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Updated: Jul 27, 2025
Magnetic Resonance Imaging of Multiple Sclerosis at 7.0 Tesla
Published on: February 19, 2021
Evaluation of the Blood-Brain Barrier, Demyelination, and Neurodegeneration in Paramagnetic Rim Lesions in Multiple
Seongjin Choi1, Sarah Lake2, Daniel M Harrison1,3
1Department of Neurology, University of Maryland School of Medicine, Baltimore, Maryland, USA.
Background:
Paramagnetic rim lesions (PRLs) are associated with chronic inflammation in multiple sclerosis (MS). 7-Tesla (7T) magnetic resonance imaging (MRI) can evaluate the integrity of the blood-brain barrier (BBB) in addition to the tissue myelination status and cell loss.
Purpose:
To use MRI metrics to investigate underlying physiology and clinical importance of PRLs.
Study Type:
Prospective.
Subjects:
Thirty-six participants (mean-age 47, 23 females, 13 males) of mixed MS subtypes.
Field Strength/Sequence:
7T, MP2RAGE, MULTI-ECHO 3D-GRE, FLAIR.
Assessment:
Lesion heterogeneity; longitudinal changes in lesion counts; comparison of T1, R2*, and χ; association between baseline lesion types and disease progression (2-3 annual MRI visits with additional years of annual clinical follow-up).
Statistical Tests:
Two-sample t-test, Wilcoxon Rank-Sum test, Pearson's chi-square test, two-group comparison with linear-mixed-effect model, mixed-effect ANOVA, logistic regression. P-values <0.05 were considered significant.
Results:
A total of 58.3% of participants had at least one PRL at baseline. Higher male proportion in PRL+ group was found. Average change in PRL count was 0.20 (SD = 2.82) for PRLs and 0.00 (SD = 0.82) for mottled lesions. Mean and median pre-/post-contrast T1 were longer in PRL+ than in PRL-. No differences in mean χ were seen for lesions grouped by PRL (P = 0.310, pre-contrast; 0.086, post-contrast) or PRL/M presence (P = 0.234, pre-contrast; 0.163, post-contrast). Median χ were less negative in PRL+ and PRL/M+ than in PRL- and PRL/M-. Mean and median pre-/post-contrast R2* were slower in PRL+ compared to PRL-. Mean and median pre-/post-contrast R2* were slower in PRL/M+ than in PRL/M-. PRL presence at baseline was associated with confirmed EDSS Plus progression (OR 3.75 [1.22-7.59]) and PRL/M+ at baseline with confirmed EDSS Plus progression (OR 3.63 [1.14-7.43]).
Data Conclusion:
Evidence of BBB breakdown in PRLs was not seen. Quantitative metrics confirmed prior results suggesting greater demyelination, cell loss, and possibly disruption of tissue anisotropy in PRLs.
Evidence Level:
2 TECHNICAL EFFICACY: Stage 2.
Insights
Paramagnetic rim lesions (PRLs) in multiple sclerosis (MS) show greater demyelination and cell loss but not blood-brain barrier breakdown. PRL presence predicts disease progression, highlighting their clinical importance.
Area of Science:
- Neuroimaging
- Neurology
- Radiology
Background:
- Paramagnetic rim lesions (PRLs) are linked to chronic inflammation in multiple sclerosis (MS).
- 7-Tesla (7T) MRI offers advanced evaluation of blood-brain barrier (BBB) integrity, tissue myelination, and cell loss.
Purpose of the Study:
- To investigate the underlying physiology and clinical significance of PRLs using advanced MRI metrics.
- To correlate MRI findings of PRLs with disease progression in MS patients.
Main Methods:
- A prospective study involving 36 participants with mixed MS subtypes.
- Utilized 7T MRI with MP2RAGE, MULTI-ECHO 3D-GRE, and FLAIR sequences.
- Assessed lesion heterogeneity, longitudinal changes, and compared T1, R2*, and magnetic susceptibility (χ) metrics, correlating with clinical follow-up.
Main Results:
- 58.3% of participants had PRLs at baseline; a higher male proportion was observed in the PRL+ group.
- PRLs showed longer T1 and slower R2* values, indicating greater demyelination and cell loss, but no evidence of BBB breakdown.
- PRL presence at baseline was significantly associated with confirmed Expanded Disability Status Scale (EDSS) Plus progression (OR 3.75).
Conclusions:
- Quantitative MRI metrics confirm greater demyelination and cell loss in PRLs.
- No evidence of blood-brain barrier breakdown was detected within PRLs.
- PRL presence is a significant predictor of future disease progression in multiple sclerosis.
