For decades, clinicians treating multiple sclerosis have interpreted the appearance of new or expanding brain lesions on MRI scans as a sign that a patient's disease is getting worse. Now, after conducting both a five-year study, and a 10-year study, MS researchers in the Jacobs School of Medicine and Biomedical Sciences at University at Buffalo are finding that it may be the atrophy or disappearance of these lesions into cerebrospinal fluid that is a better indicator of who will develop disability.

Brain lesions in general are a sign of damage to the brain, such as physical trauma, a stroke, normal aging, or chronic disease. People with MS receive MRI scans as part of their routine care so doctors can track the appearance of new lesions and the enlargement of existing ones, typically seen as indicators of disease progression. The researchers noted that according to this premise, the loss of brain lesions could inadvertently be seen as a sign that the patient's condition is improving. 

In order to focus specifically on the disappearance of lesions that likely indicate pathological change like atrophy, not beneficial change, like resolution or remyelination, the researchers looked exclusively at lesions seen on previous scans that were later replaced by cerebrospinal fluid. The researchers looked specifically at the rate of brain lesion loss because of atrophy compared to accumulation of lesion volume seen both at baseline and follow-up. They found that the amount of lesion volume that atrophied was the only significant lesion parameter that correlated with clinical disability as measured by the Expanded Disability Status Scale.

Researchers didn't find a link between people who developed more or larger lesions and developed increased disability, but they did find that atrophy of lesion volume predicted the development of more physical disability. While patients with relapsing remitting MS showed the highest amount of new lesions during the study, patients with progressive MS had the most accelerated volume of brain lesion atrophy. The researchers said this indicates that this new imaging biomarker could be particularly important in transitional phases between relapsing and progressive MS subtypes.

Another important finding of the studies is that atrophied brain lesions were shown to be a more robust predictor of disability progression than the development of whole brain atrophy itself, the most accepted biomarker of neurodegeneration in MS.

The five-year study was published in the Journal of Neuroimaging. The findings from the 10-year study were presented at the annual meeting of the American Academy of Neurology in Los Angeles in April.