Microstructural basis of contusion expansion in traumatic brain injury: insights from diffusion tensor imaging

Traumatic brain injury (TBI) is often exacerbated by events that lead to secondary brain injury, and represent potentially modifiable causes of mortality and morbidity. Diffusion tensor imaging was used to characterize tissue at-risk in a group of 35 patients scanned at a median of 50 hours after injury. Injury progression was assessed in a subset of 16 patients with two scans. All contusions within the first few days of injury showed a core of restricted diffusion, surrounded by an area of raised apparent diffusion coefficient (ADC). In addition to these two well-defined regions, a thinner rim of reduced ADC was observed surrounding the region of increased ADC in 91% of patients scanned within the first 3 days after injury. In patients who underwent serial imaging, the rim of ADC hypointensity was subsumed into the high ADC region as the contusion enlarged. Overall contusion enlargement tended to be more frequent with early lesions, but its extent was unrelated to the time of initial imaging, initial contusion size, or the presence of hemostatic abnormalities. This rim of hypointensity may characterize a region of microvascular failure resulting in cytotoxic edema, and may represent a ‘traumatic penumbra'' which may be rescued by effective therapy.     

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.     

弥散张量纤维束成像在脑深部肿瘤手术中的应用

目的探讨弥散张量纤维束成像（DTT）在指导脑深部肿瘤手术中的价值。方法对25例脑深部肿瘤病人（实验组）利用DTT对肿瘤与毗邻纤维束的位置关系及纤维束状态进行评估,结合常规MRI设计手术入路及切除范围;另24例病人（对照组）仅根据常规MRI设计手术人路及切除范围。对两组肿瘤的全切除率及术后致残率进行对比分析。结果实验组中,肿瘤全切除18例,部分切除7例;术后出现神经功能缺损或障碍加重3例。对照组中,肿瘤全切除13例,部分切除11例;术后出现神经功能缺损或障碍加重11例。两组肿瘤全切除率差异无统计学意义（P〉0．05）,而对照组术后致残率明显高于实验组（P〈0．01）。结论DTT能清楚显示脑深部肿瘤与毗邻纤维束的位置关系及纤维束被侵犯的程度,有助于设计合理手术入路及切除范围．对最大程度切除肿瘤同时减少术后功能缺损具有重要作用。     

Diffusion tensor imaging brain structural clustering patterns in major depressive disorder

Using magnetic resonance diffusion tensor imaging data from 45 patients with major depressive disorder (MDD) and 41 healthy controls (HCs), network indices based on a 246‐region Brainnetcome Atlas were investigated in the two groups, and in the MDD subgroups that were subgrouped based on their duration of the disease. Correlation between the network indices and the duration of illness was also examined. Differences were observed between the MDD_S subgroup (short disease duration) and the HC group, but not between the MDD and HC groups. Compared with the HCs, the clustering coefficient (CC) values of MDD_S were higher in precentral gyrus, and caudal lingual gyrus; the CC of MDD_L subgroup (long disease duration) was higher in postcentral gyrus and dorsal granular insula in the right hemisphere. Network resilience analyses showed that the MDD_S group was higher than the HC group, representing relatively more randomized networks in the diseased brains. The correlation analyses showed that the caudal lingual gyrus in the right hemisphere and the rostral lingual gyrus in the left hemisphere were particularly correlated with disease duration. The analyses showed that duration of the illness appears to have an impact on the networking patterns. Networking abnormalities in MDD patients could be blurred or hidden by the heterogeneity of the MDD clinical subgroups. Brain plasticity may introduce a recovery effect to the abnormal network patterns seen in patients with a relative short term of the illness, as the abnormalities may disappear in MDD_L.     

