Differences in Advanced Magnetic Resonance Imaging in MOG-IgG and AQP4-IgG Seropositive Neuromyelitis Optica Spectrum Disorders: A Comparative Study.

Felix A Schmidt,Joseph Kuchling,Alexander U Brandt,Susanna Asseyer,Nadja Siebert,Michael Scheel,Friedemann Paul,Claudia Chien,Klemens Ruprecht,Judith Bellmann-Strobl,Sven Jarius

doi:10.3389/fneur.2020.499910

Abstract

Aims: To explore differences in advanced brain magnetic resonance imaging (MRI) characteristics between myelin oligodendrocyte (MOG) immunoglobulin (IgG) and aquaporin-4 (AQP4) IgG seropositive (+) neuromyelitis optica spectrum disorders (NMOSD).Methods: 33 AQP4-IgG and 18 MOG-IgG seropositive NMOSD patients and 61 healthy control (HC) subjects were included. All 112 participants were scanned with the same standardized MRI-protocol on a 3-Tesla MRI-scanner. Brain volume and diffusion tensor imaging (DTI) parameters were assessed.Results: MOG-IgG+ patients showed reduced parallel diffusivity within white matter tracts compared to HC whereas AQP4-IgG+ showed no significant brain parenchymal damage in DTI analysis. AQP4-IgG+ patients showed reduced whole brain volumes and reduced volumes of several deep gray matter structures compared to HC whereas MOG-IgG+ patients did not show reduced brain or deep gray matter volumes compared to HC.Conclusions: Microstructural brain parenchymal damage in MOG-IgG+ patients was more pronounced than in AQP4-IgG+ patients, compared with HC, whereas normalized brain volume reduction was more severe in AQP4-IgG+ patients. Longitudinal imaging studies are warranted to further investigate this trend in NMOSD. Our results suggest that MOG-IgG+ and AQP4-IgG+ NMOSD patients differ in cerebral MRI characteristics. Advanced MRI analysis did not help to differentiate between MOG-IgG+ and AQP4-IgG+ patients in our study.

Highlights

Neuromyelitis optica spectrum disorders (NMOSD) are autoimmune diseases that present with longitudinally extensive transverse myelitis (LETM) and or optic neuritis (ON)
myelin oligodendrocyte (MOG)-IgG+ patients showed reduced parallel diffusivity within white matter tracts compared to healthy control (HC) whereas AQP4-IgG+ showed no significant brain parenchymal damage in diffusion tensor imaging (DTI) analysis
AQP4-IgG+ patients showed reduced whole brain volumes and reduced volumes of several deep gray matter structures compared to HC whereas MOG-IgG+ patients did not show reduced brain or deep gray matter volumes compared to HC

Summary

Introduction

Neuromyelitis optica spectrum disorders (NMOSD) are autoimmune diseases that present with longitudinally extensive transverse myelitis (LETM) and or optic neuritis (ON). They can present with area postrema, diencephalic, cerebral or acute brainstem syndromes [1,2,3,4,5,6]. The proof of serum autoantibodies directed against aquaporin-4 (AQP4-IgG) in around 80% of cases established NMOSD as a distinct disease from multiple sclerosis (MS) [7,8,9,10]. In a subgroup of AQP4-IgG negative NMOSD patients serum antibodies targeting the myelin oligodendrocyte glycoprotein (MOG-IgG) were detected [11,12,13,14,15,16]. Cortical encephalitis and seizures or cranial nerve involvement have been reported in MOG-IgG+ patients [24,25,26,27]

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