Neuroradiological aspects of Devic's neuromyelitis optica

INTRODUCTION: Neuromyelitis optica (NMO) is a rare inflammatory and demyelinating disorder of the central nervous system, restricted to optical nerves and spinal cord. The main neuroradiological aspects, now summarized into a complete set of diagnosis criteria, are a normal cerebral MRI at onset and longitudinal involvement of the spinal cord concerning more than 3 vertebral segments. The clinical course and frequency of typical lesions remain unknown. OBJECTIVE: We here report neuroradiological data from patients suffering from NMO. METHODS: Brain and spinal cord MRI were systematically reviewed for 32 afro-Caribbean patients. RESULTS: A typical longitudinal spinal lesion was seen in 44.7 percent with or without edema; a lesion involving less than 3 vertebral segments in 26.3 percent and no lesion in 21.1 percent. Longitudinal study of a few bouts suggested a progressive normalisation of spinal cord appearance. Atrophy was negatively correlated with immunosuppressive treatment. Cerebral lesions usually absent at onset were correlated to the follow-up. In a non-recursive condition, patients completed diagnostic criteria for encephalic and spinal lesions in 82.8 percent and 48.1 percent. CONCLUSION: Radiology of spinal bouts showed multiple aspects besides the typical form. The notion of multiple bouts must be added to the spinal criteria to achieve good sensitivity. A typical extensive spinal lesion is usual in the follow-up, but seen after less then half of the bouts. Requiring such a lesion would delay the diagnosis.