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Detecting dopaminergic neuronal degeneration using diffusion tensor imaging in a rotenone-induced rat model of Parkinson's disease: fractional anisotropy and mean diffusivity values

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Neural Regeneration Research 2017年第9期12卷 1485-1491页

作者： Lan-xiang Liu Dan Du Tao Zheng Yuan Fang Yan-sheng Chen Hui-ling Yi Qing-yuan He Da-wei Gao Qing-lei Shi Department of Magnetic Resonance Imaging First Hospital of Qinhuangdao Department of Radiology Peking University Third Hospital College of Environmental and Chemical Engineering Yanshan University Scientific Clinical Specialist Siemens Ltd.

Dopamine content in the basal ganglia is strongly associated with the degree of dopaminergic neuron loss in the substantia nigra pars com- pacta. Symptoms of Parkinson＇s disease might not arise until more than 50% of the substantia nigra pars compacta is lost and the dopamine content in the basal ganglia is reduced by more than 80%. Greater diagnostic sensitivity and specificity would allow earlier detection of Parkinson＇s disease. Diffusion tensor imaging is a recently developed magnetic resonance imaging technique that measures mean diffusiv- ity and fractional anisotropy, and responds to changes in brain microstructure. When the microscopic barrier （including cell membranes, microtubules and other structures that interfere with the free diffusion of water） is destroyed and extracellular fluid volume accumulates, the mean diffusivity value increases; when the integrity of the microstructure （such as myelin） is destroyed, fractional anisotropy value decreases. However, there is no consensus as to whether these changes can reflect the early pathological alterations in Parkinson＇s disease. Here, we established a rat model of Parkinson＇s disease by injecting rotenone （or sunflower oil in controls） into the right suhstantia nigra. Diffusion tensor imaging results revealed that in the stages of disease, at 1, 2, 4, and 6 weeks after rotenone injection, fiactional anisotropy value decreased, but mean diffusivity values increased in the right substantia nigra in the experimental group. Fractional anisotropy values were lower at 4 weeks than at 6 weeks in the right substantia nigra of rats from the experimental group. mean diffusivity values were mark- edly greater at 1 week than at 6 weeks in the right corpus striatum of rats from the experimental group. These findings suggest that mean diffusivity and fractional anisotropy values in the brain of rat models of Parkinson＇s disease 4 weeks after model establishment can reflect early degeneration of dopaminergic neurons. ＇The change in fractional anisotropy values after d

关键词： nerve regeneration diffusion tensor imaging fractional anisotropy mean diffusivity magnetic resonance imaging Parkinson＇s disease rotenone neurodegenerative disease biomarkers substantia nigra tyrosine hydroxylase neural regeneration

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Correlations between hippocampal functional connectivity,structural changes,and clinical data in patients with relapsing-remitting multiple sclerosis:a case-control study using multimodal magnetic resonance imaging

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Neural Regeneration Research 2022年第5期17卷 1115-1124页

作者： Xin-Quan Gu Ying Liu Jie-Bing Gu Lin-Fang Li Ling-Ling Fu Xue-Mei Han China-Japan Union Hospital of Jilin University ChangchunJilin ProvinceChina First Department of Neurology China-Japan Union Hospital of Jilin UniversityChangchunJilin ProvinceChina Cardre’s Ward Changchun Central hospitalChangchunJilin ProvinceChina

Multiple sclerosis is associated with structural and functional brain alterations leading to cognitive impairments across multiple domains including attention,memory,and the speed of information processing.The hippocampus,which is a brain important structure involved in memory,undergoes microstructural changes in the early stage of multiple sclerosis.In this study,we analyzed hippocampal function and structure in patients with relapsing-remitting multiple sclerosis and explored correlations between the functional connectivity of the hippocampus to the whole brain,changes in local brain function and microstructure,and cognitive function at rest.We retrospectively analyzed data from 20 relapsing-remitting multiple sclerosis patients admitted to the Department of Neurology at the China-Japan Union Hospital of Jilin University,China,from April 2015 to November 2019.Sixteen healthy volunteers were recruited as the healthy control group.All participants were evaluated using a scale of extended disability status and the Montreal cognitive assessment within 1 week before and after head diffusion tensor imaging and functional magnetic resonance imaging.Compared with the healthy control group,the patients with relapsing-remitting multiple sclerosis had lower Montreal cognitive assessment scores and regions of simultaneously enhanced and attenuated whole-brain functional connectivity and local functional connectivity in the bilateral hippocampus.Hippocampal diffusion tensor imaging data showed that,compared with the healthy control group,patients with relapsing-remitting multiple sclerosis had lower hippocampal fractional anisotropy values and higher mean diffusivity values,suggesting abnormal hippocampal structure.The left hippocampus whole-brain functional connectivity was negatively correlated with the Montreal cognitive assessment score(r=-0.698,P=0.025),and whole-brain functional connectivity of the right hippocampus was negatively correlated with extended disability status scale score(r=-0.649,P=0.042).The mean diffus

关键词： cognitive impairment diffusion tensor imaging fractional anisotropy functional connectivity functional magnetic resonance imaging hippocampus local consistency low frequency oscillation amplitude mean diffusivity multiple sclerosis neurodegeneration

