[Head and brain injuries. Place of imaging]

This article considers the various mechanisms of brain injury and specifies the most efficient radiologic technique for assessing patients, depending on clinical presentation. The brain injuries include either extracerebral and intracerebral lesions. The former require rapid diagnosis and therapy and the latter determine management in an intensive therapy, unit and outcome. Standard X-rays are obsolete. The CT, rapidly performed, is the most relevant imaging procedure for surgical lesions. Cortical contusions and diffuse axonal injuries are underestimated by CT and best depicted by MRI. Only late MRI has a strong correlation with neuropsychological outcome. In terms of prognosis, MRI needs to be evaluated. The indications include: a) unstable neurological status: CT; b) moderate head injury: CT may help to decide hospital admission; c) severe head injury: initial CT may be followed by MRI; d) long-term consequences: MRI. Special Indications: a) angio-MRI: suspicion of vascular lesion; b) CT with thin slices and bone window: depressed skull fracture; c) teleradiology (image transfer): to decide a patient transport from a peripheral hospital to a neurosurgical centre. In conclusion, CT remains the first-line examination to detect immediately life-threatening lesions. MRI is the examination of choice for full assessment of brain lesions.