Surrogate MRI markers of disease progression in MS are becoming increasingly needed as we approach a new era of treatment. Disability scores have poor inter-rater reproducibility and often fail to detect the gradual neurodegeneration that occurs in primary progressive MS (PPMS). State-of-the-art MRI techniques may have the potential to quantify these subtle changes. In a cross-sectional exploratory study of 17 PPMS patients we compared the correlation with clinical measures and disease duration of the diffusion tensor imaging (DTI) metric functional anisotropy (FA), which is thought in-part to represent myelin integrity, and a novel MRI development known as multicomponent DESPOT. This specifically quantifies the T1 and T2 relaxation components of water within myelin to give a measure known as “myelin water fraction (MWF) ”. Our results show a negative correlation of FA with disease duration and expanded disability status scale (EDSS) score. The changes are widespread throughout the white matter (Abstract POI16 Figure 1). Interestingly MWF provides supplementary information and there is a statistically significant (p<0.05) correlation between poor cognitive function (scaled using the EDSS subsystem score) and a reduction in MWF within the frontal white matter. Such localised changes were not detected with DTI. We will discuss the relative merits of DTI and MWF, their reproducibility and plans for longitudinal validation studies as potential biomarkers.

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Abstract POI16 Figure 1

The red pixels show areas of significant negative correlation between increasingly severe cerebral EDSS subsystem score (i.e., increasingly severe cognitive deficit and a reduction in MWF).