The development of scars, or lesions, in the brain’s cortical gray matter is a powerful predictor of neurological disability for people with multiple sclerosis (MS), according to a recently published study (Treaba CA et al. Longitudinal Characterization of Cortical Lesion Development and Evolution in Multiple Sclerosis with 7.0-T MRI. Radiology. 2019 Apr 9:. doi: 10.1148/radiol.2019181719). The findings suggest a role for ultra-high-field-strength MRI in evaluating the progression of MS.
MS is a disease in which the body’s immune system attacks the protective covering surrounding the nerves of the central nervous system. Recent research has shown that cortical lesions, or lesions in the gray matter of the outer layer of the brain, develop early in the course of the disease. These lesions are not easy to see with conventional-strength MRI. In the new study, researchers tracked MS patients using a 7-Tesla MRI scanner to determine if the lesions are correlated with neurological disability and disease progression. “In this study, we wanted to track the evolution of these lesions and better understand where in the cortex these lesions develop more frequently.”
The researchers followed 20 relapsing-remitting and 13 secondary-progressive MS patients over time, along with 10 age-matched healthy controls. (Relapsing-remitting is the type of MS in which the symptoms sometimes improve and sometimes worsen, while secondary-progressive is characterized by more significant disability).
Twenty-five of the MS patients, or 80 percent, developed new cortical lesions, and the 7T MRI detected them more frequently compared to previous studies at lower-field 3T MRI strength. On average, the number of lesions that developed in the cortical region was more than twice the number that developed in the white matter of the brain. The total volume of cortical lesions was a predictor of neurological disability at both baseline and follow-up assessment.
“The 7T brain scans showed that the cortical sulci are the regions where most of these lesions develop,” Dr. Mainero said. “We also found that these lesions can predict disability progression more than white matter lesions, which are the typical lesions of MS we’ve been studying for years.”
While the reasons for the accumulation of lesions in the sulci are not definitively known, researchers note that the flow of cerebrospinal fluid is likely to be restricted there, which might make the sulci more vulnerable to inflammatory responses.
The results suggest that assessment of cortical lesions should represent a main component in the evaluation of progression of disease burden in MS,
“This can have a very powerful impact on how we monitor patients with MS,” said Dr C Mainero, lead author of the study, “We can also use this tool to see how potential treatments can affect the development and evolution of cortical lesions.”