title: Long-term MRI findings in neuromyelitis optica: seropositive versus seronegative patients.
abstract: OBJECTIVE
  Neuromyelitis optica (NMO) is a severe demyelinating inflammatory disorder associated with serum antibodies against aquaporin 4 (AQP4-Ab). A significant number of patients with NMO remain seronegative over time. Long-term observational magnetic resonance imaging (MRI) studies of the CNS in patients with NMO are rare or of limited duration. The objective of this study is to determine long-term MRI characteristics of seropositive and seronegative patients, and assess possible overlap with multiple sclerosis (MS).
  
  
  METHODS
  Clinical and radiological characteristics of 28 patients with NMO at onset and of 17 patients after an average follow-up time of 9 years were recorded. Fifty percent of patients were seropositive for AQP4-Ab. Onset and final brain/spinal MRI scans were retrospectively analysed and compared.
  
  
  RESULTS
  Significantly more patients in the seronegative group had brain lesions at onset. Spinal lesions of seropositive patients were longer and showed increased cord swelling at onset MRI scans. After the follow-up time the differences between both groups disappeared. Patients in the seropositive group tended to develop brain lesions over time. No patient fulfilled Barkhof's or McDonald's radiological criteria for MS at onset or over time.
  
  
  CONCLUSIONS
  Brain MRI features show differences between seropositive and seronegative patients at time of onset in NMO, but differences between groups vanish over time. None of the AQP4-negative patients fulfill radiological MS criteria on a long-term basis, suggesting that seronegative NMO constitutes an independent entity.
authors.affiliation: Department of Neurology, TC Bilim University, Istanbul, Turkey. asliatamer@superonline.com
authors.forename: A
authors.initials: A
authors.lastname: Kıyat-Atamer
authors.forename: E
authors.initials: E
authors.lastname: Ekizoğlu
authors.forename: E
authors.initials: E
authors.lastname: Tüzün
authors.forename: M
authors.initials: M
authors.lastname: Kürtüncü
authors.forename: E
authors.initials: E
authors.lastname: Shugaiv
authors.forename: G
authors.initials: G
authors.lastname: Akman-Demir
authors.forename: M
authors.initials: M
authors.lastname: Eraksoy
mesh_terms: D000328:Adult; D051401:Aquaporin 4 / Q000276:immunology; D001323:Autoantibodies / Q000097:blood*; D001921:Brain / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000175:diagnosis; D059906:Neuroimaging; D009471:Neuromyelitis Optica / Q000097:blood / Q000276:immunology* / Q000473:pathology*; D013116:Spinal Cord / Q000473:pathology*; D013997:Time Factors
chemical_list: D051401:Aquaporin 4; D001323:Autoantibodies