MAGENT

Emergency · LIVE

modified Brain Injury Guidelines (mBIG)

Apply the Khan 2020 modified Brain Injury Guidelines and return mBIG tier 1, 2, or 3 from caller-assigned GCS, neurologic findings, medications, ethanol, skull fracture, and hematoma sizes.

LIVE $0.005 USDC GET /api/calc/mbig

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

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

What it computes

Apply the Khan 2020 modified Brain Injury Guidelines and return mBIG tier 1, 2, or 3 from caller-assigned GCS, neurologic findings, medications, ethanol, skull fracture, and hematoma sizes.

When to use

When an agent already has caller-assigned mild-TBI findings and CT hematoma sizes for an adult with traumatic ICH and needs the 2020 mBIG tier, not original Joseph 2014 BIG, not PECARN, and not Canadian CT Head.

When not to use

  • Not a medical device. Not a diagnosis. Not a neurosurgical plan or observation-order.
  • Khan 2020 is for adults with mild TBI and traumatic ICH. magent does not read CT, measure hematoma thickness, assay ethanol, or compute GCS. All inputs are caller-assigned.
  • This is the 2020 modified Brain Injury Guidelines, not original Joseph 2014 BIG. Any EDH is mBIG 3. Anticoagulant or antiplatelet excluding aspirin alone is mBIG 3; aspirin monotherapy is not scored as mBIG 3 on this API.
  • Discharge requiring GCS 15 and published observation hours are not returned. Neurologic deterioration is not scored here.

Formula

first-match worst-wins mBIG 3 then 2 then 1 (Khan 2020 modified criteria): mBIG 3 if GCS <= 12 or focal_neuro_or_pupillary_abnormality or ac_ap_excluding_aspirin or displaced skull fracture or sdh_mm >= 8 or iph_mm >= 8 or multiple_iph or sah scattered or sah_mm > 3 or any EDH or IVH; else mBIG 2 if etoh_gt_80 or nondisplaced skull fracture or sdh_mm >= 4 or iph_mm >= 4 or sah localized or sah_mm >= 1; else mBIG 1

Citation

Title
Multicenter assessment of the Brain Injury Guidelines and a proposal of guideline modifications
Authors
Khan AD, Elseth AJ, Brosius JA, et al.
Source
Trauma Surg Acute Care Open. 2020;5(1):e000483
DOI
10.1136/tsaco-2020-000483

Worked example

GCS 15, SDH 3 mm, SAH none/trace is mBIG 1

Given: ac_ap_excluding_aspirin=falseedh=falseetoh_gt_80=falsefocal_neuro_or_pupillary_abnormality=falsegcs=15iph_mm=0ivh=falsemultiple_iph=falsesah_mm=0sah_pattern=none_or_tracesdh_mm=3skull_fracture=none

  1. No mBIG 3 feature: GCS 15, no focal or pupillary abnormality, no AC/AP excluding aspirin, skull fracture none, SDH 3 mm < 8, IPH 0, SAH none_or_trace and 0 mm, no EDH, no IVH
  2. No mBIG 2 feature: EtOH not >80, no nondisplaced fracture, SDH 3 mm < 4, IPH 0, SAH none_or_trace and <1 mm
  3. mBIG 1

SDH 5 mm is mBIG 2

Given: ac_ap_excluding_aspirin=falseedh=falseetoh_gt_80=falsefocal_neuro_or_pupillary_abnormality=falsegcs=15iph_mm=0ivh=falsemultiple_iph=falsesah_mm=0sah_pattern=none_or_tracesdh_mm=5skull_fracture=none

  1. SDH 5 mm is >=4 and <8 and no mBIG 3 feature is met
  2. mBIG 2

Any EDH is mBIG 3

Given: ac_ap_excluding_aspirin=falseedh=trueetoh_gt_80=falsefocal_neuro_or_pupillary_abnormality=falsegcs=15iph_mm=0ivh=falsemultiple_iph=falsesah_mm=0sah_pattern=none_or_tracesdh_mm=3skull_fracture=none

