# Fisher — Original Fisher CT grouping for aneurysmal subarachnoid hemorrhage

> Historical four-group CT blood-distribution system developed to study later cerebral vasospasm after aneurysmal SAH. Group 3, not group 4, carried the strongest original association; thick SAH remains group 3 even when ICH or IVH is present. It is not an ordinal injury-severity scale, a current-vasospasm test or a treatment algorithm.

**Situação:** vigente · **Órgão:** Encéfalo · **Órgão emissor:** Fisher et al. / neurovascular literature · **Versão:** 1980 original grouping; interpretation corrected 2019; aSAH care context through 2026 · **Ano:** 1980

> ⚠️ Uma versão mais nova pode existir (em revisão).

## Procedência e vigência
- Família: léxico
- Tipo de lógica: flat
- Modalidade: CT
- Fonte primária: Fisher CM, Kistler JP, Davis JM. Relation of cerebral vasospasm to subarachnoid hemorrhage visualized by computerized tomographic scanning (1980) — https://doi.org/10.1227/00006123-198001000-00001
- Última verificação: 2026-07-24
- Última checagem: 2026-08-12

## Lógica de decisão
Use the term original Fisher group, follow the explicit classification priority, and never map a bare number to modified Fisher or to a treatment decision.

## Categorias

| Código | Rótulo | Critérios | Conduta | Risco | Localizador | Verificado |
| --- | --- | --- | --- | --- | --- | --- |
| 1 | Grade 1 | Original Fisher group 1: no subarachnoid blood is detected on the CT and there is no intracerebral or intraventricular clot that would meet group 4. Record scan timing and quality because blood can be unapparent or clear over time. | A negative CT category is not a rule-out pathway. If aneurysmal SAH is suspected or confirmed, continue the time-appropriate emergency diagnostic and neurovascular pathway; do not discharge, withhold aneurysm evaluation or omit surveillance because the group is 1. | No visible blood was the low-blood historical reference, but group 1 is not a current individual vasospasm or DCI probability and does not mean that suspected SAH, delayed imaging or limited CT technique is benign. | Fisher et al., Neurosurgery 1980;6:1-9, DOI 10.1227/00006123-198001000-00001, original group definitions; Rosen and Macdonald, PMC3621041, Table 6; Vergouwen et al., joint ESO/EANS/ESMINT guideline 2026, PMC13151661, current emergency aSAH care independent of group. | ✓ |
| 2 | Grade 2 | Original Fisher group 2: diffuse subarachnoid blood or thin vertical layers, with every vertical layer less than 1 mm and no localized clot. Intracerebral or intraventricular clot with only this thin pattern instead meets group 4. | Treat suspected or confirmed aneurysmal SAH as an emergency and use current specialist care, aneurysm-securing, nimodipine and DCI-monitoring guidance as clinically appropriate. Original group 2 alone neither mandates nor withholds a procedure or medication. | Thin diffuse blood had a weaker historical vasospasm association than the localized or thick group-3 pattern. The original ordering is nonmonotonic and does not provide a modern patient-specific probability of vasospasm, DCI or outcome. | Fisher et al. 1980, DOI 10.1227/00006123-198001000-00001; Rosen and Macdonald, PMC3621041, Table 6, diffuse or vertical layers less than 1 mm; Komiyama 2019, PMC6838856, group-2/group-4 boundary; Vergouwen et al. 2026, PMC13151661, current aSAH care. | ✓ |
| 3 | Grade 3 | Original Fisher group 3: a localized subarachnoid clot and/or any vertical subarachnoid blood layer at least 1 mm thick. This remains group 3 when intracerebral or intraventricular clot coexists; exactly 1 mm is on the group-3 side. | Use current aneurysmal-SAH emergency care and close neurologic/DCI surveillance based on the complete clinical picture. The historically strongest vasospasm association does not itself diagnose current vasospasm or select clipping, coiling, hemodynamic augmentation or another intervention. | This pattern had the strongest original and early prospective association with later severe cerebral vasospasm. That historical signal is qualitative here and must not be converted into a contemporary individual percentage or a diagnosis of present DCI. | Fisher et al. 1980, DOI 10.1227/00006123-198001000-00001, localized clot and thick vertical-layer group; Kistler et al., Neurology 1983, PMID 6682190, prospective historical association; Komiyama 2019, PMC6838856, thick SAH plus IVH or ICH remains original group 3; Vergouwen et al. 2026, PMC13151661, current care. | ✓ |
| 4 | Grade 4 | Original Fisher group 4: intracerebral or intraventricular clot with only diffuse thin subarachnoid blood or no subarachnoid blood. If localized clot or a vertical SAH layer at least 1 mm is present, classify as original group 3 instead. | Follow the emergency aneurysmal-SAH pathway and separately assess IVH or ICH, hydrocephalus, ventricular obstruction, mass effect and deterioration. Group 4 does not itself choose CSF diversion, surgery, endovascular therapy or the intensity of treatment. | Original group 4 had a lower historical vasospasm association than group 3, demonstrating the scale's nonmonotonic design. This does not imply less hemorrhagic injury, lower hydrocephalus risk, better prognosis or lower clinical acuity. | Fisher et al. 1980, DOI 10.1227/00006123-198001000-00001; Rosen and Macdonald, PMC3621041, Table 6; Komiyama 2019, DOI 10.1177/1591019919856511 and PMC6838856, full clarification that group 4 requires diffuse or no SAH with ICH or IVH; Vergouwen et al. 2026, PMC13151661, current care context. | ✓ |