DTI对脑深部胶质瘤手术入路设计的临床意义

目的探讨术前DTI检查及脑白质纤维束重建对设计脑深部胶质瘤手术入路的临床意义。方法随机选取脑深部胶质瘤病人60例,30例术前仅行MRI检查作为对照组,根据易达及避开功能区的原则选择手术入路;30例术前行MRI+DTI检查作为DTI组,行脑白质纤维三维重建,明确脑白质纤维束与肿瘤的三维空间结构关系,以避开重要纤维束及功能区的原则设计手术入路;比较两组病人术后1个月KPS评分的差异。结果对照组镜下全切19例,次全切7例,部分切除4例,全切率63.3%;DTI组镜下全切18例,次全切7例,部分切除5例,全切率60.0%。两组镜下全切率比较,差异无统计学意义(P0.05)。对照组KPS评分为(81.67±20.69)分,DTI组KPS评分为(91.67±16.42)分;两组KPS评分比较,差异有统计学意义(P0.05)。结论术前DTI检查及脑白质纤维束重建对设计脑深部胶质瘤手术入路有重要指导意义,起到保护重要白质纤维束和降低病残率的作用。     

Regional alterations of brain microstructure in Parkinson's disease using diffusion tensor imaging

This study tested the hypothesis that diffusion tensor imaging can detect alteration in microscopic integrity of white matter and basal ganglia regions known to be involved in Parkinson's disease (PD) pathology. It was also hypothesized that there is an association between diffusion abnormality and PD severity and subtype. Diffusion tensor imaging at 4 Tesla was obtained in 12 PD and 20 control subjects, and measures of fractional anisotropy and mean diffusivity were evaluated using both region‐of‐interest and voxel‐based methods. Movement deficits and subtypes in PD subjects were assessed using the Motor Subscale (Part III) of the Unified Parkinson's Disease Rating Scale. Reduced fractional anisotropy (P < .05, corrected) was found in PD subjects in regions related to the precentral gyrus, substantia nigra, putamen, posterior striatum, frontal lobe, and the supplementary motor areas. Reduced fractional anisotropy in the substantia nigra correlated (P < .05, corrected) with the increased rating scale motor scores. Significant spatial correlations between fractional anisotropy alterations in the putamen and other PD‐affected regions were also found in the context of PD subtypes index analysis. Our data suggest that microstructural alterations detected with diffusion tensor might serve as a potential biomarker for PD. © 2011 Movement Disorder Society     

弥散张量成像在胶质瘤术前评估中的应用

目的探讨磁共振弥散张量成像在胶质瘤术前评估中的价值。方法对19例经病理证实胶质瘤的患者术前进行弥散张量成像,观察白质纤维束与肿瘤的关系,测量肿瘤实质区和周边水肿区的FA值。结果颅内胶质瘤所致白质纤维异常有三种基本改变：移位、浸润和破坏。19例中10例移位伴破坏,5例单纯浸润,4例浸润伴破坏;肿瘤的实质区和周边水肿区的FA值与对侧大脑白质FA值相比较存在显著差异（P〈0．05）。肿瘤的实质区和周边水肿区FA值之间无统计学显著差异（P〉0．05）。结论弥散张量成像技术可以显示胶质瘤与周围白质纤维束的关系,FA值不能区分肿瘤实质与周边水肿区。     

Acute white matter changes following sport‐related concussion: A serial diffusion tensor and diffusion kurtosis tensor imaging study

Recent neuroimaging studies have suggested that following sport‐related concussion (SRC) physiological brain alterations may persist after an athlete has shown full symptom recovery. Diffusion MRI is a versatile technique to study white matter injury following SRC, yet serial follow‐up studies in the very acute stages following SRC utilizing a comprehensive set of diffusion metrics are lacking. The aim of the current study was to characterize white matter changes within 24 hours of concussion in a group of high school and collegiate athletes, using Diffusion Tensor and Diffusion Kurtosis Tensor metrics. Participants were reassessed a week later. At 24 hours post‐injury, the concussed group reported significantly more concussion symptoms than a well‐matched control group and demonstrated poorer performance on a cognitive screening measure, yet these differences were nonsignificant at the 8‐day follow‐up. Similarly, within 24‐hours after injury, the concussed group exhibited a widespread decrease in mean diffusivity, increased axial kurtosis and, to a lesser extent, decreased axial and radial diffusivities compared with control subjects. At 8 days post injury, the differences in these diffusion metrics were even more widespread in the injured athletes, despite improvement of symptoms and cognitive performance. These MRI findings suggest that the athletes might not have reached full physiological recovery a week after the injury. These findings have significant implications for the management of SRC because allowing an athlete to return to play before the brain has fully recovered from injury may have negative consequences. Hum Brain Mapp 37:3821–3834, 2016. © 2016 Wiley Periodicals, Inc .     

