Classification of severe head injury based on magnetic resonance imaging

Object. In 1991 a new pioneering classification of severe head injuries had been proposed, based on CT findings. Unfortunately CT cannot visualise all lesions. Especially brain stem lesions may escape CT in spite of modern eq uipment, but may be demonstrated by MRI. The high incidence of CT negative but MRI positive posttraumatic brain stem lesions has already been demonstr ated in a limited number of cases. A statistically significant evaluation i s still missing. Therefore we have investigated a series of 102 comatose pa tients, in whom a statistical evaluation of MRI findings and their correlat ion with mortality and outcome of survivors was possible. Patients and Methods. MRI was obtained within 8 days after servere head inj ury in 102 patients with a minimum of 24 hours of coma. The location of the lesions, identified by a neuroradiologist who was unaware of the clinical findings, was correlated with mortality, outcome of surviors and duration o f coma. The correlation was analysed statistically. Follow-up ranged from 3 months to 3 years with a mean of 22 months. Four groups of lesions gave significant correlations: Grade I lesions were lesions of the hemispheres only; Grade II lesions were unilateral lesions of the brain stem at any level wit h or without supratentorial lesions; Grade III lesions were bilateral lesions of the mesencephalon with or witho ut supratentorial lesions. Grade IV lesions were bilateral lesion of the pens with or without any of t he foregoing lesions of lesser grades. Results. Mortality increased from 14% in grade I lesions to 100% in grade I V lesions. The Glasgow outcome score differed significantly for each grade. The mean duration of coma increased from 3 days in grade I patients to 13 days in grade III. The correlations between the lesions grade I to IV with mortality, outcome of survivors and duration of coma were highly significan t. Conclusion. The statistically significant correlations between the 4 groups of severe head injury patients, as identified by MRI, with mortality and o utcome of survivors justify a new classification based on early MRI finding s.