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）。

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			<td style="width:119px;">Catalog Number</td>
			<td style="width:167px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:329px;">3T human MRI system</td>
			<td style="width:327px;">Philips Medical Systems (Best, the Netherlands)</td>
			<td style="width:119px;"></td>
			<td>Achieva/Intera</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:329px;">Cardiac phased array receive coil</td>
			<td style="width:327px;">Philips Medical Systems</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:329px;">Pillows, straps, bolsters, and other positioning devices</td>
			<td style="width:327px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:329px;">Computer with MATLAB software</td>
			<td style="width:327px;">The Mathworks, Inc (Natick, MA)</td>
			<td style="width:119px;"></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.

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

Magnetic Resonance Imaging Quantification of Pulmonary Perfusion using Calibrated Arterial Spin Labeling

This demonstrates a MR imaging method to measure the spatial distribution of pulmonary blood flow in healthy subjects 
during normoxia (inspired O2, fraction (FIO2) = 0.21) hypoxia (FIO2 = 0.125), and hyperoxia 
(FIO2 = 1.00). In addition, the physiological responses of the subject are monitored in the MR scan environment. MR images 
were obtained on a 1.5 T GE MRI scanner during a breath hold from a sagittal slice in the right lung at functional residual capacity. An arterial 
spin labeling sequence (ASL-FAIRER) was used to measure the spatial distribution of pulmonary blood flow 1,2 and a multi-echo fast 
gradient echo (mGRE) sequence 3 was used to quantify the regional proton (i.e. H2O) density, allowing the quantification 
of density-normalized perfusion for each voxel (milliliters blood per minute per gram lung tissue). 
With a pneumatic switching valve and facemask equipped with a 2-way non-rebreathing valve, different oxygen concentrations 
were introduced to the subject in the MR scanner through the inspired gas tubing. A metabolic cart collected expiratory gas via expiratory tubing. Mixed expiratory O2 and CO2 concentrations, oxygen consumption, carbon dioxide production, respiratory exchange ratio, 
respiratory frequency and tidal volume were measured. Heart rate and oxygen saturation were monitored using pulse-oximetry. 
Data obtained from a normal subject showed that, as expected, heart rate was higher in hypoxia (60 bpm) than during normoxia (51) or hyperoxia (50) and the arterial oxygen saturation (SpO2) was reduced during hypoxia to 86%. Mean ventilation was 8.31 L/min BTPS during hypoxia, 7.04 L/min during normoxia, and 6.64 L/min during hyperoxia. Tidal volume was 0.76 L during hypoxia, 0.69 L during normoxia, and 0.67 L during hyperoxia. 
Representative quantified ASL data showed that the mean density normalized perfusion was 8.86 ml/min/g during hypoxia, 8.26 ml/min/g during normoxia and 8.46 ml/min/g during hyperoxia, respectively. In this subject, the relative dispersion4, an index of global heterogeneity, was increased in hypoxia (1.07 during hypoxia, 0.85 during normoxia, and 0.87 during hyperoxia) while the fractal dimension (Ds), another index of heterogeneity reflecting vascular branching structure, was unchanged (1.24 during hypoxia, 1.26 during normoxia, and 1.26 during hyperoxia). 
Overview. This protocol will demonstrate the acquisition of data to measure the distribution of pulmonary perfusion noninvasively under conditions of normoxia, hypoxia, and hyperoxia using a magnetic resonance imaging technique known as arterial spin labeling (ASL). 
Rationale: Measurement of pulmonary blood flow and lung proton density using MR technique offers high spatial resolution images which can be quantified and the ability to perform repeated measurements under several different physiological conditions. In human studies, PET, SPECT, and CT are commonly used as the alternative techniques. However, these techniques involve exposure to ionizing radiation, and thus are not suitable for repeated measurements in human subjects.

A MR imaging method to study the distribution of pulmonary blood flow under a variety of physiological conditions, in this case exposure to three different inspired oxygen concentrations: hypoxia, normoxia, and hyperoxia, is described. This technique utilizes human pulmonary physiology research techniques in an MR scanning environment.

