Clinical decision rules for CT in minor head injury

GM Healy, CE Redmond, V Meyer, R Kavanagh, RP Killeen, J Ryan 


Head injury accounts for 1% of attendances to our emergency department. While intra-cranial haemorrhage (ICH) occurs in approximately 8%1 and mortality is low (0.2%2), it is the commonest cause of death in young people in the UK2. Consequently, there is frequent over-investigation, with some patients undergoing unnecessary scans involving radiation exposure. Computed Tomography (CT) is the gold standard for those in whom ICI is suspected and clinical decision rules have been developed to aid identification of patients at risk. We have recently completed a review of 168 consecutive patients with minor head injury attending the adult Emergency Department (annual attendance 52,000) of our university hospital between January-April 2014. We retrospectively compared the following head injury clinical decision rules: National Institute of Clinical Excellence (NICE)2, Canadian CT Head rule1, Royal College of Radiologists guidelines (iRefer) and Scandinavian guidelines3.

Seventy-nine patients underwent CT brain examinations, acquired using spiral or sequential CT protocols with 3mm reconstruction. Eight patients (5%) had an ICH and one patient died as a result of this injury. Use of the NICE, iRefer and Scandinavian guidelines would have resulted in 43, 33 and 71 examinations but missed one, three and one cases of ICH respectively. Applying the Canadian rule, 71 examination would have been performed and all cases of ICH identified. All four clinical decision rules would have identified the patient who died from an ICH. These findings mirror the results of a recent trial in Iran, where CT brain examinations carried out in 500 consecutive patients4 found the Canadian guidelines to be the most accurate. We have also demonstrated that the iRefer guidelines perform poorly in our cohort.


Correspondence: Gerard M Healy, Department of Radiology, St Vincent’s University Hospital, Elm Park, Dublin 4

Email: [email protected]



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