Emergency CT head scans in traumatic and atraumatic conditions.

Head trauma and suspected subarachnoid hematoma are encountered frequently by the emergency physician. There are few data to indicate which patients need immediate computerized tomography (CT) and what is the role of lumbar puncture in subarachnoid hemorrhage. Reviewed are the classification of head trauma and subarachnoid hemorrhage, indications for immediate CT, persons needing contrast enhancement, and the use of CT in comparison to skull films, digital subtraction angiography, and magnetic resonance.