Author Of 2 Presentations
LB1197 - Myelin water imaging provides evidence for unique anatomical-functional relationships between myelin damage and different cognitive domains in MS (ID 2022)
Abstract
Background
Background: An improved understanding of the impact of demyelination on multiple sclerosis (MS) related cognitive impairment is crucial for targeting and testing therapies with the potential to slow cognitive decline. Demyelination can be assessed using myelin water imaging, a quantitative magnetic resonance imaging (MRI) technique that measures signal from water in the myelin bilayers, providing a specific measure of myelin (myelin water fraction, MWF).
Objectives
Objective: To determine if there is an anatomical-functional relationship between myelin content and location with cognitive performance.
Methods
Methods: 76 MS participants (mean (SD) age:50.4y(10.6y), 51F) underwent T2 relaxation imaging to calculate MWF maps and cognitive testing (Symbol Digit Modalities Test (SDMT); Selective Reminding Test (SRT); Controlled Oral Word Association Test (COWAT); Brief Visuospatial Memory Test-Revised (BVMT-R)). Nonparametric permutation testing with FSL Randomise was used to determine which white matter (WM) MWF voxels were associated with cognitive test performance for each test (p<0.01, after multiple comparisons correction), creating test-specific maps of associated WM areas. Pearson ́s correlations assessed relationships between mean MWF in the cognitive test-specific WM areas and respective test scores. MS patients were categorized into cognitively impaired, mildly impaired and cognitively preserved groups based on published norms. Kruskal Wallis ANOVA with post hoc pairwise comparisons investigated mean MWF differences between cognitive groups.
Results
Results: MWF in several WM areas was significantly associated with SDMT, SRT and BVMT-R scores but not the COWAT. All tests found voxels within the corona radiata, posterior thalamic radiation and parts of the corpus callosum significant. Unique WM areas were the inferior longitudinal fasciculus and anterior cingulum for SDMT and the retrolenticular part of the internal capsule for the BVMT-R. Mean MWF in the test-specific WM areas correlated significantly with performance on the SDMT (r=0.58, p= 4.11 x 10-8), SRT (r=0.56, p= 4.14 x 10-7) and BVMT-R (r=0.56, p= 1.0 x 10-6). Mean MWF in the test-specific WM areas was significantly lower in the cognitively impaired group relative to the cognitively preserved group (p<0.01).
Conclusions
Conclusions: There is an anatomical-functional relationship between myelin damage and cognitive performance in MS with unique WM patterns for different cognitive domains.
LB1271 - MRI insights into myelin damage in Susac Syndrome (ID 2169)
Abstract
Background
Susac’s Syndrome (SuS) is a rare autoimmune endotheliopathy of the brain, retina and cochlea that mimics multiple sclerosis (MS). Lesions presumed to be microinfarcts classically involve the corpus callosum (CC). While one brain biopsy reported demyelination, and MRI studies have shown reduced fractional anisotropy in the CC, the specific processes underlying SuS pathology are not yet clear. Myelin water imaging (MWI) and diffusion basis spectrum imaging (DBSI) can provide information about microstructural changes occurring in SuS. MWI provides a quantitative measurement of myelin, termed the myelin water fraction (MWF). DBSI yields various physiologically relevant metrics characterized by water diffusion: the apparent diffusion coefficient (ADC) which relates to overall tissue damage; fractional anisotropy (FA), which decreases with white matter (WM) damage; and radial diffusivity (RD) which increases with myelin loss.
Objectives
Determine in vivo WM microstructural changes in Susac Syndrome compared to MS and healthy controls (HC) using MWI and DBSI.
