Cortical lesions are known to affect cognitive and physical disability in multiple sclerosis (MS), and assessing such burden may help to better understand disease progression and treatment.
Daniel M. Harrison, MD, of the University of Maryland, and colleagues conducted an observational clinical imaging study to better understand the clinical relevance of measures of cortical lesion burden in MS using high-field MRI.
Thirty-six people with MS (30 with relapsing-remitting, six with secondary or primary-progressive) and 15 healthy controls participated in the imaging study, which used 7-Tesla MRI performed with 0.5-mm isotropic resolution magnetization-prepared rapid acquisition gradient echo (MPRAGE) and whole-brain, 3-dimensional, 1.0-mm isotropic resolution magnetization-prepared, fluid-attenuated inversion recovery (MRPFLAIR).
Lesions were classified as leukocortical, intracortical, or subpial. Physical disability was measured by the Expanded Disability Status Scale (EDSS) and cognitive disability was measured with the Minimal Assessment of Cognitive Function in MS battery. Brain structure volumes and white matter lesion volume were also reported.
Researchers reported that cortical lesions were found in 35 of 36 participants (97%), with a median of 16 lesions per person (range 0-99). Leukocortical lesion volume was found to correlate with white matter lesion volume (P=0.50; P=.003), but not with cortical volume. Subpial leasion volume inversely correlated with cortical volume (P=-0.36; P=.04) but not with white matter lesion volume. Total count and volume of cortical lesions (median) were significantly increased in participants with EDSS scores of 5.0 or more compared to those with scores less than 5.0 (count: 29 [11-99] vs 13 [0-51]; volume: 2.81 × 10−4 [1.30 × 10−4 to 7.90 × 10−4] vs 1.50 × 10−4 [0 to 1.01 × 10−3]) and in cognitively impaired participants compared to unimpaired participants (count: 21 [0-99] vs 13 [1-54]; volume: 3.51 × 10−4 [0 to 1.01 × 10−4] vs 1.19 × 10−4 [0 to 7.17 × 10−4]).
Cortical lesion volume correlated with EDSS scores more so than white matter lesion volume (P=0.59 vs 0.36). Increasing cortical lesion volume aligned with a 3-fold increase in odds of cognitive impairment (odds ratio [OR], 3.36; 95% CI, 1.07-10.59; P = .04) and a 14-fold increase in odds after adjustment for white matter lesion volume and atrophy (OR, 14.26; 95% CI, 1.06-192.37; P = .045).
Overall, leukocortical lesions had the greatest effect on cognition (OR for log [leukocortical lesion volume], 9.65; 95% CI, 1.70-54.59, P = .01), differing from subpial lesions. Assessing lesion burden may therefore provide a better understanding of MS disability and disease progression and may indicate target areas for treatment.
Cortical lesions (CLs) contribute to physical and cognitive disability in multiple sclerosis (MS). Accurate methods for visualization of CLs are necessary for future clinical studies and therapeutic trials in MS.
Daniel M. Harrison, MD, of the University of Maryland, and colleagues evaluated the clinical relevance of measures of CL burden derived from high-field magnetic resonance imaging (MRI) in MS.An observational clinical imaging study was conducted at an academic MS center. Participants included 36 individuals with MS (30 relapsing-remitting, 6 secondary or primary progressive) and 15 healthy individuals serving as controls. The study was conducted from March 10, 2010, to November 23, 2012, and analysis was performed from June 1, 2011, to September 30, 2014.