Memory retrieval brain–behavior disconnection in mild traumatic brain injury: A magnetoencephalography and diffusion tensor imaging study

Mild traumatic brain (mTBI) injury is often associated with long‐term cognitive and behavioral complications, including an increased risk of memory impairment. Current research challenges include a lack of cross‐modal convergence regarding the underlying neural–behavioral mechanisms of mTBI, which hinders therapeutics and outcome management for this frequently under‐treated and vulnerable population. We used multi‐modality imaging methods including magnetoencephalography (MEG) and diffusion tensor imaging (DTI) to investigate brain–behavior impairment in mTBI related to working memory. A total of 41 participants were recruited, including 23 patients with a first‐time mTBI imaged within 3 months of injury (all male, age = 29.9, SD = 6.9), and 18 control participants (all male, age = 27.3, SD = 5.3). Whole‐brain statistics revealed spatially concomitant functional–structural disruptions in brain–behavior interactions in working memory in the mTBI group compared with the control group. These disruptions are located in the hippocampal–prefrontal region and, additionally, in the amygdala (measured by MEG neural activation and DTI measures of fractional anisotropy in relation to working memory performance; p < .05, two‐way ANCOVA, nonparametric permutations, corrected). Impaired brain–behavior connections found in the hippocampal–prefrontal and amygdala circuits indicate brain dysregulation of memory, which may leave mTBI patients vulnerable to increased environmental demands exerting memory resources, leading to related cognitive and emotional psychopathologies. The findings yield clinical implications and highlight a need for early rehabilitation after mTBI, including attention‐ and sensory‐based behavioral exercises.     

Dementia in Parkinson's disease: diffusion tensor imaging

OBJECTIVE: Dementia occurs frequently in patients with Parkinson's disease (PD). However, the nature of the dementing process remains controversial. We evaluated various cognitive functions in patients with PD, compared fractional anisotropy (FA) values between PD patients with and without dementia. METHODS: Thirty-seven consecutive patients with Hoehn-Yahr stage III or IV PD participated in this study. Patients were divided into two groups: (i) PD with dementia group (PDD) and (ii) PD without dementia group (PDND). There were 11 PDD and 26 PDND cases. Ten controls were also studied. RESULTS: The PDD group showed significant FA reduction in the bilateral posterior cingulate bundles compared with PDND. FA values in the left posterior cingulate bundle showed significant correlations with many cognitive parameters. INTERPRETATION: Our results showed that the posterior cingulate areas play some important roles in the dementing process in PDD. However, as the pathological processes responsible for dementia in PD patients may be multifaceted, further studies are necessary.     

应用弥散张量成像实现神经纤维追踪的方法*☆

背景：目前的神经纤维追踪方法众说纷纭,不同的追踪方法往往对数据的要求比较严格,格式比较单一,并且在特定的条件下,才能进行纤维追踪,但都没有统一可执行标准。因此需要研究一种简便通用的神经纤维追踪处理方法。 目的：提出一种简便通用,并且可以在不同的数据采集方法情况下,转变为固定的数据采集格式的弥散张量神经纤维追踪方法。 方法：首先采用MRIcro软件在原始DTI图像上,找出梯度因子b值,组成梯度方向文件并把DICOM原始文件软件转换成Analyze格式文件,然后利用SPM软件对格式文件标准化,最后采用DTI-track软件进行神经纤维追踪处理。 结果与结论：通过对DTI图像进行处理,证明该方法能有效的得出扩散梯度因子b值文件,并且能把不同的DTI数据转变为统一的格式进行DTI处理,得到预期的DTI纤维追踪图像,为DTI研究提供了一个简便有效的具体实现方法。 关键词：弥散张量成像;纤维追踪;扩散梯度因子;神经纤维;功能磁共振     

The effect of meditation on brain structure: cortical thickness mapping and diffusion tensor imaging

