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

Abstract

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 (r 5 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. Cognitive dysfunction is a common but frequently overlooked clinical manifestation of multiple sclerosis (MS). 1 Frequently affected cognitive domains include executive function, processing speed, and memory. 2 Cognitive impairment in MS deleteriously affects social and vocational activities, may result in unemployment, and appears to lead to an increased vulnerability to psychiatric illness. 3 Despite the impact of cognitive dysfunction in MS, our understanding of its pathophysiology is limited. Conclusions: Leukocortical (type I) and subpial (III-IV) CLs identified on 7T FLASH-T2Conventional and quantitative MRI have identified potential biomarkers and better defined the pathophysiology of cognitive dysfunction in MS. 4 To date, global rather than regional metrics of cortical atrophy and cortical lesion (CL) volume using double inversion recovery (DIR) sequences at 3 tesla (3T) better account for the variance seen in cognitive performance in MS-supplanting conventional white matter (WM) MRI metrics. 5,6 These findings are not entirely unexpected because MS neuropathology has highlighted the cortex as a major location of demyelination. 7 Although 3T DIR is an innovative improvement over conventional imaging

Ultra-High-Field MRI Visualization of Cortical Multiple Sclerosis Lesions with T2 and T2*: A Postmortem MRI and Histopathology Study

“…In turn, type I lesions and, to a lesser extent, type III-IV lesions had a relationship with cognitive performance. 27 At 3T, DIR detected 538% more intracortical lesions than T2WI and 152% more intracortical lesions than FLAIR. 18 This finding was supported by another study in which DIR detected 43% more cortical lesions than FLAIR.…”

FLAIR2: A Combination of FLAIR and T2 for Improved MS Lesion Detection

“…7 Focal GM lesions appear in the earliest stages of MS 8,9 and are associated with physical and cognitive disability. 10,11 Moreover, cortical lesion load was shown to be a predictor of progression of clinical disability during 5 years 12 and to improve predictions for the conversion from relapsing-remitting to secondary-progressive MS compared with assessing WM lesions alone. 13 Given the importance of cortical lesions in MS, there is great interest in their visualization.…”

Spring cleaning: time to rethink imaging research lines in MS?

“…In the context of the diagnostic workup, baseline detection of cortical (mostly leukocortical) lesions in clinically isolated syndrome (CIS) improves the accuracy of diagnosis [46]. Despite this, MRI has been only partially successful in detecting cortical demyelination even through the implementation of several MRI approaches, such as double inversion recovery (DIR) [47], phase-sensitive inversion recovery (PSIR) [48], and high-resolution T2*-weighted sequences [49, 50]. Some of the reasons for low cortical lesion contrast are the background higher T2 relaxation times of the cortex relative to white matter (unfortunately highest in the subpial cortical layers) as well as the partial volume effects of the adjacent cerebrospinal fluid (CSF).…”