胼胝体和扣带回弥散张量成像改变对皮质下缺血性血管性痴呆患者认知功能障碍的影响

目的应用磁共振弥散张量成像(DTI)技术,探讨皮质下缺血性血管性痴呆(SIVD)患者胼胝体和扣带回弥散张量参数改变与认知功能的关系。方法对60例SIVD患者和40例年龄匹配的非痴呆对照者,采用测定感兴趣区弥散张量参数的方法,比较其纤维束完整性差异及与MMSE的关系。结果 (1)与对照组比较,SIVD组胼胝体膝部、双侧扣带回的FA值显著下降及ADC值显著升高,而胼胝体压部的FA值和ADC值无显著性差异。(2)胼胝体膝部、双侧扣带回的FA值与MMSE评分呈明显正相关。结论胼胝体和扣带回弥散张量改变有助于SIVD患者认知功能障碍的早期预测。     

Diffusion tensor imaging and tractography of distal peripheral nerves at 3 T.

OBJECTIVE: We studied whether distal peripheral nerves could be imaged using quantitative diffusion tensor imaging (DTI) with a 3-T MRI scanner, and visualized using tractography. METHODS: Altogether 6 healthy subjects were studied. The diffusion was quantified with apparent diffusion coefficient (ADC) and fractional anisotropy (FA) maps, and the direction of main diffusivity was visualized with color-coded orientation maps and tractography. RESULTS: We present the first DTI and tractography results of human distal peripheral nerves. The courses of median, ulnar, and radial nerves in the upper limb and of tibial and peroneal nerves in the lower limb were first analyzed quantifying ADC and FA, and then visualized in 3D with tractography. Tractography illustrated nicely the 3D courses of both upper and lower limb nerves which were reliably distinguished from the surrounding muscle tissue and ligaments. CONCLUSIONS: Quantitative DTI and tractography can be used to image and visualize distal peripheral nerves. SIGNIFICANCE: DTI is a quantitative method that could provide useful information for the diagnosis and follow-up of nerve lesions, entrapments, and regeneration. Peripheral nerves as well-delineated structures also containing abundant branching into bundles of different diameters, could be used as 'living phantoms' for testing and validating different tractography methods.     

Motor outcome of deep intracerebral haemorrhage in diffusion tensor imaging: comparison of data from different locations along the corticospinal tract

Abstract

Objectives:

Although diffusion tensor imaging (DTI) is widely studied to assess the motor outcome after ischaemic stroke, there is paucity of data regarding outcomes of intracerebral haemorrhage (ICH). The aim of this study was to determine the DTI data from different locations along the corticospinal tract (CST) and association to motor outcome.

Methods:

We prospectively recruited patients with deep ICH admitted to our hospital from November 2010 to July 2012.Diffusion tensor imaging was performed within 14?days after the onset of ICH. Fractional anisotropy (FA) was measured along the CST at corona radiata, perihaematomal oedema, cerebral peduncle and pons. Corticospinal tract integrity was classified into three types by diffusion tensor tractography (DTT): type A with preserved CST, type B with partially interrupted CST and type C with completely interrupted CST. Motor outcome was assessed by Motricity index (MI) at admission, after 1 and 3?months.

Results:

Forty-eight patients were enrolled with a mean age of 62?years. The median time interval from onset of ICH to DTI study was 7?days. The patients in type C had significantly worse MI at admission (P?<?0.001), after 1?month (P?<?0.001) and after 3?months (P?<?0.001) as compared to those with type A and type B. Lower rFA at the corona radiata was significantly correlated with poorer motor outcome at admission, after 1?month and after 3?months.

Discussion:

Clinical motor outcome of ICH within 2?weeks can be identified with a statistically significant decrease in rFA at the corona radiata.     

