 The study aims to improve the emergency evaluation of patients with an acute head injury, especially a mild head injury. About 80 of head CT scan performed on head injury patients in the Emergency Department of the Tampere University Hospital are negative no acute traumatic lesion. There is an urgent need to update the head CT imaging criteriaindications in the context of acute head injury in order to reduce the number of unnecessary scanning. More selective head CT indications result in considerable health care savings and decreased exposure to ionizing radiation, among other benefits. 