基于纤维束示踪的空间统计分析在帕金森病扩散张量成像中的应用研究

目的 通过磁共振扩散张量成像(DTI)的基于纤维束示踪的空间统计分析(TBSS)技术研究帕金森病(PD)脑白质微结构的损害.方法 PD患者31例和健康对照组34名行磁共振检查,扫描序列包括常规磁共振平扫和DTI,通过TBSS技术比较PD组与对照组白质纤维束的各向异性分数(FA)值,寻找FA值有显著性差异的脑白质纤维束,并分析PD组白质纤维束损伤与MoCA、MMSE、HAMD、ADL和UPDRSIII评分的相关性.结果 PD组有多个纤维束FA值明显低于健康对照组,主要包括胼胝体、上纵束、扣带束、视辐射、额叶及颞叶皮层下弓形纤维、脑干及内囊的白质束.其中胼胝体压部、左上纵束、右上纵束、小脑中脚FA值与MMSE评分呈正相关;右上纵束、左皮质脊髓束、左小脑上脚、右皮质脊髓束和小脑中脚FA值与HAMD评分呈负相关;胼胝体压部、左上纵束、右上纵束FA值与ADL评分呈负相关.结论 磁共振DTI的TBSS技术能够发现PD患者白质微结构的损害及其与认知和抑郁之间的关系,有助于研究PD患者认知功能障碍和抑郁的发生机制.     

弥散张量成像对早期帕金森病的研究价值

目的:探讨弥散张量成像(DTI)对早期原发性单侧症状帕金森病(PD)的诊断价值,为临床诊断及疾病分级提供参考及依据.方法:26例未经治疗的早期原发性单侧症状帕金森病患者为PD组,20例健康正常人为对照组,对两组均进行常规磁共振(MRI)及DTI检查,检查前对PD组均进行UPDRS评分及Hoehn&Yahr分期,DTI测量双侧黑质、壳核、尾状核头部及丘脑的各向异性分数(FA值)及表观弥散系数(ADC值).结果:PD组症状对侧黑质的FA值较同侧及对照组双侧均值显著减低(t=2.987,P=0.004;t=3.072,P=0.003),其余感兴趣区FA值及所有感兴趣区ADC值组内及组间均无明显差异;症状对侧黑质FA值与UPDRS评分无明显相关性.结论:单侧症状PD患者症状对侧黑质早期就存在FA值减低,DTI技术可作为早期帕金森病诊断的一项无创性检查方法,但对判断疾病的严重程度无帮助.     

原发性单侧症状帕金森病黑质的DTI研究

目的:研究帕金森病(PD)黑质的DTI 改变状况,探讨PD早期诊断的线索.方法:以原发单侧症状PD患者10例为PD组,年龄和性别相匹配的健康志愿者10名为对照组.两组分别予以磁共振DTI脑检查,测量计算双侧黑质区域的ADC 值和FA 值,并将PD组和对照组进行对比分析.结果:原发单侧症状PD组患者症状对侧的黑质FA值较同侧和健康对照组FA值明显下降(分别为0.254±0.083,0.314±0.022,0.409±0.043;t=-2.424,P=0.038<0.05和t=5.112,P=0.001<0.05).对照组双侧黑质FA值之间差异无显著意义(分别为0.406±0.046,0.419±0.030;t=-1.1871,P=0.301>0.05).PD组症状的同侧黑质FA值与对照组之间差异也有显著意义(分别为0.409±0.043,0.314±0.022;t=6.214,P=0.002<0.05).PD组症状对侧和同侧黑质部位ADC值与对照组之间差异无显著意义(分别为t=0.140,P=0.893>0.05和t=0.334,P=0.748>0.05).结论:单侧症状PD患者的对侧黑质早期就可能存在神经元的缺失或轴突功能受损,提示黑质部位FA值分析可作为PD早期或亚临床诊断的线索之一.     

