Contribution of cortical lesion subtypes at 7T MRI to physical and cognitive performance in MS

Objectives: Evaluate cross-sectionally the contribution of focal cortical lesion (CL) subtypes at ultra-high-field MRI and traditional MRI metrics of brain damage to neurologic disability and cognitive performance in a heterogeneous multiple sclerosis (MS) cohort. Methods: Thirty-four patients with early or established disease including clinically isolated syndrome, relapsing-remitting MS, and secondary progressive MS were scanned on a human 7-tesla (7T) (Siemens) scanner to acquire fast low-angle shot (FLASH) T2*-weighted images for characterization of white matter and deep gray matter lesion volume, and CL types. Patients also underwent anatomical 3T MRI for cortical thickness estimation, and neuropsychological testing within 1 week of the 7T scan. Twenty-seven patient scans were acceptable for further analysis. Neurologic disability was measured using the Expanded Disability Status Scale. Results: Type III-IV CLs had the strongest relationship to physical disability (rho = 0.670, p < 0.0001). White matter lesion volume and type I CLs are each significantly associated with 6 of 11 neuropsychological test variables. Type III-IV CLs significantly correlate with 4 of 11 neuropsychological test variables whereas type II CLs, deep gray matter lesion volume, and cortical thickness metrics are less frequently associated with cognitive performance. Conclusions: Leukocortical (type I) and subpial (III-IV) CLs identified on 7T FLASH-T2* sequences are potential cortical biomarkers of cognitive and neurologic status in MS.