Alzheimer病患者扣带回后部损害磁共振扩散张量成像的研究

目的探讨Alzheimer病(AD)患者扣带回后部磁共振扩散张量成像(DTI)的特点及其与认知功能改变的相关性。方法对16例AD患者和12名健康老人(正常对照组)行DTI、T1Flair及T2Flari检查,测量扣带回后部各向异性分数值(FA)、平均弥散度(MD)及其λ1、λ2及λ33个特征值,分析上述诸项数值与简易精神状态检查量表(MMSE)评分之间的相关性。结果与正常对照组相比,AD组患者扣带回后部的FA值显著降低(P<0.05),而MD、λ1、λ2及λ3值明显升高(均P<0.05);FA值与MMSE评分不相关(r=-0.054,P>0.05),而MD值与MMSE评分呈显著负相关(r=-0.664,P<0.01);λ1、λ2及λ3值均与MMSE评分呈负相关(r=-0.643,r=-0.69,r=-0.654,均P<0.01)。结论AD患者表现为扣带回后部各向异性损害,且损害程度与临床认知功能评分呈负相关;这种损害反映了AD病理机制中皮质-皮质及皮质-皮质下联系的丢失;DTI可以用来监测AD疾病的进展及评价药物的临床疗效。     

Altered cingulate white matter connectivity in panic disorder patients

OBJECTIVE: Functional imaging studies of panic disorder subjects suggest an increased activation of the cingulate regions of the brain. Aim of the current study was to explore the white matter connectivity differences between subjects with panic disorder and healthy comparison subjects. METHOD: Structural white matter connectivity, as determined from fractional anisotropy (FA) values obtained by diffusion tensor imaging, was assessed for anterior and posterior cingulate regions in 24 panic disorder patients and 24 age and sex-matched healthy comparison subjects. RESULTS: Subjects with panic disorder exhibited significantly greater FA values in left anterior and right posterior cingulate regions (by 13.3% and 19.6%, respectively) relative to comparison subjects. White matter connectivity for these two cingulate regions was also positively correlated with clinical severity, as determined by Panic Disorder Severity Scale. FA values in left anterior cingulate region negatively correlated with the time of Trail Making Tests and positively with Digit Symbol Substitution Test. CONCLUSIONS: Findings suggest a potential 'enhancement' in white matter connectivity in left anterior and right posterior cingulate regions in panic disorder, and that these changes may play an important role in mediating clinical symptoms of panic disorder.     

磁共振张量成像对脑梗死预后的评价

目的利用磁共振弥散张量成像(DTI)探讨脑梗死病人脑白质纤维束各向异性特征和白质纤维束受损与临床预后关系。方法对23例脑梗死患者行DTI检查,以三维立体弥散张量成像为基础的色彩图进行图像后处理,评价脑梗死区周边纤维束的情况,将纤维束分为受压移位、变细萎缩和破坏中断三类,并与临床预后、神经功能缺损程度比较。结果三维成像所见与病人预后关系密切。所有脑白质纤维束萎缩和中断的患者,在随访过程中存在不同程度脑功能损伤,而脑白质受压移位的病人神经功能完全或近乎完全恢复。结论在脑梗死中,DTI能直接观察到白质纤维束的变化,对于评估临床预后具有重要作用。     

轻微型肝性脑病磁共振扩散加权成像和扩散张量成像的定量研究

目的通过磁共振扩散加权成像(DWI)和扩散张量成像(DTI)定量分析轻微型肝性脑病(MHE)患者脑功能的异常改变,探讨DWI和DTI在MHE中的应用价值。方法30例肝硬化患者经神经心理测试评分量表测试后,分为MHE组16例和无MHE单纯肝硬化组14例,同时选取15例健康志愿者为正常对照组。所有受试者均行DWI与DTI扫描,选取脑内8个部位为感兴趣区,计算各部位的表观扩散系数(ADC)值和各向异性分数(FA)值。结果18例肝硬化患者于T1WI图像上可见到双侧内囊、苍白球对称性高信号。额叶、枕叶白质、胼胝体膝部、胼胝体压部、内囊前肢、内囊后肢、尾状核头部由正常组、单纯肝硬化组至MHE组ADC值逐渐增加,且MHE组的ADC值较肝硬化组和正常组增加,差异有统计学意义(P<0.05);胼胝体膝部和压部的FA值由正常组、单纯肝硬化组至MHE组逐渐降低,差异有统计学意义(P<0.05)。结论DWI与DTI联合应用能够预测肝硬化患者MHE的进展程度,具有潜在的临床价值。     

