复发-缓解型多发性硬化边缘系统白质纤维束定量DTI改变

目的 探讨复发-缓解型多发性硬化(relapsing remitting multiple sclerosis,RRMS)患者边缘系统白质纤维束定量弥散张量的改变.方法 RRMS患者24例,年龄和性别相匹配的健康志愿者24例为对照进行MRI扫描,获取常规MRI图像和弥散张量成像(DTI)图像,经GE工作站处理后进行测量分析,比较2组边缘系统主要纤维束(扣带束、穹窿束和终纹束)不同部分各向异性指数(FA)值和平均弥散系数(MD)值的变化.结果 在考虑年龄和性别因素的影响后.RRMS组患者穹窿柬(F=15.605,P=0.000135)、右侧穹窿/终纹束(F=15.772,P=0.000127)、左侧穹窿/终纹束(F=8.53,P=0.004)的FA值较健康对照组明显降低; RRMS组患者穹窿束(F=13.28,P=0.0004)、右侧终纹柬(F=10.943,P= 0.002)、右侧穹窿/终纹束(F= 7.326,P=0.008)的MD值较健康对照组明显增高;RRMS组患者左/右侧的前、后扣带束、右侧终纹束(F= 0.986, P=0.326)、左侧终纹束的FA和对照组比较无明显差异,RRMS组患者左/右侧的前、后扣带束、左侧终纹束、左侧穹窿/终纹束的MD值较健康对照比较差异均无统计学意义.结论 DTI可作为反映RRMS边缘系统纤维束病理性改变的较敏感的检测方法.     

复发-缓解型多发性硬化患者表现正常胼胝体经Hofer's新方案分区的各向异性定量研究

目的 研究在复发-缓解型多发性硬化(RRMS)中通过Hofer's 新分区方案的表现正常胼胝体部分各向异性(FA)值的定量改变.方法 采集35例临床确诊的RRMS患者和35例年龄、性别匹配的健康对照定量弥散张量成像(DTI)数据.比较RRMS患者和对照组胼胝体Hofer's新分区方案不同区域的FA值改变及其与脑实质分数(brain parenchymal fraction, BPF)、T2病灶容积之间的关系.结果 在健康志愿者中,Hofer's新分区方案FA值组内比较差异具有统计学意义(P＜0.001),FA(区V)＞FA(区I)＞FA(区IV)＞FA(区II)＞FA(区III);在RRMS患者中同样观察到这些区域的FA值具有不均一性:FA(区V)＞FA(区I)＞FA(区II)＞FA(区III)＞FA(区IV);RRMS患者区II(F=4.159,P=0.046)、区III(F=9.257,P=0.004)、区IV(F=12.234,P=0.001)的FA值较健康对照组明显降低;胼胝体的区V的FA值同样出现降低趋势,但无统计学意义(P=0.179);胼胝体的区I的FA值未见明显改变(P=0.787).在Hofer's新分区方案中,胼胝体组内FA值和BPF之间(P值范围:0.086～0.969)、FA值和T2病灶容积之间(P值范围:0.127～0.658) 均无相关性.结论 RRMS患者的表现正常胼胝体 (区II、区III、区IV) 存在微观病理改变,这些改变可能和胼胝体原发性缺血、局部微病灶等因素有关.Hofer's新分区方案的DTI分析有助于更好地理解RRMS临床变化.     

