脊髓型多发性硬化脑灰质弥散张量成像研究

目的 运用DTI直方图分析,研究脊髓型多发性硬化（SMS）患者是否存在脑灰质异常及脑灰质DTI指标与临床评分的相关性.方法 对25例SMS患者和35例正常志愿者行常规MRI和DTI检查,分割提取脑灰质后,研究SMS患者脑灰质平均弥散率（MD）和分数各向异性（FA）直方图的异常变化.结果 OSMS患者脑灰质体积明显小于正常志愿者（P＜0.001）.OSMS患者脑灰质MD和FA直方图指标与正常志愿者间存在显著差异（P＜0.01）.在OSMS患者,所有脑灰质DTI直方图指标与扩展残疾状态评分（EDSS）均无相关性,但锥体束和感觉系统（PSS）评分与脑灰质平均MD（r=0.54,P=0.005）和MD直方图峰高（r=-0.41,P=0.04）中度相关.结论 OSMS患者脑灰质存在明显萎缩和弥散异常,这可能与继发于脊髓病变的逆行性脑灰质神经元变性有关.     

复发好转型多发性硬化磁化传递成像研究

目的利用磁化传递率(MTR)直方图分析,研究复发好转型多发性硬化(RRMS)脑异常改变及MTR直方图指标与扩展残疾状态 (EDSS)评分的相关性.方法对29例RRMS患者和35例正常志愿者行T2WI和磁化传递成像检查,计算出每个体素的MTR值后,绘制出全脑MTR直方图并对其进行分析.结果 RRMS患者的全脑MTR直方图明显左移,峰高降低.RRMS患者的全脑平均MTR [(29.45±1.83)%]明显低于正常志愿者[(30.37±1.37)%](P=0.025),MTR直方图峰位置[(32.51±2.02)%]也明显低于正常志愿者[(33.51±1.39)%](P=0.022).在RRMS患者,全脑MTR直方图峰高与EDSS评分中度相关 (r=-0.411, P=0.027).结论脑MTR直方图分析可显示RRMS患者脑异常改变,脑MTR直方图峰高可用于监测该病的临床进展.     

临床孤立综合征和复发缓解型多发性硬化MR弥散张量成像的对比研究

目的探讨MS最早期阶段即CIS是否已存在可被DTI发现的异常改变及其严重程度,揭示其可能反映的病理改变,与临床状态的关系,从而更加深入认识CIS与MS的关系。方法选择19例CIS患者、19例临床确诊的RRMS患者和19例性别、年龄与之匹配的健康志愿者为研究对象。用1.5T超导型磁共振扫描仪采集数据,包括常规T1WI、T2WI、DTI,经后处理得到：T2WI上病灶的体积、平均弥散率及各向异性分数,全脑（WB）、表现正常脑组织（NABT）的平均弥散率、各向异性分数直方图,其中提取出下列指标：平均值、直方图峰高和峰位置。应用社会统计软件包（SPSS11.5）对以上观察内容进行统计学分析。结果CIS与RRMS患者病灶体积、平均弥散率、平均各向异性分数均无显著性差异。WB及NABT平均弥散率正常对照组、CIS组、RRMS组依次增高,平均各向异性分数正常,对照组、CIS组、RRMS组依次减低,且均有显著性差异（P〈0.05）,NABT平均弥散率图峰高正常对照组、CIS组、RRMS组依次降低,平均各向异性分数图峰位置正常,对照组、CIS组、RRMS组依次左移,且均有显著性差异（P〈0.05）。CIS患者各项DTI指标与扩展残疾状态量表评分均无显著性相关。RRMS患者病灶平均分数各向异性（r=-0.566,P=0.012）、WB的平均弥散率（r=0.497,P=0.030）、NABT的平均弥散率（r=0.692,P=0.001）与EDSS评分存在显著性相关关系。结论本研究表明DTI可以敏感的显示CIS及MS全脑病变,作为MS最早期表现的CIS患者全脑包括病灶、NABT均已发生了病理改变,但其病灶与MS比较无显著性差异,而NABT的严重程度较MS轻微。     

