MRI only conversion to multiple sclerosis following a clinically isolated syndrome

J Neurol Neurosurg Psychiatry. 2011 Feb;82(2):176-9. doi: 10.1136/jnnp.2010.208660. Epub 2010 Jun 2.


Objectives: Using current diagnostic criteria, patients who present with a clinically isolated syndrome (CIS) may develop multiple sclerosis (MS) by subsequently exhibiting dissemination in space and time on clinical (clinically definite (CD) MS) or radiological (MRI) grounds. This study investigated the frequency of radiological without clinical conversion to MS after long term follow-up as this has not previously been defined.

Methods: Two cohorts who underwent serial clinical and MRI studies from presentation with a CIS and who were followed-up over a mean of 6 and 20 years were investigated. The distribution and formation of lesions visible on brain MRI were assessed using the revised McDonald criteria (2005). Radiologically defined (RD) MS was determined by fulfilment of the MRI but not the CDMS criteria.

Results: 105 people were followed-up for 6 years after a CIS, of whom 51% developed CDMS, 15% RDMS and the remainder were classified as still having had a CIS. 70 people were followed-up at 20 years, of whom 61% and 11% had developed CDMS and RDMS, respectively.

Conclusion: About 10-15% of CIS patients may develop MS on MRI criteria only, without further clinical events for up to two decades.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Brain / pathology
  • Cohort Studies
  • Disability Evaluation
  • Disease Progression
  • Female
  • Follow-Up Studies
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Multiple Sclerosis / diagnosis*
  • Multiple Sclerosis / pathology
  • Retrospective Studies