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Relationship between paramagnetic rim lesions and slowly expanding lesions in multiple sclerosis
Alberto Calvi1, Margareta A Clarke2, Ferran Prados3
1Queen Square MS Centre, Department of Neuroinflammation, Institute of Neurology, Faculty of Brain Sciences, University College London (UCL), London, UK.
Background:
Magnetic resonance imaging (MRI) markers for chronic active lesions in MS include slowly expanding lesions (SELs) and paramagnetic rim lesions (PRLs).
Objectives:
To identify the relationship between SELs and PRLs in MS, and their association with disability.
Methods:
61 people with MS (pwMS) followed retrospectively with MRI including baseline susceptibility-weighted imaging, and longitudinal T1 and T2-weighted scans. SELs were computed using deformation field maps; PRLs were visually identified. Mixed-effects models assessed differences in Expanded Disability Status Scale (EDSS) score changes between the group defined by the presence of SELs and or PRLs.
Results:
The median follow-up time was 3.2 years. At baseline, out of 1492 lesions, 616 were classified as SELs, and 80 as PRLs. 92% of patients had ⩾ 1 SEL, 56% had ⩾ 1 PRL, while both were found in 51%. SELs compared to non-SELs were more likely to also be PRLs (7% vs. 4%, p = 0.027). PRL counts positively correlated with SEL counts (ρ= 0.28, p = 0.03). SEL + PRL + patients had greater increases in EDSS over time (beta = 0.15/year, 95% confidence interval (0.04, 0.27), p = 0.009) than SEL+PRL-patients.
Conclusion:
SELs are more numerous than PRLs in pwMS. Compared with either SELs or PRLs found in isolation, their joint occurrence was associated with greater clinical progression.
Insights
Slowly expanding lesions (SELs) and paramagnetic rim lesions (PRLs) are MRI markers in multiple sclerosis (MS). The co-occurrence of SELs and PRLs in MS patients is linked to increased disability progression.
Area of Science:
- Neurology
- Radiology
- Immunology
Background:
- Multiple Sclerosis (MS) exhibits chronic active lesions, including Slowly Expanding Lesions (SELs) and Paramagnetic Rim Lesions (PRLs), detectable via Magnetic Resonance Imaging (MRI).
- Understanding the interplay between SELs and PRLs is crucial for predicting MS disease course.
Purpose of the Study:
- To investigate the relationship between Slowly Expanding Lesions (SELs) and Paramagnetic Rim Lesions (PRLs) in patients with Multiple Sclerosis (MS).
- To determine the association of SELs and PRLs with clinical disability progression in MS patients.
Main Methods:
- Retrospective analysis of MRI scans (susceptibility-weighted imaging, T1- and T2-weighted) from 61 individuals with MS (pwMS) over a median follow-up of 3.2 years.
- SELs were quantified using deformation field maps, while PRLs were identified visually.
- Mixed-effects models were employed to assess changes in Expanded Disability Status Scale (EDSS) scores in relation to the presence of SELs and/or PRLs.
Main Results:
- Out of 1492 lesions, 616 were classified as SELs and 80 as PRLs at baseline. 92% of patients had at least one SEL, and 56% had at least one PRL.
- A significant association was found between SELs and PRLs, with SELs being more likely to also present as PRLs (7% vs. 4%, p=0.027).
- Patients exhibiting both SELs and PRLs showed a significantly greater increase in EDSS scores over time (beta=0.15/year, p=0.009) compared to those with only SELs or PRLs.
Conclusions:
- Slowly Expanding Lesions (SELs) are more prevalent than Paramagnetic Rim Lesions (PRLs) in individuals with MS.
- The concurrent presence of both SELs and PRLs is a stronger indicator of clinical progression in MS than either lesion type alone.