### Citações por categoria
- **1**: Fisher CM, Kistler JP, Davis JM. Relation of cerebral vasospasm to subarachnoid hemorrhage visualized by computerized tomographic scanning (1980) — https://doi.org/10.1227/00006123-198001000-00001 · Fisher et al., Neurosurgery 1980;6:1-9, DOI 10.1227/00006123-198001000-00001, original group definitions; Rosen and Macdonald, PMC3621041, Table 6; Vergouwen et al., joint ESO/EANS/ESMINT guideline 2026, PMC13151661, current emergency aSAH care independent of group.
- **2**: Fisher CM, Kistler JP, Davis JM. Relation of cerebral vasospasm to subarachnoid hemorrhage visualized by computerized tomographic scanning (1980) — https://doi.org/10.1227/00006123-198001000-00001 · Fisher et al. 1980, DOI 10.1227/00006123-198001000-00001; Rosen and Macdonald, PMC3621041, Table 6, diffuse or vertical layers less than 1 mm; Komiyama 2019, PMC6838856, group-2/group-4 boundary; Vergouwen et al. 2026, PMC13151661, current aSAH care.
- **3**: Fisher CM, Kistler JP, Davis JM. Relation of cerebral vasospasm to subarachnoid hemorrhage visualized by computerized tomographic scanning (1980) — https://doi.org/10.1227/00006123-198001000-00001 · Fisher et al. 1980, DOI 10.1227/00006123-198001000-00001, localized clot and thick vertical-layer group; Kistler et al., Neurology 1983, PMID 6682190, prospective historical association; Komiyama 2019, PMC6838856, thick SAH plus IVH or ICH remains original group 3; Vergouwen et al. 2026, PMC13151661, current care.
- **4**: Fisher CM, Kistler JP, Davis JM. Relation of cerebral vasospasm to subarachnoid hemorrhage visualized by computerized tomographic scanning (1980) — https://doi.org/10.1227/00006123-198001000-00001 · Fisher et al. 1980, DOI 10.1227/00006123-198001000-00001; Rosen and Macdonald, PMC3621041, Table 6; Komiyama 2019, DOI 10.1177/1591019919856511 and PMC6838856, full clarification that group 4 requires diffuse or no SAH with ICH or IVH; Vergouwen et al. 2026, PMC13151661, current care context.

## Referências cruzadas
- _fronteira compartilhada_ → [Modified Fisher — Modified Fisher CT scale for aneurysmal subarachnoid hemorrhage](https://radcommons.laudos.ai/systems/modified-fisher.md) — The original Fisher groups and modified Fisher grades use different category maps. Original group 4 means ICH or IVH with diffuse thin or no SAH; modified Fisher grade 4 means thick SAH with IVH.
- _substitui_ → [Modified Fisher — Modified Fisher CT scale for aneurysmal subarachnoid hemorrhage](https://radcommons.laudos.ai/systems/modified-fisher.md) — The modified Fisher scale refines the original Fisher grading of subarachnoid blood.

## Histórico de versões

| Data | Evento | Detalhe | Situação |
| --- | --- | --- | --- |
| 2026-07-26 | revised | Monitored source changed (version_regex). Detected automatically; awaiting reviewer confirmation. | needs_review |
| 2019-06-10 | revised | Komiyama published an interpretive clarification of the common group-4 misreading: thick or localized SAH remains group 3 even with ICH or IVH; group 4 requires diffuse thin or no SAH with ICH or IVH. This did not revise the original category definitions. | confirmed |
| 1980-01-01 | published | Fisher, Kistler and Davis published four CT blood-distribution groups for aneurysmal SAH and their historical relation to later cerebral vasospasm. | confirmed |


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> Conteúdo de referência reescrito. Confira a publicação primária vigente. Não é dispositivo médico nem substitui o julgamento clínico. O radiologista responsável pelo laudo permanece o autor e o responsável.

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