We would like to thank the whole Service of Neuroradiology. We would like to thank Lis Prussen for her work in the library.

注:此协议遵循中心医院去卢森堡在卢森堡的准则。 1，准备弥散张量成像的视觉通路的神经外科及跟进<ol style="margin-left: 40px;"><li>至少有一天在手术前严格轴向采用32梯度方向，一个B0图像进行核磁共振成像扫描。请随时与神经放射学单位保持密切联系。 注意:请明确的神经放射手术后的图像是相同的操作之前。 </li><li>使用3特斯拉MRI检查，执行3DT1加权和DTI序列扫描。手术后进行3DT1加权序列为好。 </li></ol> 2，利用规划站<ol><li> T2加权，3DT1加权和DTI序列扫描数据传输到数字成像和通信医学（DICOM）。这个过程需要长达7分钟。 注:唐`停止该程序befo再有转印的所有序列。因此能够停止并在稍后继续根据手术的日期。 </li><li>打开手术导航系统计划。单击文件，然后导入DICOM标准。重复此过程三次，上面提到的所有序列。 <ol><li>单击添加查看。单独添加每一个序列。唐`尝试进行查看。 </li></ol></li><li>点击工具。打开DTI张量的准备。在屏幕中间的观察的新窗口。 </li><li>完成以下四个步骤。 <ol><li>进行梯度分配作为第一步骤。 <ol><li>从1000至800秒/平方毫米上的窗口的右下角改变b值。 </li><li>调整窗口右上角的门槛。做手工通过写一个号码或移动光标。 20可能是一个可接受的值。它是一种个人的经验，它不是强制性的。 </li></ol></li><li>进行梯度注册作为第二步骤。 <ol> &lt;li&gt;单击该按钮全部自动。这个过程需要长达5分钟。 </li><li>点击确认所有注册。未经验证的注册是不可能继续。 </li></ol></li><li>进行配准作为第三步骤。 <ol><li> Coregister MR1和手动B0 MR2的图像。最后确认所有注册。 注:可以自动执行此步骤。但是，结果可能不总是令人满意的末端。 </li></ol></li><li>执行的张量运算作为第四和最后一个步骤， <ol><li>确保FA / DEC / ADC上。如果不点击。 </li><li>点击计算。这个程序将只需要几秒钟。 </li></ol></li></ol></li><li>保存所有的数据，然后继续fibertracking。不要停止不保存一切。 </li></ol> 3 Fibertracking 注:解剖的视觉通路的知识是成功的结果非常重要。 <ol stYLE ="缘左:40PX;"&gt; <li>准备找三个要点，其中的纤维要经过。 </li><li>确定使用解剖知识视交叉。 <ol><li>使用投资回报为出发点，让纤维通过。感兴趣区由医师确定。 </li><li>另外，部分涉嫌的区域。点击分割左下方，并会出现另一个窗口。分割区解剖学定义的区域。 <ol><li>手工绘制的区域。向上和向下滚动，以包括整个视交叉。保存程序并返回。 </li></ol></li><li>跟踪纤维无论是从感兴趣的区域或从该分段区或两者。 </li><li>该纤维到达左膝状体核（LGN），这是视觉通路的第二个重要的点。的最大角度是50的假大片的风险会升高与如果角度过大。 <ol><li>存在这样的可能性，以段的LGN所示的视交叉然后跟踪的纤维。具有分段从视交叉或反之亦然LGN和结束运行视交叉，轨道纤维之后。 </li></ol></li><li>段的视觉皮层。然后像在视交叉的情况。这可能需要一些时间，因为3DT1加权图像包含160片。 </li><li>从跟踪视觉皮层的LGN的纤维。所以能够从LGN跟踪他们的视觉皮层为好。 </li><li>如果视觉皮层是由肿瘤或水肿入侵然后使用感兴趣区域中发生的分段区域，然后让在LGN的方向运行的纤维。 请注意:如果水肿是分段它有时可能侵入视觉皮层然后再视皮层可能不能够完全分割，因为计算机`吨区分它们。 That`s为什么有必要把投资回报率。 </li><li>重复一切为了另一个半球。 </li><li>开始第一健康半球。 注意:可以先从另一个太多，但它可能会更容易先跟踪健康半球的纤维，成为有关情况的第一个想法。这不是强制性的，它仅仅是一个建议。 </li></ol></li><li>段的脑损伤和水肿。请按3.2.2如上所述。 <ol><li>为了区分更好分配为每分段的面积或病变的一种颜色。 </li></ol></li><li>的情况下的突发事件的或在紧急情况下的各步骤后保存的程序。 </li><li>本地导出整个数据。它可以直接导出到手术室，但isn`t建议。 <ol><li>按文件，然后导出三维物体。请确保只导出导航考试。 </li><li>唐`出口混合考试。 </li></ol></li><li>进入头颅。选择合适的病人，然后按Stealthmerge。选择3DT1加权图像作为参考考试。 </li><li>创建3D模型，并插入了一切。 </li><li>导入数据In中的手术室。 </li></ol>

