Magnetic Resonance Imaging of Neuromyelitis Optica (Devic’s Syndrome)

Neuromyelitis optica (NMO, also known as Devic’s syndrome) is a demyelinating disease of the central nervous system characterized by recurrent optic neuritis and acute transverse myelitis. The disease was initially considered a variant of multiple sclerosis (MS). However, recent literature had suggested that NMO is a distinct disease from MS, with poorer prognosis and different therapy. Therefore, it is important to distinguish NMO from MS as soon as possible. The presentations of optic neuritis and acute transverse myelitis in patients with NMO can be separate or simultaneous in clinical course, and the variations in clinical symptoms make early recognition and diagnosis of NMO difficult. We report two cases of NMO with their manifestations on magnetic resonance imaging (MRI) in our hospital. With the use of MRI and the specific autoantibody NMO-IgG, NMO can be diagnosed earlier and more accurately. Correspondence Author to: Tai-Yuan Chen Department of Medical Imaging, Chi-Mei Medical Center No. 901, Zhong-Hua Road, Yongkang, Tainan 710, Taiwan J Radiol Sci 2012; 37: 45-50 MRi of Neuromyelitis Optica 46 J Radiol Sci March 2012 Vol.37 No.1 cell (WBC) count = 13600/uL), and anti-dsDNA was within normal limit (anti-dsDNA=1.8IU/mL). A nerve conduction velocity study revealed bilateral lumbosacral plexopathy. With a clinical suspicion of acute transverse myelitis, contrast-enhanced MRI of the whole spine was performed. Swelling of the spinal cord with contiguous high signal intensity on T2-weighted images was identified from level C6 to T6 (Fig. 1a, 1b). Entire cross section of the spinal cord was involved, and no obvious enhancement after intravenous gadolinium administration was observed (Fig. 1c). The findings were consistent with acute transverse myelitis, and no other intracranial abnormality was identified on the serial brain MR images. Cerebrospinal fluid (CSF) analysis showed negative oligoclonal band and no pleocytosis (WBC count = 0/mm3). Considering the patient’s history of optic neuritis, NMO was strongly suspected. Therefore, we checked serum NMO-IgG and the result was positive. table 1. the comparison between MS and NMO [2, 3, 8-12]