视神经脊髓炎皮质脊髓束与胼胝体的DTI研究

目的利用扩散张量成像（DTI）研究视神经脊髓炎（NMO）患者脑白质纤维束扩散异常的发生机制.方法对19例脑MRI正常的NMO患者及19例性别和年龄匹配的正常志愿者进行DTI检查.重建出皮质脊髓束（CST）和胼胝体,并测量其平均扩散率（MD）、分数各向异性（FA）、最大本征值（λ1）和横向本征值（λ2-3）.然后,分析大脑脚、内囊和侧脑室水平CST感兴趣区（ROI）的扩散指标的异常变化.结果与正常志愿者比较,NMO患者CST的MD（P＜0.001）和λ2-3（P=0.002）明显增加,而胼胝体的MD、FA、λ1和λ2-3 均无显著变化（P＞0.05）.在NMO患者,沿着CST的ROI分析显示在大脑脚和内囊水平CST的MD和λ2-3明显增高,FA轻度降低,而λ1无显著变化.在侧脑室水平CST的所有扩散指标均无显著变化.结论 NMO患者脑白质纤维束表现为局部受累模式.继发于脊髓病灶的逆行性变性可能是NMO患者CST扩散异常的原因.     

中脑和基底节神经核团MR扩散张量成像在帕金森病诊断中的作用

目的探讨中脑和基底节神经核团的磁共振扩散张量成像（DTI）在帕金森病（PD）诊断及病情评估中的应用价值。方法回顾性分析2017年7月~2020年11月在我院就诊的27例PD患者（PD组）及23例正常人群（对照组）的临床及MR资料。对两组进行常规MR平扫及DTI检查,测量各受试者双侧黑质、红核、尾状核头、丘脑、苍白球、壳核的DTI参数,包括各项异性分数（FA）、平均扩散系数（MD）。比较各核团FA和MD值在PD组和对照组间的差异。分析存在组间差异的参数单独及联合应用的诊断效能,以及和病程、Hoehn-Yahr分级及统一帕金森病评定量表运动部分（UPDRS Ⅲ）评分的相关性。结果PD组黑质、尾状核头、丘脑、苍白球及壳核的FA值均低于对照组,尾状核头MD高于对照组（P < 0.05）。受试者工作特征曲线分析示联合应用黑质、尾状核头、丘脑、苍白球及壳核的FA值和尾状核头的MD值诊断PD的曲线下面积（AUC）为0.981,均明显大于各参数单独应用于诊断PD的AUC（P < 0.05）。尾状核头MD值与PD患者UPDRS Ⅲ评分呈正相关（r=0.402, P=0.038）,丘脑FA值与PD患者Hoehn-Yahr分级（r=-0.490, P=0.009）、UPDRS Ⅲ评分（r=-0.547, P=0.003）呈负相关。结论中脑、基底节神经核团DTI参数有助于PD的诊断及病情严重程度的评估,联合应用多个核团DTI参数具有较好的诊断效能。      

多发性硬化早期胼胝体的DTI改变

目的：探讨多发性硬化（MS）早期常规MR扫描表现正常的胼胝体的磁共振弥散张量成像（DTI）的改变。方法：20例病程相对较短（平均2.3年）的MS患者和20个年龄性别相匹配的健康志愿者为对照进行MR扫描,获取高分辨常规MRI（T1WI、T2WI、FLAIR）图像及DTI图像,获得表现正常胼胝体（NACC）和额、枕区的表现正常白质（NAWM）的部分各向异性指数（FA）值和平均扩散系数（MD）值。结果：早期MS患者的NACC与正常对照比较其FA值显著下降（P＜0.001）、MD值显著增加（P＜0.001）,但早期MS患者额、枕区的NAWM和正常对照比较其FA值（P=0.216）、MD值（P=0.673）差异均无统计学意义。NACC区的平均MD值和反映脑实质中央性萎缩的Evans指数间存在相关性（r＝0.648,P=0.043）。结论：定量磁共振弥散张量值（FA值和MD值）的变化表明MS疾病早期损害优先出现在胼胝体,胼胝体的结构特点可能是其在MS早期易受损害的重要原因。定量DTI可用于监控和评估早期MS患者NACC的改变和预后。     

