Name: quantitative magnetic resonance imaging of skeletal muscle disease
Uploaded: 2016-12-18T13:00:00.000+00:00
Duration: 9 min 30 s
Description: Watch this Scientific Journal Video about Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease at JoVE.com

We acknowledge grant support from the National Institutes of Health: NIH/NIAMS R01 AR050101 (BMD), NIH/NIAMS R01 AR057091 (BMD/JHP), NIH/NIBEB K25 EB013659 (RDD), and the Vanderbilt CTSA award RR024975. We also thank the reviewers for the comments and the subject for participating in these studies.

注:读者提醒，涉及人类受试者的研究都必须由当地机构审查委员会（IRB）在研究人类受试者使用的批准。研究参与者必须的目的，程序，风险和建议的研究益处通知;替代疗法或程序的可用性;报酬的可用性;以及他们的隐私权，并撤回其同意，并停止其参与。此前MRI测试环节，调查员必须出示一个潜在的研究参与者与IRB批准的知情同意书（ICD），解释其内容，并要求潜在的研究参与者，如果他/她希望参加学习。如果是这样，参与者必须签署和日期对ICD之前完成任何这里的协议的步骤。 1.操作测试前的一天<ol><li> 限制生活习惯，可能混淆ðATA <ol><li>指导参与者不前测试48小时内执行中度或剧烈运动。指导参与者测试前的24小时内，从过度的非处方药和酒精的摄入量弃权。指导参与者之前测试6小时内使用烟草或咖啡因摄入量不要。 </li><li>在测试之前，确认参与者已经符合这些指令。 </li></ol></li><li> 准备核磁共振成像系统 <ol><li>确保所有必要的设备的可用性，如在材料和设备的表中。 </li><li>定义一个MRI方案; 5 -建议参数列在表1中找到。 </li></ol></li></ol> 2.测试的天:准备MRI数据采集<ol><li> 进行安全筛选 <ol><li>屏幕在MRI环境潜在危害由具有MRI安全-T下雨医护人员呈现研究参与者与合适的MRI安全的形式，例如，在www.mrisafety.com找到。 </li><li>如果有任何植入磁性或磁性敏感的对象，确保其可用于MRI扫描安全。 </li></ol></li><li> 准备核磁共振成像系统 <ol><li>确保所有人员进入，里面的MRI系统的房间之前删除了所有的磁性和磁性敏感的物体。每次有人进入核磁共振室进行一次此项检查。 </li><li>通过将接收线圈在MRI系统的病人床准备MRI系统。此外，将有板材和带枕头在床上枕头床垫。可有周围放置大腿绑带和垫或枕头在膝盖下放置。 </li><li>启动软件界面，输入患者数据，以及打开成像协议。 </li></ol></li><li> 在MRI扫描仪表研究参与者的位置 &lt;OL&gt; <li>观察研究参与者，因为他/她检查他/她的身体及衣服的磁性敏感的物体。在一个上锁的集装箱固定核磁共振室外面这些对象。完成此步骤后，立即进入核磁共振室的研究参与者。 </li><li>仰卧，脚先位置上病床参与者位置。放置身体部分将被成像为接近表的中线作为实用。膝盖下方放置垫或枕头，为提供低应力消除背部和放置一个枕头头下。要限制运动，轻轻但有效保证大腿，小腿和脚，并确保参与者舒服。 </li><li>周围放置参与者的大腿RF接收线圈，并将其连接到MRI系统。 </li></ol></li><li> 指导参与者和完成最后预测试步骤 <ol><li>提供有关如何与研究者沟通说明。提供在p听力保护和可用于在需要时要求注意的信令设备articipant。