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The authors declare that they have no competing financial interests.

DTI是一种技术，使神经外科医生形象化白质在体内 8。视觉通路是这些大片之一。虽然这种方法为医生提供关于病人有关的大脑，我们不得不说，这种技术的一些局限性做还存在雄辩区病变的治疗提供新的可能性。第一个也是最明显的挑战是脑转移，其中正在调查4仍然是一个问题。之后通过除去肿瘤或我们`吨有相同的条件下在手术前的脑脊液损失打开硬脑膜和操纵后在脑?...

弥散张量成像（DTI）用于在人脑中1描绘WMT非侵入。它已被用于在过去的十年中，以减少手术1期间伤及大脑口才方面的风险。 英国贸工部在50例患者行2012年3月和2014年1月间，以塑造视觉通路。贸工部可能通过提供关于白质束的解剖位置的重要信息保存完善的大脑雄辩地区在手术过程中。它已被纳入战略规划切除复杂的脑部病变1。然而，视觉通路的写照仍然是一个挑战，因为没有标准，英国贸工部，放置种子数量和效果12诠释的参数。 不同的算法已经被至今19-21实现。一些方法集中在确定性方法19，22-25。另一些人用概率方法，26,27,29。最近，采用Q-球张量场，扩散光谱成像和高角分辨率弥散成像（HARDI）正在使用的技术来描绘等等的视觉通路1,13-15,18白质。然而，在必要时对HARDI是显著长45分钟，该软件是不能商购获得，并强调科学应用18。教学期间为HARDI似乎是长于DTI 18。 所提出的协议是容易可行的，可以避免发病率和改善术后结果用于神经外科手术的日常例程。额外的时间用于该协议是小于9分钟，比其他协议1,9,12,16显著更快。承认许多复杂的算法近来已经开发出了纸张限制的事实本身的使用可商购的和FDA批准的软件。然而它是强制性的，以顾及它们上面提到了这种技术的局限性。

<table><tbody><tr><td>3-Tesla-MRI</td><td>General Electric</td><td>Signa LX version 9.1</td><td></td></tr><tr><td>Surgical Navigation System Program</td><td>Medtronic</td><td>9734478</td><td></td></tr><tr><td>Surgical Navigation System Program</td><td>Medtronic</td><td>4500810331&amp;nbsp; 20016318</td><td></td></tr></tbody></table>

dti of the visual pathway - white matter tracts and cerebral lesions

<html> DTI是标识白质（WMT）非侵入性地在使用扩散测量健康和非健康患者的技术。类似的视觉通路（VP），WMT不与古典MRI或显微镜手术中可见。 DIT将有助于神经外科医生，以防止破坏的副总裁，同时消除邻近该WMT病变。我们已经进行了英国贸工部对50例患者手术前后2012年3月至2014年1月要浏览我们使用了3DT1加权序列。此外，我们进行了T2加权和DTI序列。所使用的参数为，FOV:20​​0×200毫米，切片厚度:2毫米，并采集矩阵:96×96得到的2×2×2mm的几乎各向同性的体素。轴向核磁共振进行了使用32梯度方向，一个B0形象。我们使用回波平面-成像（EPI）和资产并行成像中的2的加速度因子和为800秒/平方毫米的b值。扫描时间小于9分钟。 ENT"&gt;获得使用FDA批准它使用被称为连续跟踪（事实）光纤分配一个简单的纤维跟踪方法的手术导航系统的程序进行处理的贸工部的数据，这是基于对感兴趣的区域间线的传输（投资回报率），这是由医生确定。50的最大角度，足协启动0.10的值，为0.20平方毫米/停止的ADC值S被用于跟踪技术参数。 有一些限制这种技术。在有限的捕获时间帧强制折衷的图像质量。另一个重要的一点不容忽视的是在手术中的脑转移。至于后者术中MRI检查可能会有帮助。另外需要的假阳性或假阴性束的风险要考虑到这可能会危及最终结果。

<html>该协议使医生能够充分地描绘了​​VP的主要部分。它可以随着时间稍微量，以防止损害患者旁边口​​才区域脑病变使用。术后控制也显示出了良好的效果。 VP是描绘在图7中后，病人从胶质母细胞瘤手术。 图2给出了副总裁复发胶质母细胞瘤后。作者承认提出该协议描绘迈耶环这仍然是一个重大挑战困难的事实。 <im...

