扩散张量成像在精神分裂症患者脑部结构的临床应用

目的：用扩散张量成像（DTI）的磁共振技术探讨研究精神分裂症患者可能的脑部结构的病理改变。方法：对15例成年男性精神分裂症患者和15例成年男性健康对照者行DTI磁共振检查,比较患者组和健康对照组的部分各向异性（FA）差异性。结果：精神分裂症患者右侧额中回、额下回、右侧颞上回、左侧颞下回、左侧颞中回、左侧扣带回、左侧中央前回的各项分数异性（FA）值较健康对照组低（P〈0.05）。未发现患者组白质FA值有明显增高的脑区。结论：额叶区域白质结构的异常可能是精神分裂症患者额叶的执行功能损害的病理生理学机制之一。     

急性一氧化碳中毒脑损伤的磁共振扩散张量成像

目的：利用磁共振扩散张量成像(DTI )评估急性一氧化碳(CO)中毒患者的脑结构损伤情况。方法25例急性(5.0 d±1.44 d) CO 中毒患者和37例性别、年龄、利手、受教育程度匹配的健康志愿者进行 DTI 扫描,获得扩散张量纤维束成像(DTT)图像,并分别测量双侧小脑半球(齿状核)、黑质、海马、额叶白质(侧脑室前角前下方、侧脑室体部上方)、尾状核头、苍白球、丘脑、内囊前肢、内囊后肢、枕叶白质(视中枢)、顶叶白质(侧脑室体部上方)及胼胝体膝部、压部共26个感兴趣(ROI)的各向异性分数(FA)值和表观扩散系数(ADC)值,进行组间配对 t 检验。结果病患组双侧苍白球、双侧内囊前肢、双侧黑质、右侧小脑、左侧额叶下部白质、右额叶上下部白质、胼胝体膝部的 FA 值显著低于对照组(P <0.05)。病患组右侧黑质、左侧苍白球的 ADC 值显著降低(P <0.05),病患组右额叶上下部白质及双侧枕叶白质 ADC 值显著升高(P <0.05)。结论急性 CO 中毒患者广泛脑微结构受损,提示脑微结构的原发损伤可能是 CO 中毒迟发性脑病潜在的病理生理基础。     

磁共振扩散张量成像在颈髓病变中的应用

目的：探讨磁共振扩散张量成像（DTI）技术在颈髓病变诊断中的临床应用。方法：应用1.5T磁共振机器对39例颈髓病变患者和15例健康志愿者行MRI常规和DTI检查,测定病变区和对照部位的FA值、ADC值并进行对照分析,并重建白质纤维束图。结果：健康志愿者颈髓的FA值为0.66±0.06,ADC值为（0.96±0.14）×10^-3mm^2/s。颈椎病病例FA值为0.47±0.05、ADC值为（1.16±0.28）×10^-3mm^2/s;与对照组统计学分析FA值明显降低（P〈0.01）,ADC值明显增高（P〈0.01）。颈髓急性损伤病例FA值为0.38±0.08、ADC值为（0.89±0.25）×10^-3mm^2/s;与对照组统计学分析FA值明显降低（P〈0.01）,ADC值与对照组无明显差异（P=0.130〉0.05）。颈髓炎症：FA值为0.40±0.06、ADC值为（1.25±0.40）×10^-3mm^2/s;与对照组统计学分析FA值明显降低（P〈0.01）,ADC值明显增高（P〈0.01）。所有病例通过DTI技术成功显示了白质纤维束在病变区变形、移位及中断等改变。结论：DTI可以探测到颈髓病变中常规MR未能发现的病灶;白质纤维束成像可以显示白质束的受损情况。     

