Neuromyelitis optica (NMO) is a rare disease of the central nervous system restricted to optic nerves and spinal cord. The main neuroradiological criteria are a normal cerebral MRI at onset and longitudinal involvement of the cord affecting more than 3 vertebral segments.

This paper reports the results of 74 MRI in 32 clinical NMO Afro-Caribbean patients. A typical longitudinal lesion of the cord was present in 44.7 percent; a lesion involving less than 3 vertebral segments in 26.3 percent and no lesion in 21.1 percent. Follow-up suggested a progressive normalisation of the cord images. Atrophy was negatively correlated with immunosuppressive treatment. Cerebral lesions, usually absent at onset, were correlated to the duration of follow-up. In non-remitting cases cerebral and cord criteria were respectively met in 82.8 and 48.1 percent.

The paper concludes that MRI of the cord during periods of recurrent clinical activity showed multiple features besides the typical ones. The notion of multiple recurrences must be added to the spinal criteria to achieve a good sensitivity. A typical extensive lesion is usual in the follow-up, but present in less half the cases during the recurrences. If it presence was considered a condition for the diagnosis, the latter would be delayed.

33 references.