结合fMRI与DTI在脑胶质瘤诊治中的初步应用

目的：探讨DTI在脑胶质瘤定性、定级诊断中的作用,并尝试联合应用fMRI与DTI技术进行脑肿瘤术前定位及术中导航。方法：对18例脑胶质瘤患者进行常规T1WI、T2WI扫描及DTI、fMRI功能成像,测量肿瘤的实质部分、坏死或囊变区以及瘤周水肿区域的ADC值、FA值等参数。采用SPM软件对fMRI图像数据进行处理和统计分析,观察运动功能激活区、重要白质纤维束与颅内肿瘤病灶之间的相互关系。结果：高级别胶质瘤实体部分ADC值明显低于低级别胶质瘤,而FA值明显高于低级别胶质瘤,两者之间有显著性差异。高、低级别胶质瘤实质部分ADC值的分界点为1.21×10-3mm2/s,FA值分界点为0.17。联合应用fMRI与DTI可全面观察脑运动或视觉等重要功能激活区、重要白质纤维束与颅内肿瘤病灶之间的相互关系。结论：应用DTI可以在术前对胶质瘤进行分级,将fMRI与DTI功能影像应用于脑肿瘤导航手术可为术前计划提供必要信息,在术中避免损伤脑功能区及锥体束等重要结构,为手术提供双重保障。     

白质纤维束成像在脑星形胶质细胞瘤中的作用

目的：探讨白质纤维束成像（Diffusion tensor tractography,DTT）技术在脑星形胶质细胞瘤研究中的价值。材料与方法：对33例经病理证实的脑星形胶质细胞瘤患者进行常规MR成像、弥散张量成像（DTI）和DTT,分析肿瘤瘤周白质纤维束的改变形式与肿瘤分级的关系。结果：无论是高级别还是低级别肿瘤,瘤周白质纤维束都可以发生移位（77.78%~100%）,而白质纤维束的破坏和中断主要与星形胶质细胞瘤的恶性程度有关,随着肿瘤级别的升高,白质纤维束的破坏和中断的发生率也逐渐升高（7.69%~72.73%）。结论：DTT技术在显示脑星形胶质细胞瘤分级方面有重要的价值。     

扩散张量各向异性分数在星形细胞瘤中的诊断价值

目的评价MR扩散张量成像(DTI)各向异性分数(FA)在星形细胞瘤中的应用价值.方法经手术及病理证实的星形细胞瘤共26例,其中低级别星形细胞瘤10例,高级别星形细胞瘤16例.行常规MR 、DTI检查.构建 FA 图,并测量肿瘤、水肿区及正常白质的FA值.结果正常白质纤维在FA图上表现为高信号.低级别星形细胞瘤多呈低信号,边缘清晰,周围白质纤维呈高信号,信号未见明显减低. 高级别星形细胞瘤亦多呈低信号,边缘模糊,肿瘤实体区与水肿区FA值无显著性差异(P＞0.05);所有病例肿瘤实体区和水肿区 FA值与邻近正常脑白质进行比较,存在显著性差异(P＜0.05),即FA图不能明确区分肿瘤边缘及水肿区,但能将二者和正常白质纤维束鉴别.结论 DTI可清楚显示肿瘤与周围白质纤维的解剖关系,指导临床制定手术方案.     

弥漫性胶质瘤3.0T磁共振扩散张量成像及纤维束成像的初步研究

目的探讨扩散张量成像（DTI）及纤维束成像在弥漫性胶质瘤的诊断、分级以及显示肿瘤与周围结构关系等方面的作用。方法使用3.0T磁共振ASSET-SE-EPI序列对37例弥漫性胶质瘤患者（WHO分级：Ⅱ级16例,Ⅲ级11例,Ⅳ级10例）进行DTI成像。分别测定病灶实性部分、灶周水肿区、病灶及水肿周围T2WI显示信号正常区域、病灶同侧远处T2WI显示信号正常区域及对侧大脑半球相对应区域的MD值和FA值。对灶周白质纤维束进行三维纤维束成像。结果肿瘤及瘤周水肿区的MD值明显高于对侧正常脑实质（P〈0.01）,而FA值则均明显低于对侧正常脑实质（P〈0.01）。Ⅱ级肿瘤内的FA值明显低于Ⅲ级和Ⅳ级（PⅡ-Ⅲ=0.024;PⅡ-Ⅳ=0.030）。各级别胶质瘤肿瘤内与瘤周水肿区之间的MD值和FA值均无统计学差异（P〉0.05）。三维纤维束成像显示,Ⅱ级胶质瘤对周围白质纤维束主要是推移;Ⅲ级胶质瘤周围水肿区均可见纤维束较明显的破坏,肿瘤周围T2WI信号正常白质区内也有部分纤维束被肿瘤浸润甚至破坏;Ⅳ级胶质瘤周围水肿区及T2WI信号正常白质区内均有明显的纤维束浸润、破坏。结论各级别弥漫性胶质瘤瘤周白质纤维束均有不同程度的浸润破坏,反映了弥漫性胶质瘤浸润性生长的特征。MD值和FA值可用于区分胶质瘤与正常脑组织。FA值可用于区分低级别胶质瘤与高级别胶质瘤。DTI方向编码彩图和三维纤维束成像可以清楚、直观地显示肿瘤与周围白质纤维束的关系。     