使用校准动脉自旋标记磁共振肺灌注显像定量

This demonstrates a MR imaging method to measure the spatial distribution of pulmonary blood flow in healthy subjects 
during normoxia (inspired O2, ...

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 ...

Simultaneous PET/MRI Imaging During Mouse Cerebral Hypoxia-ischemia

Dynamic changes in tissue water diffusion and glucose metabolism occur during and after hypoxia in cerebral hypoxia-ischemia reflecting a bioenergetics disturbance in affected cells. Diffusion weighted magnetic resonance imaging (MRI) identifies regions that are damaged, potentially irreversibly, by hypoxia-ischemia. Alterations in glucose utilization in the affected tissue may be detectable by positron emission tomography (PET) imaging of 2-deoxy-2-(18F)fluoro-&#7429;-glucose ([18F]FDG) uptake. Due to the rapid and variable nature of injury in this animal model, acquisition of both modes of data must be performed simultaneously in order to meaningfully correlate PET and MRI data. In addition, inter-animal variability in the hypoxic-ischemic injury due to vascular differences limits the ability to analyze multi-modal data and observe changes to a group-wise approach if data is not acquired simultaneously in individual subjects. The method presented here allows one to acquire both diffusion-weighted MRI and [18F]FDG uptake data in the same animal before, during, and after the hypoxic challenge in order to interrogate immediate physiological changes.

The method presented here uses simultaneous positron emission tomography and magnetic resonance imaging. In the cerebral hypoxia-ischemia model, dynamic changes in diffusion and glucose metabolism occur during and after injury. The evolving and irreproducible damage in this model necessitates simultaneous acquisition if meaningful multi-modal imaging data are to be acquired.

同时PET / MRI成像在小鼠脑缺氧缺血

Dynamic changes in tissue water diffusion and glucose metabolism occur during and after hypoxia in cerebral hypoxia-ischemia reflecting a bioenergetics ...

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 ...

Cardiac Magnetic Resonance Imaging at 7 Tesla

CMR at an ultra-high field (magnetic field strength B0&#160;&#8805; 7 Tesla) benefits from the signal-to-noise ratio (SNR) advantage inherent at higher magnetic field strengths and potentially provides improved signal contrast and spatial resolution. While promising results have been achieved, ultra-high field CMR is challenging due to energy deposition constraints and physical phenomena such as transmission field non-uniformities and magnetic field inhomogeneities. In addition, the magneto-hydrodynamic effect renders the synchronization of the data acquisition with the cardiac motion difficult. The challenges are currently addressed by explorations into novel magnetic resonance technology. If all impediments can be overcome, ultra-high field CMR may generate new opportunities for functional CMR, myocardial tissue characterization, microstructure imaging or metabolic imaging. Recognizing this potential, we show that multi-channel radio frequency (RF) coil technology tailored for CMR at 7 Tesla together with higher order B0 shimming and a backup signal for cardiac triggering facilitates high fidelity functional CMR. With the proposed setup, cardiac chamber quantification can be accomplished in examination times similar to those achieved at lower field strengths. To share this experience and to support the dissemination of this expertise, this work describes our setup and protocol tailored for functional CMR at 7 Tesla.

The sensitivity gain inherent to ultrahigh field magnetic resonance holds promise for high spatial resolution imaging of the heart. Here, we describe a protocol customized for functional cardiovascular magnetic resonance (CMR) at 7 Tesla using an advanced multi-channel radio-frequency coil, magnetic field shimming and a triggering concept.

7号特斯拉的心脏磁共振成像

CMR at an ultra-high field (magnetic field strength B0&#160;&#8805; 7 Tesla) benefits from the signal-to-noise ratio (SNR) advantage inherent at higher ...