MR扩散张量成像评价脑室旁白质软化症脑性瘫痪患儿认知功能的研究

目的 探讨MR DTI及白质纤维束成像(FT)在评价脑室旁白质软化症(PVL)脑性瘫痪患儿认知功能中的应用价值,为揭示PVL患儿认知功能障碍的可能神经基础提供帮助.方法 选取46例临床确诊为脑性瘫痪的PVL患儿,同时选择足月无窒息史的健康儿童16名进行对照研究.应用发育商(DQ)评价患儿认知功能,根据DQ值将患儿分为轻(11例)、中(19例)、重度(16例)认知障碍组.对受试儿童进行常规MRI及DTI检查,计算各组患儿主要白质纤维束各向异性分数(FA)值,患儿组与对照组间进行非配对t检验,各认知障碍组及对照组组间比较采用单因素方差分析.结果 与对照组相比,患儿组左侧皮质脊髓束(患儿组:0.476 ±0.064;对照组:0.531±0.064),双侧内囊前肢(患儿组:左侧0.357±0.050,右侧0.370±0.040;对照组:左侧0.405±0.081,右侧0.405±0.036),双侧内囊后肢(患儿组:左侧0.483±0.044,右侧0.485±0.046;对照组:左侧0.546±0.091,右侧0.547±0.083),双侧弓状束(患儿组:左侧0.367±0.069,右侧0.363±0.064;对照组:左侧0.433±0.097,右侧0.421±0.091),双侧丘脑后辐射(患儿组:左侧0.390±0.059,右侧0.382±0.047;对照组:左侧0.459±0.067,右侧0.446±0.064),双侧前扣带束(患儿组:左侧0.362±0.056,右侧0.345±0.056;对照组:左侧0.423±0.057,右侧0.417±0.080),双侧上纵束(患儿组:左侧0.323±0.050,右侧0.341±0.056;对照组:左侧0.426±0.102,右侧0.416±0.092)及胼胝体压部(患儿组:0.535±0.090;对照组:0.606±0.060)的FA值显著减低,差异有统计学意义(t值为2.037 ～3.745,P值均＜0.05);随认知障碍程度的加重,所有纤维束的FA值逐渐下降,各认知障碍组及对照组进行组间比较发现双侧皮质脊髓束、内囊前肢、内囊后肢、左侧弓状束、双侧丘脑后辐射、前扣带束、上纵束及胼胝体压部的FA值差异有统计学意义(F值为3.021 ～7.146,P值均＜0.05).进一步两两比较显示,以上纤维束的FA值在对照组与重度认知障碍组间比较,差异均有统计学意义(P值均＜0.05).结论 PVL患儿认知功能障碍与脑内广泛白质纤维束损伤有关,DTI及FT在评价PVL患儿认知功能方面有较高的应用价值.     

3.0T磁共振扩散张量成像对特发性癫痫的初步研究

目的:利用磁共振扩散张量成像(DTI)探讨特发性癫痫患者脑微观结构的改变,分析其与临床变量的相关性。方法:21例特发性癫痫患者及21例年龄、性别及教育程度相匹配的健康人作为对照组参与本研究。所有受试者均为右利手。原始扫描图像首先经DTI Studio软件处理获得表观扩散系数(ADC)图、部分各向异性(FA)图。数据处理用SPM2软件进行基于体素的全脑分析,主要步骤有图像配准、标准化、平滑。统计分析采用两独立样本t检验。结果:病例组与对照组的年龄、性别及教育程度差异均无统计学意义(P>0.05)。特发性癫痫患者FA值减低区域位于右侧颞叶、岛叶、前扣带及小脑齿状核,ADC值升高区域位于右侧内囊前肢及外囊(P<0.05,成簇水平cluster>100)。相关分析发现右侧颞叶、额叶、枕叶及左侧内囊前肢的ADC值与病程呈正相关(P<0.05,成簇水平cluster>100)。结论:DTI检查能发现特发性癫痫患者脑微观病理改变,为特发性癫痫的病理生理机制研究提供了理论依据。     

Diffusion tensor imaging with 3.0T magnetic resonance scanner in patients with idiopathic epilepsy

