Brain Tissue Volumes and Perfusion Change with the Number of Optic Neuritis Attacks in Relapsing Neuromyelitis Optica: A Voxel-Based Correlation Study

Abstract

Recent neuroimaging studies show that brain abnormalities in neuromyelitis optica (NMO) are more frequent than earlier described. Yet, more research considering multiple aspects of NMO is necessary to better understand these abnormalities. A clinical feature of relapsing NMO (RNMO) is that the incremental disability is attack-related. Therefore, association between the attack-related process and neuroimaging might be expected. On the other hand, the immunopathological analysis of NMO lesions has suggested that CNS microvasculature could be an early disease target, which could alter brain perfusion. Brain tissue volume changes accompanying perfusion alteration could also be expected throughout the attack-related process. The aim of this study was to investigate in RNMO patients, by voxel-based correlation analysis, the assumed associations between regional brain white (WMV) and grey matter volumes (GMV) and/or perfusion on one side, and the number of optic neuritis (ON) attacks, myelitis attacks and/or total attacks on the other side. For this purpose, high resolution T1-weighted MRI and perfusion SPECT imaging were obtained in 15 RNMO patients. The results showed negative regional correlations of WMV, GMV and perfusion with the number of ON attacks, involving important components of the visual system, which could be relevant for the comprehension of incremental visual disability in RNMO. We also found positive regional correlation of perfusion with the number of ON attacks, mostly overlapping the brain area where the WMV showed negative correlation. This provides evidence that brain microvasculature is an early disease target and suggests that perfusion alteration could be important in the development of brain structural abnormalities in RNMO.

Thalamic Atrophy Contributes to Low Slow Wave Sleep in Neuromyelitis Optica Spectrum Disorder

“…This finding is consistent with some previous studies [19], but discordant with others [20]. This discordance may be due to the different analytical methods used or heterogeneous patient groups.…”

Altered neurovascular coupling in neuromyelitis optica

“…Any changes in vascular components may also affect the integrity of NVU. Dysfunction of endothelial cells has been observed in NMO (Takeshita et al, ), which may lead to the regulatory dysfunction of perfusion (Sanchez‐Catasus et al, ) and eventually result in the reduced neurovascular coupling. However, the relationship between vascular damage and reduced neurovascular coupling in NMO needs to be further studied.…”

“…Astrocyte damage is thought to be a key pathological characteristic of NMO (Kawachi & Lassmann, ; Takeshita et al, ), which may disrupt the NVU and eventually result in abnormal neurovascular coupling. In addition, the previously reported neuronal (Duan et al, ; Liu et al, ; Pichiecchio et al, ; Saji et al, ; von Glehn et al, ; Wang, Zhang et al, ) and vascular impairments (Sanchez‐Catasus et al, ; Takeshita et al, ) could also affect neurovascular coupling in NMO. Based on the evidence of astrocyte damage, neuronal loss, and vascular impairments in NMO, we hypothesized that patients with NMO would show alterations in neurovascular coupling.…”

Olfactory dysfunction in neuromyelitis optica spectrum disorders

“…Brain Values are mean (SD) unless otherwise indicated. Data are presented as mean ± SD; MRI magnetic resonance imaging, NMOSDs neuromyelitis optica spectrum disorders, AQP-4 aquaporin-4, Ab antibody, OBV olfactory bulb volume, GMV gray matter volume, WMV white matter volume tissue volume changes accompanying perfusion changes in NMO were pointed by Sánchez-Catasús et al [31]. Nevertheless, neuroregeneration and synaptogenesis could also influence the volume changes in central nervous structures.…”