右利手正常年轻人脑投射纤维DTI参数图研究

目的 定量分析右利手年轻人脑投射纤维在扩散张量成像（DTI）参数图上的表现,探讨参数图的意义和相互关系。方法应用GE3T全身超导MRI仪,对30名右利手健康青年志愿者（男16名,女14名,平均年龄28．2岁）行常规颅脑MRI及DTI,重建DTI的部分各向异性FA、平均扩散系数MD和T2-weighedtrace三种参数图,观察投射纤维6个部位在参数图上的表现特征,测定三种参数值,定量分析投射纤维侧别、性别及部位的差别。结果①在投射纤维的6个部位,三种参数值皆无性别差异：②桥脑的投射纤维FA值左侧大于右侧（P=0.0111,桥脑、大脑脚、内囊前肢和半卵圆中心T2．weightedtrace值左侧大于右侧（P=0．000-0．017）,MD在所有部位双侧差别无统计学意义;③6个部位平均FA值为大脑脚〉内囊后肢〉内囊膝部〉内囊前肢、桥脑〉半卵圆中心;④投射纤维T2．weighedtrace与FA、MD之间有负相关关系（r=0．169,P=0．024;r=0．149,P=0．0471。结论FA图对投射纤维显示最清楚,FA和MD反映水分子扩散的不同方面,T2-weighedtrace图应结合FA、MD图以及常规MRI进行综合分析。     

结节性硬化患者的脑扩散张量成像初步研究

目的：利用扩散张量成像（DTI）研究结节性硬化（TS）患者脑灰质和白质内病灶的扩散特点。方法：对14例临床和影像学诊断的TS患者利用3．0T MR系统进行DTI检查，测量34个皮层病灶的平均扩散率（MD）和12个白质病灶的MD、分数各向异性（FA）、最大本征值（λ1）和横向本征值（λ23），并与对侧相应部位的扩散指标比较。结果：在TS患者，皮层和白质病灶的MD明显高于对侧（P〈0．001），白质病灶的FA明显低于对侧（P〈0．001），λ23明显高于对侧（P〈0．001），而λ1仅略高于对侧（P=0．0146）。结论：DTI可提供TS患者脑灰质和白质病灶的病理信息。     

基于健康人皮质脊髓束模板分析脑卒中皮质脊髓束损伤

目的运用磁共振扩散张量成像(diffusion tensor imaging,DTI)探究脑卒中皮质脊髓束(corticospinal tract,CST)扩散定量指标与运动功能的关系.材料与方法采集37例单侧皮质下脑卒中患者和30例健康被试的DTI数据,运用概率性纤维束成像追踪出健康被试的CST,获得健康对照组CST模板.基于健康对照组的CST模板测量两组被试双侧CST的各向异性分数(fractional anisotropy,FA)和平均扩散率(mean diffusivity,MD),进一步计算两组被试FA比率(FA ratio,rFA)、FA不对称性(FA asymmetry,FAasy)、MD比率(MD ratio,rMD)和MD不对称性(MD asymmetry,MDasy),用这六个扩散参数相关指标来评估脑卒中患者CST完整性损伤,并与患者"手+腕"及上肢运动功能评分(Fugl-Meyer Assessment,FMA)作相关性分析.结果与健康对照组相比,卒中组病灶同侧CST的FA、rFA显著降低(分别为t=-15.775,t=-11.111,P<0.001),FAasy显著增高(t=9.473,P<0.001);而MD、rMD显著增高(分别为t=9.553,t=7.733,P<0.001),MDasy显著降低(t=-8.941,P<0.001);病灶对侧CST的FA和MD均无显著变化(P>0.05).患者病程及病灶大小与各扩散指标间均无显著相关关系(P>0.05).卒中组病灶同侧CST的FA和rFA与"手+腕"及上肢FMA呈显著正相关(分别为r=0.342,P=0.038;r=0.479,P=0.003;r=0.343,P=0.038;r=0.482,P=0.003),FAasy与"手+腕"及上肢FMA呈显著负相关(分别为r=-0.353,P=0.032;r=-0.490,P=0.002).分步回归分析进一步发现,相较于病灶同侧CST的FA和rFA,FAasy与"手+腕"和上肢运动功能评分更加相关(分别为Beta=-0.353,P=0.032;Beta=-0.490,P=0.002).结论基于健康对照组CST模板测得的FA相关指标能反映CST结构完整性.FAasy与"手+腕"及上肢运动功能评分密切相关,或许可作为评估脑卒中患者手腕部和上肢运动功能障碍的重要参考指标.     

