人脑连合纤维的弥散张量纤维束成像

目的建立弥散张量纤维束成像对人脑连合纤维的显示方法,探讨显示结果与已知解剖知识的一致性.方法对1个正常志愿者进行单次激发回波平面弥散张量成像,利用纤维束成像软件包显示脑内连合纤维,观察重建的连合纤维与已知解剖知识的一致性.结果通过选择恰当的感兴趣区,设置不同的分数各向异性阈值、角度阈值、步长和体素内采样数目等参数,弥散张量纤维束成像可以清楚地显示胼胝体、穹隆和前连合等连合纤维的三维结构.显示结果与已知解剖知识具有良好的一致性.结论纤维束成像的结果与解剖学描述具有高度一致性,该方法是一种可靠的研究人脑纤维连接的方法.     

扩散张量纤维束成像对非脑回性皮层发育不良脑内主要纤维结构分析

目的用扩散张量纤维束成像技术对左侧非脑回性皮层发育不良患者脑内主要白质纤维进行研究，旨在揭示该病脑内重要纤维结构改变特征，为临床预后评估提供功能解剖学依据。方法用SIEMENS Trio2003T对患者行全脑常规检查和扩散张量成像，然后进行数据收集和后处理。结果常规MRI左侧大脑半球体积增大，顶叶脑回增宽，左侧半卵圆中心大片块样异常信号影。扩散张量纤维束成像显示左侧弓状纤维束、下纵行纤维束、扣带束、海马等重要的联络、连合纤维明显比对侧增大，左侧内囊后肢及外囊较右侧纤维束少，左侧内囊后肢交叉到对侧小脑的纤维明显减少。结论扩散张量成像技术可精确、直观显示先天性发育畸形的脑内主要纤维结构特征，可提供脑白质的先天性畸形与后天性白质结构异常鉴别的依据，同时对预后的评估有参考价值。     

联合运用VBM方法和DTI技术揭示精神分裂症的神经元基质

目的:运用基于体素形态学VBM(voxel-based morphometry)方法探索未用药的首发精神分裂症患者与正常人脑结构差异,并用弥散张量成像DTI(diffusion tensor imaging)技术观察脑白质结构完整性。方法:纳入18个首发精神分裂症患者,和19个年龄性别都相符的正常人,分别采集高分辨T1WI图像和DTI图像。T1WI图像的处理采用优化的VBM方法进行全脑分析比较。结果:与健康对照组相比,首发精神分裂症患者双侧枕叶和双侧丘脑明显的灰质密度降低,左侧顶枕束、左上纵束及右扣带回后部白质密度降低。而右枕额纤维束,右胼胝体压部到右扣带回后部有相应FA值降低。结论:联合优化的VBM以及DTI图像分析技术,发现首发精神分裂症患者枕叶视辐射区,丘脑皮质回路(边缘系统)皮质以及白质完整性受损,提示在精神分裂症早期就存在边缘系统和视觉通路的神经发育异常。     

基于Reho方法和DTI技术对强迫症脑静息态功能磁共振的研究进展

神经影像学的研究表明强迫症患者存在脑结构和功能异常,并提出了皮质-纹状体-丘脑-皮质-通路异常.本文对近年来应用局部一致性方法和扩散张量成像技术对强迫症患者脑静息态磁功能磁共振的研究结果进行了总结,结果显示强迫症患者存在异常脑功能区及异常脑白质纤维束,所发现的异常脑功能区及异常脑白质纤维束与强迫症皮质-纹状体-丘脑-皮质-通路相重叠,证实局部一致性方法和扩散张量成像技术可应用于强迫症神经生理病理通路的研究.     

