Evaluation of the nmosd 2015 imaging guideline to differentiate between diagnosis of multiple sclerosis and neuromyelitis optica spectrum disorder in Thai patients

Background & Objective: The neuromyelitis optic spectrum disorders (NMOSD) diagnostic criteria introduced in 2015 proposed many imaging criteria to differentiate between NMOSD and multiple sclerosis (MS). Criteria applied in Asian population with higher prevalence of NMOSD might not be as specific. The objective was to evaluate the NMOSD 2015 imaging guideline in Thai patients. Methods: The patients were recruited from MS and Related Disorders Clinic at a university hospital. NMOSD 2015 and McDonald 2010 diagnostic criteria were applied for diagnosis. NMOSD was classified into positive- and negative-AQP4 groups.The MRI available in the institute PAC system was reviewed by 3 neuroradiologists for features according to NMOSD 2015 imaging criteria. Percentage of each finding was calculated in all groups. Results: There were 37 MS and 101 NMOSD patients, with positive- and negative-AQP4 NMOSD in 88 and 13 cases, respectively. Most of the patients were female. Findings in brain MRI suggestive of MS were Dawson finger sign, periventricular inferior temporal lobe and corticospinal tract lesions. Involvement of corpus callosum and optic pathway was more common in MS. More patients with NMOSD showed involvement at posterior half of the optic nerve, whereas more patients with MS had involvement of optic radiation and optic tract. Spinal cord lesions more common in NMOSD included thoracic cord involvement, lesions extending more than 3 vertebral body segments and centrally located lesions in axial plane. Conclusion: Only some brain MRI features were more conclusive for NMOSD in Thai patients. Spinal cord MRI lesions were still more helpful in differentiating between MS and NMOSD.