首发精神分裂症患者的运动协调功能与前额叶白质及皮质脊髓束完整性

目的:应用弥散张量成像(DTI)探讨首发精神分裂症患者神经系统软体征中的运动协调功能与前额叶白质及皮质脊髓束各向异性比值(FA)的关系。方法:纳入42例符合美国精神障碍诊断与统计手册第4版(DSM-IV)诊断标准的首发精神分裂症患者和46例年龄、性别及受教育年限相匹配的健康对照。两组研究对象均用剑桥神经科检查(CNI)评定神经系统软体征,并接受头颅磁共振成像检查。用阳性与阴性症状量表(PANSS)评估患者组基线和半年后的临床症状。用感兴趣区测定的方法,分析患者组和对照组神经系统软体征中的运动协调领域分与前额叶白质及皮质脊髓束各层面(内囊、大脑脚、小脑中脚水平)FA值间的关系。结果:神经系统软体征中的运动协调领域分在患者组中与前额叶白质FA值呈正相关(r=0.35,P0.05),在健康对照中则与小脑中脚水平皮质脊髓束FA值呈正相关(r=0.34,P0.05)。将患者按半年后阴性症状分为高分组和低分组,高分组运动协调领域分与前额叶白质(r=0.68,P0.05)呈正相关,与小脑中脚水平皮质脊髓束(r=-0.67,P0.05)FA值呈负相关;低分组则与内囊FA值呈正相关(r=0.60,P0.05)。结论:本研究提示首发精神分裂症患者半年后阴性症状高分组、低分组及正常人群中,运动协调功能相关的脑区分别为前额叶、内囊和小脑中脚层面的皮质脊髓束,提示有必要进一步研究运动协调功能相关的脑区不同对患者预后的预测意义。     

精神分裂症白质损害与发病年龄的弥散张量成像研究

目的:应用弥散张量成像(DTI)比较精神分裂症患者脑白质与正常人群间的差异,并探究各向异性比值(FA)的改变与发病年龄之间的相关性。方法:纳入27例精神分裂症患者和29名性别、年龄及受教育程度相匹配的健康对照。两组研究对象均接受头颅磁共振检测。患者组按照发病年龄分为早发组(发病年龄18岁)和成年发病组(发病年龄≥18岁)。采用基于体素的分析方法,分别比较患者组和对照组、早发组和成年发病组之间FA值的差异,并在控制性别、病程和药物剂量影响的前提下,分析FA值与患者发病年龄的相关性。结果:与健康对照比较,患者组在右侧上纵束、右侧放射冠上部的FA值降低;患者组中早发组和成年发病组间FA值的差异无显著性。患者组FA值与发病年龄呈正相关的脑区包括右侧放射冠前部(r=0.70,P0.01)、右侧胼胝体膝部(r=0.65,P0.01);未发现呈负相关的脑区。结论:本研究提示精神分裂症患者右侧脑区上纵束及放射冠部位存在白质损害,发病年龄愈早,右侧放射冠及胼胝体膝部白质纤维的受损愈重。这对精神分裂症病理生理改变及脑结构异常的进一步研究具有提示作用。     