儿童白质发育成熟的影响因素分析

目的 分析早产、缺血缺氧性脑病(HIE)病史以及癫痫对儿童白质发育成熟的影响.资料与方法 搜集本院67例进行过头颅MRI和扩散张量成像(diffusion tensor imaging,DTI)扫描的住院患儿.其中男39例,女28例,年龄6～117个月,平均51个月.人组患儿中,8例有HIE病史,8例早产,36例癫痫.DTI数据采用基于白质骨架的空间统计分析(tract-based spatial statistics,TBSS),提取11个感兴趣区域内各向异性系数(fractional anisotropy,FA),包括中脑的大脑脚、内囊前后肢、内囊的壳核后部分、丘脑后放射、放射冠、上纵束、下额枕束缚/下纵束、胼胝体膝部、体部、压部.癫痫的严重程度根据其对发育的影响进行评分.对不同白质束的FA值进行ANOVA检验.年龄、早产、HIE病史和癫痫评分这些因素对各纤维束FA值的影响采用线性回归分析进行统计学分析.结果 方差分析显示不同的纤维束间FA值差异存在统计学意义(F=162.676,P=0.000).除了内囊的壳核后部分和胼胝体压部,多数纤维束的FA值随着年龄增大而增加.放射冠的FA值表现出随年龄增加的统计学趋势(P=0.065).HIE病史与大脑脚,内囊的壳核后部分,丘脑后放射和上纵束的FA值呈现负相关关系(r=-0.212,P=0.036;r=-0.29,P=0.017;r=-0.326,P=0.005;r=-0.269,P=0.021).早产和癫痫评分这两个因素与纤维束的FA值无统计学意义的相关性.结论 TBSS可以用于儿童DTI数据的分析.HIE病史是可以引起儿童白质发育成熟障碍的一个确切因素.     

阿尔茨海默病患者联络纤维的DTI诊断价值

目的采用磁共振扩散张量成像(diffusion tensor imaging,DTI)观察阿尔茨海默病(Alzheimer’s disease,AD)患者联络纤维的改变情况。资料与方法对10例轻中度AD患者和18名健康老年人(对照组)行常规MRI[(T1WI、T2WI、T2液体衰减反转恢复序列(FLAIR)]及DTI检查,DTI测量双侧扣带束、上纵束Ⅱ、钩束及额枕下束8个感兴趣区(ROI)的部分各向异性分数(FA)值。采用简易精神状态量表(MMSE)和蒙特利尔认知评估量表(MoCA)对AD患者的认知功能进行测定。结果与对照组相比,AD组MMSE评分和MoCA评分较对照组明显下降(P<0.05),AD组常规MRI上ROI白质信号无明显变化,ROI部位的FA值均显著下降(P<0.05),且上纵束Ⅱ的FA值与MMSE(右侧r=0.672,P=0.033,左侧r=0.919,P<0.01)和MoCA(右侧r=0,747,P=0.013;左侧r=0.679,P=0.031)评分呈正相关。结论轻中度AD患者存在联络纤维损害且上纵束Ⅱ的损害程度与认知功能密切相关。     

纤维自动量化技术在中重度OSAHS患者脑白质损伤中的应用

【摘要】目的：探讨阻塞性睡眠呼吸暂停低通气综合征（OSAHS）患者脑白质损伤的特征及其与焦虑症状的相关性。方法：将33例未经治疗的中重度OSAHS患者及28例与患者组相匹配的无睡眠障碍志愿者（NSD）纳入本研究，所有被试行3.0T MR头部扫描，获得DTI数据及高分辨率薄层T1加权图像。采用纤维自动量化（AFQ）技术，提取每例被试全脑20条主要纤维束，将每条纤维束等分为100个节段，比较两组间各条纤维束DTI指标值的差异，并将OSAHS组中受损纤维节段的DTI张量指标值与患者的焦虑量表评分进行相关性分析。结果：相对于NSD组，OSAHS组中胼胝体大钳的第77~78段的FA值减低，右侧丘脑辐射的第23~24节段的MD值增高，右下额枕束第54~57节段及右上纵束第66~68节段的AD值增高（P<0.05）。并且胼胝体大钳第78受损节段的FA值与SAS量表评分呈正相关（r=0.447，P=0.009），右下额枕束第56受损节段的AD值与SAS量表评分呈负相关（r=-0.434，P=0.013）。结论：采用AFQ分析方法能够更加精细、准确地发现OSAHS患者脑白质纤维束的受损节段，胼胝体大钳及右下额枕束的局部损伤可能是OSAHS患者出现焦虑的神经病理学基础。     

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.     

