定量研究人脑结构DTI T_2-weighted trace图与年龄的关系

目的定量研究不同年龄健康人脑结构扩散张量成像(DTI)的T2-WT参数图的特点及其与年龄的关系。方法健康右利手志愿者58人,年龄22～76岁,按年龄分为青年(≤40岁)组30人,中老年(>40岁)组28人,采集人脑常规MRI及DTI图像,经后处理得到DTI的三种参数图:T2-WT、分数各向异性(FA)及平均扩散系数(MD)图,使用FA图及MD图设置兴趣区,测量人脑10个部位的参数值,定量分析不同年龄组T2-WT参数值的特点及其与年龄的关系。结果青年组T2-WT值在桥脑、大脑脚、内囊前肢、半卵圆中心和豆状核左侧>右侧,P=0.000～0.024,差异有统计学意义。中老年组,半卵圆中心T2-WT值左侧>右侧,P=0.042,差异有统计学意义。两组比较,除侧脑室外,其他部位中老年组的T2-WT值均低于青年组,T2-WT值在桥脑、大脑脚投射纤维、内囊前肢、内囊膝部、内囊后肢和豆状核六个部位与年龄有负相关关系,P=0.000～0.038,差异有统计学意义。结论健康人脑结构T2-WT值在桥脑、大脑脚投射纤维、内囊前肢、内囊膝部、内囊后肢和豆状核与年龄有负相关关系,T2-WT图的左右对称性在中老年人脑表现更明显。     

右利手年轻人脑DTI的T_2-weighted trace参数图研究

目的研究健康右利手年轻人脑在DTI参数图T2-weighted trace上的表现特点。方法应用GE3.0TMRI仪对10名健康右利手年轻志愿者行常规颅脑MRI及DTI检查,重建DTI的T2-weighted trace、分数各向异性(fractional anisotropy,FA)以及平均扩散系数(mean diffusivity,MD)三种参数图,选择6个层面观察T2-weighted trace图的表现,并与相应的FA、MD图对比。结果年轻人脑T2-weighted trace值在个体之间有较大的差异,双侧半球有不对称性;脑室、脑沟和脑池等T2-weighted trace最低的部位,MD最高FA最低;豆状核、黑质、红核等有铁质沉积的部位T2-weighted trace值低,与周围组织对比明显;T2-weighted trace图对脑白质纤维束的显示不如FA图清楚。结论结论T2-weighed trace图是与FA、MD不同的一种DTI参数图,个体之间有较大的差异,双侧半球不完全对称,脑室、脑沟和脑池等部位的T2-weighted trace最低;T2-weighedtrace图可清楚地显示有铁质沉积的豆状核、黑质和红核。     

基于扩散张量成像的轻型颅脑创伤损伤机制研究

目的分析轻型颅脑创伤患者扩散张量成像(DTI)参数及其与神经心理学测验的相关性,探讨轻型颅脑创伤急性期损伤机制。方法共16例轻型颅脑创伤患者和15例性别、年龄、受教育程度相匹配的正常对照者,均行头部MRI检查,包括T_1WI、T_2WI、T_2-FLAIR成像和DTI,采用基于体素的形态学分析计算部分各向异性(FA)值、平均扩散率(MD)值和表观扩散系数(ADC)值,同时行神经心理学测验,包括Beck抑郁量表(BDI)、状态-特质焦虑量表[分为状态焦虑量表(SAI)和特质焦虑量表(TAI)],Spearman秩相关分析探讨各脑区FA值、MD值和ADC值与神经心理学测验的相关性。结果与正常对照者相比,轻型颅脑创伤患者右侧额叶补充运动区FA值降低,右侧额叶中央前回、缘上回和顶叶FA值升高;双侧额叶、顶叶和右侧扣带回MD值升高;双侧额叶和右侧顶叶、岛叶ADC值升高。轻型颅脑创伤患者SAI评分高于正常对照者[20.50(13.25,29.75)分对11(8,12)分;Z=-3.493,P=0.000],而BDI评分和TAI评分组间差异无统计学意义(均P0.05)。Spearman秩相关分析显示,上述异常脑区FA值(rs=0.369,P=0.478)、MD值(rs=0.295,P=0.421)和ADC值(rs=0.401,P=0.394)与SAI评分均无关联性。结论轻型颅脑创伤急性期患者存在多个脑区DTI参数和相关神经心理变化,DTI可以为轻型颅脑创伤研究提供影像学标记。     

