| 1. A Voxel-based Morphometry Study of Brain Tissue Volume Changes in Neuromyelitis Optica Patients Using High filed (3T) MRI ScannerPurpose:To explore the brain tissue volume (BTV) changes in neuromyelitis optica (NMO) patients with voxel-based morphometry (VBM) method using high filed (3.0T) MRI Scanner. To investigate the correlations between brain tissue volume changes with clinical variables.Materials and Methods:24NMO patients and24gender and age matched healthy controls were scanned at3T MR system with T2WI, FLAIR and sagittal three-dimensional (3D) volumetric T1-weighted fast spoiled gradient echo (FSPGR) sequences. Raw data was processed and analyzed using VBM8toolbox of statistical parametric mapping (SPM)8software. Comparison of focal grey matter volume (GMV) and white matter volume (WMV) between the two groups was analyzed by independent two samples t-test, and statistical maps were thresholded with uncorrected P value,0.005with a minimum cluster size of30voxels according to previous published study. For the patient group, correlation analyses were performed between brain tissue volume loss and clinical variables, including disease duration, relapse and EDSS score.Results:For global mean GMV and WMV, there is no significant difference between the two groups (P>0.05). At vertex-wise level, compared with the controls, the GMV decrease was observed in NMO patients in several regions of cerebellum, precentral gyrus, postcentral gyrus, lingual gyrus, middle temporal gyrus, inferior temporal gyrus, occipital lobe, cuneus, precuneus, limbic lobe, fusiform gyrus, calcarine, caudate, thalamus, optic tract and Brodmann area3,4,6,17,8,19(P<0.005, uncorrected). The focal WMV decrease was observed in NMO patients in cerebellum, midbrain, limbic lobe, parietal lobe, optic tract, hippocampus, parahippocampal gyrus and precuneus (P<0.005, uncorrected). The disease duration negatively correlated with GMV in bilateral cerebellum, left temporal lobe, right thalamus, right superior temporal gyrus, bilateral parietal lobe and postcentral gyrus (P<0.05). The EDSS score negatively correlated with GMV in right cerebellum and left temporal lobe (P<0.05). The relapse negatively correlated with GMV in bilateral cerebellum, bilateral inferior temporal gyrus, bilateral middle temporal gyrus, left temporal pole, fusiform gyrus, right superior temporal gyrus, right postcentral gyrus, right parietal lobe, bilateral thalamus, left parietal lobe, left postcentral gyrus, right superior parietal lobule and right precuneus (P<0.05). The EDSS score negatively correlated with WMV in left cerebellum, bilateral hippocampus and parahippocampal gyrus (P<0.05). The WMV in bilateral cerebellum negatively correlated with relapse (P<0.05).Conclusions:Regional atrophy of grey matter and white matter was found in NMO patients. Brain tissue volume in several brain areas correlated with clinical variables significantly. VBM can reveal brain volume changes sensitively and could be an imaging biomarker to monitor clinical severity and disease progression. 2. A Voxel-based Analysis of Diffusion Tensor Imaging in Neuromyelitis Optica PatientsPurpose: To explore the whole brain diffusion changes in neuromyelitis optica (NMO) patients using voxel-based analysis of diffusion tensor imaging (DTI) by multiple diffusion indices. To investigate the correlations between diffusion indices changes with clinical variables.Materials and Methods:Whole brain structural images and diffusion weighted images (DTI) were acquired in16NMO patients and16gender and age matched healthy controls. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD/λ1) and radial diffusivity (RD/λ23) of NMO patients were compared with the controls by voxel-based analysis of DTI data using independent two samples t-test, and statistical maps were thresholded with uncorrected P value,0.005with a minimum cluster size of30voxels according to previous published study. For the patient group, correlation analyses were performed between diffusion indices changes and clinical variables by Pearson correlation analysis.Results:Compared with the controls, NMO patients showed significant FA decrease in bilateral frontal lobe, occipital lobe, temporal lobe, thalamus, midbrain, optic tract and cerebellum (P<0.005, uncorrected). λ1increase in NMO patients could be seen in bilateral cerebellum, occipital lobe, frontal lobe, parietal lobe, thalamus, midbrain, parahippocampal gyrus, cingulate cortex, corpus callosum, basal ganglia, caudate nucleus, insula and limbic lobe (P<0.005, uncorrected). λ2increase in NMO patients could be seen in bilateral cerebellum, occipital lobe, temporal lobe, frontal lobe, parietal lobe, thalamus, midbrain, parahippocampal gyrus, cingulate cortex, corpus callosum, basal ganglia, caudate nucleus, limbic lobe and insula (P<0.005, uncorrected). X3increase in NMO patients could be seen in cerebellum, temporal lobe, frontal lobe, thalamus, globus pallidus, midbrain, cingulate cortex, limbic lobe and corpus callosum (P<0.005, uncorrected). MD increase in NMO patients could be seen in cerebellum, occipital lobe, frontal lobe, thalamus, cingulate cortex, corpus callosum, basal ganglia, right caudate nucleus and limbic lobe (P<0.005, uncorrected). No significant correlation was found between diffusion indices changes with clinical variables (P>0.05).Conclusions: DTI could reveal the significant diffusion abnormalities in NMO by diffusion indices of AD, RD and MD sensitively, especially AD and MD. This study revealed that the cortical damage in NMO is mainly characterized by axonal injury while the white matter damage is characterized by both axonal injury and demyelination. 