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Updated: Oct 3, 2025
Magnetic Resonance Imaging of Multiple Sclerosis at 7.0 Tesla
Published on: February 19, 2021
Quantitative MRI findings indicate diffuse white matter damage in Susac Syndrome
P Johnson, J K Chan1, I M Vavasour2
1Department of Medicine (Neurology), University of British Columbia, Canada.
Background:
Susac Syndrome (SuS) is an autoimmune endotheliopathy impacting the brain, retina and cochlea that can clinically mimic multiple sclerosis (MS).
Objective:
To evaluate non-lesional white matter demyelination changes in SuS compared to MS and healthy controls (HC) using quantitative MRI.
Methods:
3T MRI including myelin water imaging and diffusion basis spectrum imaging were acquired for 7 SuS, 10 MS and 10 HC participants. Non-lesional white matter was analyzed in the corpus callosum (CC) and normal appearing white matter (NAWM). Groups were compared using ANCOVA with Tukey correction.
Results:
SuS CC myelin water fraction (mean 0.092) was lower than MS(0.11, p = 0.01) and HC(0.11, p = 0.04). Another myelin marker, radial diffusivity, was increased in SuS CC(0.27μm2/ms) compared to HC(0.21μm2/ms, p = 0.008) and MS(0.23μm2/ms, p = 0.05). Fractional anisotropy was lower in SuS CC(0.82) than HC(0.86, p = 0.04). Fiber fraction (reflecting axons) did not differ from HC or MS. In NAWM, radial diffusivity and apparent diffusion coefficient were significantly increased in SuS compared to HC(p < 0.001 for both measures) and MS(p = 0.003, p < 0.001 respectively).
Conclusions:
Our results provided evidence of myelin damage in SuS, particularly in the CC, and more extensive microstructural injury in NAWM, supporting the hypothesis that there are widespread microstructural changes in SuS syndrome including diffuse demyelination.
Insights
Susac syndrome shows significant myelin damage, especially in the corpus callosum, and widespread white matter injury. This supports diffuse demyelination in Susac syndrome (SuS).
Area of Science:
- Neuroimaging
- Autoimmune Diseases
- Neurology
Background:
- Susac syndrome (SuS) is an autoimmune endotheliopathy affecting the brain, retina, and cochlea.
- SuS can clinically mimic multiple sclerosis (MS).
Purpose of the Study:
- To evaluate non-lesional white matter demyelination in SuS compared to MS and healthy controls (HC).
- Utilize quantitative MRI techniques for precise assessment.
Main Methods:
- Acquired 3T MRI data including myelin water imaging and diffusion basis spectrum imaging.
- Analyzed non-lesional white matter in the corpus callosum (CC) and normal-appearing white matter (NAWM).
- Compared groups using ANCOVA with Tukey correction.
Main Results:
- SuS corpus callosum (CC) showed lower myelin water fraction and increased radial diffusivity compared to MS and HC.
- Fractional anisotropy was lower in SuS CC compared to HC.
- Normal-appearing white matter (NAWM) in SuS exhibited significantly increased radial diffusivity and apparent diffusion coefficient versus HC and MS.
Conclusions:
- Evidence of myelin damage in SuS, particularly in the CC.
- More extensive microstructural injury observed in NAWM in SuS patients.
- Findings support widespread microstructural changes and diffuse demyelination in Susac syndrome.
