Review Article

Brain Abnormalities in Neuromyelitis Optica Spectrum Disorder

Table 3

Diagnostic criteria of NMOa [53].

Major criteria (all criteria are required but may be separated by an unspecified interval)

(i) Optic neuritis in one or more eyes
(ii) Transverse myelitis, clinically complete or incomplete, but associated with radiological evidence of spinal cord lesion extending over three or more spinal segments on T2-weighted MRI images and hypointensity on T1-weighted images when obtained during acute episode of myelitis
(iii) No evidence for sarcoidosis, vasculitis, clinically manifest systemic lupus erythematosus or Sjögren’s syndrome, or other explanation for the syndrome

Minor criteria (at least one must be fulfilled)

(1) Most recent brain MRI scan of the head must be normal or may show abnormalities not fulfilling Barkhof criteria used for McDonald diagnostic criteria, includingb.
 (i) non-specific brain T2 signal abnormalities not satisfying Barkhof criteria as outlined in McDonald criteria
 (ii) lesions in the dorsal medulla, either in contiguity or not in contiguity with a spinal cord lesion
 (iii) hypothalamic and/or brainstem lesions
 (iv) “Linear” periventricular/corpus callosum signal abnormality, but not ovoid, and not extending into the parenchyma of the cerebral hemispheres in Dawson finger configuration
(2) Positive test in serum or CSF for NMO-IgG/aquaporin-4 antibodies

aThese criteria exclude limited or inaugural syndromes that may be NMO, such as recurrent transverse myelitis with longitudinally extensive spinal cord lesions or recurrent ON; further study is warranted to clarify their relationship with NMO, especially in the setting of seropositivity for NMO-IgG/AQP4 antibodies.
bPeriodic surveillance with brain MRI scanning is necessary to monitor for the emergence of new lesions that may lead to a revised diagnosis.