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Magnetic resonance diffusion tensor imaging of optic nerve and optic radiation in healthy adults at 3T

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International Journal of Ophthalmology(English edition) 2013年第6期6卷 868-872页

作者： Hong-Hong Sun Dong Wang Qiu-Juan Zhang Zhi-Lan Bai Ping He Department of Radiology the Second Hospital of Xi'an Jiaotong University

AIM:To investigate the diffusion characteristics of water of optic nerve and optic radiation in healthy adults and its related factors by diffusion tensor imaging（DTI）at3T.METHODS:A total of 107 healthy volunteers performed head conventional MRI and bilateral optic nerve and optic radiation DTI.The primary data of DTI was processed by post-processing software of DTI studio 2.3,obtaining fractional anisotropy value,mean diffusivity value,principal engine value,orthogonal engine value by measuring,and analyzed by the SPSS13.0 statistical software.RESULTS:The bilateral optic nerve and optic radiation fibers presented green color in directional encoded color（DEC）maps and presented high signal in fractional anisotropy（FA）maps.The FA value of the left optic nerve was 0.598±0.069 and the right was 0.593±0.065;the mean diffusivity（MD）value of the left optic nerve was（1.324±0.349）×10-3mm2/s and the right was（1.312±0.350）x10-3mm2/s;the principal engine value(λ?)of the left optic nerve was（2.297±0.522）×10-4mm2/s and the right was（2.277±0.526）×10-3mm2/s;the orthogonal engine value（λ⊥）of the left optic nerve was（0.838±0.285）×10-3mm2/s and the right was（0.830±0.280）×10-3mm2/s;the FA value of the left optic radiation was 0.636±0.057 and the right was0.628±0.056;the mean diffusivity（MD）value of the left optic radiation was（0.907±0.103）×10-3mm2/s and the right was（0.889±0.125）×10-3mm2/s;the principal eigenvalue(λⅡ)of the left optic radiation was（1.655±0.210）×10-3mm2/s and the right was（1.614±0.171）×10-3mn2/s;the orthogonal enginvalue（λ⊥）of the left optic radiation was（0.531±0.103）×10-3mm2/s and the right was（0.524±0.152）×10-3mm2/s.There was no obvious difference between the FA,MD,λ‖,λ⊥of the bilateral optic radiation and the bilateral optic nerve（P>0.05）and no obvious differencebetween male and female group.The FA,MO,λ‖,λ⊥of the bilateral optic radiation and the bilateral optic nerve had no obvious correlations to the age.CONCLUSION:DTI is sensitive to the optic nerve and radiation and the relevant DTI parameters of the optic

关键词： magnetic resonance imaging diffusion tensor imaging optic nerve optic radiation fractional anisotropy mean diffusivity

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Value of Diffusion Tensor Imaging for Quantification of Grey and White Matter Abnormalities in Minimal Hepatic Encephalopathy

Value of Diffusion Tensor Imaging for Quantification of Grey...

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作者： Deepak Bagale 重庆医科大学

学位级别：硕士

Objective: Low grade cerebral edema is a major complication inpatients with minimal hepatic encephalopathy (MHE). MR imaging offers arange of capabilities for assessing the low grade brain edema. Our purposewas to quantitatively explore the structural abnormalities of grey matter(GM) and white matter (WM) in patients with MHE by using diffusiontensor imaging (DTI) and correlate them with blood ammonia level andneuropsychological (NP) tests.Materials and methods: Eleven cirrhotic patients with MHEdiagnosed by NP tests and14sex, age, and education-matched healthycontrols (HC) recruited in this study. All subjects participated in NP testsand MRI scans including conventional T1, T2weighted imaging, highresolution T1-weighted3D anatomical images, and DTI. Laboratoryparameters, including prothrombin time, protein metabolism tests, andvenous blood ammonia, were obtained from all patients with MHE withinone week before MR scanning. Group differences in mean diffusivity (MD)and fractional anisotropy (FA) of GM and WM were compared by using volume based analysis (VBA), the correlation with blood ammonia leveland NP tests were analyzed using REST method.Results: The regions of decreased FA values in MHE patients werebilateral temporal lobe (mid temporal gyrus), bilateral insular region, rightthalamus, right frontal lobe, bilateral cerebellum, right rolandic operculum,left cuneus, right parietal lobe and bilateral supplementary motor area.While the increased MD values were found in the following GM and WMareas: bilateral middle temporal gyrus, bilateral frontal gyrus, left pallidus,right pre and postcentral gyrus, bilateral mid cingulum, left precuneus, leftsupplementary motor area, right cerebellum, left postcentral lobe. Therewere no significant correlations between blood ammonia levels of MHEpatients and FA or MD values derived from GM and WM. Along with thatwe found no significant correlations between NP test scores of MHEpatients and FA or MD values (all P <0.01).Conclusion: DTI was useful to detect the stru

关键词： Minimal hepatic encephalopathy Diffusion tensor imaging Grey matter White matter mean diffusivity Fractional anisotropy

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