脑磁图及弥散张量成像在中央区低级别胶质瘤手术中的应用

目的 探讨联合利用脑磁图(MEG)、弥散张量成像技术(DTI)和神经导航技术,在中央区低级别胶质瘤切除中神经功能保护的作用.方法 对40例涉及中央区的Ⅱ级脑胶质瘤患者,随机分成对照组和试验组两组,每组20例.对照组按照常规神经导航定位肿瘤行手术切除;试验组将脑磁图、DTI与神经导航序列影像融合进行术中导航,术中可视下定位脑皮质功能区及皮质下传导束,来实现精确切除病灶.术后3d内行MRI、DTI检查,比较两组患者的肿瘤切除程度、神经传导束完整性及术后1个月神经功能恢复情况、KPS评分.结果 试验组肿瘤全切除率85％ (17/20)显著高于对照组55％ (11/20);试验组术后致瘫率25％ (5/20)显著低于对照组60％(12/20);试验组术后1个月平均KPS评分(84.50±21.6)分显著高于对照组(64.05±33.36)分.两组在肿瘤切除率、纤维束(FA值)、神经功能保存、KPS评分上的比较,差异均具有统计学意义(均P＜0.05).结论 通过联合利用MEG、DTI及神经导航技术,可最大限度地切除中央区胶质瘤,并更好地保留患者的神经功能,提高其生存质量.     

磁共振弥散张量成像在脑梗死中的应用

目的应用磁共振弥散张量成像(DTI)技术分析缺血性脑梗死不同时期的表观弥散系数(ADC)、各向异性分数(FA)变化,并通过弥散张量纤维束成像(DTT)观察梗死灶与皮质脊髓束(CST)位置关系,以评估预后。方法 45例由于皮质脊髓束受损所致运动功能障碍的不同时期脑梗死患者作为研究组,分为超急性期(<6h)、急性期(6h～3d)、亚急性期(4d～8w)和慢性期(>8w),分析其DTI参数的变化特点,并与正常组进行比较。结果患侧FA值在超急性期无明显变化,在急性期、亚急性期及慢性期逐渐降低,与健侧和对照组比较有显著性差异(P值均<0.05);患侧ADC值在超急性期、急性期明显减低,亚急性期逐渐恢复接近于健侧,慢性期再度增高;DTT成像显示CST受损严重其预后较差。结论不同时期脑梗死病灶其FA、ADC值有一定规律变化,DTT图像可无创性的显示梗死灶与皮质脊髓束的空间位置关系,可作为评估预后的客观依据。     

磁共振弥散张量成像在诊断中枢神经系统疾病的初步应用

目的 探讨磁共振(MRI)弥散张量成像(DTI)对中枢神经系统疾病的脑白质改变的诊断价值。方法 对10名健康志愿者和64例神经系统疾病患者(脑血管病31例，脱髓鞘疾病7例，炎症7例，肿瘤10例，变性病和先天性发育不良各2例，脑萎缩3例，其他2例)进行MRI检查，包括常规T1WI,T2WI,T2Flair,EWI以及ETI序列。并分别测量FA值。结果 本组59例(92．1％)可见病变区脑白质纤维束消融，FA值减低；12例(20．3％)可见边界清楚的侵蚀状改变，肿瘤病例均可见病变区域旁的白质纤维束推压和移位。结论 DTI可早期发现白质内的病变。与传统MRI相比，DTI能更好地显示脑白质纤维束的受损和移位。     