Methods
Participants included 7 SuS patients following the proposed European Susac Consortium diagnostic criteria (mean age 43.3y (30-78y), 6F), 10 MS patients (mean age 43.2y (26-70y), 9F) and 10 HC (MWI: 44y (27-64y), 9F, DBSI: 35.9y (22-47y), 5F). 3T MRI included MWI (48-echo 3D GRASE sequence), DBSI (9 b-values, 0-1500 s/mm2, 99 directions) and a 3DT1 for anatomical reference. The CC and global WM (non-lesional tissue) were segmented and registered using FSL and the JHU atlas. One-way ANOVA with Tukey correction compared CC and global WM between groups.
Results
CC: SuS MWF (0.09±0.01) was lower than MS (0.11±0.02, p=0.03) and trending lower than HC (0.11±0.02, p=0.07). SuS ADC (0.84 ± 0.08 x 10-3μm2/ms) was higher than MS (0.73±0.04 x 10-3μm2/ms, p<0.001) and controls (0.71±0.04 x 10-3μm2/ms, p<0.001). SuS FA (0.82±0.02) was lower than HC (0.86±0.02, p= 0.02). SuS RD was higher (0.27±0.03 x 10-3μm2/ms) than HC (0.21±0.01 x 10-3μm2/ms, p=0.004) and trending higher than MS (0.23±0.05 x 10-3μm2/ms, p=0.05).
Global WM: ADC and RD findings in the Global WM were similar to CC, i.e. ADC and RD were significantly higher in SuS compared to MS and HC (all p<=0.03). However, MWF and FA was insignificantly different between the groups.
Conclusions
We report the first use of MWI in SuS. Both CC and the global WM showed non-lesional myelin damage, which was more severe than MS.
Presenter Of 1 Presentation
LB1197 - Myelin water imaging provides evidence for unique anatomical-functional relationships between myelin damage and different cognitive domains in MS (ID 2022)
Abstract
Background
Background: An improved understanding of the impact of demyelination on multiple sclerosis (MS) related cognitive impairment is crucial for targeting and testing therapies with the potential to slow cognitive decline. Demyelination can be assessed using myelin water imaging, a quantitative magnetic resonance imaging (MRI) technique that measures signal from water in the myelin bilayers, providing a specific measure of myelin (myelin water fraction, MWF).
Objectives
Objective: To determine if there is an anatomical-functional relationship between myelin content and location with cognitive performance.
Methods
Methods: 76 MS participants (mean (SD) age:50.4y(10.6y), 51F) underwent T2 relaxation imaging to calculate MWF maps and cognitive testing (Symbol Digit Modalities Test (SDMT); Selective Reminding Test (SRT); Controlled Oral Word Association Test (COWAT); Brief Visuospatial Memory Test-Revised (BVMT-R)). Nonparametric permutation testing with FSL Randomise was used to determine which white matter (WM) MWF voxels were associated with cognitive test performance for each test (p<0.01, after multiple comparisons correction), creating test-specific maps of associated WM areas. Pearson ́s correlations assessed relationships between mean MWF in the cognitive test-specific WM areas and respective test scores. MS patients were categorized into cognitively impaired, mildly impaired and cognitively preserved groups based on published norms. Kruskal Wallis ANOVA with post hoc pairwise comparisons investigated mean MWF differences between cognitive groups.
Results
Results: MWF in several WM areas was significantly associated with SDMT, SRT and BVMT-R scores but not the COWAT. All tests found voxels within the corona radiata, posterior thalamic radiation and parts of the corpus callosum significant. Unique WM areas were the inferior longitudinal fasciculus and anterior cingulum for SDMT and the retrolenticular part of the internal capsule for the BVMT-R. Mean MWF in the test-specific WM areas correlated significantly with performance on the SDMT (r=0.58, p= 4.11 x 10-8), SRT (r=0.56, p= 4.14 x 10-7) and BVMT-R (r=0.56, p= 1.0 x 10-6). Mean MWF in the test-specific WM areas was significantly lower in the cognitively impaired group relative to the cognitively preserved group (p<0.01).
Conclusions
Conclusions: There is an anatomical-functional relationship between myelin damage and cognitive performance in MS with unique WM patterns for different cognitive domains.