[Brain MRI in the assessment of severe head trauma]

Magnetic Resonance Imaging (MRI) in patients with severe head injury allows comprehensive assessment of the primary insult thus providing an indicator of possible long term prognosis. Morphological images can now be coupled to metabolic analysis, thus providing a more precise assessment of brain lesions and opening a new exciting field of research. Before embarking on such an exercise, the clinician must be familiar with the advantages and pitfalls of each MRI sequence, and must appreciate the risks associated with the transportation of the sedated and ventilated patient from ICU to the MRI suite. For practical reasons and because of the high risk of uncontrolled surges in intracranial pressure during the exam, MRI is usually performed during the third week following injury, at the time when brain edema is subsiding.