title: Diagnosis of neuromyelitis optica (NMO) spectrum disorders: is MRI obsolete?
abstract: BACKGROUND
  Neuromyelitis optica (NMO) is a severe demyelinating disease that preferentially involves spinal cord and optic nerve. It is part of a spectrum of neurological conditions associated with antibodies to aquaporin-4 (AQP4). This study investigates the role of MRI where novel, more sensitive AQP4 antibody immunoassay techniques are being used.
  
  
  METHODS
  Retrospective review of neuroimaging in 69 patients (25 antibody positive, 44 antibody negative), investigated in the context of suspected NMO or NMO spectrum disorder, was performed independently by two consultant neuroradiologists.
  
  
  RESULTS
  Longitudinally extensive, central spinal cord lesions were more frequent in AQP4 positive patients (95.2% vs 35.5%, p < 0.0001; 85.7% vs 45.2%, p = 0.015). Multiple sclerosis diagnostic criteria were less frequently fulfilled on brain MRI in antibody positive patients (5.6% vs 33.3%, p = 0.035). Juxtacortical and corpus callosal lesions were also less common in this group (16.7% vs 46.7%, p = 0.063; 5.6% vs 46.7%, p = 0.0034). Hypothalamic and periependymal disease related to the aqueduct was not seen in antibody negative patients. T1 hypointensity was more common in cord lesions of antibody positive patients (75.0% vs 35.3%, p = 0.037). However, this characteristic did not discriminate antibody positive and negative longitudinally extensive cord lesions (73.3% vs 62.5%, p = 0.66).
  
  
  CONCLUSIONS
  The NMO spectrum of diseases are among an increasing number of neurological conditions defined by serological tests. However, despite improved immunoassay techniques, MRI of the brain and spinal cord continues to be among the first-line investigations in these patients, providing valuable diagnostic information that will help guide patient management.
authors.affiliation: Department of Neuroradiology, John Radcliffe Hospital, West Wing, Level 1, OX3 9DU, Oxford, UK.
authors.forename: Jonathan James
authors.initials: JJ
authors.lastname: Downer
authors.forename: Maria Isabel
authors.initials: MI
authors.lastname: Leite
authors.forename: Ranjana
authors.initials: R
authors.lastname: Carter
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Palace
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Küker
authors.forename: Gerardine
authors.initials: G
authors.lastname: Quaghebeur
mesh_terms: D000328:Adult; D003287:Contrast Media; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009471:Neuromyelitis Optica / Q000175:diagnosis* / Q000473:pathology; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric
chemical_list: D003287:Contrast Media