Head injuries. Place of radiologic 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 a nd intracerebral lesions. The former require rapid diagnosis and therapy an d the latter determine management in an intensive therapy, unit and outcome . Standard X-rays are obsolete. The CT, rapidly performed, is the most rele vant imaging procedure for surgical lesions. Cortical contusions and diffus e axonal injuries are underestimated by CT and best depicted by MRI. Only l ate MRI has a strong correlation with neuropsychological outcome. In terms of pronosis, MRI needs to be evaluated. The indications include: a) unstabl e neurological status: CT; b) moderate head injury: CT may help to decide h ospital admission; c) severe head injury: initial CT may be followed by MRI ; d) long-term consequences: MRI. Special Indications: a) angio-MRI: suspic ion of vascular lesion; b) CT with thin slices and bone window: depressed s kull fracture; c) teleradiology (image transfer): to decide a patient trans port from a peripheral hospital to a neurosurgical centre. In conclusion, C T remains the first-line examination to detect immediately life-threatening lesions. MRI is the examination of choice for full assessment of brain les ions. (C) 2000 Editions scientifiques et medicales Elsevier SAS.