丘脑梗死后丘脑放射纤维继发变性的磁共振弥散张量成像

目的 应用磁共振弥散张量(diffusion tensor imaging,DTI)技术动态观察局灶性丘脑梗死后丘脑放射纤维的弥散变化,探讨丘脑梗死后,病灶上方的丘脑放射纤维继发性损害的发生发展规律.方法 连续收录首次发病、单侧丘脑梗死患者17例为实验组,选择健康志愿者17例作对照研究.患者分别在发病的第1周(W1)、第4周(W4)和第12周(W12)进行1次DTI检测,对照组进行1次DTI检测.每次DTI检测之前进行美国国立卫生研究院卒中评分(national institute health stroke scale,NIHSS)和Barthel生活指数(BI)以及自订的感觉障碍分级评分(Sensory disturbance rating,SDR)评定.结果梗死灶上方的半卵圆中心部分异向(fractional anisotropy,FA)值随时间延长逐渐减少(W1:0.42±0.02,W2:0.38±0.02,W12:0.34± 0.03,P<0.01),而平均弥散量(mean diffusion,MD)却无明显变化.梗死灶上方的半卵圆中心FA值的变化百分数与NIHSS、和BI的变化百分数无明显相关(P＞0.05),与SDR变化的百分数呈负相关(r＝-0.246,P<0.05).结论 局灶性丘脑梗死可以引起丘脑放射纤维继发性损害,在12周内这种继发性损害逐渐加重,而且还可能阻碍患者感觉功能的恢复.     

Diffusion tensor imaging in the study of language and aphasia

Background: Diffusion tensor imaging (DTI) is an emerging research technique that is used to map and characterise white matter tracts in the healthy and damaged brain.

Aims: The aim of this paper is to familiarise the readers with DTI while giving the tools to understand and evaluate recent developments in aphasia research that use DTI methodology.

Main Contribution: Principles of DTI technology as well as its main caveats are described. An overview of studies that used DTI to explore the language system and aphasia is given. Future directions and the potential contribution of DTI to the understanding of aphasia diagnosis and recovery are highlighted.

Conclusions: DTI is an emerging technology, increasingly being applied to further our understanding of aphasia and its recovery. So far it has contributed to our knowledge in four areas of research. In the area of brain anatomy it is used to redefine the borders between various parts of the cortex based on their structural connectivity, to acquire a more accurate map of the tracts connecting the various parts of the language system, and to measure hemispheric asymmetry. Future studies might be able to further our understanding of language anatomy and relate hemispheric asymmetry to recovery potential. Second, DTI can help in relating structure to function. So far many studies focused on repetition deficits and conduction aphasia. Future studies can explore the anatomy of other language deficits. Third, DTI has been used in the study of brain damage and recovery. Studies have documented the damage that occurs to white matter following stroke and other insults, and the spontaneous reorganisation that follows. In the future DTI might contribute to the debate about the role of the right hemisphere in recovery from aphasia. Lastly, in the area of aphasia rehabilitation there is great lack of data. The studies reviewed here have shown that rehabilitation potential is dependent on white matter integrity and that white matter changes can occur as a result of therapy. Future studies should further our understanding of the role of white matter integrity in recovery, therefore contributing to the question of why some patients show good recovery while others do not. Future studies should also try and map white matter changes that are associated with successful versus unsuccessful rehabilitation, and with different stages of recovery.     

Diffusion tensor analysis of temporal and extra-temporal lobe tracts in temporal lobe epilepsy

OBJECTIVE: To determine whether the major temporal lobe white matter tracts in patients with temporal lobe epilepsy manifest abnormal water diffusion properties. METHODS: Diffusion tensor MRI measurements were obtained from tractography for uncinate, arcuate, inferior longitudinal fasciculi and corticospinal tract in 13 children with left temporal lobe epilepsy and normal conventional MRI, and the data were compared to measurements in 12 age-matched normal volunteers. The relationship between tensor parameters and duration of epilepsy was also determined. RESULTS: All four tracts in the affected left hemisphere showed lower mean anisotropy, planar and linear indices, but higher spherical index in patients versus controls. Diffusion changes in the left uncinate and arcuate fasciculus correlated significantly with duration of epilepsy. Arcuate fasciculus showed a reversal of the normal left-right asymmetry. Various diffusion abnormalities were also seen in the four tracts studied in the right hemisphere. CONCLUSION: Our findings indicate abnormal water diffusion in temporal lobe and extra-temporal lobe tracts with robust changes in the direction perpendicular to the axons. Diffusion abnormalities associated with duration of epilepsy suggest progressive changes in ipsilateral uncinate and arcuate fasciculus due to chronic seizure activity. Finally, our results in arcuate fasciculus are consistent with language reorganization to the contralateral right hemisphere.     