  1. Khan 2020 classifies any epidural hematoma as mBIG 3
  2. mBIG 3

Also searched as

  • modified Brain Injury Guidelines
  • mBIG 2020
  • Khan mBIG
  • modified BIG
  • traumatic ICH guidelines
  • mBIG 1 2 3
  • mild TBI ICH stratification
  • Brain Injury Guidelines modified

Try

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

/api/calc/mbig?gcs=15&focal_neuro_or_pupillary_abnormality=false&ac_ap_excluding_aspirin=false&etoh_gt_80=false&skull_fracture=none&sdh_mm=3&iph_mm=0&multiple_iph=false&sah_pattern=none_or_trace&sah_mm=0&edh=false&ivh=false

Full URL: https://api.magentlab.com/api/calc/mbig?gcs=15&focal_neuro_or_pupillary_abnormality=false&ac_ap_excluding_aspirin=false&etoh_gt_80=false&skull_fracture=none&sdh_mm=3&iph_mm=0&multiple_iph=false&sah_pattern=none_or_trace&sah_mm=0&edh=false&ivh=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/mbig?gcs=15&focal_neuro_or_pupillary_abnormality=false&ac_ap_excluding_aspirin=false&etoh_gt_80=false&skull_fracture=none&sdh_mm=3&iph_mm=0&multiple_iph=false&sah_pattern=none_or_trace&sah_mm=0&edh=false&ivh=false"

Parameters

Name Type Required Description
gcs integer required Caller-assigned Glasgow Coma Scale total, integer 3-15. Khan 2020 methods: GCS of 12 or less is an abnormal neurologic examination and is mBIG 3. magent does not compute eye, verbal, or motor GCS.
focal_neuro_or_pupillary_abnormality boolean required Focal neurologic deficit or abnormal pupillary findings as assigned by the caller (Khan 2020 abnormal neurologic examination). true or false. true is mBIG 3. magent does not examine the patient.
ac_ap_excluding_aspirin boolean required Anticoagulant or antiplatelet therapy excluding aspirin alone, as assigned by the caller. true or false. true is mBIG 3. Aspirin monotherapy is false. magent does not read a medication list.
etoh_gt_80 boolean required Blood alcohol concentration >80 mg/dL as assigned by the caller (Khan 2020 intoxication definition, US legal driving limit). true or false. true excludes mBIG 1 (mBIG 2 unless a mBIG 3 feature is also met). magent does not assay ethanol.
skull_fracture string required · none, nondisplaced, displaced Skull fracture as assigned by the caller from CT: none (mBIG 1 row), nondisplaced (mBIG 2), or displaced (mBIG 3). magent does not read CT.
sdh_mm number required Largest subdural hematoma thickness in millimetres as assigned by the caller (0-40). mBIG 1 if <4, mBIG 2 if >=4 and <8, mBIG 3 if >=8. magent does not measure SDH or read CT.
iph_mm number required Largest intraparenchymal hemorrhage size in millimetres as assigned by the caller (0-40). mBIG 1 if <4, mBIG 2 if >=4 and <8, mBIG 3 if >=8. Use 0 when no IPH. magent does not measure IPH or read CT.
multiple_iph boolean required Multiple intraparenchymal hemorrhages as assigned by the caller. true or false. true is mBIG 3. magent does not count lesions on CT.
sah_pattern string required · none_or_trace, localized, scattered Traumatic SAH pattern as assigned by the caller from Khan 2020 sulci/hemisphere definitions that replace original BIG trace/localized/scattered: none_or_trace (<=3 sulci and <1 mm), localized (one hemisphere, >3 sulci, 1-3 mm), or scattered (bi-hemispheric or >3 mm). magent does not read CT.
sah_mm number required SAH thickness in millimetres as assigned by the caller (0-20). mBIG 1 if <1, mBIG 2 if 1-3, mBIG 3 if >3. Use 0 when none. Combined with sah_pattern; either scattered pattern or >3 mm is mBIG 3. magent does not measure SAH.
edh boolean required Any epidural hematoma as assigned by the caller. true or false. Any EDH is mBIG 3 (Khan 2020 safety modification versus original BIG size bands). magent does not read CT.
ivh boolean required Intraventricular hemorrhage as assigned by the caller. true or false. true is mBIG 3. magent does not read CT.

