MRI only conversion to multiple sclerosis following a clinically isolated syndrome.
OBJECTIVE
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.


CONCLUSIONS
About 10-15% of CIS patients may develop MS on MRI criteria only, without further clinical events for up to two decades.
Department of Neuroinflammation, UCL Institute of Neurology, University College London, Queen Square, London, UK. d.chard@ion.ucl.ac.uk
D T
DT
Chard
C M
CM
Dalton
J
J
Swanton
L K
LK
Fisniku
K A
KA
Miszkiel
A J
AJ
Thompson
G T
GT
Plant
D H
DH
Miller
D000328:Adult; D001921:Brain / Q000473:pathology; D015331:Cohort Studies; D004185:Disability Evaluation; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000175:diagnosis* / Q000473:pathology; D012189:Retrospective Studies