Emerging imaging markers in radiologically isolated syndrome: implications for earlier treatment initiation

The presence of central nervous system lesions fulfilling the criteria of dissemination in space and time on MRI leads to the diagnosis of a radiologically isolated syndrome (RIS), which may be an early sign of multiple sclerosis (MS). However, some patients who do not fulfill the necessary criteria for RIS still evolve to MS, and some T2 hyperintensities that resemble demyelinating lesions may originate from mimics. In light of the recent recognition of the efficacy of disease-modifying therapy (DMT) in RIS, it is relevant to consider additional imaging features that are more specific of MS. We performed a narrative review on cortical lesions (CL), the central vein sign (CVS), and paramagnetic rim lesions (PRL) in patients with RIS. In previous RIS studies, the reported prevalence of CLs ranges between 20.0 and 40.0%, CVS + white matter lesions (WMLs) between 87.0 and 93.0% and PRLs between 26.7 and 63.0%. Overall, these imaging findings appear to be frequent in RIS cohorts, although not consistently taken into account in previous studies. The search for CLs, CVS + WML and PRLs in RIS patients could lead to earlier identification of patients who will evolve to MS and benefit from DMTs.