磁共振扩散张量成像在评估帕金森病脑内白质改变中的应用

目的 利用磁共振扩散张量成像技术(diffusion tensor imaging,DTI)评价帕金森病患者脑白质纤维束与正常老年组间的差异.方法 对23例临床诊断为原发性帕金森病(Parkinson's disease, PD)患者和相匹配的22例正常老年人行DTI成像,采用人工勾画感兴趣区(region of interest,ROI)的方法在DTI参数图,包括部分各向异性图(fractional anisotropy,FA)和平均扩散系数图(mean diffusivity,MD)上测量脑内主要白质纤维束的FA值及MD值,采用t检验的方法进行组间比较.结果 PD组双侧钩束、后扣带束及上纵束的FA值低于对照组(P＜0.05),双侧后扣带束及右侧上纵束的MD值高于正常组(P＜0.05).结论 PD的病理改变不仅存在于黑质纹状体系统,也累及白质纤维.     

高原和平原地区健康成人脑白质扩散张量成像TBSS分析

目的 采用扩散张量成像(DTI)及基于纤维束追踪空间统计分析(TBSS)研究平原与高原健康成人的脑白质微细结构差异.方法 对16名高原健康成人和与之年龄、受教育程度相匹配的20名平原健康成人行DTI检查,应用TBSS方法分析两组受检者脑白质纤维DTI的相关参数:各向异性分数(FA)、轴向扩散系数(AD)、平行扩散系数(RD)、平均扩散系数(MD).对两组各项参数进行比较.结果 与平原组比较,高原组在胼胝体体部、胼胝体压部、胼胝体膝部、两侧上纵束、两侧上放射冠、右侧内囊前肢、内囊豆状核后肢、右侧丘脑辐射线(包括视辐射线)的AD值显著增高(P＜0.05,FWE校正);MD值显著升高的脑区是胼胝体体部、右侧上纵束、右侧上放射冠、右侧内囊前肢(P＜0.05,FWE校正);RD值显著升高的脑区是胼胝体体部、右侧上纵束.结论 通过DTI及TBSS分析,高原健康成人相对于平原健康成人脑白质纤维存在差异.     

首发精神分裂症幻听患者的全脑白质变化研究

目的 探讨首发精神分裂症(SCH)幻听患者的全脑白质微细结构的改变.方法 分别对25例首发SCH幻听患者和25例正常对照者行扩散张量成像(DTI)扫描,采用基于纤维束示踪的空间统计分析(TBSS)方法分析2组全脑各向异性(FA)图,使用非参数的随机排列检验(random permutation test)对2组全脑DTI的FA值进行统计分析比较,得出有差异的脑区.结果 与正常组相比,首发SCH幻听组左侧额眶回与顶下小叶的白质FA值明显降低,差异具有统计学意义(P＜0.05).结论 TBSS方法能较全面、准确地分析首发SCH幻听患者早期脑白质细微结构的改变.     