颈髓弥散张量成像在肌萎缩性侧索硬化诊断中的应用

目的 初步探讨颈髓弥散张量成像(DTI)在肌萎缩性侧索硬化(ALS)诊断中的应用价值. 方法 选择自2000年1月至2007年1月中山大学附属第二医院骨科收治的28例ALS患者为患者组,20例同期门诊查体健康成年人为对照组,对2组成员进行常规MRI扫描及DTI检查,获取颈髓MD值及FA值的直方图,并对ALS患者颈髓DTI弥散张量值与患者ALS残损功能评分量表(ALSFRS)评分进行相关性分析. 结果 与对照组相比,患者组颈髓FA值和颈髓横断面积明显降低,差异有统计学意义(P<0.05);MD值轻微增加,差异无统计学意义(P>0.05).患者颈髓FA值与ALSFRS评分高度相关(r=0.730,P=0.000),与MD值等指标无相关关系. 结论 ALS患者颈髓DTI显像FA值显著降低,FA值可能成为ALS诊断中的神经影像学阳性支持指标:颈髓的弥散张量值与ALSFRS结合,可以更伞面反映ALS患者的病情进展.     

皮质下缺血性血管性认知损害扩散张量成像研究

目的通过扩散张量成像(DTI)探讨皮质下缺血性血管性认知损害患者白质微结构变化及其与认知功能之间的相关性。方法采集49例皮质下缺血性脑血管病患者[轻度血管性痴呆(VaD)10例、非痴呆型血管性认知损害(VCIND)20例、认知功能正常19例]DTI数据并观察皮质下白质微结构改变,分析VaD组患者DTI参数与认知功能间的相关性。结果与对照组相比,VaD组内侧前额叶、前扣带回、胼胝体干、双侧顶叶、右侧颞叶、双侧眶额叶,以及VCIND组右侧额下回、右侧海马、双侧楔前叶FA值减低(均P=0.000);与VCIND组比较,VaD组内侧前额叶、前扣带回、胼胝体、双侧顶叶、右侧颞叶FA值减低(P=0.000)。与对照组相比,VaD组内侧前额叶、胼胝体、双侧顶叶、双侧颞叶、前扣带回,以及VCIND组双侧楔前叶、右侧海马MD值升高(均P=0.000);与VCIND组相比,VaD组右侧内侧前额叶、前扣带回、胼胝体干、双侧顶叶、双侧颞叶MD值升高(均P=0.000)。VaD组内侧前额叶FA值与数字连线测验A时呈显著负相关(r=-0.782,P=0.007),双侧额下回MD值与数字连线试验A时程呈显著正相关(r=0.877,P=0.001)。结论 DTI对皮质下缺血性认知损害患者白质微结构改变更敏感,能够反映患者认知功能早期异常改变;内侧前额叶白质微结构的改变是影响患者执行能力的重要因素。     

4000/扩散张量成像对正常成人皮质脊髓束通路初步研究

目的：扩散张量成像（DTI）对健康成人皮质脊髓束通路的研究,分析不同部位皮质脊髓束通路FA值,为皮质脊髓束病理改变的研究提供正常解剖依据。材料与方法：健康成人30名, GE 1.5T及工作站行数据收集和后处理, 测量延髓、脑桥、大脑脚、基底节、放射冠及半卵园中心等层面的皮质脊髓束（CST）通路FA值。结果：延髓及半卵园中心平面的各层面FA值左右差异无显著性;脑桥、大脑脚、基底节、放射冠等水平面的各层面的FA值左右侧差异有显著性,可认为左侧较右侧高。结论：皮质脊髓束通路FA值左右侧在不同水平的层面上有差异,左侧高于右侧,可能与右利手有关。     

