Alterations in the Brain Structure and Functional Connectivity in Aquaporin-4 Antibody-Positive Neuromyelitis Optica Spectrum Disorder

Abstract

Purpose: To investigate the mechanisms underlying the gray matter volume (GMV) and functional connectivity (FC) changes in aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (NMOSD) patients. Methods:This cross-sectional study consisted of 21 patients with aquaporin-4 antibody-positive NMOSD and 22 age-and sex-matched healthy controls. All participants underwent cerebral magnetic resonance imaging and testing each individual's visual acuity was done.Results: Neuromyelitis optica spectrum disorder patients showed significantly reduced GMV in the left calcarine, left thalamus and right lingual gyrus of the NMOSD patients when compared to HC (P < 0.05). NMOSD patients showed significantly decreased FC values (P < 0.05) in both the left and right calcarine, right lingual gyrus and left thalamus, respectively, when compared to HC. We also observed a positive correlation between the FC values of the left thalamus, bilateral calcarine gyrus and the visual acuity, respectively (P < 0.05). Furthermore, a negative association was seen between the duration of the disease, frequency of optic neuritis, and the FC values in the lingual gyrus, bilateral calcarine gyrus, and right lingual gyrus, respectively (P < 0.05). Conclusion:Reduced visual acuity and frequency of optic neuritis are associated with alterations in the GMV and FC in NMOSD. Our current study, which provides imaging evidence on the impairment involved in NMOSD, sheds light on pathophysiological responses of optic neuritis attack on the brain especially on the visual network.

Recontextualizing Neuromyelitis Optica as a Systemic Condition: A Perspective

“…Case studies have also demonstrated a potential for developing acute anosmia and dysphagia [31,32]. Optic neuritis and visual acuity loss have been demonstrated to occur due to physical changes in the cerebrum, specifically decreased gray matter volume and compromised functional connectivity [33]. Acute non-obstructive hydrocephalus has been discovered in patients with NMOSD, most likely due to the loss of AQP4, [34] a loss which mouse-model studies demonstrate cannot be compensated for by AQP1 [35].…”

A window into the future? MRI for evaluation of neuromyelitis optica spectrum disorder throughout the disease course

“… 147 , 148 The alterations in functional connectivity were shown to be associated with reduced visual and acuity and frequency of optic neuritis. 143 The exceptional resolution that ultrahigh-field 7-T MRI provides could further characterize structural changes in the CNS of NMOSD patients on a submillimeter level. Studies have used 7-T MRI to differentiate between NMOSD and MS and have shown that most NMOSD patients have small, subcortical lesions without a central venule, and an absence of cortical pathology.…”

“…147,148 The alterations in functional connectivity were shown to be associated with reduced visual and acuity and frequency of optic neuritis. 143 The exceptional resolution that ultrahigh-field 7-T MRI provides could further characterize structural changes in the CNS of NMOSD patients on a submillimeter level.…”

“…Several studies using resting-state and task-based functional MRI (fMRI) have shed light on the dynamic changes occurring in specific regions of the CNS in NMOSD. [142][143][144][145][146] One resting-state fMRI study showed that while the normal global topological structure was preserved, there was decreased functional connectivity in the visual and sensorimotor networks, and a positive correlation between neuronal reorganization and EDSS scores was demonstrated. 142 Other studies have illustrated that NMOSD patients with a history of optic neuritis undergo selective reorganization of the visual network with connectivity changes.…”

Irregular Baseline Brain Activity in Coronary Artery Disease Patients with Cognitive Impairment: A Resting-state Functional Magnetic Resonance Imaging Study

“…Rs-MRI is relatively easy to perform since it simply requires patients to remain still with their eyes closed. Therefore, the technique has a wide range of potential applications in clinical studies [ 8 , 9 ]. Quantitative measurement of low-frequency oscillation [LFO] amplitude offers another potentially useful tool for the detection of synchronization of LFO between spatially distinct brain regions [ 10 ].…”