复发-缓解型多发性硬化患者及复发型视神经脊髓炎患者双侧视放射的扩散张量成像研究

目的运用扩散张量成像(DTI)技术探讨复发-缓解型多发性硬化(RRMS)和复发型视神经脊髓炎(RNMO)患者看似正常视放射区DTI指标是否存在差异。材料与方法 RRMS患者、RNMO患者及年龄与性别相匹配的健康志愿者各20例行DTI检查,分别测量双侧视放射的FA值及MD值,并采用扩展残疾状态量表(EDSS)对两组患者进行评分。应用SPSS 17.0配对t检验、单因素方差分析及Dunnett-t检验分别分析患者组及健康对照组组内及组间两侧视放射的FA值及MD值,以及用Spearman软件分析DTI定量值与EDSS评分的相关性。结果 (1)健康对照组、RRMS及RNMO患者组组内双侧视放射FA值(t=0.41,P=0.68;t=0.10,P=0.92;t=0.63,P=0.54)及MD值(t=0.72,P=0.48;t=0.20,P=0.84;t=0.20,P=0.84)均没有明显差异(P0.05);RRMS及RNMO患者组左右两侧视放射FA值(P=0.00;P=0.00)均比健康对照组显著下降,MD值(P=0.00;P=0.00)均比健康对照组显著升高(P0.05);RNMO组双侧视放射FA值比RRMS组下降(P=0.02),而MD值(P=0.50)无明显差别;(2)RRMS组及RNMO组双侧视放射FA值(r=-0.19,P=0.42;r=0.20,P=0.41)及MD值(r=0.11,P=0.64;r=-0.33,P=0.15)与EDSS评分均没有明显的相关性(P0.05)。结论 RRMS及RNMO患者看似正常的视放射区均有受累,但二者视放射受累的程度不一致,FA值对鉴别MS及NMO具有潜在的应用价值,并可作为监测MS及NMO临床进展的重要生物学指标。     

肝豆状核变性豆状核损害磁共振扩散张量成像初步研究

目的探讨磁共振扩散张量成像(DTI)在肝豆状核变性(HLD)患者豆状核(苍白球、壳核)损害的扩散特点。方法对临床和实验室检查确诊的未经治疗的14例肝豆状核变性患者及15例年龄、性别匹配健康志愿者(正常对照组)行颅脑MRI扫描,包括常规MRI平扫及DTI扫描,测量豆状核(苍白球、壳核)的部分各向异性(FA)、平均扩散系数(MD)、第一本征值(λ1)、第二本征值(λ2)和第三本征值(λ3),比较两者的差异性。结果(1)苍白球:与正常对照组相比,HLD患者FA值减低(t=2.24,P=0.035),MD值升高(t=4.10,P=0.000、),λ1值升高(t=3.96,P=0.001),λ2值升高(t=3.17,P=0.005),λ3值升高(t=2.56,P=0.02)。(2)壳核:与正常对照组相比,HLD患者同样表现为FA值减低(t=2.35,P=0.028),MD值升高(t=5.13,P=0.000),λ1值升高(t=5.32,P=0.000),λ2值升高(t=4.22,P=0.001),λ3值升高(t=4.15,P=0.001)。结论肝豆状核变性患者豆状核损害表现为FA值的降低,MD、λ1、λ2、λ3值的升高,DTI可提供肝豆状核变性患者豆状核在扩散水平损害的信息。     

