This study will be proposed to every patient that correspond to eligibility criteria, such as presenting a severe headache (Visual Analog Scale ≥ 6/10) within 3 hours before arriving to the emergency.
After signing the informed consent, a blood sample will be taken in order to dosage S100B protein of each patient, and then they will have a brain scan.
The trial ends after the brain scan for each patient. Results of brain scans will be compared with results of S100B dosage.