遗忘型轻度认知障碍脑白质纤维束扩散张量成像研究

目的：使用3．0T 磁共振扩散张量成像（DTI）技术观察遗忘型轻度认知障碍（aMCI）患者脑白质纤维束的改变,探讨 DTI 对 aMCI 的临床诊断价值。方法：对16例 aMCI 患者和12例健康志愿者（对照组）行 DTI 扫描,测量两组受试者的胼胝体膝部、压部、双侧的内囊后肢、小脑中脚、上纵束、下纵束、下额枕束和扣带束的各向异性（FA）和表观扩散系数（ADC）值并进行统计学分析。结果：aMCI 组双侧下额枕束的 FA 值均较对照组低,右上纵束的 ADC 值较对照高,差异具有统计学意义（P ＜0．05）;其它部位白质纤维束的 FA 和 ADC 值在两组间的差异无统计学意义（P ＜0．05）。结论：aM-CI 患者的下额枕束和上纵束发生了微观结构的变化,可能在一定程度上参与了遗忘型轻度认知障碍的发生,DTI 对于aMCI 的诊断具有重要的临床价值。     

脑白质束扩散张量与阿尔茨海默病患者的神经心理学量表评分的多元线性回归分析

目的应用线性回归方法,通过对阿尔茨海默病(AD)的相关脑白质束扩散张量分析,找出与AD患者神经心理学评分的相关关系并建立回归方程。资料与方法对20例轻度AD患者、30例中重度AD患者以及25名年龄相匹配的正常老年自愿者进行扩散张量成像(DTI)扫描。DTI采用单次激励平面回波成像(EPI)序列,扩散敏感梯度施加在25个不同方向,生成平均扩散系数(MD)、部分各向异性(FA)参数图,结合彩色向量图及纤维追踪图分别测定各白质束的参数值,包括双侧扣带束、上纵束、下纵束、下额枕束、钩束、穹窿体、胼胝体膝部及压部。利用多元线性回归分析,建立各DTI参数与简易智能量表(MMSE)评分的回归模型。结果对照组与轻度AD组比较仅穹窿体和左侧扣带束的FA值存在明显差异;轻度AD组与中重度AD组比较穹窿体、双侧钩束、扣带束、下纵束、胼胝体膝部及压部及右侧下额枕束的FA值均存在统计学差异。对照组与轻度AD组的MD值在穹窿体区存在统计学差异,而轻度AD组与中重度AD组在穹窿体、双侧钩束、下额枕束、左侧扣带束、右侧上、下纵束、胼胝体膝部及压部均存在MD值的显著差异。回归模型提示穹窿体和左侧扣带束的FA值与MMSE评分存在正线性相关关系,...     

基于扩散张量成像对颈椎源性疼痛患者脑白质微结构异常的研究

目的 采用基于纤维束的空间统计方法(TBSS)检测颈椎源性疼痛(CSP)患者的脑白质微结构异常。方法 对45例CSP患者(患者组)和45名性别、年龄匹配的健康志愿者(对照组)进行全脑扩散张量成像(DTI)扫描,应用FSL软件中的TBSS方法对患者组和对照组的DTI数据集进行分析,探索两组间各向异性分数(FA)、平均扩散系数(MD)、径向扩散系数(RD)和轴向扩散系数(AD)具有统计学差异的脑区。同时,将上述DTI参数与CSP患者的各项临床指标进行相关分析。结果 与对照组相比,CSP患者胼胝体、前放射冠、左侧上纵束的FA值存在不同程度降低,同时,患者组的胼胝体、丘脑后辐射、内囊、前后及上放射冠、双侧上纵束均表现出MD值和RD值升高,而AD值在两组间无统计学差异。此外,CSP患者胼胝体膝部的FA值与视觉模拟评分(VAS)呈线性负相关(r=-0.458,P<0.01),左侧上纵束的MD值与VAS呈正相关(r=0.495,P<0.01)。结论 CSP患者部分白质纤维束呈现出FA值降低合并MD值和RD值同时升高,特定脑区的FA值和MD值与疼痛强度密切相关,提示相应DTI参数可能成为评...     