皮质下缺血性血管病患者联络纤维的扩散张量成像分析和认知功能相关研究

【摘要】 目的 运用磁共振成像（magnetic resonance imaging,MRI）基于白质地图的扩散张量成像（diffusion tensor imaging,DTI）技术研究皮质下缺血性血管病（subcortical ischemic vascular disease,SIVD）患者联络纤维的超微结构改变,并分析DTI参数与认知功能的关系。 方法 连续入选40例SIVD患者,分为血管性认知障碍组18例,无认知障碍组22例,另设立20例正常老年人为对照组。对三组进行MRI检查并对其白质改变进行评分,对联络纤维进行基于白质地图分析（atlase based analysis,ABA）DTI成像,比较组间部分各向异性指数（fractional anisotrophy,FA）、平均扩散率（mean diffusivity,MD）差异,并对SIVD患者DTI参数与蒙特利尔认知评估量表（Montreal Cognitive Assessment,MoCA）得分进行相关性分析。 结果 无认知障碍组较正常组在右侧矢状层（下纵束/下额枕束）、右侧扣带（海马部）及左侧上额枕束的FA值减低;认知障碍组较正常组存在广泛的联络纤维FA值降低,差异均具有显著性。无认知障碍组与正常组比较,仅左侧扣带海马部及左侧上纵束MD值无显著差异,余联络纤维的MD值均显著增高;认知障碍组较正常组存在广泛的联络纤维MD值增高,差异均具有显著性。与无认知功能障碍组比较,认知功能障碍组在双侧矢状层（下纵束/下额枕束）、双侧扣带扣带回部、海马部、双侧上纵束、双侧上额枕束及双侧钩束的FA值减低,MD值增高,差异具有显著性。SIVD患者双侧矢状层（下纵束/下额枕束）、扣带扣带回部、上纵束、上额枕束及钩束和左侧扣带海马部的FA值与MoCA评分呈正相关,MD值与MoCA评分呈负相关。 结论 SIVD患者联络纤维的FA值减低,MD值增高,且DTI参数与其认知功能密切相关。     

阿尔茨海默病患者扣带回后部各向异性与葡萄糖代谢关系研究

目的 用磁共振扩散张量成像(DTI)研究阿尔茨海默病患者扣带回后部各向异性损害的特点及其与葡萄糖代谢改变的关系.方法 对16例AD患者和12例年龄及性别相当的健康老年人行DTI、T1液体衰减反转恢复序列(FLAIR)及T2-FLAIR检查,测量扣带回后部部分各向异性分数值(FA)和平均弥散度(MD),分析FA、MD值与MMSE评分之间的相关关系;正电子发射计算机断层摄影(PET)观察扣带回后部葡萄糖代谢改变,并分析FA、MD与葡萄糖代谢改变的关系.结果 与对照组相比,AD患者扣带回后部的FA值显著降低(P=0.018),MD值显著升高(P=0.020),葡萄糖代谢率显著降低(P=0.020);MD值与葡萄糖代谢率呈负相关(r=-0.700,P=0.05),而FA值与葡萄糖代谢率无相关关系(r=-0.054,P=0.844).结论 AD患者表现为扣带回后部各向异性损害,且损害程度与葡萄糖代谢率呈负相关;这种损害反应了AD病理机制中皮质-皮质及皮质-皮质下联系的丢失;扣带回后部FA、MD值可以用来监测疾病的进展情况及评价AD治疗药物的临床疗效.     

