MRI of the spinal cord in neuromyelitis optica and recurrent longitudinal extensive myelitis

Background and purpose. - Neuromyelitis optica (NMO) is a severe inflammatory and necrotizing disease that clinically affects the optic nerves and spinal cord in a relapsing course. We assessed the baseline and follow-up MRI characteristics of cord attacks in NMO and recurrent longitudinal extensive myelitis (RLEM). Methods. - We retrospectively reviewed MRI data of 20 Afro-Caribbean patients diagnosed with either NMO or RLEM. MRI data from 51 cord or mixed attacks were evaluated, and 65 follow-up MRI studies were available for 30 baseline acute examinations. Results. - The cervical cord was involved in 63% of cases. Four attacks were limited to the brainstem. MRI of the spinal cord revealed longitudinal extensive signal abnormalities extending over three vertebral segments, associated with cord swelling in 67% of the 51 relapses. Gadolinium enhancement was observed, preferentially surrounding edema, in 69% of attacks. In the axial plane, signal abnormalities typically involved central areas of the cord. Cavitation was observed in 16% of attacks. Cord attacks recurred in the same or contiguous areas in 67% of cases. Follow-up MRI revealed a gradual decrease in cord swelling and T2 signal hyperintensity, with fragmentation of signal abnormalities in some cases. Cord atrophy was evident in 57% of the follow-up MRI. Conclusion. - Given the poor prognosis of NMO and RLEM, radiologists need to be aware of the MRI pattern to prevent further attacks with the use of aggressive treatment. (C) 2009 Elsevier Masson SAS. All rights reserved.