Proton MR spectroscopic findings correspond to neuropsychological functionin traumatic brain injury

BACKGROUND AND PURPOSE: Traumatic brain injury (TBI) causes substantial irr eversible damage to neurons. Our aim was to investigate whether proton MR s pectroscopic measures of diffuse cellular integrity were related to neurops ychological dysfunction after TBI, METHODS: Twelve patients with TBI (mean, 53 +/- 23 days postinjury) and 14 control subjects were included in the study using paired MR spectroscopy an d neuropsychological assessment. N-acetylaspartate (NAA), creatine, and cho line were measured in normal-appearing occipitoparietal white and occipital gray matter using short-echo quantitative spectroscopy. A composite measur e of neuropsychological function was calculated from z-scored individual te sts probing the major functional domains commonly impaired after head traum a. RESULTS: Patients with TBI displayed reduced NAA in white matter and elevat ed choline in gray matter, suggestive of neuronal injury and inflammation, respectively. NAA and creatine in white and gray matter were significantly associated with composite neuropsychological function and many individual n europsychological tests. Gray matter choline, although abnormal, was not re lated to neuropsychological function, CONCLUSION: The concordance between neurometabolic levels and behavioral fu nction supports the hypothesis that diffuse axonal injury is an important c ontributor to brain dysfunction after TBI.