磁共振弥散张量成像在脑血管病中的应用

磁共振弥散张量成像（DTI）是一种较新的成像技术,主要用于评估影响脑白质尤其是白质纤维束完整性的疾病,是当前惟一的一种能有效观察和追踪脑白质纤维束的非侵入性检查方法。该技术可定量分析病变组织和正常组织的弥散特征,直观显示颅内病变与白质纤维之间的关系,为诊断疾病和判断预后提供更多的信息。本文就DTI基本原理及其在脑血管病中的临床应用作一概述。     

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。     

磁共振弥散张量成像对功能区脑肿瘤手术的参考价值

[目的]评价磁共振弥散张量成像(DTI)对功能区脑肿瘤手术的指导意义和应用价值.[方法]对25例患者行头部DTI检查,立体显示肿瘤与脑白质纤维束的关系,术前评估,设计手术入路,对所有病例行显微外科肿瘤切除手术治疗.[结果]本组脑肿瘤中累及脑白质纤维束区域主要位于锥体束和内囊,其中脑白质纤维束破坏13例,移位12例.肿瘤全切除11例,次全切除14例,无手术死亡.术前存在脑白质纤维束受累所致的神经功能阳性体征者术后改善13例,无变化者10例,加重2例.[结论]DTI能够清晰显示脑肿瘤对白质纤维束的累及关系,对神经外科优化手术设计、决定手术切除范围和评估术后神经功能具有指导意义.     

弓形束成像技术在语言功能研究中的应用

一、弥散张量纤维束成像技术 弥散张量纤维束成像是以弥散张量成像(diffusion tensor imaging,DTI)为基础的纤维束重建技术,其主要原理是根据各个体素中水分子的主要弥散方向,判断最小弥散阻抗的传导路径,达到重建白质纤维通路的目的.弥散张量纤维束成像是目前显示活体脑白质结构的唯一方法[1],该方法能够高度可重复地重建出与解剖结构一致的白质结构.     

弥散张量纤维束成像在高血压性脑出血中的初步应用

目的 应用磁共振弥散张量纤维束成像技术观察基底节区高血压性脑出血内囊白质纤维束的受损情况,探讨弥散张量成像纤维束技术在高血压性脑出血中的临床应用价值.方法 于入院时采用Brunnstrom评分法对20例基底节区高血压性脑出血患者偏瘫肢体运动功能进行评价,对所有患者进行磁共振弥散张量成像检查,应用日本东京大学的Volume-one 1.72下的Dtv.Ⅱ.R2软件进行白质纤维束成像,比较观察双侧内囊白质纤维束形态.结果 健侧内囊白质纤维束解剖形态与正常人大致相吻合,患侧内囊白质纤维束则受血肿的侵犯,表现为受压、移位、不同程度的破坏;患侧皮质脊髓束受损级别和患肢肌力有明显相关性(r's=-0.8911,P<0.05).结论 通过弥散张量纤维束成像可以了解基底节区高血压性脑出血患者内囊白质纤维束的损伤情况,这有助于临床医生全面掌握病情.     

磁共振弥散张量成像在急性脑梗死患者运动功能预后判断临床价值研究

目的判断磁共振弥散张量成像(DTI)在急性脑梗死患者运动功能预后的临床价值。方法对30例急性脑梗死患者行磁共振(MRI)和DTI影像学检查,检测参数为部分各向异性值(FA),同时对脑梗死患者进行Brunnstrom评分。结果脑梗死患者患侧白质FA值显著低于健侧(P<0.01),统计学分析结果显示患侧皮质脊髓束损伤程度与偏瘫侧肌力明显相关(Y=0.774,P<0.05),30例患者DTI分级与肌力减弱程度呈正相关(rs=0.75,P<0.05)。结论 DTI技术能清楚显示脑梗死白质纤维束的受累程度,能够较好的评价患者运动功能损伤,对急性脑梗死患者运动功能预后判断有重要临床价值。     

弥散张量成像技术对胶质瘤侵袭性的评价

弥散张量成像技术(DTI)是一种白质纤维束成像的无创新技术,不仅可在大体解剖结构上显示白质纤维与胶质瘤的关系,而且可在显微结构水平反映胶质瘤细胞对白质纤维的侵袭破坏程度。本文就DTI在评价胶质瘤侵袭性中的应用进行综述。     