A convergent line of neuroscientific evidence suggests that meditation alters the functional and structural plasticity of distributed neural processes underlying attention and emotion. The purpose of this study was to examine the brain structural differences between a well-matched sample of long-term meditators and controls. We employed whole-brain cortical thickness analysis based on magnetic resonance imaging, and diffusion tensor imaging to quantify white matter integrity in the brains of 46 experienced meditators compared with 46 matched meditation-naïve volunteers. Meditators, compared with controls, showed significantly greater cortical thickness in the anterior regions of the brain, located in frontal and temporal areas, including the medial prefrontal cortex, superior frontal cortex, temporal pole and the middle and interior temporal cortices. Significantly thinner cortical thickness was found in the posterior regions of the brain, located in the parietal and occipital areas, including the postcentral cortex, inferior parietal cortex, middle occipital cortex and posterior cingulate cortex. Moreover, in the region adjacent to the medial prefrontal cortex, both higher fractional anisotropy values and greater cortical thickness were observed. Our findings suggest that long-term meditators have structural differences in both gray and white matter.     

Relationship between suicidality and impulsivity in bipolar I disorder: a diffusion tensor imaging study

Mahon K, Burdick KE, Wu J, Ardekani BA, Szeszko PR. Relationship between suicidality and impulsivity in bipolar I disorder: a diffusion tensor imaging study.
Bipolar Disord 2012: 14: 80–89. © 2012 The Authors.
Journal compilation © 2012 John Wiley & Sons A/S. Background: Impulsivity is characteristic of individuals with bipolar disorder and may be a contributing factor to the high rate of suicide in patients with this disorder. Although white matter abnormalities have been implicated in the pathophysiology of bipolar disorder, their relationship to impulsivity and suicidality in this disorder has not been well‐investigated. Methods: Diffusion tensor imaging scans were acquired in 14 bipolar disorder patients with a prior suicide attempt, 15 bipolar disorder patients with no prior suicide attempt, and 15 healthy volunteers. Bipolar disorder patients received clinical assessments including measures of impulsivity, depression, mania, and anxiety. Images were processed using the Tract‐Based Spatial Statistics method in the FSL software package. Results: Bipolar disorder patients with a prior suicide attempt had lower fractional anisotropy (FA) within the left orbital frontal white matter (p < 0.05, corrected) and higher overall impulsivity compared to patients without a previous suicide attempt. Among patients with a prior suicide attempt, FA in the orbital frontal white matter region correlated inversely with motor impulsivity. Conclusions: Abnormal orbital frontal white matter may play a role in impulsive and suicidal behavior among patients with bipolar disorder.     

人脑皮质脊髓束的年龄相关变化

We don't have Chinese abstract. However, If you need abstract in Chinese. I'll make the abstract in chinese and attach it     

Use of diffusion tensor imaging to assess the impact of normobaric hyperoxia within at-risk pericontusional tissue after traumatic brain injury

Ischemia and metabolic dysfunction remain important causes of neuronal loss after head injury, and we have shown that normobaric hyperoxia may rescue such metabolic compromise. This study examines the impact of hyperoxia within injured brain using diffusion tensor imaging (DTI). Fourteen patients underwent DTI at baseline and after 1 hour of 80% oxygen. Using the apparent diffusion coefficient (ADC) we assessed the impact of hyperoxia within contusions and a 1 cm border zone of normal appearing pericontusion, and within a rim of perilesional reduced ADC consistent with cytotoxic edema and metabolic compromise. Seven healthy volunteers underwent imaging at 21%, 60%, and 100% oxygen. In volunteers there was no ADC change with hyperoxia, and contusion and pericontusion ADC values were higher than volunteers (P<0.01). There was no ADC change after hyperoxia within contusion, but an increase within pericontusion (P<0.05). We identified a rim of perilesional cytotoxic edema in 13 patients, and hyperoxia resulted in an ADC increase towards normal (P=0.02). We demonstrate that hyperoxia may result in benefit within the perilesional rim of cytotoxic edema. Future studies should address whether a longer period of hyperoxia has a favorable impact on the evolution of tissue injury.     