Watch this Scientific Journal Video about DTI of the Visual Pathway - White Matter Tracts and Cerebral Lesions at JoVE.com

DTI of the Visual Pathway - White Matter Tracts and Cerebral Lesions

弥散张量成像（DTI）进行尝试描绘视觉通路的主要部件。该目标是利用一种FDA批准的标准商业工作站可能被用于日常例程以试图减少在病人的视觉通路的手术损伤。

贸工部视觉通路的 - 白质及脑病变

DTI is a technique that identifies white matter tracts (WMT) non-invasively in healthy and non-healthy patients using diffusion measurements. Similar to ...

dti-of-the-visual-pathway-white-matter-tracts-and-cerebral-lesions

Research

JoVE Journal

Medicine

13.9K 次观看.  Centre Hospitalier de Luxembourg. 弥散张量成像（DTI）进行尝试描绘视觉通路的主要部件。该目标是利用一种FDA批准的标准商业工作站可能被用于日常例程以试图减少在病人的视觉通路的手术损伤。 

视频: DTI of the Visual Pathway - White Matter Tracts and Cerebral Lesions

Dissection of Human Vitreous Body Elements for Proteomic Analysis

The vitreous is an optically clear, collagenous extracellular matrix that fills the inside of the eye and overlies the retina. 1,2 Abnormal interactions between vitreous substructures and the retina underlie several vitreoretinal diseases, including retinal tear and detachment, macular pucker, macular hole, age-related macular degeneration, vitreomacular traction, proliferative vitreoretinopathy, proliferative diabetic retinopathy, and inherited vitreoretinopathies. 1,2 The molecular composition of the vitreous substructures is not known. Since the vitreous body is transparent with limited surgical access, it has been difficult to study its substructures at the molecular level. We developed a method to separate and preserve these tissues for proteomic and biochemical analysis. The dissection technique in this experimental video shows how to isolate vitreous base, anterior hyaloid, vitreous core, and vitreous cortex from postmortem human eyes. One-dimensional SDS-PAGE analyses of each vitreous component showed that our dissection technique resulted in four unique protein profiles corresponding to each substructure of the human vitreous body. Identification of differentially compartmentalized proteins will reveal candidate molecules underlying various vitreoretinal diseases.

This video shows an effective technique for differentiating and dissecting the various semi-transparent structures of the human vitreous body in post mortem eyes.

人类蛋白质组分析玻璃体元素剖析

The vitreous is an optically clear, collagenous extracellular matrix that fills the inside of the eye and overlies the retina. 1,2 Abnormal interactions ...

科研

医学

Probing the Brain in Autism Using fMRI and Diffusion Tensor Imaging

Newly emerging theories suggest that the brain does not function as a cohesive unit in autism, and this discordance is reflected in the behavioral symptoms displayed by individuals with autism. While structural neuroimaging findings have provided some insights into brain abnormalities in autism, the consistency of such findings is questionable. Functional neuroimaging, on the other hand, has been more fruitful in this regard because autism is a disorder of dynamic processing and allows examination of communication between cortical networks, which appears to be where the underlying problem occurs in autism. Functional connectivity is defined as the temporal correlation of spatially separate neurological events1. Findings from a number of recent fMRI studies have supported the idea that there is weaker coordination between different parts of the brain that should be working together to accomplish complex social or language problems2,3,4,5,6. One of the mysteries of autism is the coexistence of deficits in several domains along with relatively intact, sometimes enhanced, abilities. Such complex manifestation of autism calls for a global and comprehensive examination of the disorder at the neural level. A compelling recent account of the brain functioning in autism, the cortical underconnectivity theory,2,7 provides an integrating framework for the neurobiological bases of autism. The cortical underconnectivity theory of autism suggests that any language, social, or psychological function that is dependent on the integration of multiple brain regions is susceptible to disruption as the processing demand increases. In autism, the underfunctioning of integrative circuitry in the brain may cause widespread underconnectivity. In other words, people with autism may interpret information in a piecemeal fashion at the expense of the whole. Since cortical underconnectivity among brain regions, especially the frontal cortex and more posterior areas 3,6, has now been relatively well established, we can begin to further understand brain connectivity as a critical component of autism symptomatology.
A logical next step in this direction is to examine the anatomical connections that may mediate the functional connections mentioned above. Diffusion Tensor Imaging (DTI) is a relatively novel neuroimaging technique that helps probe the diffusion of water in the brain to infer the integrity of white matter fibers. In this technique, water diffusion in the brain is examined in several directions using diffusion gradients. While functional connectivity provides information about the synchronization of brain activation across different brain areas during a task or during rest, DTI helps in understanding the underlying axonal organization which may facilitate the cross-talk among brain areas. This paper will describe these techniques as valuable tools in understanding the brain in autism and the challenges involved in this line of research.