白质纤维束成像在颅脑疾病中的初步临床应用研究

目的 评价白质纤维束成像在颅脑疾病中的临床应用价值。方法 11例志愿者、15例缺血性脑卒中患者、3例胶质母细胞瘤及2例脑膜瘤患者行扩散张量成像。应用日本东京大学的dTV软件观察白质纤维束形态；对锥体束和胼胝体进行三维显示。结果 全部志愿者和患者均可清楚地观察白质纤维束形态。15例缺血性脑卒中患者可观察到锥体束不同程度的中断，5例脑肿瘤患者可以观察到锥体束和胼胝体受压、移位。结论 本研究表明，使用扩散张量-白质纤维束成像，可以在活体内清楚、立体地观察锥体束和胼胝体等白质纤维束形态变化以及与颅内病灶之间的关系。     

高阶弥散张量纤维束成像评估胶质瘤研究进展北大核心CSCD

胶质瘤为中枢神经系统常见恶性肿瘤,手术切除为治疗最有效治疗手段,而术前评估极为重要。基于弥散张量成像(DTI)的弥散张量纤维束成像(DTT)可无创显示活体内脑白质纤维束走行,定量评估胶质瘤病理分级、与白质纤维的解剖关系及瘤周白质纤维损伤程度。本文就高阶DTT评估胶质瘤研究进展进行综述。     

磁共振弥散张量成像技术及其在中枢神经系统临床应用进展

1994年,Basser等首次提出磁共振弥散张量成像（diffusiontensorimaging,DTI）的概念,它可研究脑白质纤维的微观结构及形态结构,探测白质纤维束的生理或病理状态下的变化,并利用多参数进行定量分析。弥散张量纤维束成像（diffusiontensor tracyography,DTT）是基于DTI上的一种新的可视化成像技术,是目前唯一可在活体上显示脑白质纤维束的无创性成像方法。DTI及DTT可清晰显示神经纤维束生理和病理的各向异性和构象特征,对疾病的诊断与鉴别诊断、肿瘤定性与分级、预后评估、制订治疗方案以及疗效评价等方面具有重要意义,近几年也成为国内外研究的热点,并取得很大成就。     

3.0T磁共振弥散张量成像在急性脑梗死评估中的应用研究

目的 利用3.0T磁共振弥散张量成像(DTI)及扩散张量纤维束成像(DTT)评价急性脑梗死所致皮质脊髓束(CST)损伤程度与临床预后的关系.方法 搜集以急诊就诊脑梗死患者32例,均首次发病,行常规磁共振(MRI)、DTI和DTT检查,用dTV.Ⅱ软件处理,获得各向异性分数[纤维束重组成像(FA)]图及方向编码彩色图,并重组双侧CST 3D纤维束图.对梗死区及健侧相应区域白质进行FA测量,观察梗死灶与皮质脊髓束的关系,并对其行2次临床神经功能症状评分,作为临床评价标准.结果 急性脑梗死患者梗死区FA值显著低于健侧,两侧相比差异有统计学意义(t=-6.3333,P<0.0000).病变侧CST表现为受压、变形、移位和中断,CST损伤程度与临床神经功能症状经检验呈显著负相关关系(r=-0.97361,P<0.0001).结论 3.0T磁共振DTI能对急性脑梗死患者脑白质损伤做出直观显示,能较好评价白质损伤程度,为临床治疗及预后判断提供依据.     

MR扩散张量在临床脑梗死运动功能康复评估中的应用

目的使用扩散张量成像（DTI）研究脑梗死不同时期的扩散张量的变化规律，并试图通过扩散张量纤维束成像（DTT）探讨皮质脊髓束（CST）损伤与运动功能恢复的关系。方法26例脑梗死患者行常规MRI及DTI检查，测量各期病灶及对侧相应正常区域脑组织的平均扩散系数（DCavg）、部分各向异性系数（FA）、容积比（1-VR）及相对各向异性系数（RA）值，同时进行统计学分析；并行白质纤维束三维重建。结果各期病灶与对侧各参数值间的差异均有统计学意义（P〈0．01）；各期病灶各参数值间的差异亦有统计学意义（P〈0．01）。DTT可显示脑白质纤维束的破坏、推移或扭曲等征象，CST的损伤情况与运动功能的恢复有良好的相关。结论梗死灶DTI各参数值的变化具有规律性，DTT对观察CST的损害程度、预测恢复程度、指导临床康复治疗具有重要的参考价值。     

