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Updated: Jul 12, 2026
Comprehensive Autopsy Program for Individuals with Multiple Sclerosis
Published on: July 19, 2019
Quantitative susceptibility mapping of paramagnetic rim lesions in early multiple sclerosis: A cross-sectional study
Lars Skattebøl1,2, Rigmor Lundby3, Mathias H Øverås1,2
1Department of Neurology, Oslo University Hospital, Oslo, Norway.
Objective:
Chronic inflammation in multiple sclerosis is associated with neurodegeneration and progressive functional decline. Quantitative susceptibility mapping (QSM) is an MRI technique that visualizes paramagnetic rim lesions (PRLs), which are indicative of chronic inflammation. In this cross-sectional study, we explored the prevalence of PRLs in multiple sclerosis and assessed their associations with clinical disability, tissue magnetic susceptibility, and brain age predictions.
Methods:
All participants from the NOR-MS study with a 3T MRI T1-weighted magnetization-prepared rapid gradient echo and QSM were included (n = 42, mean age = 39.4 years, 59.5 % females, median disease duration = 0.1 years [IQR: 0.02-5.42]). The presence and characteristics of PRLs were evaluated by an experienced neuroradiologist. PRL and non-PRL susceptibility were categorized into separate groups through manual segmentation and voxel-wise analysis. We utilized a validated simple fully convolutional network and T1-weighted images to estimate brain age, and its derivative - brain age gap (BAG). Clinical disability was assessed using the Expanded Disability Status Scale (EDSS).
Results:
PRLs were identified in 14.3 % (n = 6) of study participants, and correlated with EDSS (rho = 0.86, p = 0.03). The mean paramagnetic rim susceptibility was 25.6 ± 14.1 parts per billion and correlated with EDSS (rho = 0.93, p = 0.008). EDSS was significantly higher in the PRL-positive group (median EDSS 2.25 vs 1.5, p = 0.02). The PRL-positive group exhibited a mean 5.6-year higher BAG (p = 0.01) than the PRL-negative group.
Conclusion:
PRLs were present in a significant subset of study participants with MS and were associated with greater disability and higher BAG.
Insights
Paramagnetic rim lesions (PRLs) visualized by quantitative susceptibility mapping (QSM) indicate chronic inflammation in multiple sclerosis (MS). These lesions are linked to increased clinical disability and a higher brain age gap in MS patients.
Area of Science:
- Neuroimaging
- Neurology
- Radiology
Background:
- Chronic inflammation in multiple sclerosis (MS) contributes to neurodegeneration and functional decline.
- Quantitative susceptibility mapping (QSM) is an MRI technique that identifies paramagnetic rim lesions (PRLs), markers of chronic inflammation.
Purpose of the Study:
- To investigate the prevalence of PRLs in MS patients.
- To assess the association of PRLs with clinical disability, tissue magnetic susceptibility, and brain age predictions.
Main Methods:
- A cross-sectional study included 42 MS participants with 3T MRI (T1-weighted and QSM).
- PRLs were evaluated by a neuroradiologist; susceptibility was analyzed voxel-wise.
- Brain age gap (BAG) was estimated using a convolutional neural network; clinical disability was assessed using the Expanded Disability Status Scale (EDSS).
Main Results:
- PRLs were detected in 14.3% of participants and correlated with EDSS (rho=0.86, p=0.03).
- Mean paramagnetic rim susceptibility (25.6 ± 14.1 ppb) correlated with EDSS (rho=0.93, p=0.008).
- PRL-positive individuals had higher EDSS (median 2.25 vs 1.5, p=0.02) and a mean 5.6-year greater BAG (p=0.01).
Conclusions:
- Paramagnetic rim lesions are present in a significant subset of MS patients.
- PRLs are associated with increased clinical disability and a higher brain age gap in MS.