Neuroimaging techniques, such as functional MRI and Diffusion Tensor Imaging have become increasingly useful in characterizing the cognitive and neural deficits in autism. An examination of brain connectivity in autism at a network level along with adaptations for scanning children with developmental disabilities is presented.

探讨孤独症的脑功能磁共振成像和弥散张量成像

Newly emerging theories suggest that the brain does not function as a cohesive unit in autism, and this discordance is reflected in the behavioral ...

Co-analysis of Brain Structure and Function using fMRI and Diffusion-weighted Imaging

The study of complex computational systems is facilitated by network maps, such as circuit diagrams. Such mapping is particularly informative when studying the brain, as the functional role that a brain area fulfills may be largely defined by its connections to other brain areas. In this report, we describe a novel, non-invasive approach for relating brain structure and function using magnetic resonance imaging (MRI). This approach, a combination of structural imaging of long-range fiber connections and functional imaging data, is illustrated in two distinct cognitive domains, visual attention and face perception. Structural imaging is performed with diffusion-weighted imaging (DWI) and fiber tractography, which track the diffusion of water molecules along white-matter fiber tracts in the brain (Figure 1). By visualizing these fiber tracts, we are able to investigate the long-range connective architecture of the brain. The results compare favorably with one of the most widely-used techniques in DWI, diffusion tensor imaging (DTI). DTI is unable to resolve complex configurations of fiber tracts, limiting its utility for constructing detailed, anatomically-informed models of brain function. In contrast, our analyses reproduce known neuroanatomy with precision and accuracy. This advantage is partly due to data acquisition procedures: while many DTI protocols measure diffusion in a small number of directions (e.g., 6 or 12), we employ a diffusion spectrum imaging (DSI)1, 2 protocol which assesses diffusion in 257 directions and at a range of magnetic gradient strengths. Moreover, DSI data allow us to use more sophisticated methods for reconstructing acquired data. In two experiments (visual attention and face perception), tractography reveals that co-active areas of the human brain are anatomically connected, supporting extant hypotheses that they form functional networks. DWI allows us to create a "circuit diagram" and reproduce it on an individual-subject basis, for the purpose of monitoring task-relevant brain activity in networks of interest.

We describe a novel approach for simultaneous analysis of brain function and structure using magnetic resonance imaging (MRI). We assess brain structure with high-resolution diffusion-weighted imaging and white-matter fiber tractography. Unlike standard structural MRI, these techniques allow us to directly relate anatomical connectivity to functional properties of brain networks.

使用功能磁共振成像和弥散加权成像脑结构与功能分析

The study of complex computational systems is facilitated by network maps, such as circuit diagrams. Such mapping is particularly informative when ...

神经科学

Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases

Diffusion tensor imaging (DTI) techniques provide information on the microstructural processes of the cerebral white matter (WM) in vivo. The present applications are designed to investigate differences of WM involvement patterns in different brain diseases, especially neurodegenerative disorders, by use of different DTI analyses in comparison with matched controls. 	
DTI data analysis is performed in a variate fashion, i.e. voxelwise comparison of regional diffusion direction-based metrics such as fractional anisotropy (FA), together with fiber tracking (FT) accompanied by tractwise fractional anisotropy statistics (TFAS) at the group level in order to identify differences in FA along WM structures, aiming at the definition of regional patterns of WM alterations at the group level. Transformation into a stereotaxic standard space is a prerequisite for group studies and requires thorough data processing to preserve directional inter-dependencies. The present applications show optimized technical approaches for this preservation of quantitative and directional information during spatial normalization in data analyses at the group level. On this basis, FT techniques can be applied to group averaged data in order to quantify metrics information as defined by FT. Additionally, application of DTI methods, i.e. differences in FA-maps after stereotaxic alignment, in a longitudinal analysis at an individual subject basis reveal information about the progression of neurological disorders. Further quality improvement of DTI based results can be obtained during preprocessing by application of a controlled elimination of gradient directions with high noise levels.	
In summary, DTI is used to define a distinct WM pathoanatomy of different brain diseases by the combination of whole brain-based and tract-based DTI analysis.