指示的需要，并在所有成像序列之间仍然停留参与者。 </li><li>推进患者床到MRI扫描仪，使得要被成像的身体部分被对准到MRI扫描仪的中心。 </li><li>退出核磁共振室后，确认病人通信系统工作，看到参与者舒服。整个协议，与参与者定期沟通，以确保他/她的安慰和遵守指令。 </li></ol></li></ol> 3.测试日:获取MRI数据<ol><li> 准备步骤 <ol><li>作为MRI系统确定之前每个成像序列（中心频率，接收器增益校准等 ）的工具的设置和校准，监督这些过程，并确保每个步骤正在执行correctl年。 </li><li>使用合适的软件接口，获得一组定位的图像（也称为导频或侦察图像）;使用表2中建议的参数。 </li><li>确定放置中心片的qMRI数据采集，通过确定损坏的区域和/或相对于重复性的解剖标志切片位置引用。 </li></ol></li><li> 发送和接收线圈校准步骤 <ol><li>对于这些步骤，以及所有后续的成像步骤，定义解剖其中优化静磁场（B 0），被称为"垫片"的处理的均匀性的区域。 见图1A为感兴趣的垫补体积的典型放置用于本研究（VOI）。 </li><li>如果MRI扫描仪具有多元件传输线圈，获得的RF校准数据集。 </li><li>如果MRI扫描仪具有多元件接收线圈，获取线圈的空间灵敏度图。 </li></ol></li><li> 获取结构MRI数据 <ol><li>获取高分辨率，多排，T 1 -加权使用快速自旋回波（FSE）序列图像;在本研究中使用的摄像参数在表1中提供。 </li><li>获取高分辨率，多排，T2加权使用FSE序列图像;在本研究中使用的摄像参数在表2中提供。 </li></ol></li><li> 采集的数据进行实时质量控制和制作后处理更正 <ol><li>获得三维（3D）多梯度回波数据为B 0，场图的计算。在本研究中使用的摄像参数在表3中提供。 </li><li>检查字段映射到确保有不大于±60赫兹（偏差约0.5每百万份在3特斯拉）在图像。如果有，采用另一种方法，以匀场（不同方法，不同的贴装VOI的， 等 ）。 </li><li>取得的三维数据为章动角的地图的计算。在本研究中使用的摄像参数在表2中提供。 </li><li>检查字段映射到确保没有从标称下垂角过度偏离领域。对于在本协议中使用的RF脉冲，偏差比标称下垂角为±30％的被认为是过度的。 </li></ol></li><li> 采集qMRI数据 <ol><li>获取3D图像于T 1的计算，采用反转恢复序列。在本研究中使用的摄像参数在表3中给出。 </li><li>重复的T 1测量脂肪信号抑制的存在（FS;此参数是abbrevia特德·T 1，FS）。 </li><li>获得单切片图像于T 2的计算，采用多自旋回波序列。使用表3所示的摄像参数。 </li><li>重复的T 2测量FS（T 2，FS）的存在。 </li><li>获得三维图像为QMT参数的计算中，使用具有FS脉冲饱和序列和表4中给出的摄像参数。 </li><li>获取多层数据的扩散张量参数的计算，使用一系列弥散加权图像。在这些研究中所用的成像参数在表4中给出。 </li><li>获得3D数据的脂肪/水图像的计算，采用六大系列梯度回波图像。在这些研究中所用的成像参数在表5中给出。 </li></ol></li><li> 完成qMRI协议后 <ol><li>确保这件事所有图像都相适应的质量通过检查他们的潜在可纠正的文物和通过测量足够的信噪比。 </li><li>对于每个qMRI数据集，在所述图像序列定义感兴趣（投资回报）若干区域，并检查该信号作为相关的参数的函数（例如，对于在步骤3.5.1和3.5.2获得的T 1依赖性数据，绘制信号作为TI的函数，并确保数据遵循）在步骤4.1.2下面列出的反转恢复功能。 </li><li>完成个人筛查磁敏感对象后，进入核磁共振室。从磁铁将其删除，删除所有带和填充，并协助参与者退出核磁共振成像扫描仪和核磁共振室。 </li><li>传输数据，使用符合当地卫生隐私法，到本地工作站的处理方法;数据可以在医学（DICOM）文件或在供应商可以导出为数码影像通讯的专有格式（在该协议中使用的方法）。 </li></ol></li></ol> 4.分析qMRI数据<ol><li> 计算参数图 <ol><li>使用设计用于科学计算和图像分析的计算机程序。通过检查在图像中的信号强度的直方图，形成一个信号基于阈值的图像掩模，它描绘信号的区域从噪声的区域。完成以下中的图像的信号部分的每个像素中的步骤。 </li><li>通过测量信号强度■每个反转时间（TI），用于分析的T 1的数据。然后，适合S中的值来降低预延迟模型中的反转恢复: <img alt="公式1" src="/files/ftp_upload/52352/52352equation1.jpg" /> 其中M 0是表示在平衡状态下的磁化的信号强度，S f是反转比例和TD是预延迟时间。然后，随着FS中的数据拟合到相同的模型，允许的纵向弛豫时间与FS T 1，FS常数确定。 </li><li>通过在每个TE测量S分析的T 2的数据。然后，与数据拟合到单指数衰减模型: <img alt="方程2" src="/files/ftp_upload/52352/52352equation2.jpg" /> 其中，N是信号在基线偏移。读者也可决定适合数据的多指数模型，如下面的是: <img alt="Equation3" src="/files/ftp_upload/52352/52352equation3.jpg" /> 其中J是指数部件和f和T 2，j的编号，与第 j 个分量相关联的信号部分和T 2的值。或者，读取器可以使用非负最小二乘（NNLS）方法3。在第l东北黑钙土情况下，多指数弛豫分析（MERA）工具箱33是免费提供的;其他程序可用了。重复这些分析为具有和不具有FS中的数据。 </li><li>分析QMT数据，测量S代表每个照射功率和频率偏移。更正使用下垂角地图名义辐射功率（由下面的等式中ω1表示）。通过使用B 0，映射到调整所施加的偏移频率校正频率偏移（以下等式Δf）所示 。然后，将数据拟合到以下模型34,35 <img alt="公式4" src="/files/ftp_upload/52352/52352equation4.jpg" /> 其中，从大分子池的自由水池汇率，是自由水池的纵向弛豫率，是大分子池（假定为1秒-1）的纵向弛豫率，是对PSR，被经t <sub&gt; 2的游离水池，ω1CWPE是饱和脉冲的平均功率。大分子池的纵向磁化的饱和率，是由一个超洛伦兹模型中描述，如由Henkelman和同事34,35在工作中所述。 </li><li>分析DTI数据，首先使用仿射变换算法36向每个扩散加权图像注册到相应的非扩散加权图像。然后，对于每个像素，测量在非扩散加权图像，并在每个扩散加权方向为S中的值。形成扩散编码方向组成的矩阵。利用多元，加权最小二乘回归，回归的扩散编码矩阵和表格D信号数据。角化D和执行特征值和特征向量的一个数量级分类。然后计算平均扩散率（MD）为: <img alt="Equation5"SRC ="/文件/ ftp_upload / 52352 / 52352equation5.jpg"/&gt; 其中λ1，λ2，λ3是扩散张量的本征值。也算分数各向异性（FA）为: <img alt="公式6" src="/files/ftp_upload/52352/52352equation6.jpg" /> </li><li>分析使用基于化学位移（如FattyRiot算法，可从https://github.com/welcheb/FattyRiot免费下载）分离的水和脂肪信号的定量方法的FWMRI数据。 </li></ol></li><li> 定义分析感兴趣区 <ol><li>指定的ROI对解剖图像（通过定义每个感兴趣肌肉的边界）。一个例子示于图1。 </li><li>调整感兴趣区以匹配qMRI图像的矩阵大小。如有必要，调整感兴趣区的对准到qMRI地图匹配（例如，如果参加者移动收购之间，可能需要在ROI位置的转换，以避免重复肌肉边界）。 </li><li>检查每个投资回报率。如果需要，确保不像素包括包含部分卷文物，非收缩组织和流程的文物;请参阅图1中的例子。 </li><li>计算qMRI值的平均值和标准偏差在所选择的感兴趣区中的所有像素。 </li></ol></li></ol>

