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Updated: Jan 11, 2026
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 molecular imaging of brain tissue pathology in presymptomatic multiple sclerosis
V A G Ricigliano1, B Stankoff2
1Neurology Unit, GHNE-Paris-Saclay Hospital, 91400 Orsay, France; Université Paris-Saclay, UNIACT, Neurospin, Inserm UMR 1129, CEA, Gif-sur-Yvette, France.
Abstract:
The presence of focal lesions suggestive of multiple sclerosis (MS) seen with magnetic resonance imaging (MRI) in asymptomatic individuals defines the radiologically isolated syndrome (RIS). Pathologically, tissue changes in RIS subjects recapitulate, although being less extensive and pronounced, those observed in definite MS, with an amount of innate immune cell activation, myelin loss, gliosis, metabolic modifications, and structural damage affecting the neuro-axonal compartment. Conventional MRI, however, is not able to capture these biological abnormalities at the cellular and molecular level. Positron emission tomography (PET) with specific radiolabeled compounds could fill this gap, identifying in vivo and with higher granularity the processes underling the abnormal MRI signals. This review presents data obtained with PET in RIS individuals and discusses the potential application of this technique in exploring the different pathophysiologic changes going on in the RIS brain, with technical considerations on radiotracers already tested in MS or newly developed. By breaking up the study of complex tissular changes into single biological phenomena, the use of PET in RIS could encourage early interventions to selectively target each one of them, with potential consequences on the clinical conversion to MS.
Insights
Radiologically isolated syndrome (RIS) shows early multiple sclerosis (MS) pathology. Positron emission tomography (PET) can reveal cellular changes, potentially guiding early interventions for MS.
Area of Science:
- Neuroimaging
- Neurology
- Molecular Imaging
Background:
- Radiologically isolated syndrome (RIS) presents asymptomatic individuals with MRI-detected lesions suggestive of multiple sclerosis (MS).
- Pathological changes in RIS mirror MS, including immune activation, myelin loss, and neuro-axonal damage, though less severe.
- Conventional MRI lacks the cellular and molecular resolution to fully characterize these early pathological changes.
Purpose of the Study:
- To review the application of positron emission tomography (PET) in studying radiologically isolated syndrome (RIS).
- To discuss how PET can identify in vivo pathophysiological processes underlying abnormal MRI signals in RIS.
- To explore the potential of PET in guiding early, targeted interventions for RIS, potentially altering conversion to MS.
Main Methods:
- Review of existing data on PET imaging in RIS subjects.
- Discussion of technical considerations for radiotracers used in MS and RIS.
- Analysis of how PET can provide higher granularity of biological abnormalities compared to conventional MRI.
Main Results:
- PET imaging offers in vivo insights into cellular and molecular processes in the RIS brain.
- Specific radiotracers can detect innate immune cell activation, myelin dynamics, and metabolic changes.
- PET can differentiate and quantify various pathophysiological phenomena occurring in RIS.
Conclusions:
- PET imaging is a valuable tool for detailed investigation of RIS pathophysiology.
- Understanding these processes with PET may enable early, targeted therapeutic strategies.
- PET could potentially impact the clinical trajectory of individuals with RIS, including their conversion to MS.
