Purpose: To prospectively and externally validate published national and international guidelines for the indications of computed tomography (CT) in patients with a minor head injury.
Materials and methods: The study protocol was institutional review board approved. All patients implicitly consented to use of their deidentified data for research purposes. Between February 2002 and August 2004, data were collected in consecutive adult patients with blunt minor head injury (Glasgow Coma Scale score of 13-14 or 15) and a risk factor for neurocranial traumatic complications at presentation at four Dutch university hospitals. Primary outcome was any neurocranial traumatic CT finding. Secondary outcomes were clinically relevant traumatic CT findings and neurosurgical intervention. Sensitivity and specificity of each guideline for all outcomes and the number of patients needed to scan to detect one outcome (ie, the number of patients needed to undergo CT to find one patient with a neurocranial traumatic CT finding, a clinically relevant traumatic CT finding, or a CT finding that required neurosurgical intervention) were estimated.
Results: Data were available for 3181 patients. Only the European Federation of Neurological Societies guidelines reached a sensitivity of 100% for all outcomes. Specificity was 0.0%-0.5%. The Dutch guidelines had the lowest sensitivity (76.5%) for neurosurgical interventions. The best specificities for traumatic CT findings and neurosurgical interventions were reached with the criteria proposed by the United Kingdom National Institute for Clinical Excellence (NICE) (46.1% and 43.6%, respectively), albeit at relatively low sensitivities (82.1% and 94.1%, respectively). The number of patients needed to scan ranged from six to 13 for traumatic CT findings and from 79 to 193 for neurosurgical interventions.
Conclusion: All validated guidelines demonstrated a trade-off between sensitivity and specificity. The lowest number of patients needed to scan for either of the outcomes was reached with the NICE criteria.
Supplemental material: radiology.rsnajnls.org/cgi/content/full/2452061509/DC1 (c) RSNA, 2007.