弥散张量成像技术在评估脑卒中患者白质纤维束损伤及预后方面的研究进展

弥散张量成像(DTI)技术利用组织中水分子的自由热运动的各向异性的原理,并通过特殊的软件处理成像,对大脑白质纤维束的三维几何结构进行研究,重建脑部白质神经连接,可直观地显示脑内病变对白质纤维形态结构直接或间接的影响。本文对DTI在脑卒中患者白质纤维束损伤及预后评估中的研究进展进行综述。     

针刺阳陵泉对脑梗死患者白质结构的影响

目的研究针刺阳陵泉穴后脑卒中患者白质结构的变化。方法6 例脑卒中恢复期左侧偏瘫的患者,以假穴为对照,在针刺左侧阳陵泉前后对患者进行弥散张量成像(DTI)检查,采用西门子1.5 T磁共振仪采集数据,应用FSL软件包中的基于传导束的空间统计(TBSS)方法对针刺前后的数据进行比较。结果针刺阳陵泉穴对脑白质各向异性(FA)的影响强于假穴的区域包括左侧中央前、后回,颞中、下回,辅助运动区,额下回,内囊,穹窿和双侧顶下回。这些区域中走行的纤维束有锥体束、弓状束、胼胝体纤维和皮层间联络纤维,涉及运动代偿、体感、语言和记忆等多个功能网络。结论与假穴相比,针刺阳陵泉可使脑梗死患者的白质超微结构出现变化,主要的变化区域出现在健侧半球,与多个脑功能网络相关。     

首发和慢性精神分裂症幻听患者的扩散张量成像研究

目的:探索首发和慢性精神分裂症幻听患者是否存在听觉、语言及记忆/边缘系统网络的相关白质纤维异常。方法:纳入21例首发和12例慢性精神分裂症幻听患者及人口学参量匹配的26例健康对照。收集所有研究对象的DTI数据,采用基于纤维束的空间统计分析方法比较两组患者和对照组间的白质纤维差异。结果:与对照组相比,首发精神分裂症幻听患者在胼胝体、上纵束、下额枕束、钩束、扣带束、外囊及内囊前肢区域部分各向异性(FA)显著降低,径向扩散张量(RD)显著升高。慢性精神分裂症幻听患者表现出比首发患者更广泛的白质损害,且除FA和RD的改变外,部分脑区还表现出轴向扩散张量(AD)的升高。结论:精神分裂症幻听患者存在连接语言、听觉和记忆/边缘系统网络的多种白质纤维异常。慢性精神分裂症幻听患者与首发患者相比可能表现出更严重的神经退行性改变。     

BDNF gene effects on brain circuitry replicated in 455 twins

Brain-derived neurotrophic factor (BDNF) plays a key role in learning and memory, but its effects on the fiber architecture of the living brain are unknown. We genotyped 455 healthy adult twins and their non-twin siblings (188 males/267 females; age: 23.7±2.1 years, mean±SD) and scanned them with high angular resolution diffusion tensor imaging (DTI), to assess how the BDNF Val66Met polymorphism affects white matter microstructure. By applying genetic association analysis to every 3D point in the brain images, we found that the Val-BDNF genetic variant was associated with lower white matter integrity in the splenium of the corpus callosum, left optic radiation, inferior fronto-occipital fasciculus, and superior corona radiata. Normal BDNF variation influenced the association between subjects' performance intellectual ability (as measured by Object Assembly subtest) and fiber integrity (as measured by fractional anisotropy; FA) in the callosal splenium, and pons. BDNF gene may affect the intellectual performance by modulating the white matter development. This combination of genetic association analysis and large-scale diffusion imaging directly relates a specific gene to the fiber microstructure of the living brain and to human intelligence.     