目的:利用磁共振扩散张量成像(DTI)探讨特发性癫痫患者脑微观结构的改变,分析其与临床变量的相关性.方法:21例特发性癫痫患者及21例年龄、性别及教育程度相匹配的健康人作为对照组参与本研究.所有受试者均为右利手.原始扫描图像首先经DTI Studio软件处理获得表观扩散系数(ADC)图、部分各向异性(FA)图.数据处理用SPM2软件进行基于体素的全脑分析,主要步骤有图像配准、标准化、平滑.统计分析采用两独立样本t检验.结果:病例组与对照组的年龄、性别及教育程度差异均无统计学意义(P＞0.05).特发性癫痫患者FA值减低区域位于右侧颞叶、岛叶、前扣带及小脑齿状核,ADC值升高区域位于右侧内囊前肢及外囊(P＜0.05,成簇水平cluster＞100).相关分析发现右侧颞叶、额叶、枕叶及左侧内囊前肢的ADC值与病程呈正相关(P＜0.05,成簇水平cluster＞100).结论:DTI检查能发现特发性癫痫患者脑微观病理改变,为特发性癫痫的病理生理机制研究提供了理论依据.     

强迫症患者脑部白质异常的磁共振扩散张量成像研究

目的 运用磁共振扩散张量成像技术,探索强迫症患者脑部白质异常的部位.方法 对15例强迫症患者和15例年龄、性别及文化程度相匹配的健康志愿者,分别行脑部DTI扫描.选择双侧眶额叶白质、顶叶白质、扣带束、上纵束、内囊前肢、丘脑后辐射以及胼胝体嘴、胼胝体膝、胼胝体压部作为感兴趣区,分别测量以上部位的FA值进行统计学分析,并与强迫症症状严重性进行相关性分析.结果 与正常对照组相比,强迫症组右侧前扣带回、胼胝体嘴部的FA值降低(P<0.05),左侧前扣带回及右侧前额叶的FA值升高(P<0.05).结论 本研究发现强迫症患者存在多个脑白质区的结构异常,以上部位的异常可能在强迫症的发病中起重要作用.     

1HMR波谱联合扩散张量成像在海洛因中毒性脑损伤中的价值

目的 探讨HMR波谱(HMRS)及扩散张量成像(DTI)联合应用在显示海洛因中毒性脑损伤中的价值.方法 对7例海洛因依赖患者(吸毒组)及8名健康志愿者(对照组)行MR、HMRS及DTI检查.HMRS感兴趣区选在前额叶,分别测量灰质及白质中乙酰天冬氨酸(NAA)/肌酸(Cr)、胆碱(Cho)/Cr及Cho/NAA的比值.DTI感兴趣区选在胼胝体膝部(GCC)、胼胝体压部(SCC)、内囊前肢(AIC)、内囊后肢(PIC)、外囊(Ec)及前额叶白质(WMPFL),并分别测量其各向异性分数(FA)及表观扩散系数(ADC).2组间比较采用独立样本t检验.结果 所有受检者MRI均未见明显异常.IHMRS吸毒组前额叶灰质及白质中NAA/Cr比值降低,分别为1.40±0.16、1.72±0.41,对照组分别为1.57±0.09、2.08±0.21,2组差异有统计学意义(t值分别为2.183、2.190,P值均<0.05).DTI吸毒组GCC、SCC及AIC的FA值降低,分别为0.70±0.04、0.76±0.41、0.55±0.03,对照组分别为0.76±0.03、0.82±0.03、0.64±0.03,2组差异有统计学意义(t值分别为3.830、3.713、5.555,P值均<0.05);吸毒组SCC、PIC及EC的ADC值升高,分别为(8.18±0.48)×10-4(7.54±0.22)×10-4(7.72±0.30)× 10-4mm2/s,对照组分别为(7.50±0.26)×10-4、(7.15±0.20)×10-4(7.19±0.39)×10-4mm2/s,2组差异有统计学意义(t值分别为3.477、3.507、2.895,P值均<0.05).结论 联合HMRS及DTI技术可较全面地显示海洛因中毒性脑损伤早期脑灰白质改变情况.     

