Neurology · LIVE

Fisher SAH CT grade (1980)

Fisher

Return the Fisher 1980 original CT group 1-4 from a caller-assigned grade, with the published group description.

LIVE $0.005 USDC GET /api/calc/fisher

Markdown: /docs/fisher.md · Canonical: https://magentlab.com/docs/fisher

Not a medical device. Not a diagnosis, dose, or listing recommendation.

What it computes

Return the Fisher 1980 original CT group 1-4 from a caller-assigned grade, with the published group description.

When to use

When an agent needs the original Fisher 1980 CT groups 1-4 and must not invent modified Fisher 2006 grades or a linear vasospasm-risk percentage.

When not to use

• Not a diagnosis and not a medical device. magent does not read the CT.
• This is Fisher 1980 original groups 1-4 only. It does not implement modified Fisher (Frontera 2006).
• Group 3 (thick SAH: localized clots and/or vertical layers ≥1 mm) was the high-vasospasm group in 1980. Group 4 is diffuse or no subarachnoid blood with ICH or IVH — not a worse grade than 3. magent does not invent a linear vasospasm risk from the integer.

Formula

Fisher 1980 original CT group 1-4 as assigned by the caller

Citation

Title

Relation of cerebral vasospasm to subarachnoid hemorrhage visualized by computerized tomographic scanning

Authors

Fisher CM, Kistler JP, Davis JM

Source

Neurosurgery. 1980;6(1):1-9

DOI

10.1227/00006123-198001000-00001

Worked example

Also searched as

• Fisher grade
• Fisher scale
• Fisher CT grade
• Fisher 1980
• SAH CT grade
• subarachnoid hemorrhage CT grade
• Fisher group
• original Fisher scale

Try

Opens the live endpoint. Unpaid browser requests show the paywall; agents should send Accept: application/json.

/api/calc/fisher?grade=1

Full URL: https://api.magentlab.com/api/calc/fisher?grade=1

Call

Expect HTTP 402 until you retry with PAYMENT-SIGNATURE. Incomplete query params return HTTP 400 before any quote or charge.

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/fisher?grade=1"

Parameters

Bulk (POST)

POST the same path with a JSON items array. The first item is the GET unit; each additional item is $0.002. Invalid items return HTTP 400 before settlement.

POST /api/calc/fisher Max 25 unit_amount + extra_item_amount * (n - 1) extra $0.002 PREVIEW

• 1 to 25 items. Each item uses the same keys as the GET query parameters.
• POST of 1 item costs the same as GET. Lists longer than 25: chunk into multiple POSTs. Extra items still execute; do not pad dummy rows.
• The first invalid item fails the whole request (index in the 400 JSON). You are not charged.
• HTTP 200 is {count, path, items}. Each items[i] is the GET 200 body for that row.
• Catalog misses (empty matches, found=false) stay paid 200s inside that slot.
• x402 resource URL is this path plus n and body_sha256. Browsers that prefer text/html get the same paywall as GET; Pay retries POST with the same items.

Example request (fixture)

{
  "items": [
    {
      "grade": "1"
    },
    {
      "grade": "1"
    }
  ]
}

Open bulk paywall →

Opens a two-item fixture on the API host. Unpaid browsers get the same MetaMask paywall as GET; Pay retries POST with those items.

Example 200 (fixture)

{
  "count": 2,
  "path": "/api/calc/fisher",
  "items": [
    {
      "description": "No blood detected",
      "components": [
        {
          "factor": "grade",
          "points": 1,
          "present": true
        }
      ],
      "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
      "citation": {
        "authors": "Fisher CM, Kistler JP, Davis JM",
        "doi": "10.1227/00006123-198001000-00001",
        "id": "fisher-1980",
        "pmid": "7354892",
        "source": "Neurosurgery. 1980;6(1):1-9",
        "title": "Relation of cerebral vasospasm to subarachnoid hemorrhage visualized by computerized tomographic scanning"
      },
      "formula": "fisher",
      "formula_expression": "Fisher 1980 original CT group 1-4 as assigned by the caller",
      "max_score": 4,
      "score": 1,
      "grade": 1
    },
    {
      "description": "No blood detected",
      "components": [
        {
          "factor": "grade",
          "points": 1,
          "present": true
        }
      ],
      "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
      "citation": {
        "authors": "Fisher CM, Kistler JP, Davis JM",
        "doi": "10.1227/00006123-198001000-00001",
        "id": "fisher-1980",
        "pmid": "7354892",
        "source": "Neurosurgery. 1980;6(1):1-9",
        "title": "Relation of cerebral vasospasm to subarachnoid hemorrhage visualized by computerized tomographic scanning"
      },
      "formula": "fisher",
      "formula_expression": "Fisher 1980 original CT group 1-4 as assigned by the caller",
      "max_score": 4,
      "score": 1,
      "grade": 1
    }
  ]
}

Response

Example JSON

Machine form of the same example. Frozen fixture. Not a live lookup.

{
  "description": "No blood detected",
  "components": [
    {
      "factor": "grade",
      "points": 1,
      "present": true
    }
  ],
  "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
  "citation": {
    "authors": "Fisher CM, Kistler JP, Davis JM",
    "doi": "10.1227/00006123-198001000-00001",
    "id": "fisher-1980",
    "pmid": "7354892",
    "source": "Neurosurgery. 1980;6(1):1-9",
    "title": "Relation of cerebral vasospasm to subarachnoid hemorrhage visualized by computerized tomographic scanning"
  },
  "formula": "fisher",
  "formula_expression": "Fisher 1980 original CT group 1-4 as assigned by the caller",
  "max_score": 4,
  "score": 1,
  "grade": 1
}

Client errors (HTTP 400)

Invalid params return 400 without charge. Shared HTTP 402 and 503 meanings: Payments.

Related tools

• Hunt-Hess — Return the Hunt and Hess 1968 subarachnoid-hemorrhage surgical-risk grade from a caller-assigned grade 1-5, applying the paper's next-less-favorable bump when serious systemic disease is present.
• Ottawa SAH Rule — Apply the Perry 2013 Ottawa SAH Rule and return whether investigation is indicated from age and five caller-assigned high-risk findings.

Payment

Unpaid requests return HTTP 402 even if query parameters or POST items are missing or invalid, so CDP and agents can index the path. After a PAYMENT-SIGNATURE, invalid params return HTTP 400 JSON before settlement. magent does not charge. Fix the params, then request a new 402 quote for that complete URL. Catalog misses (empty matches, found=false) are valid paid 200s. Unpaid valid requests return HTTP 402 with a base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote: retry the same PAYMENT-SIGNATURE. Full handshake and shared payment errors: Payments. Stdio MCP: /docs/mcp.

Guarantees

• HTTP 402 is unpaid, including a missing query. After PAYMENT-SIGNATURE, invalid parameters return HTTP 400 before settlement. You are not charged.
• exact: settlement finishes before the tool (paymentFlow upfront). batch-settlement: verify/deposit before the tool; chargedCumulativeAmount commits after HTTP 2xx. Uncertain or failed settlement fails closed (HTTP 503). Retry the same PAYMENT-SIGNATURE.
• HTTP 402 is unpaid only. Do not sign a second authorization because of a 503.
• Execution is timeout-bounded and concurrency-capped.
• Calculator inputs are stored encrypted for allowlisted operators (Magent Console). They are not in public logs, SSH lookups, catalog, or rollups. Request logs store path without query.