磁共振弥散张量成像在诊断脑膜瘤和胶质瘤中的应用研究

磁共振弥散张量成像(diffusion tensor imaging,DTI)是最近几年逐步发展起来的一种水成像技术,是通过各项异性分数(fractional anisotropy,FA)和表观弥散系数(apparent diffusion coefficient,ADC)测量值定量反映脑白质纤维束的损伤程度和完整性,正确地判断肿瘤与白质纤维束的关系,鉴别脑肿瘤的良恶性,给临床治疗和预后提供有价值的信息。     

磁共振弥散张量成像在脑室旁白质软化症中的应用

目的通过对12例脑室旁白质软化症(PVL)患儿的磁共振弥散张量成像(DTI)及白质纤维素成像(FT)研究,评价DTI及FT在缺氧缺血性脑损伤后脑内主要白质纤维束变化方面的应用价值。方法选取12例临床确诊为脑瘫的PVL患儿,同时选择无窒息史的健康儿童志愿者12例进行对照研究。对这两组儿童进行MRI及DTI检查(扩散敏感梯度方向15个)。根据矢量元素和部分各向异性值(FA值)生成彩色弥散张量图(DTI图),通过DTI图选取所有可识别白质纤维束的中心部分作为感兴趣区(ROI),计算患儿与对照组各主要白质纤维束的FA值,进行配对t检验。结果试验组和对照组的ICAL、脑干CST、ML、MCP以及外囊(EC)白质纤维束示踪图像肉眼未见直观差异,而患儿组ICPL、AF、PTR、CR、CG、SLF以及胼胝体压部的白质纤维较对照组明显变细。所有12名患儿的ICPL、AF、PTR、CR、CG、SLF、SCC以及GCC的FA值较健康对照组同侧对应位置FA值显著减低(P<0.05),而患儿与对照组的ICAL、ML、MCP以及脑干CST的FA值配对t检验未见显著差异(P>0.05)。结论DTI及FT在评价缺氧缺血性脑损伤后脑内主要白质纤维束变化方面有较高的应用价值。     

功能磁共振成像和弥散张量纤维束成像技术对提高脑肿瘤的全切率的作用

目的:分析功能磁共振成像(f MRI)与弥散张量纤维束成像技术(DTI)在脑肿瘤患者手术治疗中的作用。方法:选取2013年2月~2017年6月我院收治的行脑肿瘤手术的68例患者为研究对象,根据术前检查方式分为对照组(32例)与观察组(36例)。两组均给予神经导航下显微肿瘤切除术,对照组术前行MRI增强检查,观察组在对照组基础上行f MRI、DTI检查,观察两组肿瘤切除情况及预后。结果:观察组肿瘤全切率明显高于对照组(P0.05);治疗后观察组KPS评分明显高于对照组(P0.05)。结论:对脑肿瘤手术患者行f MRI与DTI检查,有助于提高肿瘤全切率,改善患者预后,值得推广应用。     

DTI多参数综合分析在颅内星形细胞瘤临床分级及神经外科手术中的应用价值研究

目的：探讨DTI多参数综合分析及DTT技术在星形细胞瘤分级、术前计划制定、术后疗效评价中的应用价值。方法：星形细胞瘤患者33例,术前和/或术后行常规T1WI、T2WI、T1WI增强、DTI检查。测量病灶不同区域及对侧正常白质区的DCavg值、FA值、ADC值、1-VR值及RA值;扩散张量纤维束成像（DTT）重建病变周围脑白质纤维束。结果：各组中的病灶不同区域的各测量值均存在显著差异（P<0.05）。低级别星形细胞瘤肿瘤周围的白质纤维束多呈推挤水肿改变,2例患者术后白质纤维束移位水肿减轻,预后良好,而高级以浸润破坏为主, 3例患者术后无改善。结论：DTI多参数均有助于区分肿瘤不同区域,有助于低、高级别星形细胞瘤的鉴别;DTI及DTT有助于肿瘤患者术前计划的制定和手术效果的评价。     

