Multiple Sclerosis: The Role of Chronic Lesions

Multiple sclerosis (MS) causes increasing disability due to long-term inflammation in the brain and spinal cord. This ongoing inflammation, called smoldering neuroinflammation, is tough to treat with current medications. Chronic active white matter lesions are a big part of this problem. Initially, these lesions were only seen in autopsies. But now, we have advancements in brain imaging that allow us to see them in living patients. One type of lesion, called paramagnetic rim lesions (PRLs), shows up as a rim around the damaged area, made of cells containing iron. Another type, slowly expanding lesions, grows over time in a circular pattern. Recent studies suggest that people with these lesions might have a more severe form of MS. Because PRLs are specific to MS, they're now part of the diagnosis process. They could also help predict who will progress quickly. As we learn more about these lesions, we'll be able to understand MS better and develop new treatments. But first, we need to make sure the imaging techniques are reliable and easy to use.