Emergency · LIVE

NEXUS Chest CT

Apply the Rodriguez 2015 NEXUS Chest CT-Major and Chest CT-All decision instruments and return whether each is negative (all of that instrument's caller-assigned criteria absent). Does not order a CT.

LIVE $0.005 USDC GET /api/calc/nexus_chest_ct

Markdown: /docs/nexus-chest-ct.md · Canonical: https://magentlab.com/docs/nexus-chest-ct

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

What it computes

Apply the Rodriguez 2015 NEXUS Chest CT-Major and Chest CT-All decision instruments and return whether each is negative (all of that instrument's caller-assigned criteria absent). Does not order a CT.

When to use

When an agent has caller-assigned findings after blunt trauma and needs the published NEXUS Chest CT selective-CT instruments, not the NEXUS Chest CXR instrument and not Hoffman 2000 NEXUS C-spine.

When not to use

• Not a medical device. Not a diagnosis. magent does not examine the patient or read a radiograph.
• This tool is the Rodriguez 2015 Chest CT-Major and Chest CT-All instruments only. It is not the NEXUS Chest CXR seven-item instrument (nexus-chest) and not the Hoffman 2000 NEXUS C-spine rule.
• Derivation and validation enrolled blunt trauma age >14 undergoing chest imaging at eight US level I trauma centers. magent does not take numeric age; the caller assigns all flags, including abnormal_cxr.
• These are one-way rule-out instruments. Presence of a criterion does not mandate CT. Do not order a CT from a positive instrument.

Formula

ct_major_negative iff no abnormal_cxr and no distracting_injury and no chest_wall_tenderness and no sternal_tenderness and no thoracic_spine_tenderness and no scapular_tenderness; ct_all_negative iff Major-negative and no rapid_deceleration_mechanism

Citation

Title

Derivation and Validation of Two Decision Instruments for Selective Chest CT in Blunt Trauma: A Multicenter Prospective Observational Study (NEXUS Chest CT)

Authors

Rodriguez RM, Langdorf MI, Nishijima D, Baumann BM, Hendey GW, Medak AJ, Raja AS, Adelman EE, Mower WR

Source

PLoS Med. 2015;12(10):e1001883

DOI

10.1371/journal.pmed.1001883

Worked example

Also searched as

• NEXUS Chest CT
• NEXUS Chest CT-Major
• NEXUS Chest CT-All
• Rodriguez Chest CT
• selective chest CT blunt trauma
• Chest CT-Major
• Chest CT-All
• NEXUS Chest CT decision instrument

Try

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

/api/calc/nexus_chest_ct?abnormal_cxr=false&distracting_injury=false&chest_wall_tenderness=false&sternal_tenderness=false&thoracic_spine_tenderness=false&scapular_tenderness=false&rapid_deceleration_mechanism=false

Full URL: https://api.magentlab.com/api/calc/nexus_chest_ct?abnormal_cxr=false&distracting_injury=false&chest_wall_tenderness=false&sternal_tenderness=false&thoracic_spine_tenderness=false&scapular_tenderness=false&rapid_deceleration_mechanism=false

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/nexus_chest_ct?abnormal_cxr=false&distracting_injury=false&chest_wall_tenderness=false&sternal_tenderness=false&thoracic_spine_tenderness=false&scapular_tenderness=false&rapid_deceleration_mechanism=false"

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/nexus_chest_ct 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": [
    {
      "abnormal_cxr": "false",
      "chest_wall_tenderness": "false",
      "distracting_injury": "false",
      "rapid_deceleration_mechanism": "false",
      "scapular_tenderness": "false",
      "sternal_tenderness": "false",
      "thoracic_spine_tenderness": "false"
    },
    {
      "abnormal_cxr": "false",
      "chest_wall_tenderness": "false",
      "distracting_injury": "false",
      "rapid_deceleration_mechanism": "false",
      "scapular_tenderness": "false",
      "sternal_tenderness": "false",
      "thoracic_spine_tenderness": "false"
    }
  ]
}

