This study group from New York looked at diffuse grey matter (GM) and white matter (WM) metabolic abnormalities in 18 people with early RRMS, with a mean EDSS of 1.3 on immunomodulatory medication. They were scanned every six months for three years with T1-weighted and T2-weighted MRI and proton MR spectroscopy at 3T. They used H-MRSI for the quantification of N-acetylaspartate (NAA) for neuronal health, creatine (Cr) for glial cell density, choline (Cho) for membrane turnover, and myo-inositol (mI) for astrocyte status. Global absolute concentrations of NAA, Cho, and mI were obtained for all GM and WM in the 360cm volume of interest. Results showed that the average WM Cr, Cho and mI concentrations, over all time points, were 8%, 12% and 11% higher than controls. The WM NAA was 6% lower. WM glial abnormalities, consistent with glial breakdown and astrogliosis, are more pronounced than the axonal deficits attributed to dysfunction. There was no correlation between metabolic concentrations and EDSS, relapse rate, lesion volume or GM/WM/CSF fractions. The glial changes progressed, while the axons showed partial recovery, which is likely related to response to treatment.
Authors: Kirov II, Tal A, Babb JS
Source: Neurology. 2012 Nov 21. [Epub ahead of print]
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