Mean diffusivity and fractional anisotropy histogram analysis of the cervical cord in MS patients

The spinal cord is frequently involved in multiple sclerosis (MS), and cord damage may be an important contributor to disability. Diffusion tensor magnetic resonance imaging (DT-MRI) provides quantitative information about the structural and orientational features of the central nervous system. In order to assess whether diffusion tensor-derived measures of cord tissue damage are related to clinical disability, mean diffusivity (MD) and fractional anisotropy (FA) histograms from the cervical cord were acquired from a large cohort of MS patients. Diffusion-weighted sensitivity-encoded (SENSE) echo planar images of the cervical cord, and brain dual-echo and diffusion-weighted scans were acquired from 44 patients with MS and 17 healthy controls. Cord and brain MD and FA histograms were produced. An analysis of variance model, adjusting for cord volume and patient age, was used to compare cord DT-MRI parameters from controls and patients. A multivariate linear regression model was used to identify DT-MRI variables independently associated with disability. Average cervical cord FA was significantly lower in MS patients compared to controls. Cord cross-sectional area, average FA and average MD were all significantly correlated with the degree of disability (r values ranging from 0.36 to 0.51). The multivariate linear regression model retained average cord FA and average brain MD as variables independently associated with disability, with a correlation coefficient of 0.73 (P < 0.001). DT-MRI reveals a loss of cervical cord tissue structure in MS patients. The strong correlation found between a composite DT-MRI score and disability suggests that a full and accurate assessment of cervical cord damage in MS provides information that usefully contributes to an explanation of the clinical manifestations of the disease.     

Diffusion tensor imaging of post mortem multiple sclerosis brain

Magnetic resonance imaging (MRI) is being used to probe the central nervous system (CNS) of patients with multiple sclerosis (MS), a chronic demyelinating disease. Conventional T(2)-weighted MRI (cMRI) largely fails to predict the degree of patients' disability. This shortcoming may be due to poor specificity of cMRI for clinically relevant pathology. Diffusion tensor imaging (DTI) has shown promise to be more specific for MS pathology. In this study we investigated the association between histological indices of myelin content, axonal count and gliosis, and two measures of DTI (mean diffusivity [MD] and fractional anisotropy [FA]), in unfixed post mortem MS brain using a 1.5-T MR system. Both MD and FA were significantly lower in post mortem MS brain compared to published data acquired in vivo. However, the differences of MD and FA described in vivo between white matter lesions (WMLs) and normal-appearing white matter (NAWM) were retained in this study of post mortem brain: average MD in WMLs was 0.35x10(-3) mm(2)/s (SD, 0.09) versus 0.22 (0.04) in NAWM; FA was 0.22 (0.06) in WMLs versus 0.38 (0.13) in NAWM. Correlations were detected between myelin content (Tr(myelin)) and (i) FA (r=-0.79, p<0.001), (ii) MD (r=0.68, p<0.001), and (iii) axonal count (r=-0.81, p<0.001). Multiple regression suggested that these correlations largely explain the apparent association of axonal count with (i) FA (r=0.70, p<0.001) and (ii) MD (r=-0.66, p<0.001). In conclusion, this study suggests that FA and MD are affected by myelin content and - to a lesser degree - axonal count in post mortem MS brain.     

