Evaluation of traumatic brain injured patients in correlation with functional status by localized 1H-MR spectroscopy

Objective: To determine whether proton magnetic resonance spectroscopy (H-1-MRS) could be a useful tool for detecting microscopic diffuse axonal injury to evaluate the functional status of patients with traumatic brain injury (TBI). Design: A comparative study. Setting: An inpatient rehabilitation unit in Korea. Subjects: We examined eight adult patients who had severe TBI approximately five months before. Fourteen normal controls were employed for comparison. Main measures: Image-guided localized in vivo H-1-MRS was performed in the parietal white matter and occipital grey matter regions in brain in which no definite abnormalities in MR imaging were found at the time of H-1-MRS examination. We evaluated functional status for all patients with the Functional Independence Measure (FIM) on the same day as the H-1-MRS examination and compared the results. Results: In the parietal white matter, the [N-acetyl aspartate/creatine] ratios were significantly lower, and the [choline/creatine] and [myo-inositol/creatine] ratios were significantly higher than those of normal controls. Significant correlations of the [N-acetyl aspartate/creatine] and [myo-inositol/creatine] ratios in the parietal white matter with FIM scores were observed (p < 0.05). Conclusions: A spectral feature of the decreased [N-acetyl aspartate/creatine] and increased [choline/creatine] and [myo-inositol/creatine] ratios in parietal white matter may be a marker for diffuse axonal injury in patients with TBI and has a significant correlation with the functional status of the patients. Localized H-1-MRS has the potential to be used for detecting diffuse axonal injury in vivo in TBI patients, which can be used to guide evaluation of the functional status of TBI patients receiving rehabilitation.