DTI联合IVIM-DWI技术对脑胶质瘤分级的诊断价值

目的:联合应用磁共振扩散张量成像(DTI)和体素内不相干运动扩散加权成像(IVIM-DWI)对脑胶质瘤进行分级诊断,评估其临床应用价值。方法:收集2017年6月-2019年3月共42例临床高度怀疑胶质瘤的患者,术前均未进行放化疗及其他抗肿瘤干预,均行多模态MRI扫描及DTI和IVIM-DWI成像,汇总影像资料,测量DTI各向异性指数FA值、平均扩散系数MD值;IVIM微循环灌注系数D*值、真性水分子扩散系数D值、灌注分数f值,通过DTI-Fibertrak纤维束示踪成像技术后处理脑内白质纤维束。追踪外科手术及预后情况的完整治疗记录,最后将术前影像诊断结果与术后病理学结果对照分析。结果:42例患者低级别胶质瘤19例(LGG,WHOⅠ~Ⅱ级),高级别胶质瘤23例(HGG,WHOⅢ~Ⅳ级),其中II级19例、III级14例、IV级9例。利用IVIM-DWI和DTI技术,HGG灌注系数D*值高于LGG,HGG扩散系数D值及灌注分数f值均低于LGG,HGG所有FA值、MD值均低于LGG,以上差异均有统计学意义(P<0.05)。DTI的白质纤维束成像对胶质瘤瘤体内的纤维束破坏、边界及外周侵袭范围、与功能区关系可进行明确区分。结论:DTI联合IVIM-DWI成像技术,对于胶质瘤能够进行分级诊断,并且对术前评估、治疗方案选择均具有指导意义和重要的临床应用价值。     

弥散张量成像对基底节区胶质瘤手术的临床意义

目的探讨弥散张量成像（DTI）对指导手术切除基底节区胶质瘤及降低致残率的临床意义。 方法收集2009~2014年间我科收治的48例基底节区胶质瘤患者,术前行MRI+DTI,用纤维束示踪方法重建出锥体束,明确肿瘤和锥体束的三维空间结构关系,以避开锥体束设计手术入路,按纤维束受肿瘤侵袭程度指导手术切除肿瘤范围,术后评估神经功能状况。同时选取同期30例基底节区胶质瘤未行DTI的手术患者作为对照组,了解两者两组全切率及术后4周KPS评分的差异。 结果对照组镜下全切19例,次全切7例,部分切除4例,全切率63.3%;DTI组镜下全切29例,次全切13例,部分切除6例,镜下全切率60.4%,两组镜下全切率比较,P>0.05,差别无统计学差异;对照组KPS评分为77.67±19.09分;DTI组KPS评分为87.29±14.84分,两组KPS评分比较,P < 0.05,差别有统计学意义。 结论术前DTI检查对指导手术切除基底节区胶质瘤有重要临床意义,起到降低患者致残率和提高术后生存质量的作用,但无提高肿瘤全切率。       

磁共振弥散张量成像及纤维束成像对脑胶质瘤分级的诊断价值

目的 联合应用弥散张量成像(diffusion tensor imaging,DTI)与弥散张量纤维束成像(diffusion tensor tractography,DTT),探讨其在胶质瘤分级诊断中的应用价值.方法 25例脑胶质瘤患者进行常规MR及弥散张量成像,经组织病理学证实其中9例低级别(Ⅰ～Ⅱ级)胶质瘤,16...     

Intraoperative visualization of the pyramidal tract by diffusion-tensor-imaging-based fiber tracking

Functional neuronavigation allows intraoperative visualization of cortical eloquent brain areas. Major white matter tracts, such as the pyramidal tract, can be delineated by diffusion-tensor-imaging based fiber tracking. These tractography data were integrated into 3-D datasets applied for neuronavigation by rigid registration of the diffusion images with standard anatomical image data so that their course could be superimposed onto the surgical field during resection of gliomas. Intraoperative high-field magnetic resonance imaging was used to compensate for the effects of brain shift, which amounted up to 8 mm. Despite image distortion of echo planar images, which was identified by non-linear registration techniques, navigation was reliable. In none of the 19 patients new postoperative neurological deficits were encountered. Intraoperative visualization of major white matter tracts allows save resection of gliomas near eloquent brain areas. A possible shifting of the pyramidal tract has to be taken into account after major tumor parts are resected.     

