Background: In 2005, the McDonald MRI criteria for dissemination in space were revised to improve diagnosis of multiple sclerosis (MS) in non-Caucasians.
Methods: We included patients with a first clinically isolated syndrome (CIS) to assess their performance in the Afro-Caribbean population. Baseline brain and spine MRI examinations were available within 3 months after onset of CIS. The development of a second clinical event was used as the main outcome indicating clinically definite MS.
Results: A total of 66 patients (52F/14M) were included between January 1998 and January 2008 (mean age: 34.7; median follow-up: 34 months). CIS was classified as spinal cord (30.3%), optic neuritis (28.8%), brainstem (24.2%), multiregional (10.6%), hemispheric (4.5%), or undetermined (1.5%). Overall conversion rate was 42.4% (median: 11 months). The McDonald criteria revised for dissemination in space were fulfilled in 33.3% (sensitivity: 0.39 (+/-0.18); specificity: 0.66 (+/-0.15), positive predictive value: 0.46 (+/-0.20), negative predictive value: 0.60 (+/-0.15).
Conclusion: The Afro-Caribbean population is characterized by a strong proportion of CIS in the spinal cord and a lower burden of disease on the baseline brain MRI. This may explain the low sensitivity of the 2005 McDonald criteria for dissemination in space. Further prospective studies emphasizing MRI spinal cord features are needed to improve diagnostic criteria in a population of African descent.