[MRI of closed head injury].

The superiority of MR imaging to demonstrate the presence of intra- or extra-axial hemorrhage or edematous lesions, including axonal injuries, following closed head trauma has been proven over the last 15 years. CT remains the initial imaging modality in the evaluation of these patients because it is easier to obtain and allows detection of lesions requiring immediate surgical management. However, MRI should replace CT in patients with moderate to mild trauma in order to better precise the extent and degree of injuries, especially in a context of litigation. MRI could also be used following CT to further assess patients following severe trauma for prognosis purposes and better classification of traumatic injuries as well as therapeutic management.