Article
Assessment and time-course of post-concussive metabolic cerebral changes using high field magnetic resonance spectroscopy: a clinical study
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Published: | May 30, 2008 |
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Objective: The aim of the study is to study the value of N-Acetylaspartate (NAA) as a neuron specific metabolite and its changes with high field proton magnetic resonance spectroscopy (MRS) soon after cerebral concussion and weeks later.
8 patients with a mean age of 28 were admitted to the neurosurgical ER within 12 hrs after concussion. The accepted definition of concussion was transient amnesia, loss of consciousness, headache, dizziness, fatigue or confusion. GCS 14-15, age 16-70 and absence of neurological deficit were the other inclusion criteria.
Exclusion criteria included a brain CT positive for traumatic brain lesions and the presence of “risk factors”. All patients were evaluated with magnetic resonance imaging (Siemens Allegra,3.0T, Erlangen, Germany); the slice was placed on the fronto parietal white mater. The following parameters were evaluated: ratio NAA/Cr, NAA/Cho, presence of lactate, lipids. NAA/Cr was chosen as the reference ratio. In normal appearing left and right centrum semiovale, anterior mesial region (grey-white matter junction) and posterior mesial region. Statistical data analysis was performed with one-sample t-test (p<0.05).
We found a significant (p<0.05) lowering of NAA values in 4 patients (50%) studied within 24-48 hours after trauma. In 3 cases, the NAA values remained significantly lower even at the control MRS within 26-29 days later.
NAA is considered a marker of neuronal damage. Our results also show evidence of metabolic changes following postconcussive injury with normal findings in conventional MR imaging. Despite the smallness of data, cerebral metabolic alterations continued to prevail although the clinical symptoms usually normalized within 1-2 weeks. These data support the hypothesis of the use of MRS as a possible tool for monitoring the full recovery of brain metabolic function in a clinical setting.