高扩散梯度因子值扩散张量成像在评价单侧大脑中动脉闭塞供血区及远隔部位脑白质中的应用价值

目的 采用高b值DTI研究常规MRI上无异常的单侧大脑中动脉闭塞供血区及远隔部位脑白质的影像特征.方法 选取34例常规MRI无异常信号的单侧大脑中动脉闭塞患者,行高b值(2200 s/mm2) DTI成像.所得图像进行后处理,镜像对称法选取双侧放射冠区侧脑室体部层面、内囊前肢、内囊后肢、大脑脚、脑桥中部层面为R0I,测量患者以上部位患、健侧的各向异性分数(FA)值、ADC值及本征值(λ1、λ2、λ3),采用配对t检验比较患者患侧与健侧各测量值.结果 34例患者中,大脑中动脉M1段闭塞左侧16例、右18例.放射冠区健侧FA值、ADC值及λ1、λ2、λ3值分别为0.443±0.033,(5.804±0.282)×10-3、( 5.651±0.350)×10-3、(6.099±0.353)×10-3、(6.372±0.355)×10-3 m2/s,患侧各值分别为0.419±0.032,(5.975±0.272)×10-3、(5.704±0.365)× 10-3、(6.412±0.368)× 10-3、(6.605±0.343)×10-3 mm2/s,患侧FA值较健侧减小(t=11.614,P＜0.01),ADC、λ1、λ2及λ3值较健侧增大(t值分别12.421、7.447、10.244、9.890,P值均＜0.01).患侧内囊前肢及后肢FA值分别为0.609 ±0.026、0.674±0.033,λ1值分别为(5.330±0.462) ×101、(5.171±0.456)×10-3 mm2/s,健侧对应部位FA值和λ,值分别为0.622±0.026、0.694±0.034,(5.064±0.448) ×10-3、(4.924±0.365)×10-3 mm2/s,患侧内囊前、后肢FA值较健侧减小(t值分别7.823、8.013,P值均＜0.01),λ1值较健侧增大(t值分别7.811、8.800,P值均＜0.01),ADC、λ2及λ3值两侧比较差异无统计学意义.大脑脚、脑桥的各测量值在两侧间比较差异均无统计学意义.结论 高b值DTI可敏感评价MRI无异常信号的闭塞脑动脉供血区的脑白质损害,其远隔部位脑白质未见损害.     

早期帕金森病扩散张量成像的初步研究

目的 评价MRI扩散张量成像(DTI)技术在早期帕金森病(PD)中的诊断价值.资料与方法 对30名早期PD患者和30例匹配的健康老年对照组的黑质-纹状体区进行了常规MR平扫和DTI扫描,对双侧黑质-纹状体纤维环路穿越的部位:黑质致密部、底丘脑核、苍白球、壳核、尾状核连续层面的FA值和DCavg值进行测量和统计分析.结果 PD组黑质致密部、黑质致密部与底丘脑核之间部位的FA值显著低于对照组(P值<0.05).苍白球、壳核、尾状核等部位的FA值和DCavg值与对照组相比无显著差异.结论 DTI能无创性定量测量早期PD黑质.纹状体区病变的FA值和DCavg值,是对早期PD黑质.纹状体区进行定量评估的一种敏感的研究手段.     

基于TBSS的急性CO中毒患者脑白质微细结构损伤研究

目的应用扩散张量成像(DTI)观察急性CO中毒患者脑白质结构的改变,应用影像技术量化脑白质损害程度,推测急性CO中毒迟发性脑病相关机制。方法对25例急性CO中毒患者和25例性别与年龄相匹配的健康志愿者进行头部磁共振DTI扫描,采用基于纤维束示踪的空间统计方法(TBSS),分析急性CO中毒患者脑白质平均扩散系数(MD)、各向异性分数(FA)的变化,探讨其与患者认知功能障碍间的相关性。结果与健康对照组对比,急性CO中毒患者组的放射冠、胼胝体的MD增高而FA降低(P<0.05);双侧上纵束,内、外囊,丘脑和脑干的MD增加但无FA改变(P<0.05)。与临床量表分数相关性比较发现,差异脑区FA值与MMSE评分呈一定正相关(P<0.05),差异脑区MD值与MMSE评分呈一定负相关(P<0.05)。结论DTI准确反映急性CO中毒导致脑内白质广泛的血管源性水肿以及脑白质纤维束完整性损害,可能量化反应病情缺氧脑损伤程度、预测迟发性脑病,同时DTI参数的改变还可以一定程度反映患者认知障碍情况。     