应用弥散张量成像技术检测慢性原发性闭角型青光眼患者脑白质结构

目的 采用磁共振弥散张量成像(DTI)检测慢性闭角型青光眼(PACG)患者脑白质病变,用各向异性指数(FA)改变分析病变部位。方法 回顾性分析2008-2009年在天津医科大学总医院眼科就诊并行颅脑MRI检查患者的临床资料,其中确诊为慢性PACG并同时行DTI扫描的患者25例为慢性PACG组,根据视野损害程度分为轻度组和重度组;选取同一时间段行颅脑DTI扫描的健康人25例为正常对照组。采用FSL和DTIstudio软件处理原始数据得到FA图,输入SPM5软件做标准化处理,然后进行灰白质分割,对分割后的白质FA图进行平滑处理,最后对慢性PACG组和正常对照组FA图进行两样本t检验比较,采用FWE方法校正统计结果,取P＜0.05有统计学意义,将结果叠加于标准模板,显示阈值设定为10个体素。采用同样方法分析慢性PACG轻度组和重度组FA图差异。结果剔除头动明显受试者图像后,慢性PACG组和正常对照组各有22例入组,慢性PACG组分为轻度组13例、重度组9例。与正常对照组比较,慢性PACG患者双侧视束脚周段FA值明显降低(P＜0.05,FWE校正),左侧包含98个体素,右侧包含56个体素。慢性PACG轻度组与重度组FA值差异无统计学意义(P＞0.05)。结论 DTI可检测慢性PACG患者脑白质结构病变。FA值可反应双侧视束脚周段病变。     

阴性症状为主的精神分裂症男性患者认知功能及灰质密度改变

目的:运用基于体素的脑形态测量学方法(VBM),探讨以阴性症状为主的精神分裂症男性患者大脑结构形态学的改变,及其与精神病理学症状的关系。方法:15例阴性症状为主的成年男性精神分裂症患者和15例正常对照参与实验,所有研究对象均接受威斯康星卡片分类测验(WCST)与磁共振检查,获取磁共振T1加权像和高分辨率3D图像后进行VBM分析,比较患者组和正常对照组局部脑区灰质密度的差异性。结果:在威斯康星测验中,阴性症状为主的精神分裂症患者完成测查的总应答数、错误应答数和持续性错误数显著高于正常对照组,正确应答数和完成分类数与正常对照组没有显著差异。VBM分析显示患者右侧额上回,左侧额中回,左额内侧回,右侧楔叶,左侧颞中回的灰质密度较正常对照组低,未发现患者组灰质密度有明显增高的脑区。结论:以阴性症状为主的精神分裂症患者存在显著的额叶执行功能低下;双侧额叶灰质密度的下降可能是其执行功能损害的病理生理基础。     

血压正常2型糖尿病患者大脑微结构改变的VBM及TBSS研究

目的:基于纤维束示踪空间统计分析(TBSS)研究大脑扩散张量成像(DTI)图像,观察血压正常2型糖尿病(T2DM)患者脑白质微结构的改变,并探讨双侧大脑半球间的脑白质改变方法:本研究纳入20名血压正常的T2DM患者及20名年龄、性别匹配的正常对照。采用3.0T磁共振扫描仪采集大脑结构像和DTI数据,应用基于体素的形态学分析(VBM)和TBSS方法比较两组受试者间的大脑体积,白质各向异性分数(FA)和平均扩散系数(MD)值的差异,以及两组受试者左右侧大脑半球DTI参数比值的差异。结果:与正常对照相比,血压正常的T2DM患者大脑体积未见显著减小(P0.05);大脑白质完整性广泛受损,尤以胼胝体膝部、左侧内囊前肢、辐射冠前上部、扣带束及上额-枕束为著;右侧上辐射冠、后辐射冠、扣带束及上纵束FA值和MD值均有改变(P0.05);双侧大脑半球上辐射冠MD值升高,以左侧升高更为显著(P0.05)。结论:血压正常的T2DM患者双侧大脑半球白质微结构广泛损伤,尤以左侧为著,TBSS分析有助于早期检出上述改变。     

缺陷型及非缺陷型精神分裂症脑白质异常—基于体素的脑形态学研究

目的:应用基于体素的脑形态测量学方法,比较缺陷型与非缺陷型精神分裂症患者大脑白质结构损害的差异.方法:采用GE 1.5T MRI成像系统,对缺陷型精神分裂症(n=10)、非缺陷型精神分裂症(n=11)及正常对照(n=15)进行全脑扫描,获取脑解剖结构MR T1图像.随后在SPM2平台上使用VBM工具箱逐例进行全自动数据分析,再进行成组t检验.结果:与正常对照相比,缺陷型患者的白质密度降低区域主要是左侧额叶回下,而非缺陷型患者为左侧额叶回下、右颞中回、右枕叶舌回以及胼胝体.两型患者的比较显示,缺陷型患者双侧额上回以及右侧顶叶的白质密度低于非缺陷型组,而左侧额内侧回的白质密度高于非缺陷型组.结论:这是第一项运用VBM法考察缺陷型与非缺陷型患者之间脑白质损害不同的形态学研究.研究结果为缺陷型患者额一顶环路受损的假说提供了新的证据.     

