": "high",
  "verdict": "40%"
}

Actual result

{
  "score": 4
}

Code and reproducibility

This tool’s code on GitHub

Download code and tests

Sources, version and reproduction instructions

The code tests are technical checks. Clinical approval and professional translation review are recorded separately.

Relationship with cancer research

General context — relationship to be defined

A resource for general clinical contexts. This edition does not assign a specific oncological relationship; selecting it for a study requires a justified question, population and purpose.