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Updated: Jun 14, 2025
Magnetic Resonance Imaging of Multiple Sclerosis at 7.0 Tesla
Published on: February 19, 2021
Longitudinal Multiparametric Quantitative MRI Evaluation of Acute and Chronic Multiple Sclerosis Paramagnetic Rim
Ahmed M Elkady1,2,3, Colm Elliott3, Dumitru Fetco1,2,3
1McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada.
Background:
Multiple sclerosis (MS) paramagnetic rim lesions (PRLs) are markers of chronic active biology and exhibit complex iron and myelin changes that may complicate quantification when using conventional MRI approaches.
Purpose:
To conduct a multiparametric MRI analysis of PRLs.
Study Type:
Retrospective/longitudinal.
Subjects:
Ninety-five progressive MS subjects with at least one persistent PRL who were enrolled in the CONSONANCE trial.
Field Strength/Sequence:
3-T/Susceptibility-weighted, T1-weighted, T2-weighted, and fluid-attenuated inversion recovery.
Assessment:
Acute/chronic PRLs and non-PRLs were measured at screening, 24, 48, and 96 weeks using quantitative magnetic susceptibility (QS), R2*, and standardized T1w/T2w ratio (sT1w/T2w). PRL analyses were performed for whole lesion, core, and rim. The correlations between PRL core and rim sT1w/T2w, QS, and R2* were assessed.
Statistical Tests:
Linear mixed models. A P-value <0.05 was considered significant.
Results:
There was a significant decrease in sT1w/T2w (-0.24 ± -5.3 × 10-3) and R2* (-3.6 ± 2.2 Hz) but a significant increase in QS (+21 ± 1.3 ppb) using whole-lesion analysis of chronic PRLs compared to non-PRLs at screening. Tissue damage accumulated at the 96-week time point was more evident in acute/chronic PRLs compared to acute/chronic non-PRLs (ΔsT1w/T2w = -0.21/-0.24 ± 0.033/0.0053; ΔR2* = -4.4/-3.6 ± 1.4/2.2 Hz). New, acute PRL sT1w/T2w significantly increased in lesion core (+4.3 × 10-3 ± 1.2 × 10-4) and rim (+5.6 × 10-3 ± 1.2 × 10-4) 24 weeks post lesion inception, suggestive of partial recovery. Chronic PRLs, contrastingly, showed significant decreases in sT1w/T2w over the initial 24 weeks for both core (-2.1 × 10-4 ± 2.0 × 10-5) and rim (-2.4 × 10-4 ± 2.0 × 10-5), indicative of irreversible tissue damage. Significant positive correlations between PRL core and rim sT1w/T2w (R2 = 0.53), R2* (R2 = 0.69) and QS (R2 = 0.52) were observed.
Data Conclusion:
Multiparametric assessment of PRLs has the potential to be a valuable tool for assessing complex iron and myelin changes in chronic active PRLs of progressive MS patients.
Level Of Evidence:
2 TECHNICAL EFFICACY: Stage 3.
Insights
Multiparametric MRI reveals distinct iron and myelin changes in multiple sclerosis (MS) paramagnetic rim lesions (PRLs). This advanced analysis offers a promising method for tracking disease progression and tissue damage in MS patients.
Area of Science:
- Neuroimaging
- Radiology
- Biomarkers
Background:
- Paramagnetic rim lesions (PRLs) in multiple sclerosis (MS) indicate active disease with complex iron and myelin alterations.
- Conventional MRI methods face challenges in accurately quantifying these changes.
- Understanding these alterations is crucial for monitoring MS progression.
Purpose of the Study:
- To perform a comprehensive multiparametric MRI analysis of paramagnetic rim lesions (PRLs) in progressive MS patients.
- To investigate the iron and myelin dynamics within PRLs using advanced imaging techniques.
- To correlate imaging findings with disease activity and tissue damage.
Main Methods:
- A retrospective, longitudinal study involving 95 progressive MS subjects with persistent PRLs.
- Utilized 3-Tesla MRI with susceptibility-weighted, T1-weighted, T2-weighted, and fluid-attenuated inversion recovery sequences.
- Quantitative magnetic susceptibility (QS), R2*, and standardized T1w/T2w ratio (sT1w/T2w) were measured for whole lesion, core, and rim.
Main Results:
- Chronic PRLs showed decreased sT1w/T2w and R2*, with increased QS compared to non-PRLs.
- Tissue damage accumulation was more pronounced in acute/chronic PRLs versus non-PRLs at 96 weeks.
- Acute PRLs demonstrated partial recovery, while chronic PRLs indicated irreversible damage.
Conclusions:
- Multiparametric MRI assessment of PRLs provides valuable insights into iron and myelin changes.
- This approach holds potential for evaluating chronic active PRLs in progressive MS.
- The findings support the use of advanced MRI techniques for MS lesion characterization.
