Author Of 1 Presentation
P0612 - New cortical lesions are rare in an MS cohort with stable white matter lesions: a 7T multicontrast longitudinal study (ID 1866)
Abstract
Background
Cortical lesions are common and often extensive in MS, and have been associated with worse disability and progressive disease. There is limited evidence that cortical lesions continue to form in progressive phases of the disease, when new white matter lesion formation is minimal, perhaps offering an explanation for worsening disability in progressive MS.
Objectives
We longitudinally characterized cortical lesions in an MS cohort with stable white matter lesion burden in the year prior to enrollment to determine whether new cortical lesions are more frequent in people with worsening disability.
Methods
45 adults with MS (30 relapsing remitting (RR), 13 secondary progressive (SP), and 2 primary progressive (PP)), underwent 7T brain MRI (T2*w and MP2RAGE, each with 0.5mm isometric resolution), 3T brain and spine MRI, and clinical evaluation annually for 1 year. Cortical lesions were segmented manually on 7T images and categorized as leukocortical, intracortical, or subpial. White matter and spinal cord lesion burden were also determined.
Results
At baseline, 93% of individuals (42/45) had at least 1 cortical lesion. Median cortical lesion number was higher in progressive MS (median 55, interquartile range (IQR) 96, range 2–177) than RRMS (median 15, IQR 21, range 0–108; p<0.01). Cortical lesion volume correlated with physical and cognitive measures of disability. There was only a weak correlation between subpial and white matter lesion volume (r=0.35, p<0.05). During 1 year of follow-up, 6 people (4 RR, 2 SP) developed 1 new cortical lesion each. 4 of the 6 new cortical lesions were leukocortical, 1 was intracortical, and 1 was subpial. 5 people developed new white matter lesions, none of whom developed a new cortical lesion. In 2 people, we observed white matter lesions expand into the cortex. 3/6 people with new cortical lesions were on highly effective disease-modifying therapy during the follow up period. There was no difference in new cortical lesion or new white matter lesion number in people with stable vs worsening disability.
Conclusions
Using sensitive 7T MRI techniques, cortical lesions are detected in almost all MS cases. Cortical lesions are associated with worse and progressive disability and may form independently from white matter lesions. New cortical lesions appear to form infrequently in people with stable white matter lesions, however current disease-modifying therapies may not be completely effective at stopping cortical lesion formation.