精神分裂症患者及其健康同胞脑白质密度研究

目的:观察精神分裂症患者及其健康同胞脑白质密度的特点.方法:用基于像素的形态学测量法比较三组的白质密度.结果:在左侧前额叶和胼胝体膝部,患者及同胞的白质密度值显著小于正常对照组,患者和同胞之间的差异未达到统计学意义水平.结论:左侧前额叶和胼胝体膝部白质密度值降低可能与精神分裂症的患病风险有关.     

颞叶癫痫患者脑白质纤维束追踪空间统计分析与自动识别

为了定位颞叶癫痫(TLE)患者脑白质微结构发生异常的重要脑区,本文设立了正常对照组(NC)与TLE组两组人群,采集了50位受试者(其中NC组28人,TLE组22人)的脑部弥散张量成像(DTI)影像,分别计算其部分各向异性(FA)、平均扩散率(MD)、扩散系数(AD)、径向扩散系数(RD)等参数,并采用纤维束追踪空间统计方法(TBSS),获取组间差异的脑区,然后利用支持向量机(SVM),对NC组与TLE组进行分类,并与支持向量机-递归特征消除法(SVM-RFE)进行比较,最后对重要脑区及其分布进行分析与讨论。实验结果表明,TLE患者的FA值存在明显降低的脑区主要有胼胝体、上纵束、放射冠、外囊、内囊、下额枕束、钩束、矢状层等,基本呈双侧分布,其中大部分脑区的MD、RD值明显增高,AD值虽有增高,但差异无统计学意义。支持向量机-纤维束追踪空间统计法(SVM-TBSS)利用FA、MD、RD进行分类的准确率分别为82%、76%、76%,特征融合后分类准确率为80%;SVM-RFE利用FA、MD、RD进行分类准确率分别为90%、90%和92%,特征融合后分类准确率达到100%,SVM-RFE分类性能明显优于SVM-TBSS,对分类有重要影响的特征主要分布于联络纤维和连合纤维脑区。研究结果表明,DTI参数能有效地反映TLE患者的脑白质纤维异常改变,可用于阐明其病理机制、定位病灶及实现自动诊断。     

长期舞蹈训练对白质纤维微结构影响的TBSS比较研究

舞蹈涉及复杂的感觉运动信息处理,长期舞蹈训练可能让脑产生功能与结构的可塑性改变。目前关于舞蹈训练导致的白质结构研究相当有限,缺乏统一的结果,因此对舞蹈家与正常对照组的白质纤维微结构指标进行比较研究,以探索舞蹈家白质纤维微结构的特异性改变。采集18名舞蹈家及与之匹配的25名对照被试的磁共振扩散张量成像(DTI)数据,使用基于纤维束示踪的空间统计分析(TBSS)技术,对被试白质纤维的部分各向异性分数(FA)和平均弥散率(MD)图谱进行体素级别统计分析。采用t检验,对比两组被试数据的差异。结果表明,舞蹈家在涉及感觉运动信息处理的白质纤维微结构的一致性降低:在胼胝体压部、左侧内囊前肢(左侧丘脑辐射前部)、左侧内囊后肢(左侧皮质脊髓束)存在显著降低的FA值,在左侧内囊后肢(含部分左侧下纵束、左侧上纵束与左侧皮质脊髓束)、左侧外囊(含部分下额枕束与钩束)、左侧冠状束前部与胼胝体膝部存在显著升高的MD值。以上结果提示,舞蹈训练可能导致脑内特定白质纤维束的交错更多,连接不同脑区的轴突纤维更为发散,进而影响感觉运动信息的上下行传递与左右脑信息整合效率。同时,长期舞蹈训练可能对主导运动控制的左半脑的白质通路影响明显。     

