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Updated: May 2, 2026
Magnetic Resonance Imaging of Multiple Sclerosis at 7.0 Tesla
Published on: February 19, 2021
Investigation of outer cortical magnetisation transfer ratio abnormalities in multiple sclerosis clinical subgroups
Rebecca S Samson1, Manuel J Cardoso2, Nils Muhlert3
1NMR Research Unit, UCL Institute of Neurology, London, UK r.samson@ucl.ac.uk.
Background:
Pathological abnormalities including demyelination and neuronal loss are reported in the outer cortex in multiple sclerosis (MS).
Objective:
We investigated for in vivo evidence of outer cortical abnormalities by measuring the magnetisation transfer ratio (MTR) in MS patients of different subgroups.
Methods:
Forty-four relapsing-remitting (RR) (mean age 41.9 years, median Expanded Disability Status Scale (EDSS) 2.0), 25 secondary progressive (SP) (54.1 years, EDSS 6.5) and 19 primary progressive (PP) (53.1 years, EDSS 6.0) MS patients and 35 healthy control subjects (mean age 39.2 years) were studied. Three-dimensional (3D) 1×1×1mm(3) T1-weighted images and MTR data were acquired. The cortex was segmented, then subdivided into outer and inner bands, and MTR values were calculated for each band.
Results:
In a pairwise analysis, mean outer cortical MTR was lower than mean inner cortical MTR in all MS groups and controls (p<0.001). Compared with controls, outer cortical MTR was decreased in SPMS (p<0.001) and RRMS (p<0.01), but not PPMS. Outer cortical MTR was lower in SPMS than PPMS (p<0.01) and RRMS (p<0.01).
Conclusions:
Lower outer than inner cortical MTR in healthy controls may reflect differences in myelin content. The lowest outer cortical MTR was seen in SPMS and is consistent with more extensive outer cortical (including subpial) pathology, such as demyelination and neuronal loss, as observed in post-mortem studies of SPMS patients.
Insights
Outer cortical magnetisation transfer ratio (MTR) is reduced in multiple sclerosis (MS) patients, particularly in secondary progressive MS (SPMS). This finding suggests significant outer cortical pathology in SPMS, aligning with post-mortem observations.
Area of Science:
- Neuroimaging
- Neurology
- Radiology
Background:
- Multiple Sclerosis (MS) is characterized by demyelination and neuronal loss in the outer cortex.
- Investigating in vivo evidence of these cortical abnormalities is crucial for understanding MS progression.
Purpose of the Study:
- To investigate in vivo evidence of outer cortical abnormalities in multiple sclerosis (MS) patients.
- To measure the magnetisation transfer ratio (MTR) in different MS subgroups and healthy controls.
Main Methods:
- Studied 44 relapsing-remitting (RRMS), 25 secondary progressive (SPMS), 19 primary progressive (PPMS) MS patients, and 35 healthy controls.
- Acquired 3D T1-weighted images and MTR data, segmenting the cortex into outer and inner bands to calculate MTR values.
Main Results:
- Outer cortical MTR was lower than inner cortical MTR in all groups (p<0.001).
- SPMS and RRMS patients showed decreased outer cortical MTR compared to controls (p<0.001 and p<0.01, respectively).
- SPMS patients exhibited the lowest outer cortical MTR, significantly lower than PPMS and RRMS patients (p<0.01).
Conclusions:
- Lower outer cortical MTR in controls may indicate natural myelin content variations.
- The significantly reduced outer cortical MTR in SPMS suggests extensive subpial pathology, including demyelination and neuronal loss.
- Findings support the use of MTR to assess outer cortical pathology in MS, especially in SPMS.