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。     

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.     

Diffusion tensor imaging in hydrocephalus: initial experience

PURPOSE AND BACKGROUND: Diffusion tensor imaging (DTI) is an MR imaging-based technique that provides an in vivo tool for visualization of white matter tracts. In this preliminary study, we used this technique to investigate the diffusion characteristics of white matter tracts in patients with hydrocephalus before and after surgery and compared them with age-matched volunteers. MATERIALS AND METHODS: Seven patients with different types of acute hydrocephalus (defined by acute clinical signs of increased intracranial pressure and imaging evidence of enlarged ventricles) underwent MR imaging including a DTI protocol before and after surgery for shunt placement/revision or ventriculostomy. Eight age-matched healthy subjects served as a control group. The DTI was acquired in a clinical setting that included 6 gradient directions with a b value of 1000 s/mm(2). RESULTS: Before surgery, in fiber systems lateral to the ventricles (corona radiata), the diffusion parallel to the fibers was increased (+10%) and the diffusion perpendicular to the fibers was decreased (-25%) in all patients, resulting in an overall increase in the fractional diffusion anisotropy (FA, +28%). Following surgery, the FA values approached those of control values in all except 1 patient. In the corpus callosum, the presurgery FA values in patients with hydrocephalus (HCP) were lower than those of control values, and no significant changes were seen following surgery. CONCLUSIONS: DTI can distinguish the compression characteristics of white matter before and after surgery in patients with HCP. At the acute stage of the disease, DTI characteristics point to white matter compression as a possible cause of the observed changes.     

ADC value and diffusion tensor imaging of prostate cancer: changes in carbon-ion radiotherapy

PURPOSE: To assess the apparent diffusion coefficient (ADC) value and diffusion tensor image (DTI) including fractional anisotropy (FA) of the noncancerous prostate and prostate cancer before and after carbon-ion radiotherapy (CIRT). MATERIALS AND METHODS: Nine patients with biopsy-proven prostate cancer underwent 1.5T magnetic resonance (MR) examinations. One patient with benign prostatic hypertrophy and one healthy volunteer were also examined as references. The changes in ADC values and DTI of the entire prostate calculated from b-values of 0 and 700 (s/mm(2)) were estimated between before and after CIRT. RESULTS: ADC values of prostate cancer significantly increased after CIRT by paired t-test (P < 0.01) but those of noncancerous inner gland (IG) and peripheral zone (PZ) showed no significant change. By analysis of variance, significant differences in ADC values were observed among prostate cancer and noncancerous IG and PZ before CIRT (P < 0.05). After CIRT, those significant differences had disappeared. FAs showed no significant differences in any comparisons. DTI showed changes in the direction of the main axis of the tensor in prostate cancer after CIRT. CONCLUSION: There were changes in ADC and DTI in prostate cancer after CIRT. They may be useful for monitoring prostatic structural changes under radiotherapy.     

Multiparametric tissue characterization of brain neoplasms and their recurrence using pattern classification of MR images

RATIONALE AND OBJECTIVES: Treatment of brain neoplasms can greatly benefit from better delineation of bulk neoplasm boundary and the extent and degree of more subtle neoplastic infiltration. Magnetic resonance imaging (MRI) is the primary imaging modality for evaluation before and after therapy, typically combining conventional sequences with more advanced techniques such as perfusion-weighted imaging and diffusion tensor imaging (DTI). The purpose of this study is to quantify the multiparametric imaging profile of neoplasms by integrating structural MRI and DTI via statistical image analysis methods to potentially capture complex and subtle tissue characteristics that are not obvious from any individual image or parameter. MATERIALS AND METHODS: Five structural MRI sequences, namely, B0, diffusion-weighted images, fluid-attenuated inversion recovery, T1-weighted, and gadolinium-enhanced T1-weighted, and two scalar maps computed from DTI (ie, fractional anisotropy and apparent diffusion coefficient) are used to create an intensity-based tissue profile. This is incorporated into a nonlinear pattern classification technique to create a multiparametric probabilistic tissue characterization, which is applied to data from 14 patients with newly diagnosed primary high-grade neoplasms who have not received any therapy before imaging. RESULTS: Preliminary results demonstrate that this multiparametric tissue characterization helps to better differentiate among neoplasm, edema, and healthy tissue, and to identify tissue that is likely to progress to neoplasm in the future. This has been validated on expert assessed tissue. CONCLUSION: This approach has potential applications in treatment, aiding computer-assisted surgery by determining the spatial distributions of healthy and neoplastic tissue, as well as in identifying tissue that is relatively more prone to tumor recurrence.     

