The purpose of this work was to demonstrate the feasibility of neurite orientation dispersion and density imaging(NODDI)in characterizing the brain tissue microstructural changes of middle cerebral artery occlusion(MC...The purpose of this work was to demonstrate the feasibility of neurite orientation dispersion and density imaging(NODDI)in characterizing the brain tissue microstructural changes of middle cerebral artery occlusion(MCAO)in rats at 3T MRI,and to validate NODDI metrics with histology.A multi-shell diffusion MRI protocol was performed on 11 MCAO rats and 10 control rats at different post-operation time points of 0.5,2,6,12,24 and 72 h.NODDI orientation dispersion index(ODI)and intracellular volume fraction(V_(ic))metrics were compared between MCAO group and control group.The evolution of NODDI metrics was characterized and validated by histology.Infarction was consistent with significantly increased ODI and V_(ic)in comparison to control tissues at all time points(P<0.001).Lesion ODI increased gradually from 0.5 to 72 h,while its V_(ic)showed a more complicated and fluctuated evolution.ODI and V_(ic)were significantly different between hyperacute and acute stroke periods(P<0.001).The NODDI metrics were found to be consistent with the histological findings.In conclusion,NODDI can reflect microstructural changes of brain tissues in MCAO rats at 3T MRI and the metrics are consistent with histology.This study helps to prepare NODDI for the diagnosis and management of ischemic stroke in translational research and clinical practice.展开更多
The prevalence of neurodegenerative diseases is increasing as human longevity increases. The objective biomarkers that enable the staging and early diagnosis of neurodegenerative diseases are eagerly anticipated. It h...The prevalence of neurodegenerative diseases is increasing as human longevity increases. The objective biomarkers that enable the staging and early diagnosis of neurodegenerative diseases are eagerly anticipated. It has recently become possible to determine pathological changes in the brain without autopsy with the advancement of diffusion magnetic resonance imaging techniques. Diffusion magnetic resonance imaging is a robust tool used to evaluate brain microstructural complexity and integrity, axonal order, density, and myelination via the micron-scale displacement of water molecules diffusing in tissues. Diffusion tensor imaging, a type of diffusion magnetic resonance imaging technique is widely utilized in clinical and research settings;however, it has several limitations. To overcome these limitations, cutting-edge diffusion magnetic resonance imaging techniques, such as diffusional kurtosis imaging, neurite orientation dispersion and density imaging, and free water imaging, have been recently proposed and applied to evaluate the pathology of neurodegenerative diseases. This review focused on the main applications, findings, and future directions of advanced diffusion magnetic resonance imaging techniques in patients with Alzheimer's and Parkinson's diseases, the first and second most common neurodegenerative diseases, respectively.展开更多
了解年老过程中大脑在细胞水平上发生的变化对于揭示老年人认知功能下降的原因有重要意义。扩散MRI(diffusion MRI,d MRI)技术是目前惟一可以无创探查活体组织微观结构的方法。扩散张量成像(DTI,diffusion tensor imaging)是临床上最常...了解年老过程中大脑在细胞水平上发生的变化对于揭示老年人认知功能下降的原因有重要意义。扩散MRI(diffusion MRI,d MRI)技术是目前惟一可以无创探查活体组织微观结构的方法。扩散张量成像(DTI,diffusion tensor imaging)是临床上最常用的一种d MRI技术,但是由于某些固有缺陷,它不能充分刻画大脑组织的微观结构。作者介绍三种可以有效弥补DTI不足的新型扩散成像方法:扩散峰度成像(diffusion kurtosis imaging,DKI),扩散的受阻受限合成模型(composite hindered and restricted model of diffusion,CHARMED)和神经突方向离散度与密度成像(neurite orientation dispersion and density imaging,NODDI)。联合使用DTI和这些新技术,研究者可以更深入地了解年老如何影响大脑的微观结构。展开更多