3.0T磁共振PWI与DTI在单侧大脑中动脉闭塞中的应用

目的 探讨3.0T磁共振PWI及不同b值DTI在单侧大脑中动脉闭塞中的应用价值.方法 对36例脑常规MRI显示无明显缺血改变的单侧大脑中动脉重度狭窄或闭塞患者行PWI及不同b值(3100～400 s/mm2)DTI成像,以健侧脑组织为对照,分析患侧大脑中动脉供血区脑白质MTT、rCBV、rCBF、TTP及不同b值ADC、FA值变化.结果 患侧脑白质MTT、TTP值较健侧延长(P<0.05), rCBF较健侧减小(P<0.05),患侧rCBV与健侧无统计学差异;b值自3100～1000 s/mm2,患侧ADC值大于健侧(P＜0.05);b值等于700、400 s/mm2时,患、健侧ADC值无统计学差异;b值自3100～1300 s/mm2,患侧FA值小于健侧(P＜0.05),b值自1000～400 s/mm2,两侧FA值无统计学差异.结论 对于常规MRI显示无明显缺血改变的脑动脉闭塞患者,MTT、rCBF、TTP可敏感地检测其灌注异常,高b值较常规b值ADC、FA值能够更敏感地探测其弥散改变.     

紧张型头痛患者脑白质弥散张量成像TBSS分析

目的 采用磁共振弥散张量成像(diffusion tensor imaging,DTI)研究紧张型头痛患者脑白质结构的完整性.方法 选取24例紧张型头痛患者及24例健康志愿者,收集人口学资料并进行全脑DTI扫描,利用功能磁共振软件库(fMRI software library,FSL),采用基于脑白质骨架的空间追踪法(...     

Fractional anisotropy asymmetry and the side of seizure origin for partial onset-temporal lobe epilepsy

This paper presents a fractional anisotropy asymmetry (FAA) method to detect the asymmetry of white matter (WM) integrity and its correlation with the side of seizure origin for partial onset temporal lobe epilepsy (TLE) using diffusion tensor image (DTI). In this study, FAA analysis is applied to 30 patients of partial TLE (15 left, 15 right) and 14 matched normal controls. Specifically, after registering all the images with the JHU-DTI-MNI template the average FA value of each FA skeleton section is calculated using the tract-based spatial statistics (TBSS) method. Then, FAA is calculated to quantify the WM diffusivity asymmetry of the corresponding region-pairs between the left and right hemispheres. Using FAA the regional asymmetry contributing significantly to the group differences of controls and left/right TLE, as well as the left and right TLE, is identified. As a comparison, the ROI-based average FA values for WM and corresponding FAAs are also calculated. TBSS-based analysis reflects the average of local maximal FA values along the white matter skeleton sections, and ROI-based analysis shows the average of WM FA values within each anatomical region. The FAA statistical results indicated that the FA values of anatomical region-pairs are asymmetric in the ipsilateral hemisphere with seizure origin against the contralateral hemisphere. Particularly, FAA values within the temporal lobe (superior, middle, and inferior temporal WM) are significantly different between the left and right TLE patients, consistently found from both analysis methods. The study suggests that FAA values can be potentially used to identify the seizures of origin of TLE and to help understand the relationship between fiber tracts with the side of seizure origin of TLE.     

A preliminary diffusional kurtosis imaging study of Parkinson disease: comparison with conventional diffusion tensor imaging

Introduction

Diffusional kurtosis imaging (DKI) is a more sensitive technique than conventional diffusion tensor imaging (DTI) for assessing tissue microstructure. In particular, it quantifies the microstructural integrity of white matter, even in the presence of crossing fibers. The aim of this preliminary study was to compare how DKI and DTI show white matter alterations in Parkinson disease (PD).

Methods

DKI scans were obtained with a 3-T magnetic resonance imager from 12 patients with PD and 10 healthy controls matched by age and sex. Tract-based spatial statistics were used to compare the mean kurtosis (MK), mean diffusivity (MD), and fractional anisotropy (FA) maps of the PD patient group and the control group. In addition, a region-of-interest analysis was performed for the area of the posterior corona radiata and superior longitudinal fasciculus (SLF) fiber crossing.