DTT及VBM联合评价精神发育迟滞患者脑白质变化

【摘要】目的：联合使用扩散张量纤维束示踪成像（DTT）及基于体素的形态分析法（VBM）,探讨精神发育迟滞（MR）患者的脑白质变化。方法：精神发育迟滞患者16例及同龄健康志愿者16例（对照组）,均行MR3D-T1WI及DTI扫描,采用VBM方法比较患者组与对照组中脑白质体积的差异。同时使用DTT重建特定脑白质纤维束,比较患者组与对照组中白质纤维束的FA值、ADC值、数量和长度的差异。结果：与正常对照组比较,MR患者的脑白质体积总量减少（t=2.457,P＜0.01）,扣带束、下额枕束的FA值降低（t=-2.561、-2.92,P=0.013、0.005）,胼胝体束、下额枕束、皮质脊髓束和扣带束的ADC值增高（t=3.039、2.524、2.483、2.292,P=0.006、0.016、0.016和0.025）,皮质脊髓束、胼胝体束的数量减少（t=-2.195、-2.385,P=0.033、0.024）,胼胝体束、皮质脊髓束、扣带束长度减小（t=-2.146、-2.364、-2.048,P=0.040、0.021、0.045）,差异均有统计学意义（P＜0.05）。结论：DTT及VBM方法均可发现精神发育迟滞患者脑白质异常变化,两者联合使用对精神发育迟滞的评估有重要价值。     

复发-缓解型多发性硬化投射纤维束定量DTI

目的：探讨复发-缓解型多发性硬化（RRMS）患者投射纤维定量扩散张量改变.方法：20例RRMS患者及年龄和性别相匹配的20例健康志愿者（对照组）行MRI扫描,获取常规MRI及DTI图像,分别进行测量分析,比较2组投射纤维的部分各向异性指数（FA）和平均扩散系数（MD）值的变化.主要纤维束包括丘脑前辐射（atr）、丘脑上辐射（str）、丘脑后辐射（ptr）、皮质延髓束（cpt）、皮质脊髓束（cst）等.结果：RRMS组患者与健康对照组的FA值比较：ptr（左侧：0.541±0.141 vs 0.628±0.153;右侧：0.512±0.079 vs 0.560±0.102）、cpt/atr（左侧：0.421±0.118 vs 0.503±0.104;右侧：0.437±0.064 vs 0.512±0.102）、cpt/ptr（左侧：0.405±0.056 vs 0.500±0.078;右侧：0.427±0.057 vs 0.496±0.083）、cpt/cst/str（左侧：0.476±0.115 vs 0.554±0.056;右侧：0.462±0.095 vs 0.520±0.074）,RRMS组的FA值均较健康对照组低,2组间差异有统计学意义（P〈0.05）;RRMS组患者atr的FA值（左侧：0.538±0.103,右侧：0.542±0.092）与对照组（左侧：0.564±0.087;右侧0.568±0.116）比较,差异无统计学意义（P〉0.05）.RRMS组患者与健康对照组的MD值比较：cpt/ptr（左侧：0.928±0.102 vs 0.853±0.105;右侧：0.949±0.165 vs 0.859±0.141）、cpt/cst/str（左侧：0.811±0.137 vs 0.772±0.093;右侧：0.868±0.167 vs 0.784±0.128）的MD值差异有统计学意义（P〈0.05）,RRMS组的MD值较健康对照组增高;RRMS组患者atr（左侧：0.898±0.143 vs 0.868±0.118;右侧：0.850±0.164 vs0.835±0.074）、ptr（左侧：0.874±0.203 vs 0.829±0.103;右侧：0.847±0.172 vs 0.802±0.075）、cpt/atr（左侧：0.856±0.187 vs 0.805±0.161;右侧：0.829±0.246 vs 0.820±0.093）的MD值和健康对照比较差异均无统计学意义（P〉0.05）.结论：多发性硬化患者双侧ptr、cpt/atr、cpt/ptr、cpt/cst/str存在FA值减小,双侧cpt/ptr、cpt/cst/str存在MD值的增高,提示在投射纤维中上述白质纤维束存在结构改变,DTI可以作为反映RRMS投射纤维微观病理改变的敏感检查指标.     

