Our results suggest that there are different types of pathogenesis at different stages of POAG. Atrophy and degeneration of the visual-related cortex existed in the dorsal and ventral visual pathways in the advanced-late stage of POAG but were not found in the early stage of POAG using VBM. Such GM density changes are likely associated with the pathogenesis of POAG.
Thrombin and iron are two major players in intracerebral hemorrhage-induced brain injury and our recent study found that thrombin contributes to hydrocephalus development in a rat model of intraventricular hemorrhage (IVH). This study investigated the role of red blood cell (RBC) lysis and iron in hydrocephalus after IVH. There were three parts to this study. First, male SpragueDawley rats received an injection of saline, packed, or lysed RBCs into the right lateral ventricle. Second, rats had an intraventricular injection of iron or saline. Third, the rats received intraventricular injection of lysed RBCs mixed with deferoxamine (0.5 mg in 5 mL saline) or saline. All rats underwent magnetic resonance imaging at 24 hours and were then euthanized for brain edema measurement, western blot analysis, or brain histology. We found that intraventricular injection of lysed RBCs, but not packed RBCs, resulted in ventricular enlargement and marked increases in brain heme oxygenase-1 and ferritin at 24 hours. Intraventricular injection of iron also resulted in ventricular enlargement and ventricular wall damage 24 hours later. Coinjection of deferoxamine reduced lysed RBC-induced ventricular enlargement (Po0.01). These results suggest that iron, a degradation product of hemoglobin, has an important role in hydrocephalus development after IVH.
Generalized tonic-clonic seizures (GTCS) are characterized by unresponsiveness and convulsions, which cause complete loss of consciousness. Many recent studies have found that the ictal alterations in brain activity of the GTCS epilepsy patients are focally involved in some brain regions, including thalamus, upper brainstem, medial prefrontal cortex, posterior midbrain regions, and lateral parietal cortex. Notably, many of these affected brain regions are the same and overlap considerably with the components of the so-called default mode network (DMN). Here, we hypothesize that the brain activity of the DMN of the GTCS epilepsy patients are different from normal controls, even in the resting state. To test this hypothesis, we compared the DMN of the GTCS epilepsy patients and the controls using the resting state functional magnetic resonance imaging. Thirteen brain areas in the DMN were extracted, and a complete undirected weighted graph was used to model the DMN for each participant. When directly comparing the edges of the graph, we found significant decreased functional connectivities within the DMN of the GTCS epilepsy patients comparing to the controls. As for the nodes of the graph, we found that the degree of some brain areas within the DMN was significantly reduced in the GTCS epilepsy patients, including the anterior medial prefrontal cortex, the bilateral superior frontal cortex, and the posterior cingulate cortex. Then we investigated into possible mechanisms of how GTCS epilepsy could cause the reduction of the functional integrations of DMN. We suggested the damaged functional integrations of the DMN in the GTCS epilepsy patients even during the resting state, which could help to understand the neural correlations of the impaired consciousness of GTCS epilepsy patients.
Although there is increasing evidence suggesting that there may be subtle abnormalities in idiopathic generalized epilepsy (IGE) patients using modern neuroimaging techniques, most of these previous studies focused on the brain grey matter, leaving the underlying white matter abnormalities in IGE largely unknown, which baffles the treatment as well as the understanding of IGE. In this work, we adopted multiple methods from different levels based on diffusion tensor imaging (DTI) to analyze the white matter abnormalities in 14 young male IGE patients with generalized tonic-clonic seizures (GTCS) only, comparing with 29 age-matched male healthy controls. First, we performed a voxel-based analysis (VBA) of the fractional anisotropy (FA) images derived from DTI. Second, we used a tract-based spatial statistics (TBSS) method to explore the alterations within the white matter skeleton of the patients. Third, we adopted region-of-interest (ROI) analyses based on the findings of VBA and TBSS to further confirm abnormal brain regions in the patients. At last, considering the convergent evidences we found by VBA, TBSS and ROI analyses, a subsequent probabilistic fiber tractography study was performed to investigate the abnormal white matter connectivity in the patients. Significantly decreased FA values were consistently observed in the cerebellum of patients, providing fresh evidence and new clues for the important role of cerebellum in IGE with GTCS.
Purpose: To determine the regional changes in the shapes of subcortical structures in idiopathic generalized epilepsy using a vertex-based analysis method. Earlier studies found that gray matter volume in the frontal, parietal, and temporal lobes is significantly altered in idiopathic generalized epilepsy (IGE). Research has indicated that a relationship exists between the brain's subcortical structures and epilepsy. However, little is known about possible changes in the subcortical structures in IGE.
Materials and Methods:This study aims to determine the changes in the shape of subcortical structures in IGE using vertex analysis. Fourteen male patients with IGE and 28 age-and sex-matched healthy controls were included in this study, which used high-resolution magnetic resonance imaging. We performed a vertex-based shape analysis, in which we compared patients with IGE with the controls, on the subcortical structures that we had obtained from the MRI data.Results: Statistical analysis showed significant regional atrophy in the left thalamus, left putamen and bilateral globus pallidus in patients with IGE.
Conclusion:These results indicate that regional atrophy of the basal ganglia and the thalamus may be related to seizure disorder. In the future, these findings may prove useful for choosing new therapeutic regimens.
BACKGROUND AND PURPOSE: The present study was designed to detect the abnormalities of the cerebral grey-matter density in subcortical ischemic vascular dementia patients by FSL-VBM method to promote the early diagnosis of it.METHODS: Nine subcortical ischemic vascular dementia patients and nine age-matched normal controls underwent MRI brain structure scanning that was performed on a SIEMENS AVANTO 1.5 Tesla scanner and standard T1-weighted high-resolution anatomic scans of MPRAGE sequence were obtained. The 3-demensional MPRAGE images were processed with FSL-VBM package and the cerebral gray matter density was compared between the subcortical ischemic vascular dementia patients and normal controls.RESULTS: Compared with the normal control group, the cerebral gray matter density of subcortical ischemic vascular dementia patients was found significantly decreasing, including brain regions of thalamus, parietal lobe, frontal lobe and temporal lobe (P<0.05).CONCLUSIONS: The cerebral gray matter density alterations have closed correlation with cognitive dysfunction in subcortical ischemic vascular dementia patient and can be detected by MRI. MRI has some potential value in the diagnosis of them.
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