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/mbig 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": [
    {
      "ac_ap_excluding_aspirin": "false",
      "edh": "false",
      "etoh_gt_80": "false",
      "focal_neuro_or_pupillary_abnormality": "false",
      "gcs": "15",
      "iph_mm": "0",
      "ivh": "false",
      "multiple_iph": "false",
      "sah_mm": "0",
      "sah_pattern": "none_or_trace",
      "sdh_mm": "3",
      "skull_fracture": "none"
    },
    {
      "ac_ap_excluding_aspirin": "false",
      "edh": "false",
      "etoh_gt_80": "false",
      "focal_neuro_or_pupillary_abnormality": "false",
      "gcs": "15",
      "iph_mm": "0",
      "ivh": "false",
      "multiple_iph": "false",
      "sah_mm": "0",
      "sah_pattern": "none_or_trace",
      "sdh_mm": "3",
      "skull_fracture": "none"
    }
  ]
}

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/mbig",
  "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": "Khan AD, Elseth AJ, Brosius JA, et al.",
        "doi": "10.1136/tsaco-2020-000483",
        "id": "khan-2020",
        "pmid": "32537518",
        "source": "Trauma Surg Acute Care Open. 2020;5(1):e000483",
        "title": "Multicenter assessment of the Brain Injury Guidelines and a proposal of guideline modifications"
      },
      "formula": "mbig",
      "formula_expression": "first-match worst-wins mBIG 3 then 2 then 1 (Khan 2020 modified criteria): mBIG 3 if GCS <= 12 or focal_neuro_or_pupillary_abnormality or ac_ap_excluding_aspirin or displaced skull fracture or sdh_mm >= 8 or iph_mm >= 8 or multiple_iph or sah scattered or sah_mm > 3 or any EDH or IVH; else mBIG 2 if etoh_gt_80 or nondisplaced skull fracture or sdh_mm >= 4 or iph_mm >= 4 or sah localized or sah_mm >= 1; else mBIG 1",
      "criteria": [
        {
          "value": 15,
          "factor": "gcs_le_12",
          "met": false
        },
        {
          "factor": "focal_neuro_or_pupillary_abnormality",
          "met": false
        },
        {
          "factor": "ac_ap_excluding_aspirin",
          "met": false
        },
        {
          "factor": "etoh_gt_80",
          "met": false
        },
        {
          "value": "none",
          "factor": "displaced_skull_fracture",
          "met": false
        },
        {
          "value": "none",
          "factor": "nondisplaced_skull_fracture",
          "met": false
        },
        {
          "value": 3.0,
          "factor": "sdh_ge_8",
          "met": false
        },
        {
          "value": 3.0,
          "factor": "sdh_ge_4",
          "met": false
        },
        {
          "value": 0.0,
          "factor": "iph_ge_8",
          "met": false
        },
        {
          "value": 0.0,
          "factor": "iph_ge_4",
          "met": false
        },
        {
          "factor": "multiple_iph",
          "met": false
        },
        {
          "value": "none_or_trace",
          "factor": "sah_scattered",
          "met": false
        },
        {
          "value": "none_or_trace",
          "factor": "sah_localized",
          "met": false
        },
        {
          "value": 0.0,
          "factor": "sah_mm_gt_3",
          "met": false
        },
        {
          "value": 0.0,
          "factor": "sah_mm_ge_1",
          "met": false
        },
        {
          "factor": "edh",
          "met": false
        },
        {
          "factor": "ivh",
          "met": false
        }
      ],
      "gcs": 15,
      "sah_pattern": "none_or_trace",
      "skull_fracture": "none",