经历丧子事件所致创伤后应激障碍患者的脑结构磁共振研究

目的:探讨经历丧子这一特殊创伤性事件后出现创伤后应激障碍(PTSD)患者脑内结构形态学的改变。方法:选取经历过丧子事件所致PTSD的患者15例(PTSD组)和性别、年龄、受教育程度均与PTSD组相匹配的正常健康人15例(对照组),在取得知情同意后进行功能性磁共振脑扫描,采用基于体素的形态学测量方法(VBM)对图像进行后处理,比较两组脑结构中灰质、白质体积的异同。结果:以性别、年龄、全脑体积作为协变量,使用Matlab 7.1及SPM 5软件包来分析处理高分辨率的MRI结构图,定量检测脑结构组织成分的浓度;分析发现PTSD组患者与对照组相比,右侧中央前回的皮质运动前区(t=3.88,Z=3.44)、右侧额中回(t=3.95,Z=3.49)、左侧楔前叶(t=4.44,Z=3.83)、右侧丘脑背内侧核(t=4.10,Z=3.60)的灰质体积有明显缩小,差异均具有显著统计学意义(P0.001),两组其他脑区的灰质或白质体积的差异无统计学意义。结论:PTSD组患者的右侧中央前回的皮质运动前区、右侧额中回、左侧楔前叶、右侧丘脑背内侧核的灰质体积较正常对照组有明显缩小,提示这些脑区的结构存在病理性改变。     

Tract based spatial statistical analysis and voxel based morphometry of diffusion indices in temporal lobe epilepsy

White matter (WM) microstructure can be evaluated by diffusion tensor imaging (DTI). Tract-based spatial statistical (TBSS) analysis provides a means of assessing alterations in WM tracts. In this paper, both voxel-based morphometry (VBM) and TBSS are examined using DTI data of temporal lobe epilepsy (TLE) patients and nonepileptic subjects. In addition to fractional anisotropy (FA), ellipsoidal area ratio (EAR) is used in this study. Significant reductions of FA and EAR are identified by TBSS in the parahippocampal white matter. Because of methodological differences, TBSS detects more localized abnormalities than VBM, while the EAR is more sensitive to WM alteration than FA.     

Structural brain alterations in bipolar disorder II: A combined voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) study

Background

Brain structural changes have been described in bipolar disorder (BP), but usually studies focused on both I and II subtypes indiscriminately and investigated changes in either brain volume or white matter (WM) integrity. We used combined voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) analysis to track changes in the grey matter (GM) and WM in the brains of patients affected by BPII, as compared to healthy controls.

Methods

Using VBM and DTI, we scanned 20 DSM-IV-TR BPII patients in their euthymic phase and 21 healthy, age- and gender-matched volunteers with no psychiatric history.

Results

VBM showed decreases in GM of BPII patients, compared to controls, which were diffuse in nature and most prominent in the right middle frontal gyrus and in the right superior temporal gurus. DTI showed significant and widespread FA reduction in BPII patients in all major WM tracts, including cortico-cortical association tracts.

Limitations

The small sample size limits the generalisability of our findings.

Conclusions

Reduced GM volumes and WM integrity changes in BPII patients are not prominent like those previously reported in bipolar disorder type-I and involve cortical structures and their related association tracts.     