脑基底核区缺血及出血性卒中致皮质脊髓束损伤：评价与肌力恢复的相关性

目的 利用磁共振扩散张量成像(DTI)及扩散张量纤维束成像(DTT)评价缺血性脑缺血卒中所致皮质脊髓束(CST)损伤程度,及与运动功能的关系。方法 对15例急性期大脑中动脉供血区缺血性脑卒中病人进行常规MR、DTI和DTT检查,对数据进行离线后处理,采用dTV.II软件处理,获得FA图及方向编码彩色图,并重建双侧皮质脊髓束3D纤维束图。对梗死区及健侧相应区域白质进行FA测量。采用Brunnstorm标准判断脑卒中患者患手肌力。结果 在脑卒中病人梗死区FA值显著低于健侧,两侧相比差异有显著性意义(t＝-6.3333,P<0.0000)。病变侧皮质脊髓束表现为受压、变形、移位和中断,皮质脊髓束损伤程度与患手肌力级别经检验有显著负相关关系（rs=-0.97361,P<0.0001）,CST的损伤情况与运动功能的恢复有良好的相关。结论 CST损伤严重程度与运动功能的恢复相关,DTI和DTT对观察CST的损害程度、预测恢复程度、指导临床康复治疗具有重要的价值。     

白质纤维束的弥散张量成像在脑胶质瘤外科的应用

目的:探讨MRI弥散张量成像(DTI)显示脑白质纤维束在脑胶质瘤外科的意义。方法:2003年9月至2004年12月,30例脑内肿瘤患者接受术前常规头颅MRI序列检查的同时,进行DTI序列扫描,经后处理得到各向异性分数(FA)图显示脑白质纤维束结构,并进行FA值、图像信号强度及对比度的分析研究。结果:所有病例均成功实现包括DTI序列扫描以及FA图像生成。脑白质纤维束显示为显著的高信号结构;灰质显示为等信号;脑脊液显示为低信号;脑内肿瘤呈类圆形等、低信号灶;肿瘤周围间质水肿区白质纤维束仍能在DTI的FA图上显像。DTI的FA图像对于脑白质纤维束显影的信号对比度明显优于常规的T1W图像。结论:DTI影像可以清晰显示脑白质纤维束的形态结构。结合其他序列的MRI应用于脑胶质瘤的术前诊断,可以准确判别肿瘤和周围脑白质纤维束的毗邻关系,对脑胶质瘤手术方案设计以及术后神经功能障碍的预测与预防具有重要意义。     

精神分裂症患者钩束的弥散张量成像研究

钩束是连接额叶与颞叶之间、额叶和颞顶部语言区之间的白质纤维。弥散张量成像（DTI,可以根据组织内水分子的弥散特性来检测白质纤维结构的异常改变。现将精神分裂症患者钧束的弥散张量成像研究作一综述。     

Diffusion tensor imaging and tractography of central pontine myelinolysis

OBJECTIVES: To illustrate the value of diffusion tensor imaging and tractography in the diagnosis and follow-up of central pontine myelinolysis. CASE REPORT: We report a case of central pontine myelinolysis in a 29 year old woman, also anorexic, studied using MR Diffusion Tensor Imaging (DTI) and Fibre Tracking (FT) focused on the pons, and compared with the studies of 5 normal volunteers. Tractography showed a swollen aspect of the right corticospinal fiber tract correlating with mild left lower extremity deficit at clinical evaluation. The pontine fibers were posteriorly displaced but intact. The sensory tracts were also intact. Apparent Diffusion Coefficient values were increased and Fractional Anisotropy was decreased in the lesions. Follow up imaging showed persistent abnormal ADC and FA values in the pons although the left cortico-spinal tract returned to normal, consistent with the clinical outcome. CONCLUSION: Diffusion Tensor Imaging MR and Fiber tractography are a new method to analyse white matter tracts. It can be used to prospectively evaluate the location of white matter tract lesions at the acute phase of central pontine myelinolysis and follow up.     

白质纤维束示踪成像技术在高血压脑出血中的初步应用

目的探讨白质纤维束示踪成像技术在高血压脑出血中的临床应用价值。方法对我院8例急性期情况稳定的高血压脑出血患者进行磁共振弥散张量成像,应用日本东京大学的Volume-one1.72和Diffusion Ten-sor Visualizer(dTV)软件进行三维白质纤维束示踪成像,观察以内囊为主的白质纤维束的压迫、推移、破坏情况。结果8例患者均行磁共振弥散张量成像并行内囊白质纤维束示踪成像,可清楚看到内囊白质纤维束受血肿压迫、推移、破坏情况,由患侧内囊追踪到的相对纤维束条目数少于健侧内囊(P<0.005)。结论白质纤维束示踪成像技术可以清楚显示高血压脑出血后内囊白质纤维束的受累情况。     

精神发育迟滞脑白质磁共振弥散张量成像研究

目的:通过检查精神发育迟滞(MR)患者脑白质磁共振弥散张量成像(DTI)来了解该病患者脑白质发育情况,以寻找MR患者新的诊断手段,并探讨发病机制中脑白质纤维束发育障碍的根据.方法:用DTI扫描技术对45例MR患者作了皮质脊髓束、枕额束、扣带束、胼胝体束的检查.结果:45例患者中仅4例未发现异常,枕额束有异常为27例,皮...     

