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Background: Relapsing-neuromyelitis optica (R-NMO) is the first CNS inflammatory autoimmune disease with a defined target molecule: the astrocytic water channel aquaporin-4 (AQP4). We have reported structural brain abnormalities in R-NMO patients by visual analysis on MRI images. Objective: We were interested in confirming these structural abnormalities using statistical parametric mapping; and also in finding out whether brain perfusion shows similar abnormalities. Methods: Brain structure and perfusion were compared between 15 R-NMO patients (13 female, 2 male; mean age = 40.6 ? 10.7 years) and 15 healthy volunteers (13 female, 2 male; mean age = 55.3? 3.4 years), by voxel brain morphometry on MRI images and voxel-based perfusion SPECT. Considering the difference of mean age between groups, Ancova design was used to model age and gender as nuisance covariates. Results: R-NMO patients showed significantly reduced grey matter (GM) density (one cluster of voxels: p< 0.05, corrected by multiple comparison) in the bilateral thalamus regions bordering the third ventricle. White matter (WM) density was also significantly reduced, represented by a cluster wider than the GM cluster, located bilaterally in the corpus callosum, in WM regions contiguous to the third ventricle and both lateral ventricles, mainly around the posterior lateral horns. GM and WM clusters seemed to be very close to each other in a posterior region of the left thalamus. There was no difference between groups concerning GM and WM volumes. Brain perfusion showed a very similar pattern to GM density. However hypoperfusion also extended to the left middle cingulate cortex. Conclusions: We confirmed structural abnormalities in R-NMO patients represented by differences in grey/white matter density in regions contiguous to ventricular spaces, mainly around the third. Brain hypoperfusion is probably due to GM density reduction or vice versa. Longitudinal studies are needed to clarify this, as well as further quantitative analysis to elucidate the significance of the partial mismatching between GM density and brain perfusion.

Read More: Differences in grey/white matter density and brain perfusion in patients with relapsing neuromyelitis optica: a voxel-based study