弥散张量成像显示亚急性期脑梗死神经网络损伤及各运动参数分析

背景：脑卒中后神经网络与运动功能的相关性尚未明确。 目的：应用磁共振弥散张量成像研究亚急性期脑梗死后神经网络受损情况,并分析其与神经功能缺陷及运动功能障碍的相关性。 方法：将19例亚急性期脑梗死患者和20名正常成人分别进行弥散张量成像检查,分析比较以下参数：各向异性分数、表观扩散系数和各向异性分数指数、表观扩散系数指数。同时对患者进行神经功能缺损和运动功能的各项量表评估,检测10 m步行速度。将脑梗死患者弥散张量成像的各项参数与各项量表及10 m步行速度进行相关性分析。 结果与结论：脑梗死患者各向异性分数指数和双侧内囊后肢的各向异性分数值均小于正常对照,且患侧内囊后肢的各向异性分数值小于健侧内囊后肢的各向异性分数值(P < 0.05)。患侧内囊后肢的表观扩散系数值、表观扩散系数指数大于正常对照内囊后肢的表观扩散系数值和表观扩散系数指数(P < 0.05)。患侧内囊后肢的表观扩散系数值、表观扩散系数指数与下肢Fugl-Meyer评分呈负相关(P < 0.05)。提示弥散张量成像参数与下肢运动功能障碍密切相关。脑卒中后的局灶性病变造成神经网络缺损,是下肢运动功能障碍的主要原因。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

应用弥散张量纤维束成像技术重建儿童胼胝体压部纤维束

目的 探讨儿童胼胝体压部纤维束发育规律.方法 120名健康儿童(年龄5d～14岁)分为5组,≤1岁为第1组(22名),＞1岁～3岁为第2组(20名),＞3岁～6岁为第3组(22名),＞6岁～10岁为第4组(30名),＞10岁～14岁为第5组(26名).分别行脑部常规MRI和弥散张量成像(DTI)扫描,对原始数据进行弥散...     

Brain diffusion tensor MRI in systematic lupus erythematosus: A systematic review

Diffusion tensor imaging (DTI) maps the brain's microstructure by measuring fractional anisotropy (FA) and mean diffusivity (MD). This systematic review describes brain diffusion tensor Magnetic resonance imaging (MRI) studies in systemic lupus erythematosus (SLE).The literature was reviewed following the PRISMA guidelines and using the terms “lupus”, “systemic lupus erythematosus”, “SLE”, “diffusion tensor imaging”, “DTI”, “white matter” (WM), “microstructural damage”, “tractography”, and “fractional anisotropy”; the search included articles published in English from January 2007 to April 2017. The subjects included in the study were selected according to the ACR criteria and included 195 SLE patients with neuropsychiatric manifestation (NPSLE), 299 without neuropsychiatric manifestation (non-NPSLE), and 423 healthy controls (HC). Most studies identified significantly reduced FA and increased MD values in several WM regions of both NPSLE and non-NPSLE patients compared to HC. Subclinical microstructural changes were observed in either regional areas or the entire brain in both the non-NPSLE and NPSLE groups.     

Diffusion tensor MR imaging of principal directions: a tensor tomography approach

A novel approach to reconstructing the principal directions of a diffusion tensor field directly from magnetic resonance imaging (MRI) data using a tensor tomography data acquisition approach was developed. If tensor eigenvalues are assumed to be known, the reconstruction of principal directions requires fewer measurements than the reconstruction of the full tensor field. The tensor tomography data acquisition method (rotating diffusion gradients) leads to a unique reconstruction of principal directions, whereas the conventional MRI acquisition technique (stationary diffusion gradients) leads to an ambiguous reconstruction of principal directions when the same number of measurements are used. A computer-generated phantom was used to simulate the diffusion tensor field in the mid-ventricular region of the myocardium. The principal directions of the diffusion tensor field were assumed to align with the fibre structure of the myocardium. An iterative algorithm was used to reconstruct the principal directions. Computer simulations verify that the proposed method provides accurate reconstruction of the principal directions of a diffusion tensor field.     