Diffusion tensor imaging in brainstem tuberculoma

Integrity of descending white matter tracts can be evaluated by diffusion tensor imaging. In rim-enhancing intraparenchymal lesions, this technique can assist in the differentiation of demyelinating disease from tumor or abscess. Diffusion tensor imaging characteristics of tuberculoma have not been previously reported to our knowledge. A patient with headaches, dizziness, and mild left-sided weakness underwent MRI with diffusion tensor imaging. A large, rim-enhancing lesion within the pons was discovered, which subsequently was diagnosed as tuberculoma. Tractography maps prepared from diffusion tensor imaging data revealed predominantly displaced descending fiber tracts in the region of the rim-enhancing lesion. A few tracts adjacent to the lesion appeared truncated, and this abnormal finding correlated to the patient’s clinical deficit. The tractography characteristics of diffusion tensor imaging in this patient potentially are distinct from those seen with demyelinating lesions, which may show more extensive tract truncation. Together with the consonance of exam findings and tract truncation seen in this patient, tractography may prove useful in the diagnosis of suspected tuberculoma.     

Diffusion Tensor Tractography in Hypothyroidism and its Correlation with Memory Function

Diffusion tensor tractography (DTT) was performed to determine the microstructural changes in the white matter fibre tracts of hypothyroid patients compared to controls and to correlate these changes with memory dysfunction scores. DTT and Postgraduate Institute Memory Scale test were performed in eight hypothyroid patients and eight healthy controls. Diffusion tensor imaging (DTI) measures [fractional anisotropy (FA) and mean diffusivity (MD)] from all of the major cerebral tracts were calculated and a comparison was made between the patient group and controls. Pearson's correlation was performed between Memory Dysfunction score and DTI measures. Significant changes in DTI measures were observed in various white matter fibre tracts in hypothyroid patients compared to controls. In hypothyroid patients, an inverse correlation of Memory Dysfunction score with FA was observed in the right and left inferior fronto‐occipital fasciculus, whereas a positive correlation with MD was observed in the right anterior thalamic radiation among all white matter tracts. These findings suggest that microstructural changes in white matter fibres may contribute to the underlying dysfunction in memory in hypothyroid patients.     

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。     

Diffusion tensor magnetic resonance imaging tractography in cognitive disorders

PURPOSE OF REVIEW: The advent of novel techniques for tracing connections in vivo, such as diffusion tensor magnetic resonance imaging tractography, allows us, for the first time in the human brain, to study the microstructural integrity of white matter fibres and perform virtual dissections of large scale neurocognitive networks. This review will outline the advantages and limitations of applying diffusion tensor magnetic resonance imaging to the study of cognitive and behavioural disorders in neurology and psychiatry. RECENT FINDINGS: Diffusion tensor magnetic resonance imaging has been used to re-explore the anatomy of white matter tracts in the living human brain and to create connectional models of brain function. Beyond its application to classical disconnection syndromes, diffusion tensor magnetic resonance imaging is becoming an important tool to extend the disconnectionist paradigm to neurodevelopmental and neurodegenerative disorders. SUMMARY: For the first time, we are able to correlate disconnecting lesions with clinical symptoms in vivo and test the disconnection mechanism directly in cognitive disorders. With diffusion tensor magnetic resonance imaging tractography alone and in combination with other magnetic resonance imaging techniques, researchers are able to detect abnormalities in white matter that are not visible with conventional magnetic resonance imaging.     

