| Multiple Sclerosis  

Revision of Radiologically Isolated Syndrome Diagnostic Criteria

2023 revision of RIS diagnostic criteria expanding the spectrum of RIS.

The current radiologically isolated syndrome (RIS) diagnostic criteria were defined in 2009 [1] and require the fulfilment of at least three of the four 2005 McDonald dissemination in space (DIS) criteria in otherwise asymptomatic people, i.e. 1) at least one gadolinium-enhancing lesion or 9 T2 hyperintense lesions; 2) at least one infratentorial or spinal cord lesion; 3) at least one juxtacortical lesion; 4) at least 3 periventricular lesions.

Lebrun-Frénay et al. [2] propose a revision of the RIS diagnostic criteria based on the study of their prospective cohort of 747 patients divided as follows: Groups 1 and 2 comprising 251 patients (33.6%) with one or two of the 2017 DIS criteria [3], respectively, and the 2009-RIS Group of 496 patients (66.4%) meeting the current RIS criteria. They show that patients with only one or two white matter lesions suggestive of multiple sclerosis (MS) in 2 different locations, in line with the 2017 McDonald criteria, and two of three additional risk factors for developing a clinical event (oligoclonal bands, at least one spinal cord lesion, evidence of dissemination in time on follow-up MRI defined by the presence of new T2 lesions or gadolinium-enhancing lesions) have a similar risk of presenting a clinical event at 5 years from the index MRI as patients fulfilling the 2009 RIS diagnostic criteria. Therefore, they propose extending the RIS definition to include these patients. This would allow an earlier identification of pre-symptomatic people, with impact on clinical care and future research.

Key Points:

  • Two of the following: oligoclonal bands, spinal cord lesions, new T2 lesions or gadolinium-enhancing lesions increase the risk of MS in people with one or two 2017 DIS criteria to rates similar to those in RIS.
  • The 2023 RIS criteria showed good sensitivity (86%), negative predictive value (73.1%) and accuracy (59.8%), yet low specificity (35.4%).
  • Patients younger than 37 years at the time of index MRI evolved to MS faster than those over 37.


  1. Okuda D. T., Mowry E. M., Beheshtian A. et al. Incidental MRI anomalies suggestive of multiple sclerosis: the radiologically isolated syndrome. Neurology 2009; 72(9): 800-805. doi:10.1212/01.wnl.0000335764.14513.1a. pubmed.ncbi.nlm.nih.gov/19073949/
  2. Lebrun-Frénay C., Okuda D.T., Siva A. et al. The radiologically isolated syndrome: revised diagnostic criteria. Brain 2023; awad073. doi:10.1093/brain/awad073. Online ahead ofprint.https://pubmed.ncbi.nlm.nih.gov/36864688/
  3. Thompson A.J., Banwell B.L., Barkhof F. et al. Diagnosis of multiple sclerosis: 2017 revisions of the McDonald criteria. Lancet Neurol 2018; 17(2): 162-173. doi: 10.1016/S1474-4422(17)30470-2. pubmed.ncbi.nlm.nih.gov/29275977/

Publish on behalf of the Scientific Panel on Multiple sclerosis