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Updated: Feb 15, 2026

Magnetic Resonance Imaging of Multiple Sclerosis at 7.0 Tesla
Published on: February 19, 2021
Magnetic resonance imaging changes following natalizumab discontinuation in multiple sclerosis patients with
Jérôme Hodel1, Blanche Bapst2, Olivier Outteryck3
1Departments of Neuroradiology, AP-HP, Hôpitaux Universitaires Henri Mondor, Créteil, France; Faculty of Medicine, Université Paris Est Créteil, Créteil, France.
Background:
Detecting early progressive multifocal leukoencephalopathy-immune reconstitution inflammatory syndrome (PML-IRIS) is clinically relevant.
Objective:
Evaluating magnetic resonance imaging (MRI) changes following natalizumab (NTZ) discontinuation and preceding PML-IRIS.
Methods:
MRIs (including diffusion-weighted imaging (DWI), T2-weighted fluid-attenuated inversion recovery (T2-FLAIR), post-contrast T1-weighted sequences) were performed every week following PML diagnosis in 11 consecutive NTZ-PML patients. PML expansion, punctate lesions, contrast-enhancement, and mass-effect/edema were evaluated on each MRI sequence, following NTZ discontinuation.
Results:
PML-IRIS occurred from 26 to 89 days after NTZ discontinuation. MRI changes prior to early PML-IRIS appeared significantly more pronounced using DWI compared to T2-FLAIR imaging (p < 0.003). Two DWI features (marked PML expansion, punctate lesions) systematically preceded contrast-enhancement.
Conclusion:
Subtle changes may occur on DWI preceding contrast-enhancement.
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