None of the authors has a financial conflict of interest to report.

肌肉疾病如肌营养不良症和特发性炎性肌病构成了在异构的病因，并作为单独的实体，在罕见的疾病，发病率组。例如，杜氏肌营养不良症-肌营养不良的最常见的形式-具有1在3500活男婴37,38的入射;皮肌炎，到该协议中得到应用，拥有1 10万39的发病率。这些疾病的高发病率集体然而，他们通常是重叠的病理体征 - 萎缩，炎症，脂肪浸润，膜损伤和纤维化 - 支持一组通用的方法的发?...

定量磁共振成像（qMRI）描述了开发和使用的MRI量化的物理，化学，和/或生物系统的生物特性。 QMRI要求，一个采用了系统的生物物理模型，感兴趣组织以及MRI脉冲序列组成。脉冲序列被设计为图像"信号强度敏感到的模型中感兴趣的参数。磁共振信号特性（信号强度，频率和/或相位）根据该模型测量和分析。的目标是产生具有连续分布，测量的物理单元的物理或生物参数的无偏，定量估计。常描述系统的方程进行分析和装配在逐个像素的基础上，产生一个图像，其像素值直接反映该变量的值。这样的图像被称为一个参数图。 qMRI的一种常见用法是D才有发展和生物标志物的应用。生物标记物可用于研究疾病机制，建立一个诊断，确定预后，和/或评估治疗反应。它们可以采取内源或外源分子，组织学标本，物理量，或内部图像的浓度或活性的形式。生物标志物的一些总体要求是，他们使用的测量物理单位客观地衡量一个连续分布的变量;有一个清晰的，很好地理解与感兴趣的病理学关系;要改进和临床状态的恶化敏感;并且可以与合适的准确度和精确测量。非侵入性的或微创的生物标志物是特别理想的，因为它们促进患者的舒适度和最小干扰感兴趣的病理。 一个用于开发基于图像的生物标志物的肌肉疾病的目标是，以反映那些complementar方式肌肉疾病y以比更具体地，多空间比选择性的，和/或比现有的方法侵入性更小。在这方面qMRI的一个特定优点是，它具有集成多种类型的信息，从而潜在地表征疾病过程的许多方面的潜力。这种能力是肌肉疾病非常重要，这经常表现出空间上可变的，复杂的病理，包括炎症，坏死和/或萎缩伴脂肪替代，纤维化的肌丝格（"Z盘流"）的破坏和膜损伤。的qMRI方法的另一个优点是，基于对比度的MR图像的定性或半定量描述反映不仅病理学，而且在图像采集参数，硬件差异，和人类感知。最后一个问题的一个例子是由Wokke 等人 ，谁发现脂肪浸润的半定量评估是充满变数和不正确频繁，W证明母鸡定量脂肪/水MRI（FWMRI）相比，1。 在这里描述的协议包括用于测量纵向（T 1）和横向（T 2）弛豫时间常数，定量磁化转移脉冲序列（QMT）参数，使用弥散张量的MRI（DT-MRI）的肌肉结构水的扩散系数，以及使用结构图像和FWMRI。 ，T 1为通过使用反转恢复序列，其中该净磁化矢量被反相并作为系统返回到平衡其幅度进行采样测量。 Ť2是通过重复再聚焦使用再聚焦脉冲，诸如卡尔-赛尔Meiboom-吉尔（CPMG）法的一个列车横向磁化和采样所得到的自旋回波测量。 T1和T2 2的数据可以使用非线性曲线拟合方法，要么承担多项expone的被分析微分方程边值问题的部件先验 （典型地一至三个）或通过使用适合的观测数据的大量衰减指数函数的总和，从而产生信号振幅的频谱的线性逆算法。这种方法需要一个非负最小二乘（NNLS）溶液3，并且通常包括附加正规化，以产生稳定的结果。 T1和T2 2的测量已被广泛用来研究肌肉疾病和损伤4-9。 ŧ1值通常在减少肌肉脂肪浸润地区和发炎地区4-6升高; ŧ2值升高，这两种脂肪浸润和发炎地区的10。 QMT-MRI通过估计高分子的比例来自由水的质子（池大小比率，PSR）表征在组织中的自由水和固体状高分子质子池;内在放松这些池的通货膨胀率;以及它们之间交换的速率。常见的QMT方法包括脉冲饱和度11和选择性反转恢复12,13的方法。下面的协议描述使用脉冲饱和方法，它利用了高分子质子信号的宽线宽，相对于水的质子信号的窄线宽的。通过饱和在谐振频率从水中信号足够不同大分子信号时，水的信号被降低为固体和自由水的质子池之间磁化转移的结果。的数据使用的是定量的生物物理模型进行分析。 QMT已开发和在健康的肌肉14,15应用，而最近出现的抽象描述肌肉疾病16实施。 QMT已被用于研究肌肉炎症的小动物模型，其特征在于它已经表明，炎症减少对PSR 17。因为作为MT既反映了大分子和水分含量，MT的数据也可以反映肝纤维化18,19。 DT-MRI被用于量化具有有序的，细长的细胞组织的水分子的各向异性扩散行为。在DT-MRI，水扩散六个或更多不同的方向测量;然后这些信号被装配到一个张量模型20。的扩散张量，D是对角化，得到3特征值（其是三个主要扩散）和三个特征向量（它指示对应于三个扩散系数的方向）。从D-衍生的这些和其它定量指标提供在微观水平有关组织结构和取向信息。肌肉的扩散性能，特别是D的第三特征值和扩散各向异性程度，反映肌肉发炎17和肌肉损伤由于实验损伤21，劳损22和23,24疾病。对肌肉的扩散性的其他潜在影响包括细胞直径为25和膜通透性的变化而变化。 最后，肌肉萎缩，无或无肉眼可见的脂肪浸润，是许多肌肉疾病的病理学的组成部分。肌肉萎缩可以通过使用结构图象来测量肌肉截面积或体积和FW-MRI评估脂肪浸润来评价。脂肪浸润T中1定性描述-和T2加权图像26，但脂肪和水的信号最好通过形成利用脂肪和水的质子27-29的不同的谐振频率的图像测量。定量脂肪/水的成像方法已在肌肉疾病被应用于诸如肌营养不良1,30,31，并且可以预测在这些患者31下地的损失。 <p类="jove_content"&gt;此处描述的qMRI协议使用所有这些测量中的自身免疫性炎性肌病性皮肌炎（DM）和多肌炎（PM）来表征肌肉状况。该协议的进一步细节，包括它的再现性，已被先前32发布。该协议包括在我们的系统专门编程标准脉冲序列以及射频（RF）和磁场梯度的对象。作者预期的协议也适用于特征在于肌肉萎缩，炎症和脂肪浸润其他神经肌肉疾病（如肌营养不良症）。