During the last decades,advances in the understanding of genetic,cellular,and microstructural alterations associated to Huntington's disease(HD)have improved the understanding of this progressive and fatal illness...During the last decades,advances in the understanding of genetic,cellular,and microstructural alterations associated to Huntington's disease(HD)have improved the understanding of this progressive and fatal illness.However,events related to early neuropathological events,neuroinflammation,deterioration of neuronal connectivity and compensatory mechanisms still remain vastly unknown.Ultra-high field diffusion MRI(UHFD-MRI)techniques can contribute to a more comprehensive analysis of the early microstructural changes observed in HD.In addition,it is possible to evaluate if early imaging microstructural parameters might be linked to histological biomarkers.Moreover,qualitative studies analyzing histological complexity in brain areas susceptible to neurodegeneration could provide information on inflammatory events,compensatory increase of neuroconnectivity and mechanisms of brain repair and regeneration.The application of ultra-high field diffusion-MRI technology in animal models,particularly the R6/1 mice(a common preclinical mammalian model of HD),provide the opportunity to analyze alterations in a physiologically intact model of the disease.Although some disparities in volumetric changes across different brain structures between preclinical and clinical models has been documented,further application of different diffusion MRI techniques used in combination like diffusion tensor imaging,and neurite orientation dispersion and density imaging have proved effective in characterizing early parameters associated to alteration in water diffusion exchange within intracellular and extracellular compartments in brain white and grey matter.Thus,the combination of diffusion MRI imaging techniques and more complex neuropathological analysis could accelerate the discovery of new imaging biomarkers and the early diagnosis and neuromonitoring of patients affected with HD.展开更多
目的利用神经突方向离散度和密度成像(neurite direction dispersion and density imaging,NODDI)分析阿尔兹海默病(Alzheimer’s disease,AD)和遗忘型轻度认知障碍(amnestic mild cognitive impairment,aMCI)患者双侧海马微观结构改变,...目的利用神经突方向离散度和密度成像(neurite direction dispersion and density imaging,NODDI)分析阿尔兹海默病(Alzheimer’s disease,AD)和遗忘型轻度认知障碍(amnestic mild cognitive impairment,aMCI)患者双侧海马微观结构改变,为AD的发病机制提供更多信息,并以此探究NODDI技术对AD和aMCI的临床价值。材料与方法招募15例aMCI患者、20例AD患者与20例正常对照(normal contral,NC)进行前瞻性NODDI扫描,利用MRIcro软件测量三组双侧海马神经突密度指数(neurite density index,NDI)、神经突方向离散度指数(orientation dispersion index,ODI)、各向同性水分子体积分数(volume fraction of isotropic water molecule,Viso),三组间各参数利用单因素方差分析比较差异性,并用LSD检验组间差异性,对于有差异的参数,采用Spearman相关分析差异参数与简易智能状态检查量表(Mini-Mental State Examination,MMSE)评分和蒙特利尔认知评估量表(Montreal Cognitive Assessment,MoCA)评分的相关性,获取相关系数r。结果与NC组相比,aMCI组和AD组双侧海马NDI值和ODI值明显低于NC组,差异具有统计学意义(P<0.001),Viso值显著高于NC组,差异也具有统计学意义(P<0.001)。aMCI组和AD组再进行组间比较,AD组Viso值显著高于aMCI组,差异有统计学意义(P<0.001),而NDI值和ODI值差异无统计学意义(P>0.05)。相关性分析:左侧海马NDI值(r=0.656,P<0.001)与MMSE评分正相关最强,左侧Viso值(r=-0.690,P<0.001)与MMSE评分负相关最强;同时,左侧海马NDI值(r=0.632,P<0.001)与MoCA评分正相关最强,左侧Viso值(r=-0.629,P<0.001)与MoCA评分负相关最强。结论aMCI阶段和AD阶段双侧海马神经突数量、体积和排列复杂程度都有显著降低,为探究AD的发病机制提供了更多的参考数据。同时,aMCI向AD进展的过程中,双侧海马Viso值有可能成为重要评估指标,对aMCI和AD的鉴别、随访和评估预后具有重要价值。展开更多
目的利用神经突方向离散度与密度成像(neurite orientation dispersion and density imaging,NODDI)探索帕金森病患者(Parkinson’s disease,PD)灰质核团微结构变化。材料与方法对36例PD患者和26例健康者进行MRI扫描和NODDI图像后处理,...目的利用神经突方向离散度与密度成像(neurite orientation dispersion and density imaging,NODDI)探索帕金森病患者(Parkinson’s disease,PD)灰质核团微结构变化。材料与方法对36例PD患者和26例健康者进行MRI扫描和NODDI图像后处理,比较两组神经突体积分数(intracellular volume fraction,Vic)、神经突方向分散度(orientation dispersion index,ODI),通过受试者工作特征曲线(receiver operating characteristic curve,ROC曲线)评估不同核团Vic值诊断效能。结果与对照组相比,PD患者左侧黑质(P<0.001)、丘脑(P=0.003)及右侧尾状核头(P=0.002)、壳核(P<0.001)、苍白球(P<0.001)、黑质(P<0.001)、红核(P<0.001)、丘脑(P=0.006)Vic值差异有统计学意义,且左侧黑质(P<0.001)及右侧尾状核头(P=0.038)、壳核(P=0.001)、苍白球(P=0.023)、黑质(P<0.001)、红核(P=0.023)ODI值差异有统计学意义。ROC曲线显示,右侧黑质、红核、苍白球、壳核Vic指标诊断PD的曲线下面积(area under curve,AUC)分别为0.861、0.788、0.852、0.843。此外,右侧黑质苍白球及黑质壳核Vic值联合诊断PD的AUC分别为0.925、0.921。结论NODDI技术可以定性区分PD患者和健康人群,量化分析PD脑深部灰质核团微结构改变情况。Vic指标在黑质部位显示出最佳诊断效能,且黑质苍白球及黑质壳核的联合诊断的诊断效能均优于单一核团,这一发现为PD诊断提供新的神经影像学支持。展开更多
基金National Natural Science Foundation of China(No.81570462,No.81730049,and No.81801666).