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/nexus_chest_ct",
  "items": [
    {
      "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": "Rodriguez RM, Langdorf MI, Nishijima D, Baumann BM, Hendey GW, Medak AJ, Raja AS, Adelman EE, Mower WR",
        "doi": "10.1371/journal.pmed.1001883",
        "id": "rodriguez-2015",
        "pmid": "26440607",
        "source": "PLoS Med. 2015;12(10):e1001883",
        "title": "Derivation and Validation of Two Decision Instruments for Selective Chest CT in Blunt Trauma: A Multicenter Prospective Observational Study (NEXUS Chest CT)"
      },
      "formula": "nexus_chest_ct",
      "formula_expression": "ct_major_negative iff no abnormal_cxr and no distracting_injury and no chest_wall_tenderness and no sternal_tenderness and no thoracic_spine_tenderness and no scapular_tenderness; ct_all_negative iff Major-negative and no rapid_deceleration_mechanism",
      "criteria": [
        {
          "factor": "no_abnormal_cxr",
          "met": true
        },
        {
          "factor": "no_distracting_injury",
          "met": true
        },
        {
          "factor": "no_chest_wall_tenderness",
          "met": true
        },
        {
          "factor": "no_sternal_tenderness",
          "met": true
        },
        {
          "factor": "no_thoracic_spine_tenderness",
          "met": true
        },
        {
          "factor": "no_scapular_tenderness",
          "met": true
        },
        {
          "factor": "no_rapid_deceleration_mechanism",
          "met": true
        }
      ],
      "ct_all_negative": true,
      "ct_major_negative": 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": "Rodriguez RM, Langdorf MI, Nishijima D, Baumann BM, Hendey GW, Medak AJ, Raja AS, Adelman EE, Mower WR",
        "doi": "10.1371/journal.pmed.1001883",
        "id": "rodriguez-2015",
        "pmid": "26440607",
        "source": "PLoS Med. 2015;12(10):e1001883",
        "title": "Derivation and Validation of Two Decision Instruments for Selective Chest CT in Blunt Trauma: A Multicenter Prospective Observational Study (NEXUS Chest CT)"
      },
      "formula": "nexus_chest_ct",
      "formula_expression": "ct_major_negative iff no abnormal_cxr and no distracting_injury and no chest_wall_tenderness and no sternal_tenderness and no thoracic_spine_tenderness and no scapular_tenderness; ct_all_negative iff Major-negative and no rapid_deceleration_mechanism",
      "criteria": [
        {
          "factor": "no_abnormal_cxr",
          "met": true
        },
        {
          "factor": "no_distracting_injury",
          "met": true
        },
        {
          "factor": "no_chest_wall_tenderness",
          "met": true
        },
        {
          "factor": "no_sternal_tenderness",
          "met": true
        },
        {
          "factor": "no_thoracic_spine_tenderness",
          "met": true
        },
        {
          "factor": "no_scapular_tenderness",
          "met": true
        },
        {
          "factor": "no_rapid_deceleration_mechanism",
          "met": true
        }
      ],
      "ct_all_negative": true,
      "ct_major_negative": true
    }
  ]
}

Response

Example JSON

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

{
  "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": "Rodriguez RM, Langdorf MI, Nishijima D, Baumann BM, Hendey GW, Medak AJ, Raja AS, Adelman EE, Mower WR",
    "doi": "10.1371/journal.pmed.1001883",
    "id": "rodriguez-2015",
    "pmid": "26440607",
    "source": "PLoS Med. 2015;12(10):e1001883",
    "title": "Derivation and Validation of Two Decision Instruments for Selective Chest CT in Blunt Trauma: A Multicenter Prospective Observational Study (NEXUS Chest CT)"
  },
  "formula": "nexus_chest_ct",
  "formula_expression": "ct_major_negative iff no abnormal_cxr and no distracting_injury and no chest_wall_tenderness and no sternal_tenderness and no thoracic_spine_tenderness and no scapular_tenderness; ct_all_negative iff Major-negative and no rapid_deceleration_mechanism",
  "criteria": [
    {
      "factor": "no_abnormal_cxr",
      "met": true
    },
    {
      "factor": "no_distracting_injury",
      "met": true
    },
    {
      "factor": "no_chest_wall_tenderness",
      "met": true
    },
    {
      "factor": "no_sternal_tenderness",
      "met": true
    },
    {
      "factor": "no_thoracic_spine_tenderness",
      "met": true
    },
    {
      "factor": "no_scapular_tenderness",
      "met": true
    },
    {
      "factor": "no_rapid_deceleration_mechanism",
      "met": true
    }
  ],
  "ct_all_negative": true,
  "ct_major_negative": true
}

Client errors (HTTP 400)

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

Related tools

• NEXUS Chest — Apply the Rodriguez 2011 NEXUS Chest decision instrument and return whether the seven low-risk criteria all hold (chest radiography not indicated by this instrument).
• NEXUS C-spine — Apply the Hoffman 2000 NEXUS C-spine rule and return whether the five low-risk criteria all hold (imaging not indicated by this rule).

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. HTTP 402 never includes the tool JSON.
• 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.