09 Sep 21. Featured Paper

The prevalence of paramagnetic rim lesions in multiple sclerosis: A systematic review & meta-analysis

Link to paper on PLOS ONE

Authors

Koy Chong Ng Kee Kwong, Daisy Mollison, Rozanna Meijboom, Elizabeth N. York, Agniete Kampaite, Michael J. Thrippleton, Siddharthan Chandran, Adam D. Waldman

Abstract

Background: Recent findings from several studies have shown that paramagnetic rim lesions identified using susceptibility-based MRI could represent potential diagnostic & prognostic biomarkers in multiple sclerosis (MS).

Here, we perform a systematic review & meta-analysis of the existing literature to assess their pooled prevalence at lesion-level & patient-level.

Methods: Both database searching (PubMed & Embase) & handsearching were conducted to identify studies allowing the lesion-level &/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 & 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) & 40.6% (95% CI: 26.2–56.8) for rim lesions at lesion-level & patient-level, respectively.

Pooled lesion-level & patient-level prevalences for chronic active lesions were 12.0% (95% CI: 9.0–15.8) & 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 & 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) & disease duration (p = 0.0018, R2 = 0.48).

Other moderator analyses demonstrated no significant differences according to MRI sequence, gender & 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.

Keywords

• Lesions
• Magnetic resonance imaging (MRI)
• Multiple sclerosis (MS)