精神分裂症首次发病患者的脑扩散张量成像研究

目的 利用磁共振扩散张量成像(DTI)技术研究未经药物治疗的精神分裂症首次发病(以下简称首发)患者主要脑区白质纤维束的异常.方法 选取26例首发精神分裂症患者(患者组)和20名健康志愿者(对照组)行脑DTI扫描(两组均为右利手),测量胼胝体膝部、压部、双侧额叶白质、扣带束前部及海马头的部分各向异性(FA)值.结果 (1)对照组左侧扣带束FA值(0.428±0.067)大于右侧(0.375±0.079;P＜0.05).(2)患者组两侧相对应感兴趣区FA值差异均无统计学意义(P＞0.05).(3)患者组左右侧胼胝体压部FA值(均为0.734±0.085)、左右侧扣带束前部FA值(0.300±0.068和0.306 4±0.062)均低于对照组(0.785±0.045,0.428±0.067,0.375±0.079;均P＜0.05).结论 首发精神分裂症患者存在双侧扣带束、胼胝体压部白质纤维束的受损,支持脑内连接异常假说.     

脑小血管病患者MR弥散张量成像的改变及其与认知功能障碍的关系

目的探讨脑小血管病(SVD)患者脑部MR弥散张量成像(DTI)的改变及其与认知功能障碍的关系。方法给55例SVD患者进行神经心理学量表检查,评定认知功能状态,以及行常规MRI和DTI检查,观察感兴趣区的各向异性分数(FA)、表观弥散系数(ADC)。对DTI FA值与蒙特利尔认知评估(MoCA)量表评分的相关性用Pearson相关分析。结果本组SVD患者中认知功能正常(NCI)的患者25例,非痴呆认知功能障碍(VCIND)患者30例。与NCI组比较,VCIND组双侧半卵圆中心、丘脑、额叶及左侧尾状核的FA值显著降低(P0.05~0.001);双侧豆状核、右侧尾状核FA值的差异无统计学意义;左侧尾状核ADC值显著增高(P0.05),其他部位ADC值的差异均无统计学意义。Pearson相关分析示,双侧半卵圆中心、额叶及左侧尾状核的FA值与MoCA量表评分呈正相关(r=0.279~0.375,P0.05~0.005)。结论有认知功能障碍的SVD患者额叶及脑白质DTI的FA值明显降低,并与其认知功能障碍程度有密切的关系。     

弥散张量成像在颅内环形强化病变中的诊断价值

目的 探讨弥散张量成像(diffusion tensor imaging,DTI)对颅内环形强化病变的诊断价值.方法 53例颅内单发环形强化病例术前行DTI扫描,分别测量病变坏死区、灶周水肿区及对侧正常脑实质的平均弥散系数(MD)值及各向异性分数(FA)值.并通过弥散张量纤维束成像(diffusiontensor tracking,DTT)观察病灶与白质纤维束的关系.结果 脑脓肿坏死区的MD值为(0.60±0.13)×10-3 mm2/s,FA值为0.18±0.03,高级别星形细胞瘤MD值为(2.76±0.26)×10-3mm2/s,FA值为0.07±0.02,脑转移瘤MD为(2.82±0.29)×10-3mm2/s,FA值为0.06±0.02,前者与后两者间差异有统计学意义(P<0.01).高级别星形细胞瘤水肿区的FA值(0.23±0.06)与脑转移瘤(0.17±0.06)和脑脓肿(0.15±0.03)两者水肿区FA值差异有统计学意义(P<0.01).DTT可以较准确地反映病灶与白质纤维束的关系,为手术治疗及评估预后提供依据.结论 坏死区MD值及FA值有助于脑脓肿与环形强化脑肿瘤的鉴别;水肿区FA值有助于脑星形细胞瘤与转移瘤、脑脓肿的鉴别;DTT能够为优化手术方案及评估预后提供一定帮助.     