<table><tbody><tr><td>3T human MRI system</td><td>Philips Medical Systems (Best, the Netherlands)</td><td></td><td>Achieva/Intera</td></tr><tr><td>Cardiac phased array receive coil</td><td>Philips Medical Systems</td><td></td><td></td></tr><tr><td>Pillows, straps, bolsters, and other positioning devices</td><td></td><td></td><td></td></tr><tr><td>Computer with MATLAB software</td><td>The Mathworks, Inc (Natick, MA)</td><td></td><td>r. 2014</td></tr></tbody></table>

quantitative magnetic resonance imaging of skeletal muscle disease

Quantitative magnetic resonance imaging (qMRI) describes the development and use of MRI to quantify physical, chemical, and/or biological properties of living systems. Neuromuscular diseases often exhibit a temporally varying, spatially heterogeneous, and multi-faceted pathology. The goal of this protocol is to characterize this pathology using qMRI methods. The MRI acquisition protocol begins with localizer images (used to locate the position of the body and tissue of interest within the MRI system), quality control measurements of relevant magnetic field distributions, and structural imaging for general anatomical characterization. The qMRI portion of the protocol includes measurements of the longitudinal and transverse relaxation time constants (T1 and T2, respectively). Also acquired are diffusion-tensor MRI data, in which water diffusivity is measured and used to infer pathological processes such as edema. Quantitative magnetization transfer imaging is used to characterize the relative tissue content of macromolecular and free water protons. Lastly, fat-water MRI methods are used to characterize fibro-adipose tissue replacement of muscle. In addition to describing the data acquisition and analysis procedures, this paper also discusses the potential problems associated with these methods, the analysis and interpretation of the data, MRI safety, and strategies for artifact reduction and protocol optimization.

图1示出了在多发性肌炎患者的大腿中部获得代表轴向解剖图像。还示出了垫片体积的面内投影的位置。 7 -代表参数映射每个qMRI方法，都来自同一患者获得，由图2提供。 图2A和2B分别示出了ΔB 0，和章动角场图，。在B 0?...

Watch this Scientific Journal Video about Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease at JoVE.com

Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease

神经肌肉疾病常常表现出时间上变化，空间上的异构，和多面病理。该协议的目的是表征使用非侵入性磁共振成像方法本病理。

骨骼肌疾病的定量磁共振成像

Quantitative magnetic resonance imaging (qMRI) describes the development and use of MRI to quantify physical, chemical, and/or biological properties of ...

quantitative-magnetic-resonance-imaging-of-skeletal-muscle-disease

Research

JoVE Journal

Medicine

19.3K 次观看.  Vanderbilt University. 神经肌肉疾病常常表现出时间上变化，空间上的异构，和多面病理。该协议的目的是表征使用非侵入性磁共振成像方法本病理。 

视频: Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease

Magnetic Resonance Derived Myocardial Strain Assessment Using Feature Tracking 

Purpose: An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that strain is a more sensitive and earlier marker for contractile dysfunction than the frequently used parameter EF. Current technologies for CMR are time consuming and difficult to implement in clinical practice. Feature tracking is a technology that can lead to more automization and robustness of quantitative analysis of medical images with less time consumption than comparable methods.
Methods: An automatic or manual input in a single phase serves as an initialization from which the system starts to track the displacement of individual patterns representing anatomical structures over time. The specialty of this method is that the images do not need to be manipulated in any way beforehand like e.g. tagging of CMR images.
Results: The method is very well suited for tracking muscular tissue and with this allowing quantitative elaboration of myocardium and also blood flow.
Conclusions: This new method offers a robust and time saving procedure to quantify myocardial tissue and blood with displacement, velocity and deformation parameters on regular sequences of CMR imaging. It therefore can be implemented in clinical practice.