Correlation between muscular strength and basal nuclei ischemic/hemorrhagic stroke-induced corticospinal tract injury, as detected by diffusion tensor imaging and tractography

BACKGROUND:Conventional neuroimaging diagnosis does not assist with the monitoring or evaluation of basal nuclei ischemic and hemorrhagic stroke,or motor functional recovery.Magnetic resonance,diffusion tensor imaging,and diffusion tensor tractography have all been used to observe features of cerebral white matter fibrous structures.In addition,diffusion tensor tractography is the only non-invasive imaging method to display the corticospinal tract in vivo.OBJECTIVE:To evaluate the impairment degree of corticospinal tract induced by basal nuclei ischemic and hemorrhagic stroke through the use of magnetic resonance,diffusion tensor imaging,and diffusion tensor tractography,and to analyze the correlation to muscular strength.DESIGN,TIME AND SETTING:A retrospective case analysis was performed at the Department of Medical Imaging,Neurology and Neurosurgery,Fuzhou General Hospital of Nanjing Military Area Command of Chinese PLA between November 2002 and June 2008.PARTICIPANTS:A total of 15 patients with acute or subacute cerebral ischemic stroke and nine with hemorrhagic stroke in the basal nuclei were selected.METHODS:Magnetic resonance,diffusion tensor imaging,and diffusion tensor tractography results and data were analyzed.Fractional anisotropy and directionally encoded color maps were obtained.Three-dimensional tractography of bilateral corticospinal tract was created,and corticospinal tract integrity was graded.Fractional anisotropy of infarct region and corresponding contralateral normal regions were measured,and hematoma volume in hemorrhagic stroke patients was determined.Hand motor function ability was evaluated using Brunstorm criteria.MAIN OUTCOME MEASURES:Fractional anisotropy of infarct region and corresponding contralateral normal regions; hematoma volume in hemorrhagic stroke patients; correlation between muscular strength and corticospinal tract impairment degree in ischemic stroke and hemorrhagic stroke patients before and after treatment.RESULTS:In ischemic stroke patients,the fractional anisotropy value was significantly lower in the infarct area of white matter than in the normal hemisphere(P < 0.01).The impairment degree of corticospinal tract negatively correlated with muscular strength of the corresponding hand(r=-0.97,P < 0.01).The hematoma volume of hemorrhagic stroke patients significantly negatively correlated with Spearman test results for muscular strength of the corresponding hand(r=-0.88,P < 0.01).CONCLUSION:Corticospinal tract impairment severity negatively correlated with muscular strength and motor functional recovery,which suggested that diffusion tensor imaging and diffusion tensor tractography could be used to evaluate corticospinal tract motor function.     

功能MRI和弥散张量纤维束示踪成像联合应用是评估脑出血患者躯体感觉功能恢复的有用工具？1例报告

研究背景：目前对中风之后的身体感觉机能障碍了解很少。 研究目的：我们试图证明应用功能性磁共振成像(fMRI)和扩散张量纤维束示踪(DTT)能使颅内出血(ICH)患者的身体感觉机能障碍康复。 研究设计,时间和地点：从2008年6月到11月在理疗与康复教研室进行病例研究。 参与人员：55岁的女患者,她起先右侧皮质和辐射冠自发性的颅内出血,造成左身严重的身体感觉机能障碍。 研究方法：应用PHILIPS公司Gyroscan Intera 1 .5 T扩散张量纤维束示踪系统和磁共振成像系统从开始之后的3-7周进行两个纵向评估。扩散张量纤维束示踪以分次的各向异性<0.2作为最终标准,磁共振成像通过手的触摸和被动运动来完成. 主要成果: 我们发现扩散张量纤维束示踪过程和磁共振成像上的皮质激活是伴随着身体感觉功能的恢复一起的. 研究结果: 受作用的一边在开始之后的第7周身体感觉功能会恢复到接近于正常的状态.从第3到7周的功能性磁共振成像上我们发现, 位于另一侧初级感觉皮质中心的皮质被活化.然而,在第3周的磁共振成像上却没有发生皮质激活功能而被动运动的激活功能在第7周比第3周显示的有所增强.在第3周对受创一侧(右侧)扩散张量纤维束示踪中我们没能发现内侧丘系.第7周的内侧丘系示踪, 一个内侧丘系沿着丘系内侧从辐射冠上升到初级感觉皮质. 结论: 我们证明了在这位患者的身体感觉机能恢复中应用到了功能性磁共振成像(fMRI)和扩散张量纤维束示踪(DTT). 我们推断在研究中风病人的身体感觉机能障碍的康复中功能性磁共振成像(fMRI)和扩散张量纤维束示踪(DTT)是有效的方法.     

Diffusion tensor MRI of Wallerian degeneration: a case report

Diffusion tensor imaging allows a 3D analysis of water molecular motion and an exploration of white matter tracts integrity and orientation. We report a diffusion tensor study of wallerian degeneration of the corticospinal tract following a capsulo-lenticular hemorrhage in a 49-year old man. Reduced anisotropy (loss of fiber coherence) with preserved diffusivity of the damaged corticospinal tract was observed. This highlights the feasibility of diffusion tensor imaging on clinical MR units and its ability to quantify the degree of white matter tract destruction.