Gray and white matter asymmetries in healthy individuals aged 21-29 years: a voxel-based morphometry and diffusion tensor imaging study

The hemispheres of the human brain are functionally and structurally asymmetric. The study of structural asymmetries provides important clues to the neuroanatomical basis of lateralized brain functions. Previous studies have demonstrated age-related changes in morphology and diffusion properties of brain tissue. In this study, we simultaneously explored gray and white matter asymmetry using voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) in 109 young healthy individuals (58 females and 51 males). To eliminate the potential confounding effects of aging and handedness, we restricted the study to right-handed subjects aged 21-29 years. VBM and voxel-based analysis of fractional anisotropy (FA) maps derived from DTI revealed a number of gray matter volume asymmetries (including the right frontal and left occipital petalias and leftward asymmetry of the planum temporale) and white matter FA asymmetries (including leftward asymmetry of the arcuate fasciculus, cingulum, and corticospinal tract). There was no significant effect of sex on gray and white matter asymmetry. Leftward volume asymmetry of the planum temporale and leftward FA asymmetry of the arcuate fasciculus were simultaneously demonstrated. Post hoc analysis showed that the gray matter volume of the planum temporale and FA of the arcuate fasciculus were positively related (Pearson correlation coefficient, 0.43; P < 0.0001). The results of our study demonstrate gray and white matter asymmetry in right-handed healthy young adults and suggest that leftward volume asymmetry of the planum temporale and leftward FA asymmetry of the arcuate fasciculus may be related.     

Diffusion tensor imaging in patients with primary cervical dystonia and in patients with blepharospasm

Diffusion tensor imaging (DTI) analyses the movement of water molecules within the cerebral white matter thus providing information on ultrastructural brain changes. We studied 18 patients with cervical dystonia (CD), 16 with blepharospasm (BSP) and 35 years age-matched healthy controls. DTI data were obtained with a Philips 1.5 Tesla scanner and then processed to obtain maps of fractional anisotropy (FA) and mean diffusivity (MD). Twenty-three square regions of interest of uniform size were positioned on the FA maps and then automatically transferred to the MD maps. FA and MD values in the corpus callosum, left and right putamen, right caudate, left and right pre-frontal cortical area and left supplementary motor area in CD patients differed significantly from those in healthy controls. No significant regional differences were found between patients with BSP and healthy controls. In the CD group, age, duration and severity of dystonia did not correlate with regional FA/MD values, whereas the duration of botulinum toxin treatment correlated significantly with the MD value in the right-pre-frontal cortex. The abnormal DTI findings in patients with CD suggest the presence of brain ultrastructural changes in adult-onset primary CD.     

皮质下血管性轻度认知障碍患者的多模式磁共振研究

目的 明确对皮质下缺血性血管病（subcortical ischemic vascular disease,SIVD）患者早期认知损害较 为敏感的磁共振成像（magnetic resonance imaging,MRI）指标。 方法 32例SIVD患者经过认知测试,被分为无认知障碍（no cognitive impairment,NCI）组18例,血管性 轻度认知障碍（vascular mild cognitive impairment,VaMCI）组14例,分析其认知测试指标与MRI参数之间 的关系。 结果 NCI组、VaMCI组全脑白质（whole brain white matter,WBWM）平均弥散度（mean diffusivity,MD） 分别为（0.84±0.03）×10-9·m2·s-1和（0.89±0.05）×10-9·m2·s-1,表观正常白质（normal appearing white matter,NAWM）的MD分别为（0.87±0.04）×10-9·m2·s-1和（0.92±0.05）×10-9·m2·s-1,差异 均有显著性（P均为0.003）;NCI组、VaMCI组WBWM各向异性分数（fractional anisotropy,FA）分别为 （0.37±0.02）和（0.35±0.02）,两组有显著差异（P =0.002）,两组NAWM的FA分别为（0.35±0.02）和 （0.33±0.02）,差异亦有显著性（P =0.001）。SIVD患者WBWM的MD值、NAWM的MD值和FA值与注意- 执行均相关,相关系数分别为－0.401（P =0.031）、－0.422（P =0.023）和0.409（P =0.027）,NAWM的 MD值与记忆相关,相关系数为－0.377（P =0.044）,多元逐步回归显示仅NAWM的MD值与注意-执行 （β=－0.453,P =0.009）、记忆（β=－0.414,P =0.019）和总体认知（β=－0.410,P =0.02）独立负相 关。而常规MRI参数未显示组间差异,与认知功能亦未见相关性。 结论 MRI弥散张量成像（diffusion tensor imaging,DTI）可以作为早期识别SIVD患者认知障碍的有效 手段。NAWM的MD值在认知障碍早期即下降,并与多项认知域独立相关,是较为敏感的DTI指标。     