文摘The purpose of this work was to demonstrate the feasibility of neurite orientation dispersion and density imaging(NODDI)in characterizing the brain tissue microstructural changes of middle cerebral artery occlusion(MCAO)in rats at 3T MRI,and to validate NODDI metrics with histology.A multi-shell diffusion MRI protocol was performed on 11 MCAO rats and 10 control rats at different post-operation time points of 0.5,2,6,12,24 and 72 h.NODDI orientation dispersion index(ODI)and intracellular volume fraction(V_(ic))metrics were compared between MCAO group and control group.The evolution of NODDI metrics was characterized and validated by histology.Infarction was consistent with significantly increased ODI and V_(ic)in comparison to control tissues at all time points(P<0.001).Lesion ODI increased gradually from 0.5 to 72 h,while its V_(ic)showed a more complicated and fluctuated evolution.ODI and V_(ic)were significantly different between hyperacute and acute stroke periods(P<0.001).The NODDI metrics were found to be consistent with the histological findings.In conclusion,NODDI can reflect microstructural changes of brain tissues in MCAO rats at 3T MRI and the metrics are consistent with histology.This study helps to prepare NODDI for the diagnosis and management of ischemic stroke in translational research and clinical practice.
基金supported by research grants from the program for Brain/MINDS Beyond program from the Japan Agency for Medical Research and Development(AMED)under Grant Number JP18dm0307024(to KK)MEXT-Supported Program for the Private University Research Branding Project+1 种基金ImPACT Program of Council for Science,Technology and Innovation(Cabinet Office,Government of Japan)JSPS KAKENHI Grant Number JP16K10327(to KK)
文摘The prevalence of neurodegenerative diseases is increasing as human longevity increases. The objective biomarkers that enable the staging and early diagnosis of neurodegenerative diseases are eagerly anticipated. It has recently become possible to determine pathological changes in the brain without autopsy with the advancement of diffusion magnetic resonance imaging techniques. Diffusion magnetic resonance imaging is a robust tool used to evaluate brain microstructural complexity and integrity, axonal order, density, and myelination via the micron-scale displacement of water molecules diffusing in tissues. Diffusion tensor imaging, a type of diffusion magnetic resonance imaging technique is widely utilized in clinical and research settings;however, it has several limitations. To overcome these limitations, cutting-edge diffusion magnetic resonance imaging techniques, such as diffusional kurtosis imaging, neurite orientation dispersion and density imaging, and free water imaging, have been recently proposed and applied to evaluate the pathology of neurodegenerative diseases. This review focused on the main applications, findings, and future directions of advanced diffusion magnetic resonance imaging techniques in patients with Alzheimer's and Parkinson's diseases, the first and second most common neurodegenerative diseases, respectively.
