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Canadian CT Head Rule

Records high- and medium-risk Canadian CT Head Rule criteria after checking eligibility and exclusions. The result neither diagnoses injury nor determines that imaging can be omitted.

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Check the population, units and version. The result shows the formula or classification; it does not make an automatic treatment decision.

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Method · Limits of application

Stiell 2001; Canadian CT Head Rule

Applies to the study population, not to every head injury. The result records the rule criteria; it neither diagnoses injury nor determines that imaging can be omitted.

Required fields: 0/9 completed

Complete all required fields. Optional fields are marked.

Exclusion criterion: age < 16 years, anticoagulation/coagulopathy, seizure before assessment, focal deficit, penetrating trauma, obvious depressed skull fracture, unstable vital signs due to major trauma, pregnancy, return for the same injury or unclear trauma history required

High risk: Glasgow < 15 two hours after trauma required

High risk: suspected open or depressed skull fracture required

High risk: sign of basal skull fracture (hemotympanum, raccoon eyes, CSF otorrhea or rhinorrhea, Battle sign) required

High risk: 2 or more vomiting episodes required

High risk: age ≥ 65 years required

Medium risk: retrograde amnesia for 30 minutes or more before impact required

Medium risk: dangerous mechanism (pedestrian struck, vehicle ejection, fall more than 0.9 m or 5 steps) required

Blunt head trauma ≤ 24 h ago, age ≥ 16 years; Glasgow 13–15 and documented loss of consciousness, amnesia or disorientation; inclusion confirmed? required

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Conditions of use

Check the conditions of application before calculating. The result presents the documented formula or criteria; it does not establish a diagnosis or prescription.

Scope of this implementation

Applies to the study population, not to every head injury. The result records the rule criteria; it neither diagnoses injury nor determines that imaging can be omitted.

Parameters in this edition

Exclusion criterion: age < 16 years, anticoagulation/coagulopathy, seizure before assessment, focal deficit, penetrating trauma, obvious depressed skull fracture, unstable vital signs due to major trauma, pregnancy, return for the same injury or unclear trauma history
High risk: Glasgow < 15 two hours after trauma
High risk: suspected open or depressed skull fracture
High risk: sign of basal skull fracture (hemotympanum, raccoon eyes, CSF otorrhea or rhinorrhea, Battle sign)
High risk: 2 or more vomiting episodes
High risk: age ≥ 65 years
Medium risk: retrograde amnesia for 30 minutes or more before impact
Medium risk: dangerous mechanism (pedestrian struck, vehicle ejection, fall more than 0.9 m or 5 steps)
Blunt head trauma ≤ 24 h ago, age ≥ 16 years; Glasgow 13–15 and documented loss of consciousness, amnesia or disorientation; inclusion confirmed?

Sources and documentation

Method version

Stiell 2001; Canadian CT Head Rule

Formula and criteria

Five high-risk and two medium-risk criteria. Exclusions are assessed before classification.

Population and limitations

Applies to the study population, not to every head injury. The result records the rule criteria; it neither diagnoses injury nor determines that imaging can be omitted.

Synthetic cases checked (4)

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

Case 1

reference-001

Inputs

Exclusion criterion: age < 16 years, anticoagulation/coagulopathy, seizure before assessment, focal deficit, penetrating trauma, obvious depressed skull fracture, unstable vital signs due to major trauma, pregnancy, return for the same injury or unclear trauma history: No
High risk: Glasgow < 15 two hours after trauma: No
High risk: suspected open or depressed skull fracture: No
High risk: sign of basal skull fracture (hemotympanum, raccoon eyes, CSF otorrhea or rhinorrhea, Battle sign): No
High risk: 2 or more vomiting episodes: No
High risk: age ≥ 65 years: Yes
Medium risk: retrograde amnesia for 30 minutes or more before impact: No
Medium risk: dangerous mechanism (pedestrian struck, vehicle ejection, fall more than 0.9 m or 5 steps): No
Blunt head trauma ≤ 24 h ago, age ≥ 16 years; Glasgow 13–15 and documented loss of consciousness, amnesia or disorientation; inclusion confirmed?: Yes

{
  "excl": false,
  "gcs2h": false,
  "frat": false,
  "base": false,
  "vomito": false,
  "idade65": true,
  "amnesia": false,
  "mecanismo": false,
  "contexto": "1"
}