Magnetic Resonance Derived Myocardial Strain Assessment Using Feature Tracking

An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that strain is a more sensitive and earlier marker for contractile dysfunction than the frequently used parameter EF.

磁共振衍生的心肌劳损评估使用特征跟踪

Purpose: An accurate and practical method to measure parameters like strain in myocardial tissue is of great clinical value, since it has been shown, that ...

科研

医学

An in vivo Rodent Model of Contraction-induced Injury and Non-invasive Monitoring of Recovery

Muscle strains are one of the most common complaints treated by physicians. A muscle injury is typically diagnosed from the patient history and physical exam alone, however the clinical presentation can vary greatly depending on the extent of injury, the patient's pain tolerance, etc. In patients with muscle injury or muscle disease, assessment of muscle damage is typically limited to clinical signs, such as tenderness, strength, range of motion, and more recently, imaging studies. Biological markers, such as serum creatine kinase levels, are typically elevated with muscle injury, but their levels do not always correlate with the loss of force production. This is even true of histological findings from animals, which provide a "direct measure" of damage, but do not account for all the loss of function. Some have argued that the most comprehensive measure of the overall health of the muscle in contractile force. Because muscle injury is a random event that occurs under a variety of biomechanical conditions, it is difficult to study. Here, we describe an in vivo animal model to measure torque and to produce a reliable muscle injury. We also describe our model for measurement of force from an isolated muscle in situ. Furthermore, we describe our small animal MRI procedure.

An in vivo Rodent Model of Contraction-induced Injury and Non-invasive Monitoring of Recovery

An in vivo animal model of injury is described. The method takes advantage of the subcutaneous position of the fibular nerve. Velocity, timing of muscle activation, and arc of motion are all pre-determined and synchronized using commercial software. Post injury changes are monitored in vivo using MR imaging/spectroscopy.

一个在体内收缩引起的损伤，非侵入性的监测恢复啮齿动物模型

Muscle strains are one of the most  common complaints treated by physicians. A muscle injury is typically diagnosed from the patient history and  physical ...

X-ray Diffraction of Intact Murine Skeletal Muscle as a Tool for Studying the Structural Basis of Muscle Disease

Transgenic mouse models have been important tools for studying the relationship of genotype to phenotype for human diseases including those of skeletal muscle. Mouse skeletal muscle has been shown to produce high quality X-ray diffraction patterns on third generation synchrotron beamlines providing an opportunity to link changes at the level of the genotype to functional phenotypes in health and disease by determining the structural consequences of genetic changes. We present detailed protocols for preparation of specimens, collecting the X-ray patterns and extracting relevant structural parameters from the X-ray patterns that may help guide experimenters wishing to perform such experiments for themselves.

We present detailed protocols for performing small-angle X-ray diffraction experiments using intact mouse skeletal muscles. With the wide availability of transgenic mouse models for human diseases, this experimental platform can form a useful test bed for elucidating the structural basis of genetic muscle diseases

完整毛里丝骨骼肌的X射线衍射作为研究肌肉疾病结构基础的工具

Transgenic mouse models have been important tools for studying the relationship of genotype to phenotype for human diseases including those of skeletal ...

发育生物学

Noninvasive Assessment of Cardiac Abnormalities in Experimental Autoimmune Myocarditis by Magnetic Resonance Microscopy Imaging in the Mouse

Myocarditis is an inflammation of the myocardium, but only ~10% of those affected show clinical manifestations of the disease. To study the immune events of myocardial injuries, various mouse models of myocarditis have been widely used. This study involved experimental autoimmune myocarditis (EAM) induced with cardiac myosin heavy chain (Myhc)-&#945; 334-352 in A/J mice; the affected animals develop lymphocytic myocarditis but with no apparent clinical signs. In this model, the utility of magnetic resonance microscopy (MRM) as a non-invasive modality to determine the cardiac structural and functional changes in animals immunized with Myhc-&#945; 334-352 is shown. EAM and healthy mice were imaged using a 9.4 T (400 MHz) 89 mm vertical core bore scanner equipped with a 4 cm millipede radio-frequency imaging probe and 100 G/cm triple axis gradients. Cardiac images were acquired from anesthetized animals using a gradient-echo-based cine pulse sequence, and the animals were monitored by respiration and pulse oximetry. The analysis revealed an increase in the thickness of the ventricular wall in EAM mice, with a corresponding decrease in the interior diameter of ventricles, when compared with healthy mice. The data suggest that morphological and functional changes in the inflamed hearts can be non-invasively monitored by MRM in live animals. In conclusion, MRM offers an advantage of assessing the progression and regression of myocardial injuries in diseases caused by infectious agents, as well as response to therapies.