文摘阿尔茨海默病(AD)相关认知障碍是目前最主要的认知障碍类型,相比较皮质萎缩,皮质下白质变性被认为是AD相关认知障碍的关键病理特征。弥散张量成像(duffusion tensor imaging, DTI)和神经突方向离散度和密度成像(neurite orientation dispersion and density imaging, NODDI)技术是评估大脑白质微结构,检测大脑中神经纤维束扩散特征,揭示白质纤维束走行和完整性,量化白质通路微观结构特性,评估神经树突和轴突微观层面复杂性,提供神经纤维形态学信息的常用和新型方法。本文首先介绍白质微结构概念及位置,综述DTI和NODDI技术在AD相关认知障碍中白质微结构相关研究进展。
文摘了解年老过程中大脑在细胞水平上发生的变化对于揭示老年人认知功能下降的原因有重要意义。扩散MRI(diffusion MRI,d MRI)技术是目前惟一可以无创探查活体组织微观结构的方法。扩散张量成像(DTI,diffusion tensor imaging)是临床上最常用的一种d MRI技术,但是由于某些固有缺陷,它不能充分刻画大脑组织的微观结构。作者介绍三种可以有效弥补DTI不足的新型扩散成像方法:扩散峰度成像(diffusion kurtosis imaging,DKI),扩散的受阻受限合成模型(composite hindered and restricted model of diffusion,CHARMED)和神经突方向离散度与密度成像(neurite orientation dispersion and density imaging,NODDI)。联合使用DTI和这些新技术,研究者可以更深入地了解年老如何影响大脑的微观结构。
基金supported in part by the High Magnetic Field Laboratory(NHMFL)and Advanced Magnetic Resonance Imaging and Spectroscopy(AMRIS)under Magnetic Laboratory Visiting Scientist Program Award,No.VSP#327(to RG)。
文摘During the last decades,advances in the understanding of genetic,cellular,and microstructural alterations associated to Huntington's disease(HD)have improved the understanding of this progressive and fatal illness.However,events related to early neuropathological events,neuroinflammation,deterioration of neuronal connectivity and compensatory mechanisms still remain vastly unknown.Ultra-high field diffusion MRI(UHFD-MRI)techniques can contribute to a more comprehensive analysis of the early microstructural changes observed in HD.In addition,it is possible to evaluate if early imaging microstructural parameters might be linked to histological biomarkers.Moreover,qualitative studies analyzing histological complexity in brain areas susceptible to neurodegeneration could provide information on inflammatory events,compensatory increase of neuroconnectivity and mechanisms of brain repair and regeneration.The application of ultra-high field diffusion-MRI technology in animal models,particularly the R6/1 mice(a common preclinical mammalian model of HD),provide the opportunity to analyze alterations in a physiologically intact model of the disease.Although some disparities in volumetric changes across different brain structures between preclinical and clinical models has been documented,further application of different diffusion MRI techniques used in combination like diffusion tensor imaging,and neurite orientation dispersion and density imaging have proved effective in characterizing early parameters associated to alteration in water diffusion exchange within intracellular and extracellular compartments in brain white and grey matter.Thus,the combination of diffusion MRI imaging techniques and more complex neuropathological analysis could accelerate the discovery of new imaging biomarkers and the early diagnosis and neuromonitoring of patients affected with HD.
文摘目的利用神经突方向离散度和密度成像(neurite direction dispersion and density imaging,NODDI)分析阿尔兹海默病(Alzheimer’s disease,AD)和遗忘型轻度认知障碍(amnestic mild cognitive impairment,aMCI)患者双侧海马微观结构改变,为AD的发病机制提供更多信息,并以此探究NODDI技术对AD和aMCI的临床价值。材料与方法招募15例aMCI患者、20例AD患者与20例正常对照(normal contral,NC)进行前瞻性NODDI扫描,利用MRIcro软件测量三组双侧海马神经突密度指数(neurite density index,NDI)、神经突方向离散度指数(orientation dispersion index,ODI)、各向同性水分子体积分数(volume fraction of isotropic water molecule,Viso),三组间各参数利用单因素方差分析比较差异性,并用LSD检验组间差异性,对于有差异的参数,采用Spearman相关分析差异参数与简易智能状态检查量表(Mini-Mental State Examination,MMSE)评分和蒙特利尔认知评估量表(Montreal Cognitive Assessment,MoCA)评分的相关性,获取相关系数r。结果与NC组相比,aMCI组和AD组双侧海马NDI值和ODI值明显低于NC组,差异具有统计学意义(P<0.001),Viso值显著高于NC组,差异也具有统计学意义(P<0.001)。aMCI组和AD组再进行组间比较,AD组Viso值显著高于aMCI组,差异有统计学意义(P<0.001),而NDI值和ODI值差异无统计学意义(P>0.05)。相关性分析:左侧海马NDI值(r=0.656,P<0.001)与MMSE评分正相关最强,左侧Viso值(r=-0.690,P<0.001)与MMSE评分负相关最强;同时,左侧海马NDI值(r=0.632,P<0.001)与MoCA评分正相关最强,左侧Viso值(r=-0.629,P<0.001)与MoCA评分负相关最强。结论aMCI阶段和AD阶段双侧海马神经突数量、体积和排列复杂程度都有显著降低,为探究AD的发病机制提供了更多的参考数据。同时,aMCI向AD进展的过程中,双侧海马Viso值有可能成为重要评估指标,对aMCI和AD的鉴别、随访和评估预后具有重要价值。
