Researchers have discovered a new advanced magnetic resonance imaging (MRI) biomarker for identifying remyelinated lesions in multiple sclerosis (MS) and published their findings in Annals of Neurology.
Studies have demonstrated that patients with MS can exhibit different types of lesions characterized by the extent of myelin/axon damage and repair, as well as iron content. There are various proposed causes for the heterogeneity of remyelination, such as age, lesion location, cellular composition, and the course of the disease. The heterogeneity of myelin/axon damage and repair presents a challenge for clinicians in identifying specific in vivo chronic lesion types.
“MS lesions undergo multiple waves of de- and re-myelination, which lead to the final lesion phenotype of either demyelinated, partly remyelinated, or fully remyelinated (shadow plaques),” the authors of the study wrote.
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Quantitative susceptibility mapping (QSM) reveals the magnetic susceptibility within tissues and provides clinicians with a system of measurement that is sensitive to iron accumulation and myelin content in the brain. The authors of this study used QSM to study lesions in patients with MS.
The research team enrolled 115 patients—76 with relapsing-remitting MS and 39 with progressive MS. MRI was performed in the participants, followed by the identification and segmentation of lesions. Postmortem studies were conducted in 3 patients with MS.
The researchers managed to identify 5 QSM lesion types in vivo among patients with MS. In addition, they managed to quantify their relative axon and myelin contents. The key finding in this study is that QSM maps may be suitable for identifying fully remyelinated lesions in vivo in patients with MS; this allows clinicians to partially evaluate the repair capacity of MS therapies (both existing and novel) via a single scan.
“In summary, our findings show that QSM maps permit the classification of MS lesions with various extents of damage and repair to myelin and axons,” the authors of the study concluded.
Rahmanzadeh R, Galbusera R, Lu PJ, et al. A new advanced MRI biomarker for remyelinated lesions in multiple sclerosis. Ann Neurol. Published online June 17, 2022. doi:10.1002/ana.26441