Histogram analysis of diffusion measures in clinically isolated syndromes and relapsing-remitting multiple sclerosis

Objective

The purposes of our study were to employ diffusion tensor imaging (DTI)-based histogram analysis to determine the presence of occult damage in clinically isolated syndrome (CIS), to compare its severity with relapsing-remitting multiple sclerosis (RRMS), and to determine correlations between DTI histogram measures and clinical and MRI indices in these two diseases.

Materials and methods

DTI scans were performed in 19 CIS and 19 RRMS patients and 19 matched healthy volunteers. Histogram analyses of mean diffusivity and fractional anisotropy were performed in normal-appearing brain tissue (NABT), normal-appearing white matter (NAWM) and gray matter (NAGM). Correlations were analyzed between these measures and expanded disability status scale (EDSS) scores, T₂WI lesion volumes (LV) and normalized brain tissue volumes (NBTV) in CIS and RRMS patients.

Results

Significant differences were found among CIS, RRMS and control groups in the NBTV and most of the DTI histogram measures of the NABT, NAWM and NAGM. In CIS patients, some DTI histogram measures showed significant correlations with LV and NBTV, but none of them with EDSS. In RRMS patients, however, some DTI histogram measures were significantly correlated with LV, NBTV and EDSS.

Conclusion

Occult damage occurs in both NAGM and NAWM in CIS, but the severity is milder than that in RRMS. In CIS and RRMS, the occult damage might be related to both T2 lesion load and brain tissue atrophy. Some DTI histogram measures might be useful for assessing the disease progression in RRMS patients.     

复发好转型多发性硬化的全脑DTI直方图分析

目的 利用扩散张量成像（DTI）直方图分析,明确复发好转型多发性硬化（RRMS）患者的脑异常改变及DTI直方图指标与扩展残疾状态评分（EDSS）的相关性。资料与方法 对29例RRMS患者和35名正常志愿者行常规MRI和DTI检查,获得全脑平均扩散率（MD）和分数各向异性（FA）图像后,分别计算出全脑MD和FA直方图并对其进行分析。结果 与正常志愿者比较,RRMS患者平均全脑MD直方图右移、峰高降低;平均全脑FA直方图左移、峰高增高。RRMS患者全脑MD和FA直方图指标与正常志愿者相比,均存在显著性差异（P〈0．001）。在RRMS患者,全脑平均MD（r=0．413,P=0．026）,MD直方图峰高（r=-0．424,P=0．022）和FA直方图峰位置（r=-0．594,P=0．001）与EDSS评分具有相关性。结论 RRMS患者存在明显脑扩散异常,部分DTI直方图指标可用于监测疾病进展。     

复发好转型多发性硬化表现正常脑白质DTI研究

目的:利用扩散张量成像(DTI)直方图分析,明确复发好转型多发性硬化(RRMS)患者表现正常脑白质(NAWM)的异常改变及DTI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例健康志愿者行常规MRI和DTI检查,分割提取NAWM后,绘制出NAWM的平均扩散率(MD)和部分各向异性(FA)直方图,并对其进行分析。结果:与健康志愿者比较,RRMS患者NAWM平均MD直方图右移、峰高降低;平均FA直方图左移、峰高增高。RRMS患者NAWM的平均MD、MD直方图峰位置和FA直方图峰高明显高于健康志愿者(P<0.001),而MD直方图峰高和平均FA明显低于健康志愿者(P<0.001)。在RRMS患者,所有NAWM的MD和FA直方图指标与EDSS评分均无相关性。结论:RRMS患者NAWM内存在明显扩散异常。     

Correlation of diffusion tensor and dynamic perfusion MR imaging metrics in normal-appearing corpus callosum: support for primary hypoperfusion in multiple sclerosis

