Chronic active inflammation of the brain is thought to contribute to progressive multiple sclerosis (MS) by accelerating the loss of myelin, the fatty substance that protects nerve fibers and helps send electric signals. A recently discovered biomarker of this chronic inflammation is the presence of paramagnetic rim lesions (PRLs)—small rim-like areas in the brain with persistent inflammation. These PRLs, and the associated demyelination, are linked to increased neurodegeneration and disability in people with MS.

Until now, only a few studies explored the longitudinal evolution of PRLs as a biomarker of disease progression. One problem was that it was difficult to tell from magnetic resonance images whether a PRL will persist. BNAC researchers Prof. Ferdinand Schweser and Ph.D. student Thomas Jochmann recently invented an MRI technique that is sensitive to the chemical composition and the magnetic microstructure in tissue. Together with BNAC researcher Jack Reeves, MD, Ph. D. student at the University at Buffalo, they applied the novel technique to study particularly minute tissue changes in protein and myelin in PRLs over five yeas in 116 people with MS. The novel approach used manual and automated rating methods to gauge signal intensity on novel on novel nondipolar frequency maps, an output of the new technique, revealing the interaction of molecular electromagnetic fields. The researchers found that they could predict PRL disappearance at the five-year follow-up using this method, which they referred to as “Deepole” (from “dipolar”). Age and reduced PRL volume also were associated with PRL disappearance rates, based on changes in the intensity of the Deepole signal over the follow-up.

The ability to classify PRLs based on their long-term evolution could help inform clinicians in determining type of inflammation as a biomarker for MS disability progression at the earlier disease stage.

This work was presented at the ACTRIMS Forum on Feb. 24, 2023.