Detection of demyelination in multiple sclerosis by analysis of T 2 * relaxation at 7 T

摘要

Multiple sclerosis (MS) is a relatively common cause of inflammatory demyelinating lesions of the central nervous system. In an attempt to detect and characterize ongoing demyelination in MS patient brains, we used a novel magnetic resonance imaging (MRI) technique, involving the fitting of a three-component model to the T 2 * relaxation behavior at high-field (7?T). This model allowed estimation of the amount of myelin water (and thus indirectly myelin content), axonal water, and interstitial water. In this study, 25 relapsing–remitting MS patients underwent a 7?T MRI from which 12 gadolinium-enhancing lesions, 61 non-enhancing lesions, and their corresponding contralateral normal appearing white matter (NAWM) regions were analyzed. In both enhancing and non-enhancing lesions, the amplitude of myelin water was significantly decreased, and interstitial and axonal water were increased relative to the contralateral NAWM. Longer relaxation time T 2 * of interstitial and axonal water, and lower frequency shift of axonal water, were also observed in both enhancing and non-enhancing lesions when compared to the contralateral NAWM. No significant difference was found between enhancing lesions and non-enhancing lesions. These findings suggest that the fitting of a three-component model to the T 2 * decay curve in MS lesions may help to quantify myelin loss. Highlights ? We investigated the demyelination effects on T 2 * relaxation in a clinical MS cohort at 7?T. ? 3-Component model of white matter is reproducible. ? 3-Component model was demonstrated the feasibility to detect and potentially discriminate demyelination in MS. ? The analysis of T 2 * relaxation may help to understand myelin pathology in MS.