This study demonstrates the successful establishment of magnetic resonance microscopy imaging as a non-invasive tool to assess the cardiac abnormalities in mice affected with autoimmune myocarditis. The data indicate that the technique can be used to monitor the disease-progression in live animals.

心脏异常的实验性自身免疫性心肌炎的无创性评估磁共振成像显微镜在鼠标

Myocarditis is an inflammation of the myocardium, but only ~10% of those affected show clinical manifestations of the disease. To study the immune events ...

Phosphorus-31 Magnetic Resonance Spectroscopy: A Tool for Measuring In Vivo Mitochondrial Oxidative Phosphorylation Capacity in Human Skeletal Muscle

Skeletal muscle mitochondrial oxidative phosphorylation (OXPHOS) capacity, which is critically important in health and disease, can be measured in vivo and noninvasively in humans via phosphorus-31 magnetic resonance spectroscopy (31PMRS). However, the approach has not been widely adopted in translational and clinical research, with variations in methodology and limited guidance from the literature. Increased optimization, standardization, and dissemination of methods for in vivo 31PMRS would facilitate the development of targeted therapies to improve OXPHOS capacity and could ultimately favorably impact cardiovascular health. 31PMRS produces a noninvasive, in vivo measure of OXPHOS capacity in human skeletal muscle, as opposed to alternative measures obtained from explanted and potentially altered mitochondria via muscle biopsy. It relies upon only modest additional instrumentation beyond what is already in place on magnetic resonance scanners available for clinical and translational research at most institutions. In this work, we outline a method to measure in vivo skeletal muscle OXPHOS. The technique is demonstrated using a 1.5 Tesla whole-body MR scanner equipped with the suitable hardware and software for 31PMRS, and we explain a simple and robust protocol for in-magnet resistive exercise to rapidly fatigue the quadriceps muscle. Reproducibility and feasibility are demonstrated in volunteers as well as subjects over a wide range of functional capacities.

Phosphorus-31 Magnetic Resonance Spectroscopy: A Tool for Measuring In Vivo Mitochondrial Oxidative Phosphorylation Capacity in Human Skeletal Muscle

This work demonstrates the feasibility of an in vivo phosphorus-31 magnetic resonance spectroscopy (31PMRS) technique to quantify mitochondrial oxidative phosphorylation (OXPHOS) capacity in human skeletal muscle.

磷31磁共振波谱分析:一种测量工具<em&gt;在体内</em&gt;线粒体氧化磷酸化能力人骨骼肌

Skeletal muscle mitochondrial oxidative phosphorylation (OXPHOS) capacity, which is critically important in health and disease, can be measured in vivo ...

Measurements of Motor Function and Other Clinical Outcome Parameters in Ambulant Children with Duchenne Muscular Dystrophy

While the number of new treatment options tested in patients with Duchenne muscular dystrophy (DMD) is increasing, there is still no defining of the most reliable assessments regarding therapeutic efficacy. We present clinical and radiological outcome measures used in ambulatory patients participating in our trial &#34;Treatment with L-citrulline and metformin in Duchenne muscular dystrophy&#34;. The motor function measure is a validated test in patients with neuromuscular disorders that consists of 32 items and assesses all three dimensions of motor performance including standing and transfer (D1 subscore), axial and proximal motor function (D2 subscore), and distal motor function (D3 subscore). The test shows high intra- and inter-rater variability but only when strictly following guidelines of the materials, examination steps, and calculation of scores. The 6-minute walk test, timed 10-meter walk/run test, and supine-up time are commonly used timed functional tests that also sufficiently monitor changes in muscle function; however, they strongly depend on patient collaboration. Quantitative MRI is an objective and sensitive biomarker to detect subclinical changes, though the examination costs may be a reason for its limited use. In this study, a high correlation between all clinical assessments and quantitative MRI scans was found. The combinational use of these methods provides a better understanding about disease progression; however, longitudinal studies are needed to validate their reliability.

The aim of this study is to present the most reliable clinical outcome measures and their correlations with quantitative muscle MRI in ambulant patients with Duchenne muscular dystrophy.

治疗杜氏肌营养不良患儿运动功能及其他临床结果参数的测量

While the number of new treatment options tested in patients with Duchenne muscular dystrophy (DMD) is increasing, there is still no defining of the most ...