BACKGROUND AND PURPOSE: Hypoperfusion of the normal-appearing white matter in multiple sclerosis (MS) may be related to ischemia or secondary to hypometabolism from wallerian degeneration (WD). This study evaluated whether correlating perfusion and diffusion tensor imaging (DTI) metrics in normal-appearing corpus callosum could provide support for an ischemic mechanism for hypoperfusion. MATERIALS AND METHODS: Fourteen patients with relapsing-remitting MS (RRMS) and 17 control subjects underwent perfusion MR imaging and DTI. Absolute measures of cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT) were calculated. Mean diffusivity (MD) and fractional anisotropy (FA) maps were computed from DTI data. After visual coregistration of perfusion and DTI images, regions of interest were placed in the genu, central body, and splenium of normal-appearing corpus callosum. Pearson product-moment correlation coefficients were calculated using mean DTI and perfusion measures in each region. RESULTS: In the RRMS group, CBF and CBV were significantly correlated with MD in the splenium (r = 0.83 and r = 0.63, respectively; both P < .001) and in the central body (r = 0.86 and r = 0.65, respectively; both P < .001), but not in the genu (r = 0.23 and 0.25, respectively; both P is nonsignificant). No significant correlations were found between MTT and DTI measures or between FA and any perfusion measure in the RRMS group. No significant correlations between diffusion and perfusion metrics were found in control subjects. CONCLUSION: In the normal-appearing corpus callosum of patients with RRMS, decreasing perfusion is correlated with decreasing MD. These findings are more consistent with what would be expected in primary ischemia than in secondary hypoperfusion from WD.     

临床孤立综合征和复发缓解型多发性硬化患者表现正常脑白质及脑灰质的MR扩散张量直方图比较

目的 评价扩散张量成像(DTI)对临床孤立综合征(CIS)的研究价值,了解CIS的病理变化机制及与复发缓解型多发性硬化(RRMS)的关系.方法 选择19例CIS患者(CIS组)、19例RRMS患者(RRMS组)和19例性别、年龄与之匹配的健康志愿者(正常对照组)为研究对象.用1.5 T超导型MR机采集数据,经图像后处理得到表现正常脑白质(NAWM),表现正常脑灰质(NAGM)的平均扩散率(MD)、各向异性分数(FA)直方图,其中提取出下列指标:平均值、直方图峰高和峰位置,进行单因素方差分析和秩和检验,并对3组NAWM、NAGM的MD、FA值与扩展残疾状态量表(EDSS)评分进行Spearman相关分析.结果 RRMS组患者表现正常脑白质MD为(0.83±0.04)×10-3mm2/s,较正常对照组(0.78±0.02)×10-3mm2/s、CIS组(0.79±0.02)×10-3mm2/s均显著增高(F=15.304,P＜0.01),但CIS组与正常对照组间差异无统计学意义(P＞0.05);MD图峰高CIS组明显低于正常对照组(P＜0.01);RRMS组平均FA值(0.36±0.03)较正常对照组(0.41±0.01)及CIS组(0.40±0.02)均降低(F=17.965,P＜0.01),但CIS组与正常对照组间差异无统计学意义(P＞0.05),平均FA图峰位置CIS组较正常对照组明显左移.NAGM MD在正常对照组、CIS组、RRMS组分别为(1.03±0.05)、(1.08±0.06)、(1.18±0.12)×10-3mm2/s,依次增高,且差异均有统计学意义(F=15.261,P＜0.01).CIS患者的各项DTI指标与EDSS评分均无显著性相关.RRMS患者NAGM的MD与EDSS评分呈正相关(r=0.568,P＜0.05).结论 DTI直方图可以敏感的显示及量化CIS及多发性硬化(MS)NAWM、NAGM的异常,作为MS最早期表现的CIS患者NAWM、NAGM均已发生了病理改变,但较MS病变轻.     

