Radiologically isolated syndrome (RIS) is a clinical situation in which a person has white matter lesions suggestive of multiple sclerosis (MS), as shown on an MRI scan that was done for reasons unrelated to MS symptoms. The nerve lesions in these people show dissemination in space with an otherwise normal neurological examination and without historical accounts of typical MS symptoms.[1]
MRI findings that are consistent with multiple sclerosis have been observed in healthy people who underwent MRI scanning, and 50% go on to develop symptomatic MS, sometimes with a primary progressive course.[2][3] This condition was first characterized in 2009.[4]
^Okuda, D. T.; Mowry, E. M.; Beheshtian, A.; Waubant, E.; Baranzini, S. E.; Goodin, D. S.; Hauser, S. L.; Pelletier, D. (2009-03-03). "Incidental MRI anomalies suggestive of multiple sclerosis: the radiologically isolated syndrome". Neurology. 72 (9): 800–805. doi:10.1212/01.wnl.0000335764.14513.1a. ISSN1526-632X. PMID19073949. S2CID9981947.