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Updated: Jul 12, 2025
Magnetic Resonance Imaging of Multiple Sclerosis at 7.0 Tesla
Published on: February 19, 2021
Rim lesions in MS at 3T: clinical correlation and possible radiological alternatives for daily practice at lower
Eva Vanheule1, Melissa Cambron2, Adrienn Dobai3
1Department of Radiology, AZ Sint-Jan Brugge-Oostende, Campus Brugge, Ruddershove 10, Bruges 8000, Belgium.
Background And Purpose:
Paramagnetic rim lesions (PRLs) have been described as an imaging feature specific to multiple sclerosis (MS) using high-field strength phase-sensitive MR imaging. These lesions are suggested to reflect chronic active inflammation associated with greater disease severity and a more rapid disability progression. The aim of our study is to investigate the relationship between PRLs, clinical parameters, other radiological findings and disease progression.
Material And Methods:
This cross-sectional study included MS patients treated with teriflunomide, fingolimod, natalizumab or ocrelizumab for at least 2 years. PRLs seen at 3T MRI were analysed and correlated with clinical data and radiological progression, defined as an increase of the T2/FLAIR-lesion load during therapy. In the search for alternatives for these PRLs, we defined two additional radiological markers: 'FLAIR-bullet lesions', and on post-contrast black-blood (BB) images, 'BB-bullet lesions'.
Results:
We included 84 MS patients of whom 27 (32 %) had at least 1 PRL. PRLs were associated with radiological progression under therapy (p=0.039) and higher clinical disability scores, although only significant for 9-Hole Peg Test (p=0.023). Patients with FLAIR-bullet or BB-bullet lesions at 3T MRI had a higher chance of PRL (p<0.001) with a likelihood ratio of 13.2 for FLAIR-bullets and 12.6 for BB-bullet lesions, thanks to the high negative predictive value of respectively 83 % and 90 %.
Conclusion:
PRLs are associated with an increase of T2/FLAIR-lesion load under therapy and unfavourable clinical outcome. Our newly defined 'bullet lesions' are associated with PRLs and might be an interesting MRI marker for centres without access to high-field SWI images.
Insights
Paramagnetic rim lesions (PRLs) in multiple sclerosis (MS) indicate disease progression and worse outcomes. New "bullet lesions" on MRI may help identify these active lesions when advanced imaging is unavailable.
Area of Science:
- Neurology
- Radiology
- Neuroimmunology
Background:
- Paramagnetic rim lesions (PRLs) are a specific MRI finding in multiple sclerosis (MS).
- PRLs are thought to represent chronic active inflammation.
- These lesions are linked to increased disease severity and faster disability progression.
Purpose of the Study:
- To investigate the association between PRLs and clinical parameters in MS patients.
- To explore the relationship between PRLs and radiological findings, including disease progression.
- To identify alternative MRI markers for PRLs.
Main Methods:
- Cross-sectional study of 84 MS patients on disease-modifying therapies for at least 2 years.
- Analysis of 3T MRI scans for PRLs, FLAIR-bullet lesions, and BB-bullet lesions.
- Correlation of PRLs with clinical disability and radiological progression (T2/FLAIR-lesion load increase).
Main Results:
- 32% of patients had at least one PRL.
- PRLs were associated with radiological progression (p=0.039) and higher disability (9-Hole Peg Test, p=0.023).
- FLAIR-bullet and BB-bullet lesions significantly predicted PRLs (p<0.001), with high likelihood ratios (13.2 and 12.6).
Conclusions:
- PRLs are linked to increased lesion load and unfavorable clinical outcomes in MS.
- Newly defined 'bullet lesions' are associated with PRLs.
- 'Bullet lesions' may serve as valuable MRI markers in centers lacking high-field SWI capabilities.
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