Brainstem injury diagnosed by MRI

Introduction and objectives:CT-scan allows emergency surgical evaluation of head injury lesions, but does not offer a comprehensive diagnosis of the resulting brain injuries. Magnetic Resonance Imaging (MRI) can complete the evaluation of head injury, particularly in the brain stem. We attempted to estimate the frequency of traumatic primary brain stem injuries

Material and methods:Thirty patients with moderate or severe head injury (GCS < or = 13) underwent a MRI study during the first two weeks after trauma. In order to exclude old patients with previous ischemic lesions unrelated to the head trauma, only young patients (16-40 years-old) were included. Patients with cranial surgery were also eliminated from the study. Based on previous studies, the FLAIR (8000/120/T. Inversion 2200mseg) sequence was selected.

Results:Brain stem injuries were detected in 26.6% of the patients; this was confirmed by two independent radiologists. Six patients had hyperintense lesions compatible with diffuse axonal damage, and two others showed hemorrhagic lesions. These findings were directly related to a specific neurological deficit in four patients; while in the remaining, unspecific consciousness disturbances were noted.

Conclusions:We believe that the FLAIR sequence demonstrate a type of traumatic brain stem injury (probably corresponding to diffuse axonal injury) that is more frequent and less severe in terms of prognosis than those classically described in previous CT scan studies.