Brain stem lesions after head injury.

There is little knowledge on the morphology of the brain stem in survivors of head injury, as CT fails to shown brain stem lesions, and neuropathological data is only available from autopsies. As magnetic resonance imaging (MRI) sheds new light on morphological lesions of the brain, the authors investigated 100 patients with a severe head injury. MRI was performed in a prospective study within the first seven days after head injury while the patients were still in coma and on ventilation. Relating the location of the lesions as depicted by MRI with the initial CT scan and outcome, death appeared to be closely linked to the phenomenon of bilateral pontine lesions. The extent of supratentorial lesions had no bearing on survival at all in the absence of brain stem lesions. Altogether the brain stem was affected in 52%. Obviously the occurrence of bilateral upper pontine lesions is of highest predictive value for a fatal outcome. Severe destruction of supratentorial white matter as demonstrated by MRI is not related to increased mortality, as long as the brain stem is spared.