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

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

Traumatic Brain Injury: Nuclear Medicine Neuroimaging

This chapter provides an up-to-date review of nuclear medicine neuroimaging in traumatic brain injury (TBI). 18F-FDG PET will remain a valuable tool in researching complex mechanisms associated with early metabolic dysfunction in TBI. Although evidence-based imaging studies are needed, 18F-FDG PET in the TBI acute phase appeared to be more useful in those patients in whom structural neuroimages fail to show abnormalities explaining their neurological state. 15O2-PET is also a solid technique for research in acute TBI, but in contrast to 18F-FDG PET it is not widely available due to its high cost. In the chronic TBI phase, most 18F-FDG PET studies converge to identify a diffuse cortical–subcortical hypometabolism involving key regions for cognitive function. Recent studies suggest the usefulness of 18F-FDG PET for the evaluation of therapeutic interventions in chronic TBI patients with cognitive deficits. In recent years, interest in studying cell-specific processes is growing. The use of radioligands as markers of neuroinflammation could become attractive for detecting secondary damage and serve for the evaluation of different therapeutic approaches. SPECT advances also make this technique a valid alternative for the study of TBI

Brain perfusion positive correlation with the number of optic neuritis attacks in RNMO patients.

<p>The same slices as shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0066271#pone-0066271-g001" target="_blank">Figure 1</a>, presenting the perfusion positive correlation statistical parametric map, which was found in an extensive brain area mainly located in the white matter. Note that perfusion changes included periventricular areas. Statistical parametric map was thresholded at p value <0.01 (p value <0.05 corrected for multiple comparisons at the cluster level).</p

Brain regions with negative correlation between grey matter volume and the number of optic neuritis attacks.

<p>P, P value corrected for multiple comparisons at cluster level; GM, grey matter.</p

Brain regions with positive correlation between perfusion and the number of optic neuritis attacks.

<p>P, P value corrected for multiple comparisons at cluster level; DWM, deep white matter; SWM, superficially located white matter; GM, grey matter.</p

Demographic and clinical characteristics of patients with relapsing neuromyelitis optica (n = 15).

<p>Data shown as median and range (minimum, maximum). EDSS, Kurtzke Expanded Disability Status Scale <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0066271#pone.0066271-Kurtzke1" target="_blank">[24]</a>; ON, optic neuritis; LETM, longitudinally extensive transverse myelitis; NMO-IgG, antiaquaporin-4 autoantibody;</p>*<p>Last attack MRI/SPECT time interval.</p

Multimodal negative correlation pattern with the number of optic neuritis attacks in RNMO patients.

<p>Axial, sagittal and coronal selected slices at four brain levels (levels shown as white lines in the figures on the right side), presenting overlays of negative correlation statistical parametric maps of white matter volume (in green), grey matter volume (in blue) and perfusion (in pink) on a T1-weighted high resolution MRI template. Decreases of tissue volumes and perfusion with the increase of the number of optic neuritis attacks comprised extensive brain regions, including important components of the visual system such as posterior thalamic radiations (white matter volume), middle and superior temporal gyri (grey matter volume) and the primary visual area (perfusion). Also note that tissue volume decreases included regions close to periaqueductal areas. Statistical parametric maps were thresholded at p value <0.01 (p value <0.05 corrected for multiple comparisons at the cluster level).</p

Brain regions with negative correlation between white matter volume and the number of optic neuritis attacks.

<p>P, P value corrected for multiple comparisons at cluster level; DWM, deep white matter; SWM, superficially located white matter.</p