磁共振扩散张量成像对脊髓型颈椎病的初步研究

目的探讨扩散张量成像对检出脊髓型颈椎病颈髓早期损伤的敏感性。方法对13例健康志愿者和13例脊髓型颈椎病患者行常规MRI及扩散张量成像检查。测量C3～C7四组椎间盘层面的FA值、ADC值,并对所有受检者行颈髓纤维束重建。结果病例组ADC值大于对照组(t=8.495,P0.001);病例组FA值小于对照组(t=-14.328,P0.001),两者皆有统计学意义。病例组中约92.3%(12/13)患者脊髓受压部位伪彩图信号改变;约30.8%(4/13)患者T2WI脊髓内可见高信号,扩散张量成像比常规MRI对脊髓损伤更加敏感(P=0.002)。结论扩散张量成像可以提供脊髓的病理变化信息,在早期检出脊髓损伤方面比常规MRI敏感。     

卒中后运动性失语脑微观结构扩散张量成像研究

目的运用磁共振扩散张量成像(diffusion tensor imaging,DTI)技术评价卒中后运动性失语症脑语言功能区脑微观结构变化。材料与方法收集就诊于新疆医科大学第一附属医院首次发生缺血性卒中后运动性失语症病例15例纳入病例组,并收集正常健康志愿者15例纳入健康对照组,行头颅平扫及DTI扫描,将所获图像进行后处理,获得两组的各向异性分数(fractional anisotropy,FA)、平均扩散率(mean diffusivity,MD)及纤维束走行图,比较两组间FA值、MD值及纤维束走行分析。结果病例组左侧Broca区域FA值为0.357±0.020,正常对照组Broca区FA值为0.396±0.010,病例组左侧Broca区较正常对照组减低(t=?7.22,P=0.00),差异有统计学意义(P<0.05);病例组患侧FA值为0.361±0.020,对侧镜像区域FA值为0.406±0.010,病例组患者FA值低于对侧镜像区域(t=?9.40,P=0.00),差异有统计学意义(P<0.05);病例组左侧Broca区的MD值为1.091±0.084,患侧MD值为1.098±0.100,健康对照组MD值为0.797±0.048,对侧镜像区域MD值为0.808±0.030,病例组左侧Broca区、患者MD值高于正常对照组(t=11.61,P=0.00)及对侧镜像区域(t=9.84,P=0.00),差异有统计学意义(P<0.05);梗死区域纤维束走行较对侧不同程度稀疏、缺损。结论DTI技术能够为卒中后运动性失语的患者提供影像诊断依据,为临床治疗及康复预后提供一定依据。     

White-matter diffusion anisotropy after chemo-irradiation: a statistical parametric mapping study and histogram analysis

The aim of the study was to evaluate white-matter (WM) diffusion anisotropy in medulloblastoma survivors after cranial irradiation and chemotherapy using voxel-based analysis with SPM99 and fractional anisotropy (FA) histogram-derived indices, and to identify quantitative indices for detecting and monitoring children with treatment-induced white-matter injury. Familywise error rate (FWE) that corrects for multiple comparisons was used to locate statistically significant regions of P < 0.05 in voxel-based analysis. Subsequently, the false discovery rate (FDR) controlling procedure (corrected P < 0.05) was used. FA map histogram analysis of histogram-derived indices, mean FA, mean FA peak height, and peak location was performed. Two-sample t test was used in all analyses. Using FWE-corrected P < 0.05, there was a cluster of reduced anisotropy in the periventricular white matter lateral to the left ventricular atrium. When FDR-corrected P < 0.05 was used, there were multiple clusters of reduced anisotropy in the periventricular white matter, the corpus callosum, and corona radiata. Simplified voxel-based morphometry (VBM)-like analysis of cerebrospinal fluid (CSF) did not show significant differences between patient and control subjects. 'White-matter FA map' histogram showed significant reduction in mean FA and mean FA peak location and significant increase in mean FA peak height in the patient group compared to control subjects (P = 0.003, P = 0.003, and P = 0.014, respectively). This approach of quantifying FA can be applied to characterize anisotropy in the white matter after cranial irradiation and chemotherapy and can potentially be used to detect and monitor treatment-induced neurotoxicity.