title: Ring-enhancing spinal cord lesions in neuromyelitis optica spectrum disorders.
abstract: We assessed the frequency and characteristics of ring-enhancing spinal cord lesions in neuromyelitis optica spectrum disorder (NMOSD) myelitis and myelitis of other cause.
  
  
  
  We reviewed spinal cord MRIs for ring-enhancing lesions from 284 aquaporin-4 (AQP4)-IgG seropositive patients at Mayo Clinic from 1996 to 2014. Inclusion criteria were as follows: (1) AQP4-IgG seropositivity, (2) myelitis attack and (3) MRI spinal cord demonstrating ring-enhancement. We identified two groups of control patients with: (1) longitudinally extensive myelopathy of other cause (n=66) and (2) myelitis in the context of a concurrent or subsequent diagnosis of multiple sclerosis (MS) from a population-based cohort (n=30).
  
  
  
  Ring-enhancement was detected in 50 of 156 (32%) myelitis episodes in 41 patients (83% single; 17% multiple attacks). Ring-enhancement was noted on sagittal and axial images in 36 of 43 (84%) ring enhancing myelitis episodes and extended a median of two vertebral segments (range, 1-12); in 21 of 48 (44%) ring enhancing myelitis episodes, the ring extended greater than or equal to three vertebrae. Ring-enhancement was accompanied by longitudinally extensive (greater than or equal to three vertebral segments) T2-hyperintensity in 44 of 50 (88%) ring enhancing myelitis episodes. One case of a spinal cord biopsy during ring-enhancing myelitis revealed tissue vacuolation and loss of AQP4 immunoreactivity with preserved axons. The clinical characteristics of ring-enhancing myelitis episodes did not differ from non-ring-enhancing episodes. Ring-enhancing spinal cord lesions were more common in NMOSD than other causes of longitudinally extensive myelopathy (50/156 (32%) vs 0/66 (0%); p≤0.001) but did not differ between NMOSD and MS (50/156 (32%) vs 6/30 (20%); p=0.20).
  
  
  
  Spinal cord ring-enhancement accompanies one-third of NMOSD myelitis episodes and distinguishes NMOSD from other causes of longitudinally extensive myelopathies but not from MS.
authors.affiliation: Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Nicholas L
authors.initials: NL
authors.lastname: Zalewski
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Padraig P
authors.initials: PP
authors.lastname: Morris
authors.affiliation: Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Brian G
authors.initials: BG
authors.lastname: Weinshenker
authors.affiliation: Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Claudia F
authors.initials: CF
authors.lastname: Lucchinetti
authors.affiliation: Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.|Department of Laboratory Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Sean J
authors.initials: SJ
authors.lastname: Pittock
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Karl N
authors.initials: KN
authors.lastname: Krecke
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Kaufmann
authors.affiliation: Department of Neurology, Mayo Clinic, Scottsdale, Arizona, USA.
authors.forename: Dean M
authors.initials: DM
authors.lastname: Wingerchuk
authors.affiliation: Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Neeraj
authors.initials: N
authors.lastname: Kumar
authors.affiliation: Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Eoin P
authors.initials: EP
authors.lastname: Flanagan
mesh_terms: D051401:Aquaporin 4 / Q000276:immunology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009103:Multiple Sclerosis / Q000473:pathology; D009187:Myelitis / Q000209:etiology* / Q000473:pathology; D009471:Neuromyelitis Optica / Q000150:complications* / Q000000981:diagnostic imaging; D011868:Radioisotopes; D011871:Radiology; D013118:Spinal Cord Diseases / Q000209:etiology / Q000473:pathology
chemical_list: D051401:Aquaporin 4; D011868:Radioisotopes