Diffusion tensor imaging of subcortical brain injury in patients infected with human immunodeficiency virus

Diffusion tensor imaging (DTI) was used to derive in vivo tissue status measurements of subcortical brain regions that are vulnerable to injury in human immunodeficiency virus (HIV)-infected patients. Quantitative measurements, including the mean diffusivity (MD) and fractional anisotropy (FA), were determined in lateralized basal ganglia (caudate and putamen) and centrum semiovale in 11 well-characterized HIV patients and in 11 control subjects. DTI measurements were examined for patterns of relationship with markers of clinical and cognitive progression. DTI measures acquired in subcortical regions were significantly correlated with loss of function in specific cognitive domains. Significant relationships were identified between measures for putamen and verbal memory (MD), visual memory (FA), working memory (FA), and overall cognitive impairment (MD). Measures for caudate (FA) were significantly correlated with visual memory. Measures for centrum semiovale were significantly correlated with visual memory deficits (MD) and visuoconstruction (FA). Relationships between anisotropy measures and anemia (basal ganglia) and CD4 counts (centrum semiovale) were also observed. Findings from this investigation indicate that DTI is a sensitive tool for correlating neuroanatomic pathologic features with specific cognitive deficits in patients with HIV infection.     

颈椎病磁共振扩散张量成像的研究

目的探讨颈椎病磁共振扩散张量成像（MRDTI）的特点。方法应用3．0TMRI仪对颈椎病患者进行M_RDTI检查,根据MRI显示的脊髓受压严重程度将颈椎病患者分为轻度组、中度组、重度组及严重度组。分析各组纤维示踪（FT）图的特征及各定量参数的变化。结果60例颈椎病患者FT显示纤维束狭窄、离断、稀疏,随着脊髓受压程度的加重而加重。FA值、Ez值、E3值、E⊥值、MD值在各组之间均存在差异（P〈0．05）。随着MRI评估的脊髓受压程度加重,E2值、E3值、E⊥值、MD值逐渐升高,FA值逐渐降低。结论MRDTI可以定量、直观显示颈椎病的脊髓受压程度。     

Diffusion tensor imaging reliably differentiates patients with schizophrenia from healthy volunteers

The objective of this research was to determine whether fractional anisotropy (FA) and mean diffusivity (MD) maps derived from diffusion tensor imaging (DTI) of the brain are able to reliably differentiate patients with schizophrenia from healthy volunteers. DTI and high resolution structural magnetic resonance scans were acquired in 50 patients with schizophrenia and 50 age‐ and sex‐matched healthy volunteers. FA and MD maps were estimated from the DTI data and spatially normalized to the Montreal Neurologic Institute standard stereotactic space. Individuals were divided randomly into two groups of 50, a training set, and a test set, each comprising 25 patients and 25 healthy volunteers. A pattern classifier was designed using Fisher's linear discriminant analysis (LDA) based on the training set of images to categorize individuals in the test set as either patients or healthy volunteers. Using the FA maps, the classifier correctly identified 94% of the cases in the test set (96% sensitivity and 92% specificity). The classifier achieved 98% accuracy (96% sensitivity and 100% specificity) when using the MD maps as inputs to distinguish schizophrenia patients from healthy volunteers in the test dataset. Utilizing FA and MD data in combination did not significantly alter the accuracy (96% sensitivity and specificity). Patterns of water self‐diffusion in the brain as estimated by DTI can be used in conjunction with automated pattern recognition algorithms to reliably distinguish between patients with schizophrenia and normal control subjects. Hum Brain Mapp, 2010. © 2010 Wiley‐Liss, Inc.