Diffusion tensor imaging (DTI) basically serves as an MRI-based tool to identify in vivo the microstructure of the brain and pathological processes due to neurological disorders within the cerebral white matter. DTI-based analyses allow for application to brain diseases both at the group level and in single subject data.

磁共振扩散张量成像在神经退行性疾病的分析

Diffusion tensor imaging (DTI) techniques provide information on the microstructural processes of the cerebral white matter (WM) in vivo. The present ...

Measuring Connectivity in the Primary Visual Pathway in Human Albinism Using Diffusion Tensor Imaging and Tractography

In albinism, the number of ipsilaterally projecting retinal ganglion cells (RGCs) is significantly reduced. The retina and optic chiasm have been proposed as candidate sites for misrouting. Since a correlation between the number of lateral geniculate nucleus (LGN) relay neurons and LGN size has been shown, and based on previously reported reductions in LGN volumes in human albinism, we suggest that fiber projections from LGN to the primary visual cortex (V1) are also reduced. Studying structural differences in the visual system of albinism can improve the understanding of the mechanism of misrouting and subsequent clinical applications. Diffusion data and tractography are useful for mapping the OR (optic radiation). This manuscript describes two algorithms for OR reconstruction in order to compare brain connectivity in albinism and controls.An MRI scanner with a 32-channel head coil was used to acquire structural scans. A T1-weighted 3D-MPRAGE sequence with 1 mm3 isotropic voxel size was used to generate high-resolution images for V1 segmentation. Multiple proton density (PD) weighted images were acquired coronally for right and left LGN localization. Diffusion tensor imaging (DTI) scans were acquired with 64 diffusion directions. Both deterministic and probabilistic tracking methods were run and compared, with LGN as the seed mask and V1 as the target mask. Though DTI provides relatively poor spatial resolution, and accurate delineation of OR may be challenging due to its low fiber density, tractography has been shown to be advantageous both in research and clinically. Tract based spatial statistics (TBSS) revealed areas of significantly reduced white matter integrity within the OR in patients with albinism compared to controls. Pairwise comparisons revealed a significant reduction in LGN to V1 connectivity in albinism compared to controls. Comparing both tracking algorithms revealed common findings, strengthening the reliability of the technique.

This manuscript describes deterministic and probabilistic algorithms for white matter (WM) reconstruction, used to examine differences in optic radiation (OR) connectivity between albinism and controls. Although probabilistic tractography follows the true course of nerve fibers more closely, deterministic tractography was run to compare the reliability and reproducibility of both techniques.

在人类白化病的初级视途径弥散张量成像和测量束成像连通

In albinism, the number of ipsilaterally projecting retinal ganglion cells (RGCs) is significantly reduced. The retina and optic chiasm have been proposed ...

Fiber Connections of the Supplementary Motor Area Revisited: Methodology of Fiber Dissection, DTI, and Three Dimensional Documentation

The purpose of this study is to show the methodology for the examination of the white matter connections of the supplementary motor area (SMA) complex (pre-SMA and SMA proper) using a combination of fiber dissection techniques on cadaveric specimens and magnetic resonance (MR) tractography. The protocol will also describe the procedure for a white matter dissection of a human brain, diffusion tensor tractography imaging, and three-dimensional documentation. The fiber dissections on human brains and the 3D documentation were performed at the University of Minnesota, Microsurgery and Neuroanatomy Laboratory, Department of Neurosurgery. Five postmortem human brain specimens and two whole heads were prepared in accordance with Klingler's method. Brain hemispheres were dissected step by step from lateral to medial and medial to lateral under an operating microscope, and 3D images were captured at every stage. All dissection results were supported by diffusion tensor imaging. Investigations on the connections in line with Meynert's fiber tract classification, including association fibers (short, superior longitudinal fasciculus I and frontal aslant tracts), projection fibers (corticospinal, claustrocortical, cingulum, and frontostriatal tracts), and commissural fibers (callosal fibers) were also conducted.

