Chronic Active Lesions Associated With Poorer Outcomes in Multiple Sclerosis

Published on: 

Chronic active lesions, which are identified by their darkened outer rims, are associated with more aggressive multiple sclerosis and earlier disability, according to new research from the National Institute of Health.

Chronic active lesions are not only common in patients with multiple sclerosis (MS) but are also associated with more aggressive and disabling forms of the disease, according to researchers from the National Institutes of Health (NIH).

Only recently have researchers been able to use magnetic resonance imaging (MRI) and positron emission tomography scans to see smoldering inflammation in MS, and the research published in JAMA Neurology showed that these lesions are a negative prognostic marker in MS. Damaging, chronic active lesions are identified on MRI by their darkened outer rims.

“We found that it is possible to use brain scans to detect which patients are highly susceptible to the more aggressive forms of multiple sclerosis,” Daniel S. Reich, MD, PhD, senior investigator at the NIH’s National Institute of Neurological Disorders and Stroke and the senior author of the paper, said in a statement. “The more chronic active lesions a patient has the greater the chances they will experience this type of MS.”


In a cohort of 209 patients, more than half (56%) had at least 1 rim lesion, regardless of whether they were being treated with disease-modifying therapy. The researchers also found that patients with 4 or more rim lesions had motor and cognitive disability at an earlier age than patients with fewer or no rim lesions.

In a longitudinal study of chronic MS lesions with and without rims in 23 patients with MS who had yearly MRI scans for at least 10 years, the researchers found lesions with rims were bigger than those without at the time of last MRI, but they weren’t at baseline. The mean compound annual growth rate was 2.5% per year (expansion) for lesions with rims and —4.7% per year (shrinkage) for lesions without rims.

Future studies can examine why some individuals develop chronic active lesions and others do not, the authors noted.

“Our results support the idea that chronic active lesions are very damaging to the brain,” said Reich. “We need to attack these lesions as early as possible. The fact that these lesions are present in patients who are receiving anti-inflammatory drugs that quiet the body’s immune system also suggests that the field of MS research may want to focus on new treatments that target the brain’s unique immune system—especially a type of brain cell called microglia.”


Absinta M, Sati P, Masuzzo F, et al. Association of chronic active multiple sclerosis lesions with disability in vivo [published online August 12, 2019]. JAMA Neurol. doi: 10.1001/jamaneurol.2019.2399.