多发性硬化患者弥散张量成像及其与认知功能的关系

目的: 探讨多发性硬化(MS)患者脑内病灶及脑组织的MR弥散张量成像(DTI)特点及其与认知功能的关系.材料和方法:对7例MS患者进行韦氏智力量表测查及头颅DTI检查.结果:病灶、病灶周围看似正常的组织(PWM)、看似正常的白质(NAWM)及看似正常的灰质(NAGM)较对照组相应部位脑组织的表观扩散系数(ADC)值增高,各向异性(FA)值减低.有智能损害的MS患者的NAWM、NAGM的ADC值高于智能正常的患者;而其NAGM的FA值低于智能正常的患者.结论:PWM、NAWM及NAGM组织内存在结构与功能改变,并影响认知功能.DTI有助于发现认知改变的微小结构和功能的异常.     

Diffusion tensor imaging of the corticospinal tract before and after mass resection as correlated with clinical motor findings: preliminary data

BACKGROUND AND PURPOSE: The role of diffusion tensor imaging (DTI) in neurosurgical planning and follow-up is currently being defined and needs clinical validation. To that end, we sought correlations between preoperative and postoperative DTI and clinical motor deficits in patients with space-occupying lesions involving the corticospinal tract (CST). METHODS: DTI findings in four patients with masses near the CST and not involving motor cortex were retrospectively reviewed and compared with contralateral motor strength. CST involvement was determined from anisotropy and eigenvector directional color maps. The CST was considered involved if it was substantially deviated or had decreased anisotropy. Interpretations of the DTIs were blinded to assessments of motor strength, and vice versa. RESULTS: Of the four patients with potential CST involvement before surgery, DTI confirmed CST involvement in three, all of whom had preoperative motor deficits. The patient without CST involvement on DTI had no motor deficit. After surgery, DTI showed CST preservation and normalization of the position and/or anisotropy in two of the three patients with preoperative deficits, and both of those patients had improvement in motor strength. The other patient with preoperative deficits had evidence of wallerian degeneration on DTI and had only equivocal clinical improvement. CONCLUSION: Preoperative CST involvement, as determined on DTI, was predictive of the presence or absence of motor deficits, and postoperative CST normalization on DTI was predictive of clinical improvement. Further study is warranted to define the role of DTI in planning tumor resections and predicting postoperative motor function.     

Toward a practical protocol for human optic nerve DTI with EPI geometric distortion correction

Purpose

To develop a practical protocol for diffusion tensor imaging (DTI) of the human optic nerve with echo planar imaging (EPI) geometric distortion correction.

Materials and Methods

A conventional DTI protocol was modified to acquire images with fat and cerebrospinal fluid (CSF) suppression and field inhomogeneity maps of contiguous coronal slices covering the whole brain. The technique was applied to healthy volunteers and multiple sclerosis patients with and without a history of unilateral optic neuritis. DTI measures and optic nerve tractography before and after geometric distortion correction were compared. Diffusion measures from left and right or from affected and unaffected eyes in different subject cohorts were reported.

