Spatial distribution of multiple sclerosis iron rim lesions and their impact on disability

Matthias Wittayer; Claudia E Weber; Michael Platten; Lucas Schirmer; Achim Gass; Philipp Eisele

doi:10.1016/j.msard.2022.103967

Spatial distribution of multiple sclerosis iron rim lesions and their impact on disability

Mult Scler Relat Disord. 2022 Aug:64:103967. doi: 10.1016/j.msard.2022.103967. Epub 2022 Jun 15.

Authors

Matthias Wittayer¹, Claudia E Weber¹, Michael Platten², Lucas Schirmer³, Achim Gass¹, Philipp Eisele⁴

Affiliations

¹ Department of Neurology, Medical Faculty Mannheim and Mannheim Center of Translational Neurosciences (MCTN), Heidelberg University, Theodor-Kutzer-Ufer 1 - 3, Mannheim 68167, Germany.
² Department of Neurology, Medical Faculty Mannheim and Mannheim Center of Translational Neurosciences (MCTN), Heidelberg University, Theodor-Kutzer-Ufer 1 - 3, Mannheim 68167, Germany; DKTK CCU Neuroimmunology and Brain Tumor Immunology, DKFZ, Heidelberg, Germany.
³ Department of Neurology, Medical Faculty Mannheim and Mannheim Center of Translational Neurosciences (MCTN), Heidelberg University, Theodor-Kutzer-Ufer 1 - 3, Mannheim 68167, Germany; Medical Faculty Mannheim, Institute for Innate Immunoscience, Heidelberg University, Mannheim, Germany.
⁴ Department of Neurology, Medical Faculty Mannheim and Mannheim Center of Translational Neurosciences (MCTN), Heidelberg University, Theodor-Kutzer-Ufer 1 - 3, Mannheim 68167, Germany. Electronic address: philipp.eisele@medma.uni-heidelberg.de.

PMID: 35728430
DOI: 10.1016/j.msard.2022.103967

Abstract

Background: In multiple sclerosis (MS), iron rim lesions (IRLs) on magnetic resonance imaging (MRI) have been suggested as an imaging marker of disease progression. However, the exact mechanisms how they contribute to disability are yet not completely known. Strategic lesion location may be an important factor concerning the impact of focal lesions on clinical disability. Therefore, the aim of this study was to investigate the spatial distribution of IRLs compared to non-IRLs and their impact on disability.

Methods: We retrospectively identified 67 patients with at least one IRL on MRI and 67 age- and sex-matched patients without IRLs. We compared the spatial distribution of lesions between both groups and between IRLs and non-IRLs in patients with IRLs. Furthermore, we assessed the relationship between lesion localisation and disability on a voxel-by-voxel basis and investigated the impact on structural network disruptions.

Results: Patients with IRLs had higher disability scores (median Expanded Disability Status Scale score (range): 3.0 (0 - 8.5) versus 1.5 (0 - 6.5); p = 0.001; median pyramidal functional system score (range): 1.0 (0 - 5) versus 0 (0 - 4); p = 0.003), significantly lower brain volumes (mean normal-appearing grey matter volume: 749.66 ± 60.58 versus 785.83 ± 53.71 mL; mean normal-appearing white matter volume: 723.58 ± 60.13 versus 753.25 ± 69.61 mL; mean deep grey matter volume: 33.21 ± 4.19 versus 35.85 ± 4.89 mL; p < 0.05 for all comparisons) and a significantly higher total T2 lesion volume (mean: 9.96 ± 11.6 versus 4.31 ± 8.9 mL; p < 0.001). We found no neuroanatomical regions that were more often affected by IRLs. Furthermore, comparing the overall network disruption in the IRL group, IRLs caused less network disruption/mL lesion size compared to non-IRLs (1.54% / mL versus 2.0% / mL; p < 0.05).

Conclusion: IRLs are associated with higher disability scores. However, our results suggest that a higher disability is not explained by the sheer topography of IRLs or their network disruption.

Keywords: Chronic active lesions; Iron rim lesions; MRI; Multiple sclerosis; SWI.

MeSH terms

Brain / diagnostic imaging
Brain / pathology
Humans
Iron
Magnetic Resonance Imaging / methods
Multiple Sclerosis* / diagnostic imaging
Multiple Sclerosis* / pathology
Retrospective Studies
White Matter* / pathology

Substances

Iron