1. A Voxel-based Morphometry Study of Brain Tissue Volume Changes in Neuromyelitis Optica Patients Using Ultra-high filed (7T) MRI SystemPurpose:To explore the brain issue volume (BTV) changes in neuromyelitis optica (NMO) patients with voxel-based morphometry (VBM) method using ultra-high filed (7T) MRI Scanner. To investigate the correlations between brain tissue volume changes with clinical variables. To identify the usefulness of7T MRI in brain structural research.Materials and Methods:12NMO patients and12gender and age matched healthy controls were scanned at7T MR system with T2WI, FLAIR and sagittal three-dimensional (3D) volumetric T1-weighted magnetization-prepared rapid acquisition gradient echo (MPRAGE) sequences. Raw data was processed and analyzed using VBM8toolbox of statistical parametric mapping (SPM)8software. Comparison of focal grey matter volume (GMV) and white matter volume (WMV) between the two groups was analyzed by independent two samples t-test, and statistical maps were thresholded with uncorrected P value,0.005with a minimum cluster size of30voxels according to previous published study. For the patient group, correlation analyses were performed between brain tissue volume loss and clinical variables, including disease duration, relapse and EDSS score.Results:For global mean GMV and WMV, there is no significant difference between the two groups (P>0.05). At vertex-wise level, compared with the controls, the GMV decrease was observed in NMO patients in several regions of temporal lobe, frontal lobe, precentral gyrus, postcentral gyrus, Brodmann area6,9,22, parietal lobe, fusiform gyrus, parahippocampal gyrus and cerebellum (P<0.005, uncorrected). The focal WMV decrease was observed in NMO patients in bilateral putamen nucleus, occipital lobe, parahippocampal gyrus, limbic lobe, lingual gyrus, Brodmann area6,7,17,18,19,40, supramarginal gyrus, amygdaloid nucleus, postcentral gyrus, precuneus, parietal lobe, frontal lobe and cerebellum (P<0.005, uncorrected). Both disease duration and relapse negatively correlated with GMV in left precentral gyrus, left postcentral gyrus and Brodmann area6(P<0.05). The EDSS score negatively correlated with WMV in right supramarginal gyrus (P<0.05).Conclusions:Diffuse atrophy of grey matter and white matter was found in NMO patients. VBM can reveal subtle brain volume changes. Higher field strength MRI scanner could detective the subtle brain damage more sensitively. 2. Focal Cortical Thinning in Neuromyelitis Optica Using Ultra-high Field (7T) MRI ScannerPurpose:The present study is aimed to prospectively evaluate cortical thickness changes of patients with neuromyelitis optica (NMO) without visible lesions in the grey matter using high Field (3T) and ultra-high field (7T) MRI scanner. To investigate the correlations between cortical thickness changes with clinical variables. To identify the usefulness of7T MRI in cortical thickness study.Materials and Methods:24NMO patients without visible lesions in the grey matter and24gender and age matched healthy controls were scanned at3T MR system with sagittal three-dimensional (3D) volumetric T1-weighted fast spoiled gradient echo (FSPGR) sequences.12patients with NMO without visible lesions in the grey matter on conventional MRI and12sex-and age-matched healthy control subjects were scanned at7T whole-body human MR system with sagittal three-dimensional (3D) volumetric T1-weighted magnetization-prepared rapid acquisition gradient echo (3D-MPRAGE) sequence. Cortical thickness measurement was performed by FreeSurfer software5.0. Comparison of cortical thickness between the two groups was analyzed by paired t-test, and the significance of the P-value was set at0.01because of the number of statistical tests. For the patient group, correlation analyses were performed between brain cortical thickness changes and clinical variables, including disease duration, relapse and EDSS score.Results:There is no significant difference of both global and focal cortical thickness between the two groups by analyzing3T data. As for7T data, no significant difference of global cortical thickness was found between the two groups (P>0.05). However, as compared with the controls, NMO patients showed focal cortical thinning in left middle frontal gyrus (MFGL), left fusiform gyrus (FG.L), left lingual gyrus and left inferior temporal gyrus (P<0.01,uncorrected). No significant correlation was found between cortical thickness changes with clinical variables (P>0.05).Conclusion: Significant cortical thinning was identified in NMO patients, involving visual, motor and cognition system, suggesting the presence of occult tissue damage in normal-appearance grey matter in NMO patients. This study also suggests that ultra-high field imaging may be useful for characterizing subtle lesions of the grey matter in NMO. Purpose:To prospectively evaluate how brain baseline activity changes in NMO patients using amplitude in the time domain (AM) and regional homogeneity (ReHo) as indices with ultra-high field (7T) MRI system.Materials and Methods:12NMO patients and12gender and age matched healthy controls were scanned at7T MR system to collect resting-sate fMRI data. Raw data was preprocessed using statistical parametric mapping (SPM)8software. AM and ReHo were compared between the two groups to investigate the brain baseline activity changes in NMO patients.Results: Our results showed that NMO patients had significantly increased AM in left middle frontal gyrus (MFGL), inferior frontal gyrus (IFGL), precentral gyrus (PreCG.L), Brodmann area6, Brodmann area45and Brodmann area44. NMO patients showed no regions with decreased AM. Comparing the NMO group with the healthy controls, we found ReHo decreased in right middle temporal gyrus (MTG/.R), right inferior temporal gyrus (ITG.R), right fusiform gyrus (FuGR); and increased in right medial prefrontal cortex (MPFC.R/Brodmann area9、10), right middle frontal gyrus (MFG.R), bilateral inferior frontal gyrus (IFG), Brodmann area44, Brodmann area45, left precentral gyrus (PreCG.L), postcentral gyrus (PosCG.L) and Brodmann area6.Conclusions: The abnormal baseline brain activity shown by resting-state fMRI in NMO is relevant to visual, motor and cognition systems that is consistent with the structural research results. These results demonstrate that neural activity in the resting state changes in patients with NMO. |
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