Table 5

Projected rate of cranial CT if clinical decision rules are applied

CT rate pre CDR derivationCT rate if CDR applied
CATCH (using 4 high risk factors)52.8% in full derivation population, not reported separately30.2%*
CATCH (using all 7 factors)51.9%*
CHALICE (applied to all patients)3.3% in full derivation population, not reported separately14.1%
CHALICE (if GCS 13–15)13.3%
PECARN <2 y31%‘Among all enrolled, those for whom CT scans could be avoided accounted for 25% of CTs if aged <2 y and 20% of CTs if aged ≥2 y’
PECARN ≥2 y37%
  • * This is the reported projected rate of cranial CT scan in the population who fulfil the criteria of minor head injury, as defined in CATCH only, not the whole population of children with head injury.

  • This is the projected cranial CT rate change in the population who fulfil the criteria for inclusion in PECARN only, not the whole population of children with head injury.

  • CATCH, Canadian Assessment of Tomography for Childhood Head Injury; CDR, Clinical decision rules; CHALICE, Children's Head Injury Algorithm for the Prediction of Important Clinical Events; PECARN, Paediatric Emergency Care Applied Research Network.