轻度Alzheimer病人与正常老年人全脑白质各向异性的比较

目的利用扩散张量成像研究轻度Alzheimer患者全脑范围内的白质异常.方法对16例正常志愿者和13例轻度Alzheimer患者进行了扩散张量成像扫描,经过后处理生成的FA图在SPM99下进行头颅标准化后,对AD组和对照组的全脑白质FA图进行基于体素的统计学比较.结果对照组和AD组的双侧内颞叶、右颞中回、左侧顶叶白质,左侧外囊,右上纵束和穹窿的各向异性FA值差异具有显著性意义.结论基于体素的全脑白质FA图比较能够发现AD患者中大脑白质的异常,从而更加全面地评价AD患者的结构改变.     

基于纤维束骨架的空间统计方法研究维持性透析终末期肾病患者脑白质结构变化

目的 探讨基于纤维束骨架的空间统计方法研究维持性透析终末期肾病（ESRD）患者脑白质微结构变化。方法 采用3.0T MR仪对32例行维持性血透的ESRD患者和30名健康对照行DTI扫描,应用基于纤维束骨架的空间统计（TBSS）方法分析DTI多参数图,获得部分各向异性分数（FA）、平均弥散度（MD）、轴向弥散度（AD）及径向弥散度（RD）有显著差异的脑区。将ESRD患者差异脑区FA值与简易精神状态测试（MMSE）评分进行偏相关分析。结果 与健康对照比较,ESRD患者双侧额叶白质、双侧前辐射冠、胼胝体体部及膝部、左侧颞叶白质及多条联络纤维FA值显著减低;MD值呈广泛且对称性显著升高;右侧上纵束、左侧上辐射冠AD值显著升高,左侧丘脑前辐射AD值显著降低;双侧额叶、胼胝体及双侧上纵束等白质区RD值显著升高（P均<0.05）。右侧额叶白质（r=0.404,P=0.022）及左侧上纵束（r=0.475,P=0.006）FA值与MMSE评分呈正相关。结论 ESRD患者脑区白质微结构受损,可能导致其认知障碍。     

White matter defects in first episode psychosis patients: A voxelwise analysis of diffusion tensor imaging

ObjectiveDisruptions in white matter structure have consistently been shown in schizophrenia — but mainly in patients in whom the illness is well-established. In order to determine whether white matter abnormalities are present at illness onset, and to minimise the potentially confounding effects of chronic illness and treatment, we used diffusion tensor imaging to study a large cohort of first episode psychotic patients who were medication-naive.MethodsSixty two first episode patients and 54 controls matched on age, sex, years of education and laterality index underwent diffusion tensor imaging. Data were acquired on a GE Signa NVi 1.5 Tesla System. Fractional anisotropy maps were generated on a voxel-by-voxel basis. An optimized voxel-based morphometry technique was conducted with two-stage registration approach. Group differences were examined using a non-parametric statistical method.ResultsThe voxelwise analysis revealed four clusters where fractional anisotropy values were significantly lower in patients than controls. These were localised bilaterally to regions of white matter corresponding to superior and inferior longitudinal fasciculus, forceps major, anterior and superior thalamic radiation and corpus callosum.ConclusionsReductions in white matter integrity are present early in the course of the schizophrenia and localised in fascicule that connect brain regions implicated in the disorder.     

