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Published on: February 28, 2021
Radiologically isolated syndrome and multiple sclerosis
1Nehme & Therese Tohme MS Center at the American University of Beirut Medical Center, Lebanon.
Background:
Incidental white matter lesions (WML) are increasingly seen on brain magnetic resonance imaging (MRI) in clinical practice. Demyelination consistent with MS is seen in 0.1-0.7% of the population as evident by autopsy and MRI studies. The term radiologically isolated syndrome (RIS) was coined to define a subgroup of patients with demyelinating lesions highly suggestive of multiple sclerosis (MS). The Okuda criteria for diagnosing RIS help in stratifying the risk of conversion to MS but RIS is still not considered a distinct MS phenotype.
Methods:
The authors reviewed the current literature on diagnostic criteria, natural history and treatment indications in RIS, to assess the challenges faced in diagnosing and treating such patients in clinical practice.
Results:
Typically, one-third of patients convert to clinically definite MS within 5 years, with some progressing directly into primary progressive MS (PPMS). The main risk factors for conversion are: age < 37 years, male gender and presence of spinal cord lesions. Patients with RIS have evidence of early axonal loss, brain atrophy, cognitive deficits, increased anxiety and depression, and subclinical inflammatory disease.
Conclusion:
Patients with RIS at high risk of clinical conversion might be considered for treatment, although this is still a controversial issue. Prospective follow-up of RIS patients by an MS specialist is recommended.
Insights
Radiologically isolated syndrome (RIS) patients have brain lesions suggestive of multiple sclerosis (MS). One-third convert to MS within 5 years, with treatment for high-risk cases remaining controversial.
Area of Science:
- Neurology
- Neuroimaging
- Demyelinating Diseases
Background:
- Incidental white matter lesions (WML) on MRI are common.
- Radiologically isolated syndrome (RIS) describes patients with demyelinating lesions without clinical symptoms, suggestive of multiple sclerosis (MS).
- Current diagnostic criteria for RIS help stratify conversion risk but do not define it as a distinct MS phenotype.
Purpose of the Study:
- To review current literature on diagnostic criteria, natural history, and treatment indications for RIS.
- To assess challenges in diagnosing and treating patients with RIS in clinical practice.
Main Methods:
- Literature review of diagnostic criteria, natural history, and treatment of RIS.
- Assessment of clinical practice challenges.
Main Results:
- Approximately one-third of RIS patients convert to clinically definite MS within 5 years; some progress to primary progressive MS (PPMS).
- Key risk factors for conversion include age under 37, male gender, and spinal cord lesions.
- RIS patients exhibit early axonal loss, brain atrophy, cognitive deficits, and subclinical inflammatory disease.
Conclusions:
- Treatment for high-risk RIS patients is controversial but may be considered.
- Prospective follow-up by an MS specialist is recommended for RIS patients.
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