Diffusion tensor imaging in multiple sclerosis: assessment of regional differences in the axial plane within normal-appearing cervical spinal cord

BACKGROUND AND PURPOSE: Evaluation of the spinal cord is important in the diagnosis and follow-up of patients with multiple sclerosis. Our purpose was to investigate diffusion tensor imaging (DTI) changes in different regions of normal-appearing spinal cord (NASC) in relapsing-remitting multiple sclerosis (RRMS). METHODS: Axial DTI of the cervical spinal cord was performed in 24 patients with RRMS and 24 age- and sex-matched control subjects. Fractional anisotropy (FA) and mean diffusivity (MD) were calculated in separate regions of interest (ROIs) in the anterior, lateral, and posterior spinal cord, bilaterally, and the central spinal cord, at the C2-C3 level. Patients and control subjects were compared with respect to FA and MD with the use of an exact Mann-Whitney test. Logistic regression and receiver operating characteristic (ROC) curve analysis assessed the utility of each measure for the diagnosis of RRMS. RESULTS: DTI metrics in areas of NASC in MS were significantly different in patients compared with control subjects; FA was lower in the lateral (mean +/- SD of 0.56 +/- 0.10 versus 0.69 +/- 0.09 in control subjects, P < .0001), posterior (0.52 +/- 0.11 versus 0.63 +/- 0.10, P < .0001), and central (0.53 +/- 0.10 versus 0.58 +/- 0.10, P = .049) NASC ROIs. Assessing DTI metrics in the diagnosis of MS, a sensitivity of 87.0% (95% confidence interval [CI], 66.4 to 97.1) and a specificity of 91.7% (95% CI, 73.0 to 98.7) were demonstrated. CONCLUSION: The NASC in RRMS demonstrates DTI changes. This may prove useful in detecting occult spinal cord pathology, predicting clinical course, and monitoring disease progression and therapeutic effect in MS.     

Diffusion tensor imaging of tract involvement in children with pontine tumors

BACKGROUND AND PURPOSE: Conventional MR imaging permits subcategorization of brain stem tumors by location and focality; however, assessment of white matter tract involvement by tumor is limited. Diffusion tensor imaging (DTI) is a promising method for visualizing white matter tract tumor involvement supratentorially. We investigated the ability of DTI to visualize and quantify white matter tract involvement in pontine tumors. METHODS AND MATERIALS: DTI data (echo-planar, 1.5T) were retrospectively analyzed in 7 patients with pontine tumors (6 diffuse, 1 focal), 4 patient controls, and 5 normal volunteers. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were calculated from the diffusion tensor in 6 regions of interest: bilateral corticospinal tracts, transverse pontine fibers, and medial lemnisci. Relationships between FA and ADC values and results of the neurologic examinations were evaluated. RESULTS: The corticospinal tracts and transverse pontine fibers were affected more often than the medial lemnisci. The DTI parameters (FA and ADC) were significantly altered in all tracts of patients with pontine tumors (P < .05), compared with those values in the control groups. A marginally significant (P = .057) association was seen between the severity of cranial nerve deficit and decreased FA. CONCLUSION: DTI provided superior visualization and quantification of tumor involvement in motor, sensory, and transverse pontine tracts, compared with information provided by conventional MR imaging. Thus, DTI may be a sensitive measure of tract invasion. Further prospective studies are warranted to assess the ability of DTI to delineate tumor focality and improve risk stratification in children with pontine tumors.     

Cerebral white matter damage in frontotemporal dementia assessed by diffusion tensor tractography

INTRODUCTION: We used diffusion tensor imaging (DTI) to study white matter integrity in patients with frontotemporal dementia (FTD). METHODS: The subjects comprised 20 patients (9 men, 11 women) with FTD and 17 age-matched healthy controls (9 men, 8 women). Based on the data obtained from DTI, we performed tractography of the major cerebral pathways, including the pyramidal tracts, genu and splenium of the corpus callosum (CC), bilateral arcuate fasciculi (AF), inferior longitudinal fasciculi (ILF) and uncinate fasciculi (UF). We measured the values of fractional anisotropy (FA) in each fiber and statistically compared the findings in patients with those in controls. RESULTS: We found a significant decrease in FA values in the selected association fibers as well as anterior fibers of the CC in the patients with FTD. The greatest decrease in mean FA of the UF was seen in advanced FTD. On the other hand, there were no significant differences in FA in the bilateral pyramidal tracts. CONCLUSION: The features of FTD from the view point of cerebral white matter damage were revealed by tractography based on DTI. DTI is therefore considered to be a useful method, and may provide clues to elucidating the pathogenesis of FTD.