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Updated: Oct 21, 2025
Magnetic Resonance Imaging of Multiple Sclerosis at 7.0 Tesla
Published on: February 19, 2021
The prevalence of paramagnetic rim lesions in multiple sclerosis: A systematic review and meta-analysis
Koy Chong Ng Kee Kwong1, Daisy Mollison1, Rozanna Meijboom1
1Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom.
Background:
Recent findings from several studies have shown that paramagnetic rim lesions identified using susceptibility-based MRI could represent potential diagnostic and prognostic biomarkers in multiple sclerosis (MS). Here, we perform a systematic review and meta-analysis of the existing literature to assess their pooled prevalence at lesion-level and patient-level.
Methods:
Both database searching (PubMed and Embase) and handsearching were conducted to identify studies allowing the lesion-level and/or patient-level prevalence of rim lesions or chronic active lesions to be calculated. Pooled prevalence was estimated using the DerSimonian-Laird random-effects model. Subgroup analysis and meta-regression were performed to explore possible sources of heterogeneity. PROSPERO registration: CRD42020192282.
Results:
29 studies comprising 1230 patients were eligible for analysis. Meta-analysis estimated pooled prevalences of 9.8% (95% CI: 6.6-14.2) and 40.6% (95% CI: 26.2-56.8) for rim lesions at lesion-level and patient-level, respectively. Pooled lesion-level and patient-level prevalences for chronic active lesions were 12.0% (95% CI: 9.0-15.8) and 64.8% (95% CI: 54.3-74.0), respectively. Considerable heterogeneity was observed across studies (I2>75%). Subgroup analysis revealed a significant difference in patient-level prevalence between studies conducted at 3T and 7T (p = 0.0312). Meta-regression analyses also showed significant differences in lesion-level prevalence with respect to age (p = 0.0018, R2 = 0.20) and disease duration (p = 0.0018, R2 = 0.48). Other moderator analyses demonstrated no significant differences according to MRI sequence, gender and expanded disability status scale (EDSS).
Conclusion:
In this study, we show that paramagnetic rim lesions may be present in an important proportion of MS patients, notwithstanding significant variation in their assessment across studies. In view of their possible clinical relevance, we believe that clear guidelines should be introduced to standardise their assessment across research centres to in turn facilitate future analyses.
Insights
Paramagnetic rim lesions are common in multiple sclerosis (MS) patients, but their assessment varies. Standardized guidelines are needed to improve diagnostic and prognostic accuracy for these potential MS biomarkers.
Area of Science:
- Neuroimaging
- Biomarkers
- Multiple Sclerosis Research
Background:
- Paramagnetic rim lesions (PRLs) on susceptibility-based MRI are emerging as potential biomarkers in multiple sclerosis (MS).
- Existing literature on the prevalence of PRLs requires systematic evaluation to understand their diagnostic and prognostic significance.
Purpose of the Study:
- To systematically review and meta-analyze the literature on paramagnetic rim lesions and chronic active lesions in MS.
- To estimate the pooled prevalence of these lesions at both lesion-level and patient-level.
- To explore heterogeneity and identify factors influencing lesion prevalence.
Main Methods:
- Comprehensive database searching (PubMed, Embase) and handsearching were performed.
- Meta-analysis using the DerSimonian-Laird random-effects model to pool prevalence data.
- Subgroup analysis and meta-regression to investigate sources of heterogeneity.
Main Results:
- 29 studies with 1230 patients were included.
- Pooled prevalence: 9.8% lesion-level and 40.6% patient-level for rim lesions; 12.0% lesion-level and 64.8% patient-level for chronic active lesions.
- Significant heterogeneity observed; patient-level prevalence differed between 3T and 7T MRI (p=0.0312). Age and disease duration influenced lesion-level prevalence (p<0.0018).
Conclusions:
- Paramagnetic rim lesions are present in a substantial proportion of MS patients, though assessment methods vary significantly.
- Standardized guidelines for assessing paramagnetic rim lesions are crucial for consistent research and clinical application.
- Further research is needed to fully elucidate the clinical relevance of these lesions as MS biomarkers.