Results

The image geometry after correction closely resembled reference anatomical images. Optic nerve tractography became feasible after distortion correction. The diffusion measures from the healthy volunteers were in good agreement with the literature. Statistically significant differences were found in the fractional anisotropy and orthogonal eigenvalues between affected and unaffected eyes in optic neuritis patients with poor recovery. The diffusion measures before and after geometric distortion correction were not significantly different. For cohorts without optic neuritis, the difference between diffusion measures from left and right eyes was not statistically significant.

Conclusion

The proposed technique could provide a practical DTI protocol to study the human optic nerve. J. Magn. Reson. Imaging 2009;30:699–707. © 2009 Wiley‐Liss, Inc.     

脑星形胶质细胞瘤周围区域的磁共振DTI研究

目的：采用扩散张量成像（DTI）技术研究脑星形胶质细胞瘤周围区域的细微结构改变,探讨其确定肿瘤边界的价值。方法：将28例经手术病理证实的星形胶质细胞瘤患者分为低度恶性星形细胞瘤和恶性胶质瘤两组。利用DTI检测肿瘤区、肿瘤周围区和健侧脑组织区,计算各向异性（FA）和平均扩散系数（ADC）及脑白质纤维束的情况。结果：28例星形胶质细胞瘤的3个不同区域DTI数值有显著性差异。周围区域DTI各值的均数在低度恶性和恶性胶质瘤之间进行比较,ADC、FA值的差异均有统计学意义。FA图显示低度恶性星形胶质细胞瘤多以推移周围邻近白质为主,与邻近白质边界清楚,而恶性胶质瘤组则以破坏与浸润白质束为主,边界相对模糊。结论：应用DTI成像可能对确定星形胶质细胞瘤的边界具有一定的临床意义。     

弥散张量成像对早期帕金森病的研究价值

目的:探讨弥散张量成像(DTI)对早期原发性单侧症状帕金森病(PD)的诊断价值,为临床诊断及疾病分级提供参考及依据.方法:26例未经治疗的早期原发性单侧症状帕金森病患者为PD组,20例健康正常人为对照组,对两组均进行常规磁共振(MRI)及DTI检查,检查前对PD组均进行UPDRS评分及Hoehn&Yahr分期,DTI测量双侧黑质、壳核、尾状核头部及丘脑的各向异性分数(FA值)及表观弥散系数(ADC值).结果:PD组症状对侧黑质的FA值较同侧及对照组双侧均值显著减低(t=2.987,P=0.004;t=3.072,P=0.003),其余感兴趣区FA值及所有感兴趣区ADC值组内及组间均无明显差异;症状对侧黑质FA值与UPDRS评分无明显相关性.结论:单侧症状PD患者症状对侧黑质早期就存在FA值减低,DTI技术可作为早期帕金森病诊断的一项无创性检查方法,但对判断疾病的严重程度无帮助.     

Diffusion tensor imaging and fiber tractography of C6 rat glioma

PURPOSE: To apply diffusion tensor images using 30 noncollinear directions for diffusion-weighted gradient schemes to characterize diffusion tensor imaging (DTI) features associated with C6 glioma-bearing rat brains, and ideally visualize fiber tractography datasets. MATERIALS AND METHODS: Fiber tractographies of normal male Fischer 344 rat brains were constructed from DTI datasets acquired with a 30 noncollinear diffusion gradient scheme. Cultured C6 cell were intracranially injected into the cortex of male Fischer 344 rats. The time course of the tumor growth was monitored with DTI and fiber tractography using diffusion-weighting gradients in 30 noncollinear directions. RESULTS: Fiber tractographies through the corpus callosum (CC) were easily visualized with the 30-direction gradient scheme, and the fiber trajectories of the motor cortex and striatum were well represented in normal rats. Fiber tractography indicated that the neuronal fibers of the CC were compressed or disappeared by growing C6 glioma, which affected surrounding brain tissue. CONCLUSION: We have demonstrated in this study that fiber tractography with the 30 noncollinear diffusion gradient scheme method can be used to help provide a better understanding regarding the influence of a tumor on the surrounding regions of normal brain tissue in vivo.