Radiologically isolated syndrome: A single-center, retrospective cohort study

Area of Science:

• Neurology
• Neuroimmunology
• Radiology

Background:

• Radiologically Isolated Syndrome (RIS) represents an early stage of Multiple Sclerosis (MS).
• Established risk factors influence the conversion of RIS to clinically definite central nervous system (CNS) demyelinating disease.
• Characterizing new RIS cohorts and analyzing risk factors is crucial for understanding disease progression.

Purpose of the Study:

• To characterize a new clinical cohort of RIS patients.
• To analyze established risk factors for conversion from RIS to clinically definite MS.
• To investigate the impact of disease-modifying therapies (DMTs) on disease conversion.

Main Methods:

• Retrospective analysis of medical records for 89 RIS patients diagnosed between 2005 and 2020.
• Calculation of time to first clinical demyelinating event or last follow-up.
• Cox proportional hazards models used to determine hazard ratios for known risk factors.
• Analysis of MRI findings, including new demyelinating lesions and T1-hypointense lesions.

Main Results:

• 18% of patients converted to clinically definite MS within a median of 3.4 years.
• Previously reported risk factors (age, sex, spinal cord lesions) were not significant predictors of conversion.
• 50% of patients with longitudinal brain imaging developed new demyelinating lesions.
• 26 patients (30%) received DMTs, with dimethyl fumarate and glatiramer acetate being most common.
• The DMT-treated subgroup had more recognized risk factors (p=0.028).

Conclusions:

• The median time from RIS diagnosis to clinically evident demyelinating disease is approximately 3.4 years.
• Early initiation of DMT in RIS patients may mitigate the impact of risk factors.
• DMT use may reduce the likelihood of conversion to clinically definite CNS demyelinating disease, particularly in high-risk individuals.