The Radiologically Isolated Syndrome International Cohort

The Radiologically Isolated Syndrome (RIS) corresponds to the discovery of white matter (WM) abnormalities suggestive of multiple sclerosis (MS) by their location, size, and appearance, on the brain or spinal cord Magnetic Resonance Imaging (MRI). This imaging is performed for a reason other than for suspicion of demyelinating disease in subjects without a history of neurological symptoms and a strict routine clinical neurological examination. It was defined and named in 2009 (Okuda et al.) after publishing 3 case series (French, USA, Turkey). The Radiologically Isolated Syndrome Consortium (RISC) published a cohort of subjects with an extended follow-up after the first brain MRI of MS, with 34% presenting an event (clinical conversion) at five years, 51.2 % of these subjects showed an event at ten years. The patients who offer a higher risk of developing a first clinical demyelinating event were identified such as male sex, young age, the presence of oligoclonal bands (BOCs) in the Cerebrospinal Fluid (CSF), the presence of infratentorial lesions and spinal cord lesions on the first MRI suggestive of RIS. The location and morphology of the lesions appear to be decisive for studying the risk of conversion. Our first objective is to prospectively collect data to identify the subjects who present a higher risk of developing a first clinical demyelinating event and the progression of the disease in these subjects.

Among the objectives of this worldwide cohort is the analysis of (1) environmental factors (Vit D, EBV, tobacco...), (2) MRI biomarkers, including atrophy, central veins signs, paramagnetic rings, and DTI.

(3) digital biomarkers (4) oculography (5) biological markers To summarize, this cohort will allow for analyzing features in imaging, biology and the exploration of digital and oculographic characteristics to identify predictive factors of clinical evolution of a large cohort of subjects presenting WM abnormalities suggestive of multiple sclerosis.