Expected result

{
  "ct": 1,
  "tier": 2
}

Actual result

{
  "ct": 1,
  "tier": 2
}

Case 2

reference-002

Inputs

Exclusion criterion: age < 16 years, anticoagulation/coagulopathy, seizure before assessment, focal deficit, penetrating trauma, obvious depressed skull fracture, unstable vital signs due to major trauma, pregnancy, return for the same injury or unclear trauma history: No
High risk: Glasgow < 15 two hours after trauma: No
High risk: suspected open or depressed skull fracture: No
High risk: sign of basal skull fracture (hemotympanum, raccoon eyes, CSF otorrhea or rhinorrhea, Battle sign): No
High risk: 2 or more vomiting episodes: No
High risk: age ≥ 65 years: No
Medium risk: retrograde amnesia for 30 minutes or more before impact: Yes
Medium risk: dangerous mechanism (pedestrian struck, vehicle ejection, fall more than 0.9 m or 5 steps): No
Blunt head trauma ≤ 24 h ago, age ≥ 16 years; Glasgow 13–15 and documented loss of consciousness, amnesia or disorientation; inclusion confirmed?: Yes

{
  "excl": false,
  "gcs2h": false,
  "frat": false,
  "base": false,
  "vomito": false,
  "idade65": false,
  "amnesia": true,
  "mecanismo": false,
  "contexto": "1"
}

Expected result

{
  "ct": 1,
  "tier": 1
}

Actual result

{
  "ct": 1,
  "tier": 1
}

Case 3

reference-003

Inputs

Exclusion criterion: age < 16 years, anticoagulation/coagulopathy, seizure before assessment, focal deficit, penetrating trauma, obvious depressed skull fracture, unstable vital signs due to major trauma, pregnancy, return for the same injury or unclear trauma history: No
High risk: Glasgow < 15 two hours after trauma: No
High risk: suspected open or depressed skull fracture: No
High risk: sign of basal skull fracture (hemotympanum, raccoon eyes, CSF otorrhea or rhinorrhea, Battle sign): No
High risk: 2 or more vomiting episodes: No
High risk: age ≥ 65 years: No
Medium risk: retrograde amnesia for 30 minutes or more before impact: No
Medium risk: dangerous mechanism (pedestrian struck, vehicle ejection, fall more than 0.9 m or 5 steps): No
Blunt head trauma ≤ 24 h ago, age ≥ 16 years; Glasgow 13–15 and documented loss of consciousness, amnesia or disorientation; inclusion confirmed?: Yes

{
  "excl": false,
  "gcs2h": false,
  "frat": false,
  "base": false,
  "vomito": false,
  "idade65": false,
  "amnesia": false,
  "mecanismo": false,
  "contexto": "1"
}

Expected result

{
  "ct": 0,
  "tier": 0
}

Actual result

{
  "ct": 0,
  "tier": 0
}

Case 4

reference-004

Inputs

Exclusion criterion: age < 16 years, anticoagulation/coagulopathy, seizure before assessment, focal deficit, penetrating trauma, obvious depressed skull fracture, unstable vital signs due to major trauma, pregnancy, return for the same injury or unclear trauma history: No
High risk: Glasgow < 15 two hours after trauma: No
High risk: suspected open or depressed skull fracture: No
High risk: sign of basal skull fracture (hemotympanum, raccoon eyes, CSF otorrhea or rhinorrhea, Battle sign): No
High risk: 2 or more vomiting episodes: No
High risk: age ≥ 65 years: Yes
Medium risk: retrograde amnesia for 30 minutes or more before impact: Yes
Medium risk: dangerous mechanism (pedestrian struck, vehicle ejection, fall more than 0.9 m or 5 steps): No
Blunt head trauma ≤ 24 h ago, age ≥ 16 years; Glasgow 13–15 and documented loss of consciousness, amnesia or disorientation; inclusion confirmed?: Yes

{
  "excl": false,
  "gcs2h": false,
  "frat": false,
  "base": false,
  "vomito": false,
  "idade65": true,
  "amnesia": true,
  "mecanismo": false,
  "contexto": "1"
}

Expected result

{
  "ct": 1,
  "tier": 2
}

Actual result

{
  "ct": 1,
  "tier": 2
}

Source for the active edition

Stiell et al. · Canadian CT Head Rule implementation and population · 2010

Additional reading and history

Identifier: canadian-ct-head-rule

Original clinical content: Brazilian Portuguese.

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.