The purpose of this study is to show each step of the fiber dissection technique on human cadaveric brains, the 3D documentation of these dissections, and the diffusion tensor imaging of the anatomically dissected fiber pathways.

补充电机区的光纤连接重新审视:光纤解剖，DTI和三维文档的方法

The purpose of this study is to show the methodology for the examination of the white matter connections of the supplementary motor area (SMA) complex ...

Diffusion Tensor Magnetic Resonance Imaging in Chronic Spinal Cord Compression

Chronic spinal cord compression is the most common cause of spinal cord impairment in patients with nontraumatic spinal cord damage. Conventional magnetic resonance imaging (MRI) plays an important role in both confirming the diagnosis and evaluating the degree of compression. However, the anatomical detail provided by conventional MRI is not sufficient to accurately estimate neuronal damage and/or assess the possibility of neuronal recovery in chronic spinal cord compression patients. In contrast, diffusion tensor imaging (DTI) can provide quantitative results according to the detection of water molecule diffusion in tissues. In the present study, we develop a methodological framework to illustrate the application of DTI in chronic spinal cord compression disease. DTI fractional anisotropy (FA), apparent diffusion coefficients (ADCs), and eigenvector values are useful for visualizing microstructural pathological changes in the spinal cord. Decreased FA and increases in ADCs and eigenvector values were observed in chronic spinal cord compression patients compared to healthy controls. DTI could help surgeons understand spinal cord injury severity and provide important information regarding prognosis and neural functional recovery. In conclusion, this protocol provides a sensitive, detailed, and noninvasive tool to evaluate spinal cord compression.

Here, we present a protocol for the application of diffusion tensor imaging parameters to evaluate spinal cord compression.

扩散张量磁共振成像在慢性脊髓压迫中的应用

Chronic spinal cord compression is the most common cause of spinal cord impairment in patients with nontraumatic spinal cord damage. Conventional magnetic ...

Advanced Diffusion Imaging in The Hippocampus of Rats with Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) is the most common type of acquired brain injury. Since patients with traumatic brain injury show a tremendous variability and heterogeneity (age, gender, type of trauma, other possible pathologies, etc.), animal models play a key role in unraveling factors that are limitations in clinical research. They provide a standardized and controlled setting to investigate the biological mechanisms of injury and repair following TBI. However, not all animal models mimic the diffuse and subtle nature of mTBI effectively. For example, the commonly used controlled cortical impact (CCI) and lateral fluid percussion injury (LFPI) models make use of a craniotomy to expose the brain and induce widespread focal trauma, which are not commonly seen in mTBI. Therefore, these experimental models are not valid to mimic mTBI. Thus, an appropriate model should be used to investigate mTBI. The Marmarou weight drop model for rats induces similar microstructural alterations and cognitive impairments as seen in patients who sustain mild trauma; therefore, this model was selected for this protocol. Conventional computed tomography and magnetic resonance imaging (MRI) scans commonly show no damage following a mild injury, because mTBI induces often only subtle and diffuse injuries. With diffusion weighted MRI, it is possible to investigate microstructural properties of brain tissue, which can provide more insight into the microscopic alterations following mild trauma. Therefore, the goal of this study is to obtain quantitative information of a selected region-of-interest (i.e., hippocampus) to follow up disease progression after obtaining a mild and diffuse brain injury.

The overall goal of this procedure is to obtain quantitative microstructural information of the hippocampus in a rat with mild traumatic brain injury. This is done using an advanced diffusion-weighted magnetic resonance imaging protocol and region-of-interest based analysis of parametric diffusion maps.

轻度创伤性脑损伤大鼠海马学的高级扩散成像

Mild traumatic brain injury (mTBI) is the most common type of acquired brain injury. Since patients with traumatic brain injury show a tremendous ...