      "iph_mm": 0.0,
      "sah_mm": 0.0,
      "sdh_mm": 3.0,
      "mbig_tier": 1
    },
    {
      "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": "Khan AD, Elseth AJ, Brosius JA, et al.",
        "doi": "10.1136/tsaco-2020-000483",
        "id": "khan-2020",
        "pmid": "32537518",
        "source": "Trauma Surg Acute Care Open. 2020;5(1):e000483",
        "title": "Multicenter assessment of the Brain Injury Guidelines and a proposal of guideline modifications"
      },
      "formula": "mbig",
      "formula_expression": "first-match worst-wins mBIG 3 then 2 then 1 (Khan 2020 modified criteria): mBIG 3 if GCS <= 12 or focal_neuro_or_pupillary_abnormality or ac_ap_excluding_aspirin or displaced skull fracture or sdh_mm >= 8 or iph_mm >= 8 or multiple_iph or sah scattered or sah_mm > 3 or any EDH or IVH; else mBIG 2 if etoh_gt_80 or nondisplaced skull fracture or sdh_mm >= 4 or iph_mm >= 4 or sah localized or sah_mm >= 1; else mBIG 1",
      "criteria": [
        {
          "value": 15,
          "factor": "gcs_le_12",
          "met": false
        },
        {
          "factor": "focal_neuro_or_pupillary_abnormality",
          "met": false
        },
        {
          "factor": "ac_ap_excluding_aspirin",
          "met": false
        },
        {
          "factor": "etoh_gt_80",
          "met": false
        },
        {
          "value": "none",
          "factor": "displaced_skull_fracture",
          "met": false
        },
        {
          "value": "none",
          "factor": "nondisplaced_skull_fracture",
          "met": false
        },
        {
          "value": 3.0,
          "factor": "sdh_ge_8",
          "met": false
        },
        {
          "value": 3.0,
          "factor": "sdh_ge_4",
          "met": false
        },
        {
          "value": 0.0,
          "factor": "iph_ge_8",
          "met": false
        },
        {
          "value": 0.0,
          "factor": "iph_ge_4",
          "met": false
        },
        {
          "factor": "multiple_iph",
          "met": false
        },
        {
          "value": "none_or_trace",
          "factor": "sah_scattered",
          "met": false
        },
        {
          "value": "none_or_trace",
          "factor": "sah_localized",
          "met": false
        },
        {
          "value": 0.0,
          "factor": "sah_mm_gt_3",
          "met": false
        },
        {
          "value": 0.0,
          "factor": "sah_mm_ge_1",
          "met": false
        },
        {
          "factor": "edh",
          "met": false
        },
        {
          "factor": "ivh",
          "met": false
        }
      ],
      "gcs": 15,
      "sah_pattern": "none_or_trace",
      "skull_fracture": "none",
      "iph_mm": 0.0,
      "sah_mm": 0.0,
      "sdh_mm": 3.0,
      "mbig_tier": 1
    }
  ]
}

Response

Field Type Description
formula string mbig
formula_expression string Khan 2020 first-match worst-wins mBIG 3 then 2 then 1 rule
mbig_tier integer 1, 2, or 3 from the modified criteria. Not a diagnosis or neurosurgical plan.
gcs integer GCS total used (3-15)
sdh_mm number SDH thickness in mm used
iph_mm number IPH size in mm used
sah_mm number SAH thickness in mm used
skull_fracture string none, nondisplaced, or displaced as used
sah_pattern string none_or_trace, localized, or scattered as used
criteria array Per-factor rows with factor and met; GCS, SDH, IPH, SAH mm, skull_fracture, and sah_pattern rows include value
citation object Khan 2020 TSACO citation
disclaimer string Not-a-device notice