Quantitative evaluation of white matter tract DTI parameter changes in gliomas using nonlinear registration

Diffusion tensor imaging (DTI) has been used extensively to investigate white matter architecture in the brain. In the context of neurological disease, quantification of DTI data sets enables objective characterisation of the associated pathological changes. The aim of this study is to propose a method of evaluating DTI parameter changes in gliomas in the internal capsule using nonlinear registration to delineate the white matter and enable quantitative assessment of DTI derived parameters. 20 patients selected pre-operatively with probable grade 2 or grade 3 glioma on structural MRI along with ten normal volunteers were included in this study. DTI fractional anisotropy (FA) maps were used to define a common segmented FA skeleton that was projected back onto the original individual FA maps. Objective segment classification as normal or abnormal was achieved by comparison to prediction intervals of FA and mean diffusivity (MD) defined in normal subjects. The internal capsules of each patient were segmented into 10 regions of interest (ROI) with 20 and 16 segments across the group having significantly increased or decreased FA and MD values respectively. Seven glioma patients had abnormal DTI parameters in the internal capsule. We show that the classification of tract segments was consistent with disruption, oedema or compression. The results suggest that this method could be used to detect changes in eloquent white matter tracts in individual patients.     

精神分裂症患者脑白质的磁共振扩散张量成像研究

目的应用磁共振扩散张量成像技术(DTI)对精神分裂症患者额叶及胼胝体压部脑白质损伤情况与临床症状之间的关系进行初步研究。方法对22例精神分裂症患者和20例健康志愿者进行脑部DTI扫描后,测量双侧额叶和胼胝体压部的各向异性分数值(FA),应用成组t检验对精神分裂症患者和正常健康对照组的相应区域进行比较,并用部分相关性检验对精神分裂症患者脑中各部位相应FA值与PANSS量表评分之间的关系进行统计。纤维束成像技术(DTT)重建胼胝体和扣带束。结果精神分裂症患者双侧额叶和胼胝体压部的FA值与正常对照组存在显著性差异(P<0.05),额叶FA值与PANSS量表评分之间存在正相关性(r=0.703,P<0.05),纤维束成像技术不能显示病例组和对照组的差别。结论精神分裂症患者与正常健康对照组存在脑白质细微结构的差异,DTI技术能够在一定程度上反映精神分裂症患者脑白质受损与临床症状的关系。     

A robust method for investigating thalamic white matter tracts after traumatic brain injury

Damage to the structural connections of the thalamus is a frequent feature of traumatic brain injury (TBI) and can be a key factor in determining clinical outcome. Until recently it has been difficult to quantify the extent of this damage in vivo. Diffusion tensor imaging (DTI) provides a validated method to investigate traumatic axonal injury, and can be applied to quantify damage to thalamic connections. DTI can also be used to assess white matter tract structure using tractography, and this technique has been used to study thalamo-cortical connections in the healthy brain. However, the presence of white matter injury can cause failure of tractography algorithms. Here, we report a method for investigating thalamo-cortical connectivity that bypasses the need for individual tractography. We first created a template for a number of thalamo-cortical connections using probabilistic tractography performed in ten healthy subjects. This template for investigating white matter structure was validated by comparison with individual tractography in the same group, as well as in an independent control group (N=11). We also evaluated two methods of masking tract location using the tract skeleton generated by tract based spatial statistics, and a cerebrospinal fluid mask. Voxel-wise estimates of fractional anisotropy derived from the template were more strongly correlated with individual tractography when both types of masking were used. The tract templates were then used to sample DTI measures from a group of TBI patients (N=22), with direct comparison performed against probabilistic tractography in individual patients. Probabilistic tractography often failed to produce anatomically plausible tracts in TBI patients. Importantly, we show that this problem increases as tracts become more damaged, and leads to underestimation of the amount of traumatic axonal injury. In contrast, the tract template can be used in these cases, allowing a more accurate assessment of white matter damage. In summary, we propose a method suitable for assessing specific thalamo-cortical white matter connections after TBI that is robust to the presence of varying amounts of traumatic axonal injury, as well as highlighting the potential problems of applying tractography algorithms in patient populations.     

