Proton Magnetic Resonance Spectroscopy (¹H-MRS) Study of Early Traumatic Brain Injury in Rabbits

BACKGROUND The aim of this study was to investigate the relationship between dynamic changes of cerebral metabolism and degree of trauma in rabbit models of traumatic brain injury (TBI) by using proton magnetic resonance spectroscopy (¹H-MRS). MATERIAL AND METHODS Thirty-five Chinese rabbits were randomly divided into control, mild, moderate, and severe TBI groups. ¹H-MRS was performed 1, 6, and 24 h after trauma. The concentrations of NAA, Cr, Cho, and Lac, and NAA/Cr and Cho/Cr ratios in each group, were estimated. RESULTS Compared with the control group, NAA, Cr, and Cho peaks were decreased. NAA/Cr ratio in the ipsilateral cortex was reduced in the mild, moderate, and severe TBI groups by 12.79%, 28.90%, and 45.02% at 1 h, and decreased by 25.11%, 39.81%, and 51.18% at 24 h after trauma, respectively. There were significant negative correlations between NAA/Cr ratio and severity of attack. Cho/Cr ratio in the ipsilateral cortex in the mild, moderate, and severe TBI groups was decreased by 10.86%, 15.94%, and 34.78% at 1 h, and reduced by 24.63%, 29.71%, and 42.02% at 6 h, respectively, and increased slightly at 24 h after trauma. The Lac/Cr ratio in the injured side was increased, most obviously in the severe TBI group. NAA/Cr ratio and Cho/Cr ratio showed significant changes between each group at the same time point. CONCLUSIONS ¹H-MRS can noninvasively and dynamically detect metabolic changes in early TBI. The NAA/Cr ratio is most sensitive, and has positive significance for early diagnosis and prognosis assessment of TBI.