Radiologically isolated syndrome

Area of Science:

• Neurology
• Radiology
• Immunology

Background:

• Radiologically isolated syndrome (RIS) is characterized by incidental demyelinating lesions suggestive of multiple sclerosis (MS) without clinical symptoms.
• Longitudinal data suggest approximately 50% of individuals with RIS progress to symptomatic MS within 10 years, indicating RIS may be a presymptomatic phase of MS.

Purpose of the Study:

• To review the current understanding of radiologically isolated syndrome (RIS) and its progression to multiple sclerosis (MS).
• To identify risk factors and potential biomarkers for MS development in individuals with RIS.
• To evaluate the efficacy of early immunomodulatory treatment in preventing clinical conversion in RIS.

Main Methods:

• Review of international longitudinal cohort data on RIS progression.
• Analysis of risk factors including age, sex, cerebrospinal fluid (CSF) oligoclonal bands, lesion location, and gadolinium enhancement.
• Evaluation of data from two randomized clinical trials on immunomodulatory treatments for RIS.

Main Results:

• Key risk factors for progression to clinical MS include younger age (<35), male sex, CSF-restricted oligoclonal bands, spinal cord/infratentorial lesions, and gadolinium-enhancing lesions.
• Two clinical trials demonstrated that approved MS immunomodulatory medications can prevent clinical conversion in some individuals with RIS over a 2-year period.

Conclusions:

• RIS represents a potential presymptomatic stage of MS, with identifiable risk factors for progression.
• Early intervention with immunomodulatory therapies may alter the disease course for high-risk individuals with RIS, potentially transforming patient care.