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": "Khan AD, Elseth AJ, Brosius JA, et al.",
    "doi": "10.1136/tsaco-2020-000483",
    "id": "khan-2020",
    "pmid": "32537518",
    "source": "Trauma Surg Acute Care Open. 2020;5(1):e000483",
    "title": "Multicenter assessment of the Brain Injury Guidelines and a proposal of guideline modifications"
  },
  "formula": "mbig",
  "formula_expression": "first-match worst-wins mBIG 3 then 2 then 1 (Khan 2020 modified criteria): mBIG 3 if GCS <= 12 or focal_neuro_or_pupillary_abnormality or ac_ap_excluding_aspirin or displaced skull fracture or sdh_mm >= 8 or iph_mm >= 8 or multiple_iph or sah scattered or sah_mm > 3 or any EDH or IVH; else mBIG 2 if etoh_gt_80 or nondisplaced skull fracture or sdh_mm >= 4 or iph_mm >= 4 or sah localized or sah_mm >= 1; else mBIG 1",
  "criteria": [
    {
      "value": 15,
      "factor": "gcs_le_12",
      "met": false
    },
    {
      "factor": "focal_neuro_or_pupillary_abnormality",
      "met": false
    },
    {
      "factor": "ac_ap_excluding_aspirin",
      "met": false
    },
    {
      "factor": "etoh_gt_80",
      "met": false
    },
    {
      "value": "none",
      "factor": "displaced_skull_fracture",
      "met": false
    },
    {
      "value": "none",
      "factor": "nondisplaced_skull_fracture",
      "met": false
    },
    {
      "value": 3.0,
      "factor": "sdh_ge_8",
      "met": false
    },
    {
      "value": 3.0,
      "factor": "sdh_ge_4",
      "met": false
    },
    {
      "value": 0.0,
      "factor": "iph_ge_8",
      "met": false
    },
    {
      "value": 0.0,
      "factor": "iph_ge_4",
      "met": false
    },
    {
      "factor": "multiple_iph",
      "met": false
    },
    {
      "value": "none_or_trace",
      "factor": "sah_scattered",
      "met": false
    },
    {
      "value": "none_or_trace",
      "factor": "sah_localized",
      "met": false
    },
    {
      "value": 0.0,
      "factor": "sah_mm_gt_3",
      "met": false
    },
    {
      "value": 0.0,
      "factor": "sah_mm_ge_1",
      "met": false
    },
    {
      "factor": "edh",
      "met": false
    },
    {
      "factor": "ivh",
      "met": false
    }
  ],
  "gcs": 15,
  "sah_pattern": "none_or_trace",
  "skull_fracture": "none",
  "iph_mm": 0.0,
  "sah_mm": 0.0,
  "sdh_mm": 3.0,
  "mbig_tier": 1
}

Client errors (HTTP 400)

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

HTTP Code When
400 invalid_gcs_total gcs must be an integer from 3 to 15. Returned before settlement; you are not charged.
400 invalid_sdh_mm sdh_mm must be a number from 0 to 40 (Khan 2020 mBIG subdural thickness mm). Returned before settlement; you are not charged.
400 invalid_iph_mm iph_mm must be a number from 0 to 40 (Khan 2020 mBIG intraparenchymal hemorrhage mm). Returned before settlement; you are not charged.
400 invalid_sah_mm sah_mm must be a number from 0 to 20 (Khan 2020 mBIG subarachnoid thickness mm). Returned before settlement; you are not charged.
400 invalid_flag boolean clinical flags must be true or false Returned before settlement; you are not charged.
400 invalid_items POST body must be a JSON object with only an items array Returned before settlement; you are not charged.
400 invalid_item_count items must be an array of 1 to 25 objects Returned before settlement; you are not charged.
400 invalid_item each items entry must be a JSON object Returned before settlement; you are not charged.

Related tools

  • PECARN pediatric head CT — Apply the Kuppermann 2009 PECARN prediction trees and return high, intermediate, or low risk of clinically important brain injury from caller-assigned findings after pediatric head trauma.
  • Canadian CT Head Rule — Apply the Stiell 2001 Canadian CT Head Rule and return whether CT is indicated from caller-assigned high-risk and medium-risk findings after minor blunt head injury.

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.