LESION VOLUME, INJURY SEVERITY, AND THALAMIC INTEGRITY FOLLOWING HEAD-INJURY

Magnetic resonance (MR) scans of 63 traumatic brain injury (TBI) patie nts were analyzed to examine the relationship between injury severity, lesion volume (nonthalamic cortical/subcortical lesions), ventricle-t o-brain ratio (VBR), and thalamic volume, For comparison, 33 normal co ntrol subjects were used, Patients with visible nonthalamic structural lesions showed significantly smaller thalamic volumes than patients w ithout visible lesions or control subjects. Results also indicated tha t patients with visible lesions had significantly more severe injuries than patients without lesions, Patients with moderate-severe injuries had significantly smaller thalamic volumes and greater VBRs than pati ents with mild-moderate injuries. Although several variables related t o thalamic volume, the presence of nonthalamic lesions was sufficient to result in smaller thalamic volume. Decreased thalamic volume follow ing head injury suggests that subcortical brain structures may be susc eptible to transneuronal degeneration following cortical lesions, and that this can be detected by in vivo MR-based volumetric analysis.