Results

FA values in the frontal white matter were significantly lower in PD patients than in healthy controls. Reductions in MK occurred more extensively throughout the brain: in addition to frontal white matter, MK was lower in the parietal, occipital, and right temporal white matter. The MK value of the area of the posterior corona radiata and SLF fiber crossing was also lower in the PD group.

Conclusion

DKI detects changes in the cerebral white matter of PD patients more sensitively than conventional DTI. In addition, DKI is useful for evaluating crossing fibers. By providing a sensitive index of brain pathology in PD, DKI may enable improved monitoring of disease progression.     

运动神经元病患者大脑结构异常评估:基于多模态成像

目的探究性利用多模态影像技术评估14例运动神经元病(MND)患者脑部灰白质结构改变,分析疾病表征及脑内异常的相关性。方法14例临床诊断考虑为MND患者作为实验组,认知功能评分正常,14例年龄、性别和左右利手匹配的无神经系统疾病的志愿者为对照组,行常规磁共振扫描以及T13D和DTI扫描。应用Freesurfer软件对T13D数据进行分析,组间比较全脑皮层厚度差异。应用基于纤维束示踪的空间统计方法(TBSS)和基于白质模板分割法分析DTI数据,比较全脑白质结构差异。显著差异白质结构特征值与临床指标作相关性分析。结果与对照组相比,Freesurfer结果显示MND患者右侧颞上回和左侧额中回下部局部局限性皮层厚度减低(P<0.05,非FDR校正)。TBSS结果表明胼胝体至运动皮层区域皮质脊髓束FA值和F1值呈显著性降低(P<0.05,FEW校正),而相应区域F2、L1、MD等值未见明显差异,特别是左侧上放射冠白质纤维,其FA值显著性降低(P=0.007),并与ALSFRs评分正相关(r^2=0.723,P=0.004)。结论无明显认知障碍MND患者主要表现为轻微灰质结构改变,白质结构特别是胼胝体至运动皮层的皮质脊髓束纤维结构完整性损伤,运动功能皮层信息上下传导受阻。上放射冠FA值与疾病严重程度相关,未来可用于监测疾病严重程度和发展进程。     

慢性高原病的脑磁共振弥散张量成像研究

目的：应用3.0T磁共振弥散张量成像（diffusion tensor imaging,DTI）技术,评价慢性高原病患者脑白质的各向异性分数（fractional anisotrophy,FA）。方法：本研究共包括9例慢性高原病患者和10例正常志愿者,行常规MRI扫描及DTI扫描,测定DTI图像上不同脑白质区的FA值,并比较两组FA值的差异。结果：两组常规MR检查未见明确差异,DTI示慢性高原病组双侧额叶及海马旁白质、胼胝体膝部FA值较正常志愿者组降低,差异具有统计学意义（P〈0.05）。结论：慢性高原病患者部分脑白质区FA值下降,提示脑白质纤维束完整性受损。     

Gray matter and white matter abnormalities in online game addiction

Online game addiction (OGA) has attracted greater attention as a serious public mental health issue. However, there are only a few brain magnetic resonance imaging studies on brain structure about OGA. In the current study, we used voxel-based morphometry (VBM) analysis and tract-based spatial statistics (TBSS) to investigate the microstructural changes in OGA and assessed the relationship between these morphology changes and the Young's Internet Addiction Scale (YIAS) scores within the OGA group. Compared with healthy subjects, OGA individuals showed significant gray matter atrophy in the right orbitofrontal cortex, bilateral insula, and right supplementary motor area. According to TBSS analysis, OGA subjects had significantly reduced FA in the right genu of corpus callosum, bilateral frontal lobe white matter, and right external capsule. Gray matter volumes (GMV) of the right orbitofrontal cortex, bilateral insula and FA values of the right external capsule were significantly positively correlated with the YIAS scores in the OGA subjects. Our findings suggested that microstructure abnormalities of gray and white matter were present in OGA subjects. This finding may provide more insights into the understanding of the underlying neural mechanisms of OGA.     