Magnetic Resonance Imaging of Multiple Sclerosis at 7.0 Tesla

The overall goal of this article is to demonstrate a state-of-the-art ultrahigh field (UHF) magnetic resonance (MR) protocol of the brain at 7.0 Tesla in multiple sclerosis (MS) patients. MS is a chronic inflammatory, demyelinating, neurodegenerative disease that is characterized by white and gray matter lesions. Detection of spatially and temporally disseminated T2-hyperintense lesions by the use of MRI at 1.5 T and 3 T represents a crucial diagnostic tool in clinical practice to establish accurate diagnosis of MS based on the current version of the 2017 McDonald criteria. However, the differentiation of MS lesions from brain white matter lesions of other origins can sometimes be challenging due to their resembling morphology at lower magnetic field strengths (typically 3 T). Ultrahigh field MR (UHF-MR) benefits from increased signal-to-noise ratio and enhanced spatial resolution, both key to superior imaging for more accurate and definitive diagnoses of subtle lesions. Hence, MRI at 7.0 T has shown encouraging results to overcome the challenges of MS differential diagnosis by providing MS-specific neuroimaging markers (e.g., central vein sign, hypointense rim structures and differentiation of MS grey matter lesions). These markers and others can be identified by other MR contrasts other than T1 and T2 (T2*, phase, diffusion) and substantially improve the differentiation of MS lesions from those occurring in other neuroinflammatory conditions such as neuromyelitis optica and Susac syndrome. In this article, we describe our current technical approach to study cerebral white and grey matter lesions in MS patients at 7.0 T using different MR acquisition methods. The up-to-date protocol includes the preparation of the MR setup including the radio-frequency coils customized for UHF-MR, standardized screening, safety and interview procedures with MS patients, patient positioning in the MR scanner and acquisition of dedicated brain scans tailored for examining MS.

Here, we present a protocol to acquire magnetic resonance (MR) images of multiple sclerosis (MS) patient brains at 7.0 Tesla. The protocol includes preparation of the setup including the radio-frequency coils, standardized interview procedures with MS patients, subject positioning in the MR scanner and MR data acquisition.

7.0特斯拉多发性硬化症的磁共振成像

The overall goal of this article is to demonstrate a state-of-the-art ultrahigh field (UHF) magnetic resonance (MR) protocol of the brain at 7.0 Tesla in ...

通过脱细胞定量骨骼肌脂肪浸润

Decellularization-Based Quantification of Skeletal Muscle Fatty Infiltration

Fatty infiltration is the accumulation of adipocytes between myofibers in skeletal muscle and is a prominent feature of many myopathies, metabolic disorders, and dystrophies. Clinically in human populations, fatty infiltration is assessed using noninvasive methods, including computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound (US). Although some studies have used CT or MRI to quantify fatty infiltration in mouse muscle, costs and insufficient spatial resolution remain challenging. Other small animal methods utilize histology to visualize individual adipocytes; however, this methodology suffers from sampling bias in heterogeneous pathology. This protocol describes the methodology to qualitatively view and quantitatively measure fatty infiltration comprehensively throughout intact mouse muscle and at the level of individual adipocytes using decellularization. The protocol is not limited to specific muscles or specific species and can be extended to human biopsy. Additionally, gross qualitative and quantitative assessments can be made with standard laboratory equipment for little cost, making this procedure more accessible across research laboratories.

作者聚焦：基于脱细胞化的骨骼肌脂肪浸润定量  

The present study describes decellularization-based methodologies for visualizing and quantifying intramuscular adipose tissue (IMAT) deposition through intact muscle volume, as well as quantifying metrics of individual adipocytes that comprise IMAT.

骨骼肌疾病的定量磁共振成像

摘要

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此视频中的章节

磁共振衍生的心肌劳损评估使用特征跟踪

一个在体内收缩引起的损伤，非侵入性的监测恢复啮齿动物模型

完整毛里丝骨骼肌的X射线衍射作为研究肌肉疾病结构基础的工具

心脏异常的实验性自身免疫性心肌炎的无创性评估磁共振成像显微镜在鼠标

磷31磁共振波谱分析:一种测量工具

治疗杜氏肌营养不良患儿运动功能及其他临床结果参数的测量

7.0特斯拉多发性硬化症的磁共振成像

基于脱细胞的骨骼肌脂肪浸润定量

基于脱细胞的骨骼肌脂肪浸润定量

基于脱细胞的骨骼肌脂肪浸润定量