DTI观察乳腺癌化疗前后脑白质微结构与认知功能变化

目的 探讨化疗前后乳腺癌患者脑白质微结构和认知功能变化及其相关性。方法 收集经手术病理证实的21例早期乳腺癌患者,于化疗前和化疗结束后1个月进行神经心理认知测试和全脑DTI,比较化疗前后全脑整体及脑白质区域各向异性分数（FA）和平均弥散率（MD）的差异,并与神经心理认知测试结果进行相关性分析。结果 化疗前后乳腺癌患者Stroop字测试和干扰测试、数字广度倒背测试、数字符号测试、听觉词语学习延迟5 min测试差异有统计学意义（P均<0.05）。化疗前后乳腺癌患者全脑白质整体FA、MD值差异无统计学意义（P均>0.05）;化疗后右侧丘脑后辐射、右侧矢状层、右侧上纵束FA值较化疗前降低（P均<0.05）,右侧内囊豆状核后部、右侧丘脑后辐射、右侧矢状层、双侧扣带束、双侧下额枕束MD值较化疗前升高（P均<0.05）;左侧扣带束MD值与Stroop干扰测试结果呈正相关（r=0.457,P=0.037）。结论 乳腺癌患者化疗后局部白质完整性下降,可能是某一认知领域功能减退的神经解剖学基础。     

White matter integrity in patients with classic trigeminal neuralgia: a multi-node automated fiber tract quantification study

ObjectiveTo study the characteristics of point-by-point destruction of white matter tracts in patients using automated fiber tract quantification (AFQ).MethodsThirty-four classic trigeminal neuralgia (CTN) patients and 34 healthy control (HC) subjects underwent 3.0 T diffusion tensor magnetic resonance imaging and T1-weighted imaging. The fractional anisotropy (FA) and mean diffusivity (MD) of 100 nodes of 20 fiber tracts were analyzed by AFQ, and the correlations of the FA and MD with the visual analogue scale (VAS) pain score were assessed.ResultsThe FA values of the left thalamic radiation (middle segment), left corticospinal tract, callosum forceps minor, and right uncinate fasciculus were significantly lower in CTN patients than in the HC group. The MD of the left thalamic tract (middle segment), left corticospinal tract, right superior longitudinal fasciculus, and left superior longitudinal fasciculus (anterior segment) were significantly higher in the CTN group. Additionally, the VAS pain score in CTN patients was positively correlated with FA and negatively correlated with MD.ConclusionSpecific fiber tract nodes were damaged in CTN patients, which was related to the VAS pain score. Multi-node quantitative studies of fiber tract damage are valuable for understanding the white matter tract damage pattern in CTN patients.     

Relationship between aberrant brain connectivity and clinical features in Angelman Syndrome: a new method using tract based spatial statistics of DTI color-coded orientation maps

Aim

In order to relate brain structural abnormalities to clinical features of Angelman Syndrome (AS), we determined the locations of abnormal regional white matter architecture in AS children using a sensitive and objective whole brain approach to analyze diffusion tensor imaging (DTI) color-coded orientation maps.

Methods

Using tract based spatial statistics (TBSS) of DTI color-coded orientation maps, the fraction of fibers oriented in the anteroposterior (AP), mediolateral (ML) and superioinferior (SI) directions were determined in whole brain white matter of 7 children with AS (mean age: 70 ± 25.78 months, 5 males) and 7 children with typical development (TD, mean age: 79.8 ± 17.25 months, 4 males). TBSS of FA map was also performed for comparison.

Results

Children with AS had a significantly lower AP component than the TD group in 9 clusters (3 bilateral and 3 unilateral). Bilateral clusters were located in inferior fronto-occipital fasciculus, anterior thalamic radiation and arcuate fasciculus regions. Unilateral clusters involved left brainstem, left cingulum and right uncinate regions. Similarly, children with AS had significantly lower ML component than the TD group in 4 clusters (2 in corpus callosum and 2 unilateral clusters). Unilateral clusters were located in the left cingulum and left anterior thalamic radiation regions. SI component was lower in children with AS in two clusters compared to TD (corticospinal tract and corpus callosum). FA map clusters mostly corresponded with component clusters.

Interpretation

Children with AS have a global impairment of white matter integrity including AP, ML and SI components in whole brain suggesting a potential underlying error with axon guidance mechanisms during brain development possibly due to loss of UBE3A gene expression. Some of this aberrant connectivity can be related to the clinical features of AS.