Role of Diffusion MRI Tractography in Endoscopic Endonasal Skull Base Surgery

Endoscopic endonasal surgery has gained a prominent role in the management of complex skull base tumors. It allows the resection of a large group of benign and malignant lesions through a natural anatomical extra-cranial pathway, represented by the nasal cavities, avoiding brain retraction and neurovascular manipulation. This is reflected by the patients' prompt clinical recovery and the low risk of permanent neurological sequelae, representing the main caveat of conventional skull base surgery. This surgery must be tailored to each specific case, considering its features and relationship with surrounding neural structures, mostly based on preoperative neuroimaging. Advanced MRI techniques, such as tractography, have been rarely adopted in skull base surgery due to technical issues: lengthy and complicated processes to generate reliable reconstructions for inclusion in the neuronavigation system. 
This paper aims to present the protocol implemented in the institution and highlights the synergistic collaboration and teamwork between neurosurgeons and the neuroimaging team (neurologists, neuroradiologists, neuropsychologists, physicists, and bioengineers) with the final goal of selecting the optimal treatment for each patient, improving the surgical results and pursuing the advancement of personalized medicine in this field.

We present a protocol to integrate diffusion MRI tractography in patient work-up to endoscopic endonasal surgery for a skull base tumor. The methods for adopting these neuroimaging studies in the pre- and intra-operative phases are described.

扩散MRI造影术在内窥镜内窥镜颅骨基础外科中的作用

Endoscopic endonasal surgery has gained a prominent role in the management of complex skull base tumors. It allows the resection of a large group of ...

Using Diffusion Tensor Imaging in Traumatic Brain Injury

Source: Laboratories of Jonas T. Kaplan and Sarah I. Gimbel&#8212;University of Southern California
Traditional brain imaging techniques using MRI are very good at visualizing the gross structures of the brain. A structural brain image made with MRI provides high contrast of the borders between gray and white matter, and information about the size and shape of brain structures. However, these images do not detail the underlying structure and integrity of white matter networks in the brain, which consist of axon bundles that interconnect local and distant brain regions.
Diffusion MRI uses pulse sequences that are sensitive to the diffusion of water molecules. By measuring the direction of diffusion, it is possible to make inferences about the structure of white matter networks in the brain. Water molecules within an axon are constrained in their movements by the cell membrane; instead of randomly moving in every direction with equal probability (isotropic movement), they are more likely to move in certain directions, in parallel with the axon (anisotropic movement; Figure 1). Therefore, measures of diffusion anisotropy are thought to reflect properties of the white matter such as fiber density, axon thickness, and degree of myelination. One common measure is fractional anisotropy (FA). FA values range from 0, which represents completely isotropic movement, to 1, reflecting maximum anisotropy.
<img alt="Figure 1" src="/files/ftp_upload/10276/10276fig1.jpg" /> 
Figure 1: Diffusion anisotropy. When the direction of diffusion is unconstrained and random, movement is measured in all directions equally. This is isotropic diffusion (A). When water molecules are contained within the axon of a neuron, diffusion is anisotropic, tending to occur more frequently along the direction of the axon (B). <a href="http://www.jove.com/files/ftp_upload/10276/10276fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
In this experiment we will use diffusion tensor imaging (DTI) to measure white matter integrity in traumatic brain injury (TBI). TBI occurs when an external force injures the brain, such as a blow to the head or a sudden movement like the kind that might occur in a car accident. This type of brain injury from mechanical forces is associated with diffuse axonal injury-damage to white matter throughout the brain. Because it is an injury affecting white matter integrity, standard neuroimaging techniques may not reveal the damage. However, measures of diffusion are especially sensitive to these anatomical changes. Following a study by Kraus et al.1, we compare a group of healthy controls to a group of people with TBI and use diffusion imaging to measure the effect of TBI on cerebral white matter. Furthermore, we will test the relationship between white matter integrity and cognitive function using an attention task.2 This study uses a region of interest (ROI) approach focusing on three white matter tracts: the splenium of the corpus callosum, the anterior corona radiata, and the superior longitudinal fasciculus (Figure 2).
<img alt="Figure 2" src="/files/ftp_upload/10276/10276fig2.jpg" /> 
Figure 2: Regions of interest. The three ROIs, defined from the ICBM DTI-81 atlas, are shown here in horizontal slices through the brain. In green is the splenium of the corpus callosum. The splenium is the most posterior part of the corpus callosum. In blue is the anterior corona radiata. The superior longitudinal fasciculus is shown in red. <a href="http://www.jove.com/files/ftp_upload/10276/10276fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Diffusion Tensor Imaging in Traumatic Brain Injury

弥散张量成像在创伤性脑损伤

Source: Laboratories of Jonas T. Kaplan and Sarah I. Gimbel&#8212;University of Southern California
Traditional brain imaging techniques using MRI are ...