扩散张量成像及扩散张量纤维束成像在星形细胞瘤与脑膜瘤诊断中的价值

目的 探讨DTI及扩散张量纤维束成像(DTT)诊断星形细胞瘤与脑膜瘤的价值。方法 对22例经病理证实的脑肿瘤患者(不同级别星形细胞瘤12例,良性脑膜瘤10例),测量肿瘤实质区与健侧正常脑组织的平均ADC值和FA值,比较测值,并观察两种脑肿瘤对白质纤维束的影响。结果 星形细胞瘤及脑膜瘤患者肿瘤实质区FA值均较健侧正常脑组织降低(P均<0.05);星形细胞瘤患者肿瘤实质区ADC值较健侧正常脑组织高(P<0.05),脑膜瘤患者肿瘤实质区ADC值与健侧正常脑组织差异无统计学意义(P>0.05)。星形细胞瘤与脑膜瘤患者比较,肿瘤实质区ADC值、FA值差异有统计学意义(P均<0.05)。在DTT图中,星形细胞瘤多数表现为纤维束部分中断、受压、偏移或变形、移位;脑膜瘤纤维束呈现为稀疏、移位。结论 测量肿瘤实质区ADC值和FA值可鉴别脑内和脑外肿瘤如星形细胞瘤与脑膜瘤。DTT可清晰显示脑肿瘤对白质纤维束浸润、破坏和推移,有利于术前制定手术方案。     

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。     

磁共振扩散张量成像定量分析正常臂丛神经

目的分析采用1.5T MR仪对正常成人臂丛神经进行DTI及纤维束示踪成像(DTT)的可行性及其量化特征。方法 34名健康志愿者接受DTI及DTT,测量C5~8双侧臂丛神经FA值、ADC值,采用单次激发自旋回波平面成像序列分别测量b值为700、9001、100 s/mm2时右侧C6神经根平均纤维束长度、纤维束所占体素及图像SNR。结果 34名健康志愿者中32名DTI及DTT成功。C5~8神经根平均FA值及ADC值依次为:0.46±0.03和(1.16±0.15)×10-3mm2/s、0.45±0.04和(1.13±0.19)×10-3mm2/s、0.44±0.04和(1.18±0.19)×10-3mm2/s、0.39±0.05和(1.26±0.18)×10-3mm2/s。b=900 s/mm2时,右侧C6神经根平均纤维长度、纤维束所占体素最大。b=700 s/mm2时,SNR最大(18.28±7.38);b=900 s/mm2时,SNR是最大SNR的93%。结论采用1.5T临床型MR机b值为900 s/mm2时,能成功完成正常臂丛神经DTI及DTT,清晰显示臂丛神经纤维束的FA值和结构。     

高血压基底节区脑出血锥体束损伤的弥散张量纤维束成像评价

目的探讨弥散张量纤维束成像（diffusion tensor tractography,DTT）技术在评价高血压基底节区脑出血锥体束受损中的价值。方法观察2006年11月至2008年11月住院高血压脑出血患者45例,7例手术和5例死亡剔除,33例患者纳入分析,运用DTT技术进行锥体束成像,对锥体束完整性进行分级,所有患者均予以常规治疗,在出血后6个月进行随访,应用Barthel指数（Barthelindex,BI）评价功能恢复情况。对BI评分以及锥体束完整性进行相关性分析。结果DTT所显示的急性脑出血锥体束的完整性与6个月随访的侧重于运动功能评价的BI指数有良好的相关性（r′s=0.7312,P〈0.05）,从BI评分直方图中可以看出DTT锥体束完整性分级与BI评分呈正相关。各组间比较的结果显示,A组（0级）和B组（1级）有明确锥体束中断,完整性差的6个月后BI评分,说明运动功能恢复明显较差,C组（2级）和D组（3级）运动功能的恢复较好。仅D组与C组之间比较差异无统计学意义。结论DTT评价锥体束的完整性对高血压脑出血患者运动功能的恢复有预测价值。     

3D fiber tractography with susceptibility tensor imaging

Gradient-echo MRI has revealed anisotropic magnetic susceptibility in the brain white matter. This magnetic susceptibility anisotropy can be measured and characterized with susceptibility tensor imaging (STI). In this study, a method of fiber tractography based on STI is proposed and demonstrated in the mouse brain. STI experiments of perfusion-fixed mouse brains were conducted at 7.0 T. The magnetic susceptibility tensor was calculated for each voxel with regularization and decomposed into its eigensystem. The major eigenvector is found to be aligned with the underlying fiber orientation. Following the orientation of the major eigenvector, we are able to map distinctive fiber pathways in 3D. As a comparison, diffusion tensor imaging (DTI) and DTI fiber tractography were also conducted on the same specimens. The relationship between STI and DTI fiber tracts was explored with similarities and differences identified. It is anticipated that the proposed method of STI tractography may provide a new way to study white matter fiber architecture. As STI tractography is based on physical principles that are fundamentally different from DTI, it may also be valuable for the ongoing validation of DTI tractography.