A meta-analysis of diffusion tensor imaging in mild cognitive impairment and Alzheimer's disease

We reviewed case-control studies of diffusion tensor imaging (DTI) in patients with Alzheimer's dementia (AD) and mild cognitive impairment (MCI), in order to establish the relative severity and location of white matter microstructural changes. EMBASE and MEDLINE were searched using the keywords, ([“diffusion tensor”] and [“Alzheimer*” or “mild cognitive impairment”]), as were reference lists of relevant papers. Forty-one diffusion tensor imaging studies contained data that were suitable for inclusion. Group means and standard deviations for fractional anisotropy and mean diffusivity, or p values from 2-sample tests, were extracted and pooled, using standard methods of meta-analysis and metaregression. Fractional anisotropy was decreased in AD in all regions except parietal white matter and internal capsule, while patients with MCI had lower values in all white matter regions except parietally and occipitally. Mean diffusivity was increased in AD in all regions, and in MCI in all but occipital and frontal regions.     

Two-step anomalous diffusion tensor imaging

We extend the formalism of anomalous diffusion imaging to include directional anisotropy of fitted parameters. The resulting technique is termed anomalous diffusion tensor imaging (aDTI), and allows the directional properties of the distributed diffusion coefficient (α) and the anomalous diffusion exponent, (γ) to be analysed using the same analytical techniques as regular diffusion tensor imaging (DTI). Together, these parameters quantify the rate of diffusion (α) and the complexity of the diffusion environment (γ). We generated tensor images for the anomalous exponent tensor (Γ) and distributed diffusivity tensor (A) from in vivo human brain data and present images of eigenvalues, eigenvectors, Trace/3 (Tr), fractional anisotropy (FA) and tensor shape measures. In white matter, A is found to have a median Tr = 0.56 × 10^{? 3}mm²s^{? 1}, FA = 0.58 and Γ Tr = 0.69, FA = 0.13. We observed that white matter shows a similar anisotropic geometry for the distributed diffusion tensor as for the regular diffusion tensor, whereas the anomalous exponent tensor exhibits a different shape characteristic which may be informative of tissue microstructure. Copyright © 2011 John Wiley & Sons, Ltd.     

A meta-analysis of diffusion tensor imaging studies in amyotrophic lateral sclerosis

Studies involving diffusion tensor imaging (DTI) of amyotrophic lateral sclerosis (ALS) with whole-brain voxel-based analysis yielded variable findings. A systematic review was conducted on whole-brain voxel-based diffusion tensor imaging fractional anisotropy (FA) studies of ALS patients and healthy controls (HC) in PubMed, ISI Web of Science, Embase, and MEDLINE databases from 1990 to December 25, 2010. Coordinates were extracted from clusters with significant difference in FA between ALS patients and HC. Meta-analysis was performed using signed differential mapping. Eight studies were enrolled, comprising 143 ALS patients and 145 HC. The included studies reported FA reduction at 67 coordinates in ALS and no FA increased. Significant reductions were present in the bilateral frontal white matter/cingulate gyrus and the posterior limb of bilateral internal capsule. The findings remain largely unchanged in quartile and jackknife sensitivity analyses. Our finding suggests that ALS is a multisystem disease beyond motor dysfunction and provides evidence that FA reduction in the frontal white matter and cingulate gyrus may be a special biomarker of ALS.     

基于参考图像的压缩感知磁共振扩散张量成像

基于参考图像的压缩感知磁共振扩散张量成像方法,利用相邻方向的扩散加权图像差异较小的特点,采用压缩感知理论实现快速扩散张量成像,回顾性选取扩散张量图像数据进行实验研究,在采样率为50%的均匀分布辐射线欠采样方式下进行基于参考图像的压缩感知扩散张量图像重建,结果表明重建后的扩散加权图的平均结构相似性（MSSIM）和峰值信噪比（PSNR）分别为0.904±0.044、（37.92±3.89） dB,各向异性分数图的MSSIM和PSNR分别为0.992、41.64 dB。因此,该方法在保证重建图像质量的前提下,可显著缩短数据采集时间,减少由于时间过长引起的图像伪影等问题。