弥散张量成像在脑深部肿瘤术前评估中的应用

目的 探讨弥散张量成像(DTI)在脑深部肿瘤术前评估和手术设计中的作用.方法 回顾性分析20例脑深部肿瘤病人的临床资料,利用各向异性分数(FA)图和纤维示踪图(DTT),观察白质纤维束结构、走行及其与肿瘤的毗邻关系,测量病侧白质纤维束及其对应健侧白质纤维束的FA值、弥散系数(ADC)值.结果 白质纤维束单纯推移5例,单纯破坏7例,推移并破坏8例.单纯破坏、推移并破坏者.其病侧与健侧FA值、ADC值比较均有显著差异(P <0.05);而单纯推移者,其病侧与健侧队值、ADC值比较无显著差异(P >0.05).肿瘤全切除15例,次全切除3例,部分切除2例.12例随访6个月-2年,平均1年.正常工作、学习8例,生活自理但未参加工作3例,死亡1例.结论 DTI有助于准确判断肿瘤与周围白质纤维束的毗邻关系,对脑深部肿瘤术前评估和手术设计有重要指导意义.     

Model-based variational smoothing and segmentation for diffusion tensor imaging in the brain

This article applies a unified approach to variational smoothing and segmentation to brain diffusion tensor image data along user-selected attributes derived from the tensor, with the aim of extracting detailed brain structure information. The application of this framework simultaneously segments and denoises to produce edges and smoothed regions within the white matter of the brain that are relatively homogeneous with respect to the diffusion tensor attributes of choice. This approach enables the visualization of a smoothed, scale invariant representation of the tensor data field in a variety of diverse forms. In addition to known attributes such as fractional anisotropy, these representations include selected directional tensor components and additionally associated continuous valued edge fields that might be used for further segmentation. A comparison is presented of the results of three different data model selections with respect to their ability to resolve white matter structure. The resulting images are integrated to provide better perspective of the model properties (edges, smoothed image, and so forth) and their relationship to the underlying brain anatomy. The improvement in brain image quality is illustrated both qualitatively and quantitatively, and the robust performance of the algorithm in the presence of added noise is shown. Smoothing occurs without loss of edge features because of the simultaneous segmentation aspect of the variational approach, and the output enables better delineation of tensors representative of local and long-range association, projection, and commissural fiber systems.     

缺血缺氧后5周大脑损伤患者的神经纤维束损伤：弥散张量成像证据

Hypoxic-ischemic brain injury (HI-BI) is one of the most common causes of severe neurological disability. Some studies have reported diffusion tensor imaging (DTI) findings of neonatal patients with HI-BI. However, very little is known about DTI in the adult brain. The present study reports on a 15-year-old male patient with HI-BI, who exhibited no specific focal lesions on conventional brain MRI at 5 weeks. However, neural tract injuries were revealed by DTI. Seven control subjects were also evaluated. The patient suffered from cardiac arrest due to ventricular fibrillation for a period of 10-15 minutes. At 4 weeks after onset of cardiac arrest, although he was conscious and alert, he exhibited mild quadriparesis and severe cognitive dysfunction. DTI was acquired at 5 weeks after HI-BI onset. Decreased fractional anisotropy or voxel number of neural tracts suggested partial injury of the corticospinal tract, fornix, and cingulum. Disruptions of the fornix and cingulum on DTI confirmed neural tract injury. DTI could serve as a useful tool for evaluating the state of neural tracts in patients with HI-BI.     

成人视放射弥散张量纤维束示踪成像的临床应用研究

目的 常规的影像手段对视放射纤维束的成像、分析缺乏特异性,为了弥补常规影像检查的不足,应用弥散张量成像(DTI)和弥散张量纤维束示踪成像(DTT)研究成人视放射的各向异性程度和视放射纤维束的构象特征.方法 对20例正常视放射和24例视放射区域病变的患者进行MR常规及DTI序列检查,分别测量双侧视放射区的部分各向异性(F...     

磁共振弥散张量成像在脑小血管病中的应用进展

随着人口老龄化进程的加速,脑小血管病(CSVD)的发病率也在不断上升,其导致的多种症状严重影响了患者的生活质量.MRI弥散张量成像(DTI)作为新近发展的影像技术,有无创显示白质纤维超微结构等优点,已被广泛用于疾病早期诊断、病情预测、治疗评估等多方面的研究.本文即就DTI技术在CSVD中的研究现状和未来发展前景进行综述...