MRI characteristics of neuromyelitis optica spectrum disorder

Abstract

Since its initial reports in the 19th century, neuromyelitis optica (NMO) had been thought to involve only the optic nerves and spinal cord. However, the discovery of highly specific antiaquaporin-4 antibody diagnostic biomarker for NMO enabled recognition of more diverse clinical spectrum of manifestations. Brain MRI abnormalities in patients seropositive for anti-aquaporin-4 antibody are common and some may be relatively unique by virtue of localization and configuration. Some seropositive patients present with brain involvement during their first attack and/or continue to relapse in the same location without optic nerve and spinal cord involvement. Thus, characteristics of brain abnormalities in such patients have become of increased interest. In this regard, MRI has an increasingly important role in the differential diagnosis of NMO and its spectrum disorder (NMOSD), particularly from multiple sclerosis. Differentiating these conditions is of prime importance because early initiation of effective immunosuppressive therapy is the key to preventing attack-related disability in NMOSD, whereas some disease-modifying drugs for multiple sclerosis may exacerbate the disease. Therefore, identifying the MRI features suggestive of NMOSD has diagnostic and prognostic implications. We herein review the brain, optic nerve, and spinal cord MRI findings of NMOSD. Neuromyelitis optica (NMO) is an inflammatory disease of the CNS that is characterized by severe attacks of optic neuritis (ON) and longitudinally extensive transverse myelitis (LETM). 1The past decade has witnessed dramatic advances in our understanding of NMO. Such advances were initiated by the discovery of the disease-specific autoantibody, NMO-immunoglobulin G (NMO-IgG), and subsequent identification of the main target autoantigen, aquaporin-4 (AQP4), which has distinguished NMO as a distinct disease from multiple sclerosis (MS). 2Current diagnostic criteria, however, still require both ON and myelitis for an NMO diagnosis.3 Nevertheless, the identification of anti-AQP4 antibodies beyond the current diagnostic criteria of NMO indicates a broader clinical phenotype of this disorder, so-called "NMO spectrum disorder" (NMOSD). 4,5 The NMOSD encompasses anti-AQP4 antibody seropositive patients with limited or inaugural forms of NMO and with specific brain abnormalities. It also includes anti-AQP4 antibody seropositive patients with other autoimmune disorders such as systemic

Neuromyelitis optica does not impact periventricular venous density versus healthy controls: a 7.0 Tesla MRI clinical study

“…To determine the mean signal intensity of the neighbouring normal appearing vein-free white matter, multiple ellipsoid ROIs with an area of 2mm 2 were used as a reference. Finally, the PVA (in mm 2 ) was calculated as the sum of all venous voxel.…”

“…Neuromyelitis optica spectrum disorders (NMOSD) are often disabling neuroinflammatory, autoimmune central nervous system conditions predominantly affecting the spinal cords and optic nerves [1][2][3][4]. Prior to the discovery of a serum immunoglobulin G antibody targeting the aquaporine-4 water channel [5,6], it was often considered a variant of multiple sclerosis (MS) as the clinical presentation of these two distinct central nervous system (CNS) diseases may overlap [1].…”

An unusual Guillain-Barré Syndrome mimic: a case of Spinal ADEM and review of the literature

“…of Aquaporin-4 antibodies in the blood. In NMO the spinal cord is usually inflamed around the central canal [31] and the spinal lesions involve a length of at least 3 vertebral bodies. The radiological findings of the spinal MRI, lack of optic nerve involvement and of aquaporin-4 antibodies in blood in our patient did not support the diagnosis of NMO.…”

Diffusion tensor imaging for multilevel assessment of the visual pathway: possibilities for personalized outcome prediction in autoimmune disorders of the central nervous system

“…Although parameters that are based on routine structural magnetic resonance imaging (MRI), such as T2 lesions and gadolinium (Gd) -enhancing plaques, represent highly relevant biomarkers for diagnosis [4,6] and therapy response in randomized controlled clinical trials [7,8], they provide insufficient information on functionally relevant disease severity, especially with respect to the visual system. DTI provides new markers that are sensitive and relatively specific to non-overt brain tissue damage [9].…”