MR扩散张量成像在脑梗死中的初步应用报告

目的用扩散张量MR成像(DTI)分析脑梗死不同时期的扩散张量改变,探讨DTI在脑梗死诊断中的应用价值。方法分析38例不同病期的脑梗死病人的DTI图像。结果急性期(7例)的各向同性表观扩散系数(ADCiso)图表现为低信号,各向异性指数图表现为高信号;亚急性期(18例)病变区的ADCiso图为低、等信号;各向异性指数图为混杂或低信号;慢性期(13例)病变区的ADCiso图为高信号,各向异性指数图为低信号。结论ADCiso图和各向异性指数图相结合,有可能更精确地对脑梗死进行分期,为临床提供一种新的影像学诊断方法。     

应用弥散张量成像技术判定高级别胶质瘤侵袭范围的初步研究

目的 探索高级别胶质瘤的侵袭特点,并应用磁共振弥散张量成像（DTI）定量分析高级别胶质瘤的侵袭范围.方法 回顾性纳入首都医科大学附属北京天坛医院神经外科2014年10月至2016年10月收治的10例额叶高级别胶质瘤（WHOⅢ～Ⅳ）患者.所有患者术前均行头颅MRI及DTI检查,于MRI T1加权增强扫描图像上,分别在肿瘤强化实体、距离强化实体边缘1 cm和2 cm的部位各选取1个感兴趣区;之后应用DTI技术测定3个感兴趣区的各向异性分数（FA）值和表观弥散系数（ADC）值.所有患者均行肿瘤切除术,术后对3个感兴趣区的标本依次进行相关病理学检查和肿瘤细胞比例测定.通过建立判别分析模型,对3个感兴趣区的ADC、FA值与肿瘤细胞比例进行相关性分析.结果 病理学相关结果显示,随着距离肿瘤实体边缘距离的增加,残余肿瘤细胞比例显著减少（均P＜0.05）;基质金属蛋白酶9和Ki-67的表达较肿瘤实体显著下降（均P＜0.05）.通过对3个感兴趣区的ADC、FA值与肿瘤细胞比例进行相关性分析,得到标准化典则判别函数为D=0.201ADC＋1.094FA（其中D为肿瘤细胞的比例,为标准化的数值）,该函数可通过DTI测定的ADC值和FA值预测肿瘤细胞的比例,准确率为66.7％.结论 随着距离高级别胶质瘤实体边缘距离的增加,肿瘤细胞的比例、侵袭性和增殖力均较肿瘤实体明显下降.通过建立判别分析模型,初步得出DTI参数与肿瘤细胞比例的量化关系,以期协助指导临床手术方案的制定.     

扩散张量成像技术对急性脑梗死的诊断价值

目的应用MR扩散张量成像(DTI)及扩散张量纤维束成像(DTT)技术对急性脑梗死患者进行检查,研究患者肢体活动障碍的表现及预后与皮质脊髓束的关系及ADC图对急性脑梗死的诊断价值。方法对33例急性脑梗死患者(发病时间<72h)行常规MRI检查及DTI检查,并进行皮质脊髓束三维DTT成像及b=1000的ADC成像,将患者运动障碍的程度分为无瘫痪,治疗后瘫痪恢复,治疗后瘫痪不恢复3种情况,将常规MRI图、DTI中的ADC图影像表现及DTT图皮质脊髓束形态表现与患者临床肌力表现及治疗结果相比较。结果无瘫痪13例,治疗后瘫痪恢复者9例,治疗后瘫痪不恢复者11例,DTT图显示皮质脊髓束分别为无受压,受压无中断及中断破坏。所有病例ADC图均表现为低或稍低信号。结论DTI及DTT技术,对判断脑梗死患者运动障碍的程度及预后有重要价值。     

弥散张量成像对胶质瘤手术风险的评估

目的 探讨弥散张量成像(diffusion tensor imaging,DTI)在胶质瘤手术中对于保护神经功能的临床价值.方法 38例胶质瘤患者手术前后行DTI检查和神经功能评价.根据胶质瘤与其邻近部位白质纤维束的影像学关系DTI可以被分为三种类型:Ⅰ类-挤压型,Ⅱ类-浸润型,Ⅲ类-破坏型.三组患者之间术前神经功能状态的差异以及三组患者之间术后神经功能改变情况的差异分别进行比较.结果Ⅰ类-挤压型14例,Ⅱ类-浸润型16例,Ⅲ类-破坏型8例.不同DTI类型患者的术前神经功能状态之间以及小同DTI类型患者的术后神经功能改变情况之间的差异有统计学意义(P<0.05).结论 DTI能够显示胶质瘤与临近的白质纤维束之间的关系,体现了胶质瘤不同的生长方式,它能够帮助神经外科医生选择更加安全的手术入路和决定肿瘤切除程度.     

