Head computed tomography interpretation in trauma: a primer

Noncontrast computed tomography (CT) provides important diagnostic information for patients with traumatic brain injury. A systematic approach to image interpretation optimizes detection of pathologic air, fractures, hemorrhagic lesions, brain parenchymal injury, and abnormal cerebrospinal fluid spaces. Bone and brain windows should be reviewed to enhance injury detection. Findings of midline shift and mass effect should be noted as well as findings of increased intracranial pressure such as hydrocephalus and cerebral edema, because these may immediately influence management. Compared with CT, magnetic resonance imaging may provide more sensitive detection of diffuse axonal injury but has no proven improvement in clinical outcomes. This article discusses key CT interpretation skills and reviews important traumatic brain injuries that can be discerned on head CT. It focuses on imaging findings that may deserve immediate surgical intervention. In addition, the article reviews the limits of noncontrast CT and discusses some advanced imaging modalities that may reveal subtle injury patterns not seen with CT scan.