MRI lesion volume heterogeneity in primary progressive MS in relation with axonal damage and brain atrophy.

ABSTRACT

OBJECTIVES: To investigate whether axonal damage in primary progressive (PP) multiple sclerosis (MS), as measured by proton magnetic resonance spectroscopy (HMRS) imaging and brain atrophy, is a function of T2 weighted brain lesion volume. METHODS: 34 PP MS patients were divided into two categories low (<3 cm(3), n = 18) or high (>or=3 cm(3), n = 16) T2 lesion load (LL). An Index of Brain Atrophy (IBA) was calculated and HMRS metabolite ratios were derived from a central brain area centred at the corpus callosum. RESULTS: Patient groups did not differ with regard to clinical characteristics and showed lower mean IBA and mean N-acetylaspartatecreatinine (NAACr) ratios compared to healthy controls. CONCLUSION: PP patients with low and high brain T2LL have detectable brain atrophy and NAACr reduction compared to healthy controls. In PP MS, T2 lesions alone are insufficient to explain the presence of brain atrophy and decrease in NAACr.