The value of novel MRI techniques in Parkinson-plus syndromes: Diffusion tensor imaging and anatomical connectivity studies

Conventional MRI is a well-described, highly useful tool for the differential diagnosis of degenerative parkinsonian syndromes. Nevertheless, the observed abnormalities may only appear in late-stage disease. Diffusion tensor imaging (DTI) can identify microstructural changes in brain tissue integrity and connectivity. The technique has proven value in the differential diagnosis of multiple system atrophy (MSA), progressive supranuclear palsy (PSP) and Parkinson's disease (PD). Here, we performed a systematic review of the literature on the main corticosubcortical DTI abnormalities identified to date in the context of the diagnosis of MSA and PSP with diffusion-weighted imaging, diffusion tensor imaging and anatomical connectivity studies. In good agreement with the histological data, increased diffusivity in the putamen (in MSA and PSP), in the middle cerebellar peduncles (in MSA) and in the upper cerebellar peduncles (in PSP) has been reported. Motor pathway involvement is characterized by low fraction anisotropy (FA) in the primary motor cortex in MSA-P and PSP, a high apparent diffusion coefficient (ADC) and low FA in the supplementary motor area in PSP. We then outline the value of these techniques in differential diagnosis (especially with respect to PD). Anatomical connectivity studies have revealed a lower number of fibers in the corticospinal tract in MSA and PSP (relative to PD and controls) and fewer tracked cortical projection fibers in patients with PSP or late-stage MSA (relative to patients with early MSA or PD and controls). Lastly, we report the main literature data concerning the value of DTI parameters in monitoring disease progression. The observed correlations between DTI parameters on one hand and clinical scores and/or disease duration on the other constitute strong evidence of the value of DTI in monitoring disease progression. In MSA, the ataxia score was correlated with ADC values in the pons and the upper cerebellar peduncles, whereas both the motor score and the disease duration were correlated with putaminal ADC values. In conclusion, DTI and connectivity studies constitute promising tools for differentiating between “Parkinson-plus” syndromes.     

健康者三叉神经磁共振扩散张量成像研究

目的 测量三叉神经桥池段的表观扩散系数(ADC)值和部分各向异性分数(FA)值,了解三叉神经桥池段各参数的特点。 方法 选择50例健康志愿者三叉神经桥池段距离脑干发出点0mm、3mm、6mm、9mm共四处,利用DTI图像与B-TFE或THRIVE图像融合成像,提高三叉神经桥池段显示的空间分辨率,并利用该图像测量并分别记录ADC值与FA值,对所有受检者行三叉神经桥池段追踪成像。 结果 受检者左侧与右侧三叉神经桥池段的ADC值和FA值差异均无统计学意义(P＞0.05)。越靠近脑干发出点,左右两侧三叉神经桥池段的各导出量越呈现左右不对称的趋势。双侧三叉神经桥池段距脑干不同距离各位置的DTI导出量分析发现：相邻两距离间ADC值差异均有统计学意义(P＜0.05),出脑干后随距离增加ADC值逐渐升高,但行至6～9 mm间突然回转下降;FA值在0～6 mm间随距离增加而逐渐降低,且相邻两距离间差异均有统计学意义(P＜0.05),但行至6～9 mm间FA值不再有明显变化。 结论 DTI图像能够清晰分辨双侧三叉神经桥池段,可实现DTI各项导出量的测量。随着距脑干发出点距离的不同,各导出量发生有规律的变化,预示着DTI在明确区分三叉神经的中枢神经系统段、过渡段和周围神经系统段以及检出颅神经血管压迫方面的应用前景。