Diffusion tensor imaging of normal-appearing white matter in mild cognitive impairment and early Alzheimer disease: preliminary evidence of axonal degeneration in the temporal lobe

BACKGROUND AND PURPOSE: Diffusion tensor imaging (DTI) is a sensitive technique for studying cerebral white matter. We used DTI to characterize microstructural white matter changes and their associations with cognitive dysfunction in Alzheimer disease (AD) and mild cognitive impairment (MCI). MATERIALS AND METHODS: We studied elderly subjects with mild AD (n = 6), MCI (n = 11), or normal cognition (n = 8). A standardized clinical and neuropsychological evaluation was conducted on each subject. DTI images were acquired, and fractional anisotropy (FA), axial diffusivity (DA), and radial diffusivity (DR) of normal-appearing white matter (NAWM) in frontal, temporal, parietal, and occipital lobes were determined. These diffusion measurements were compared across the 3 groups, and significant differences were further examined for correlations with tests of cognitive function. RESULTS: Compared with normal controls, AD subjects demonstrated decreased FA and increased DR in the temporal, parietal, and frontal NAWM and decreased DA in temporal NAWM. MCI subjects also showed decreased FA and decreased DA in temporal NAWM, with decreased FA and increased DR in parietal NAWM. Diffusion measurements showed no differences in occipital NAWM. Across all subjects, temporal lobe FA and DR correlated with episodic memory, frontal FA and DR correlated with executive function, and parietal DR significantly correlated with visuospatial ability. CONCLUSIONS: We found evidence for functionally relevant microstructural changes in the NAWM of patients with AD and MCI. These changes were present in brain regions serving higher cortical functions, but not in regions serving primary functions, and are consistent with a hypothesized loss of axonal processes in the temporal lobe.     

扩散张量成像在颅内肿瘤周围白质区的应用

目的：评价MR扩散张量成像技术在不同级别胶质瘤、脑膜瘤及转移瘤周围正常脑白质区的应用价值。方法：对43例颅内肿瘤患者行常规MRI及扩散张量成像检查,其中高级别胶质瘤12例,低级别胶质瘤10例,脑膜瘤12例、转移瘤9例。测量瘤周正常脑白质的FA值及对侧相应解剖部位正常脑白质的FA值,行组间统计学分析。结果：高级别胶质瘤瘤周正常脑白质FA值低于对侧正常脑白质FA值,差异有统计学意义（P〈0.05）;低级别胶质瘤、脑膜瘤及转移瘤FA值的差异无统计学意义。高级别胶质瘤瘤周正常脑白质FA值与低级别胶质瘤、脑膜瘤、转移瘤瘤周正常脑白质之间差异有统计学意义,后三者之间的差异比较无统计学意义。结论：MR扩散张量成像技术有助于颅内肿瘤的定性诊断及推测肿瘤细胞的浸润范围。     

扩散张量成像在遗忘型轻度认知障碍和Alzheimer病中的应用

目的：探讨磁共振扩散张量成像（DTI）在遗忘型轻度认知障碍（AMCI）、Alzheimer病（AD）诊断中的作用。方法：对20名aMCI患者、20名AD患者、20名正常对照者（NC）行DTI检查,分别在颞叶白质、顶叶白质、海马、胼胝体膝部及压部、上纵束Ⅱ、扣带束测ROI的FA值和ADC值。结果：NC组与aMCI组、aMCI组与AD组比较扣带束FA值均有显著性差异（P〈0．05）;NC组与AD组比较颞叶、海马、胼胝体膝部、扣带束FA值,颞叶、海马ADC值有显著性差异（P〈0．05）。结论：aMCI患者扣带束FA值异常降低;AD患者颞叶、海马、胼胝体膝部、扣带束FA值降低和颞叶、海马ADC值增高,提示DTI检查有助于aMCI、AD患者的早期诊断。