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.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. This condition was first characterized in 2009. Diagnosis
The criteria for an RIS diagnosis are as follows:
The presence of incidental MRI findings in the CNS white matter:
Ovoid and well-circumscribed homogeneous foci, with or without involvement of the corpus callosum
T2 hyperintensities larger than 3 mm in diameter, which fulfill at least 3 of the 4 Barkhof MRI criteria for DIS
The CNS abnormalities are not consistent with a vascular condition
No historical accounts of clinical symptoms consistent with neurological dysfunction. MRI anomalies do not account for apparent impairment in social, occupational, or generalized areas of functioning. MRI anomalies are not due to substance abuse, such as recreational drug use, toxic exposure, or a prior known medical condition. Exclusion of a differential diagnosis of leukoaraiosis, or extensive white matter pathology excluding the corpus callosum. MRI anomalies of the CNS are not accounted for by another disease. Discovery
RIS is discovered when an MRI scan is performed for other reasons.
The first occurrence of a clinical event characteristic of MS in nearly half of the children examined was 2 years, though in a majority of cases, radiologic evolution, i.e. the increase in the number of size of lesions as detected in subsequent MRI, developed after one year. The presence of oligoclonal bands in the CSF and spinal cord lesions were associated with an increased risk of a first clinical event characteristic of MS. It was found that children with RIS had a substantial risk of subsequent clinical symptoms and/or radiologic evolution. Research directions
Calls have been made for longer prospective studies, tracking the development of potential disease progression over a longer period of time are warranted. This would ensure criteria in RIS is satisfactory and whether consideration should be given to treating individuals with RIS on current MS medication.RIS has been linked to prodromal multiple sclerosis. Etymology
The acronym RIS was coined in 2009 by Okuda and colleagues. Siva and colleagues suggested an alternate name, radiologically uncovered asymptomatic possible inflammatory-demyelinating disease (RAPIDD). == References ==