Indication for CT

NICE Criteria for doing a CT head

Dangerous mechanism of injury: high-speed road traffic accident as a pedestrian, cyclist or vehicle occupant, fall from a height of more than 3 m, high-speed injury from a projectile or other object

CT Head Scan Timing	16 and over	Under 16
Within 1 hour	—GCS <13 initially in ED —GCS < 15 at 2 hours after injury in ED —Suspected open/depressed skull fracture —Signs of basal skull fracture —Post-traumatic seizure —Focal neurological deficit —>1 episode of vomiting —HI + warfarin	—GCS <14 initially in ED (or GCS < 15 for under 1 year) —GCS < 15 at 2 hours after injury —Suspected open/depressed skull fracture/tense fontanelle —Signs of basal skull fracture —Post-traumatic seizure —Focal neurological deficit —Bruise/swelling/laceration > 5 cm on head (for babies under 1 year) —Suspicion of NAI
Within 8 hours (or within 1 hour if presenting >8 hours after injury)	—LOC/Amnesia since injury + 1 of the following →Age > 65 →History of Bleeding/clotting disorders →Dangerous mechanism of injury →>30 minutes retrograde amnesia prior to HI —Anticoagulant or antiplatelet therapy (exclude aspirin)
Within 1 hour		2 or more of the following —Loss of consciousness > 5 minutes —Abnormal drowsiness —3+ episodes of vomiting —Dangerous mechanism of injury —Amnesia > 5 minutes —Bleeding/clotting disorders
Observe for minimum of 4 hours, CT scan within 1 hour if new risk factors identified		Only 1 of the above risk factors

Other mild head injury criteria

Canadian CT Head Rule

From a study N:3121 patients with a GCS score of 13-15

CT head is mandatory if one or more of the following high-risk criteria are present:

GCS score less than 15 at 2 h after head injury.

Suspected open or depressed skull fracture.

Any sign of basal skull fracture.

Two or more episodes of vomiting.

Patient is 65 years of age or older.

CT head is also recommended in patients in the medium-risk category:

Greater than 30 min of retrograde amnesia.

Injury via a “dangerous mechanism”.

Absence of any of the features of the Canadian CT Head Rule lowered the probability of severe injury to 0.31%

New Orleans criteria for CT head in mild TBI applies

Patients with a GCS 15 only + LOC + a normal neurological examination.

CT is advised if any of the following is present:

Age over 60 years
Headache
Vomiting
Drug/alcohol intoxication
Persistent anterograde amnesia
Post-traumatic seizure
Evidence of trauma above the clavicles

Absence of any New Orleans Criteria findings lowered the probability of severe intracranial injury to 0.61%

Features most predictive of severe intracranial injury on CT were:

Examination findings suggestive of skull fracture,

GCS score 13/15, 2 or more vomiting episodes,

Any decline in GCS

Pedestrians struck by motor vehicles.