Optical Coherence Tomography and Magnetic Resonance Imaging in Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorder.

Irreversible disability in multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) is largely attributed to neuronal and axonal degeneration, which, along with inflammation, is one of the major pathological hallmarks of these diseases. Optical coherence tomography (OCT) is a non-invasive imaging tool that has been used in MS, NMOSD, and other diseases to quantify damage to the retina, including the ganglion cells and their axons. The fact that these are the only unmyelinated axons within the central nervous system (CNS) renders the afferent visual pathway an ideal model for studying axonal and neuronal degeneration in neurodegenerative diseases. Structural magnetic resonance imaging (MRI) can be used to obtain anatomical information about the CNS and to quantify evolving pathology in MS and NMOSD, both globally and in specific regions of the visual pathway including the optic nerve, optic radiations and visual cortex. Therefore, correlations between brain or optic nerve abnormalities on MRI, and retinal pathology using OCT, may shed light on how damage to one part of the CNS can affect others. In addition, these imaging techniques can help identify important differences between MS and NMOSD such as disease-specific damage to the visual pathway, trans-synaptic degeneration, or pathological changes independent of the underlying disease process. This review focuses on the current knowledge of the role of the visual pathway using OCT and MRI in patients with MS and NMOSD. Emphasis is placed on studies that employ both MRI and OCT to investigate damage to the visual system in these diseases.
Competing Interests: Praveena Manogaran received travel support from Genzyme/Sanofi-Aventis (Boston, USA). James V. M. Hanson is partially funded by the Clinical Research Priority Program (CRPP) of the University of Zurich and he has received travel support and speaker’s fees from Biogen Idec (Switzerland). Elisabeth D. Olbert received travel support from Biogen Idec (Switzerland) and Christine Egger received travel support from Merck Serono (Germany) and travel grants from the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS). Sven Schippling has received research grants from Biogen Idec (Germany), Bayer Healthcare (Germany) and Genzyme/Sanofi-Aventis (Boston, MA, USA) and consulting/speaker fees from Bayer Healthcare (Germany), Biogen Idec (Germany and Boston, MA, USA), Merck Serono (Germany), Novartis Pharma (Switzerland), TEVA (Israel) and Genzyme/Sanofi-Aventis (Boston, MA, USA). Carla Wicki, Christina Gerth-Kahlert and Klara Landau report no disclosures.