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Positron Emission Tomography Imaging for In Vivo Measuring of Myelin Content in the Lysolecithin Rat Model of Multiple Sclerosis
Published on: February 28, 2021
In vivo imaging of chronic active lesions in multiple sclerosis
Alberto Calvi1, Lukas Haider2, Ferran Prados3
1Queen Square Multiple Sclerosis Centre, Department of Neuroinflammation, UCL Queen Square Institute of Neurology, University College London, London, UK/Unità di neurologia, Associazione Centro 'Dino Ferrari', IRCCS Fondazione Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy.
Abstract:
New clinical activity in multiple sclerosis (MS) is often accompanied by acute inflammation which subsides. However, there is growing evidence that a substantial proportion of lesions remain active well beyond the acute phase. Chronic active lesions are most frequently found in progressive MS and are characterised by a border of inflammation associated with iron-enriched cells, leading to ongoing tissue injury. Identifying imaging markers for chronic active lesions in vivo are thus a major research goal. We reviewed the literature on imaging of chronic active lesion in MS, focussing on 'slowly expanding lesions' (SELs), detected by volumetric longitudinal magnetic resonance imaging (MRI) and 'rim-positive' lesions, identified by susceptibility iron-sensitive MRI. Both SELs and rim-positive lesions have been found to be prognostically relevant to future disability. Little is known about the co-occurrence of rims around SELs and their inter-relationship with other emerging techniques such as dynamic contrast enhancement (DCE) and positron emission tomography (PET).
Insights
Chronic active lesions in multiple sclerosis (MS) persist beyond acute inflammation, driving ongoing tissue damage. Identifying these lesions using imaging markers like slowly expanding lesions (SELs) and rim-positive lesions is crucial for predicting disability.
Area of Science:
- Neuroimaging
- Neurology
- Inflammatory Diseases
Background:
- Acute inflammation in multiple sclerosis (MS) lesions typically subsides, but chronic active lesions persist.
- These chronic active lesions, common in progressive MS, feature inflammatory rims with iron-laden cells, causing continuous tissue injury.
- Identifying in vivo imaging markers for chronic active lesions is a key research objective.
Purpose of the Study:
- To review current literature on imaging chronic active lesions in MS.
- To focus on slowly expanding lesions (SELs) and rim-positive lesions as potential imaging markers.
- To explore the relationship between SELs, rim-positive lesions, and emerging techniques like DCE and PET.
Main Methods:
- Literature review of imaging studies in MS.
- Analysis of volumetric longitudinal MRI for detecting slowly expanding lesions (SELs).
- Assessment of susceptibility-weighted imaging (SWI) for identifying iron-enriched 'rim-positive' lesions.
Main Results:
- Both slowly expanding lesions (SELs) and rim-positive lesions are associated with future disability in MS patients.
- These lesion types indicate ongoing pathological processes beyond acute inflammation.
- The co-occurrence and inter-relationship of these markers with DCE and PET remain underexplored.
Conclusions:
- Chronic active lesions represent a significant target for understanding MS progression.
- Imaging markers such as SELs and rim-positive lesions hold prognostic value for MS disability.
- Further research is needed to integrate various imaging techniques for comprehensive characterization of chronic active MS lesions.