In Vivo Morphometric Analysis of Human Cranial Nerves Using Magnetic Resonance Imaging in Meni&#232;re's Disease Ears and Normal Hearing Ears

Analysis of neural structures in Meni&#232;re's Disease (MD) is of importance, since a loss of such structures has previously been proposed for this patient group but has yet to be confirmed. This protocol describes a method of in vivo evaluation of neural changes especially well suitable for cranial nerve analysis using magnetic resonance imaging (MRI). MD-patients and normal hearing persons were examined in a 3-T MR-scanner using a scan protocol including strongly T2-weighted 3D gradient-echo-sequence (3D-CISS). In the patient group, MD was additionally confirmed using MRI-based assessment of endolymphatic hydrops. Morphometric analysis was performed using a freeware DICOM viewer. Evaluation of cranial nerves included measurements of cross-sectional areas (CSAs) of the nerves at different levels as well as orthogonal diametric measurements.

To evaluate morphological changes of cranial nerves such as loss of neural structures or swelling of cranial nerves in Meni&#232;re&#39;s Disease (MD) or in healthy persons in vivo, a protocol of evaluation has been developed using magnetic resonance imaging (MRI). Additional MRI-based confirmation of MD was performed.

体内Menière 病耳和正常听觉的磁共振成像对人颅神经的形态学分析

Analysis of neural structures in Meni&#232;re's Disease (MD) is of importance, since a loss of such structures has previously been proposed for this ...

Phase Contrast Magnetic Resonance Imaging in the Rat Common Carotid Artery

Phase contrast magnetic resonance imaging (PC-MRI) is a noninvasive approach that can quantify flow-related parameters such as blood flow. Previous studies have shown that abnormal blood flow may be associated with systemic vascular risk. Thus, PC-MRI can facilitate the translation of data obtained from animal models of cardiovascular diseases to pertinent clinical investigations. In this report, we describe the procedure for measuring blood flow in the common carotid artery (CCA) of rats using cine-gated PC-MRI and discuss relevant analysis methods. This procedure can be performed in a live, anesthetized animal and does not require euthanasia after the procedure. The proposed scanning parameters yield repeatable measurements for blood flow, indicating excellent reproducibility of the results. The PC-MRI procedure described in this article can be used for pharmacological testing, pathophysiological assessment, and cerebral hemodynamics evaluation.

The overall goal of this procedure is to measure the blood flow in the rat common carotid artery by using noninvasive phase contrast magnetic resonance imaging.

大鼠颈总动脉的相位对比磁共振成像

Phase contrast magnetic resonance imaging (PC-MRI) is a noninvasive approach that can quantify flow-related parameters such as blood flow. Previous ...

Skeletal Muscle Neurovascular Coupling, Oxidative Capacity, and Microvascular Function with 'One Stop Shop' Near-infrared Spectroscopy

Exercise represents a major hemodynamic stress that demands a highly coordinated neurovascular response in order to match oxygen delivery to metabolic demand. Reactive hyperemia (in response to a brief period of tissue ischemia) is an independent predictor of cardiovascular events and provides important insight into vascular health and vasodilatory capacity. Skeletal muscle oxidative capacity is equally important in health and disease, as it determines the energy supply for myocellular processes. Here, we describe a simple, non-invasive approach using near-infrared spectroscopy to assess each of these major clinical endpoints (reactive hyperemia, neurovascular coupling, and muscle oxidative capacity) during a single clinic or laboratory visit. Unlike Doppler ultrasound, magnetic resonance images/spectroscopy, or invasive catheter-based flow measurements or muscle biopsies, our approach is less operator-dependent, low-cost, and completely non-invasive. Representative data from our lab taken together with summary data from previously published literature illustrate the utility of each of these end-points. Once this technique is mastered, application to clinical populations will provide important mechanistic insight into exercise intolerance and cardiovascular dysfunction.

Here, we describe a simple, non-invasive approach using near-infrared spectroscopy to assess reactive hyperemia, neurovascular coupling and skeletal muscle oxidative capacity in a single clinic or laboratory visit.

"一站式" 近红外光谱对骨骼肌神经血管的耦合、氧化能力及微血管功能的作用

Exercise represents a major hemodynamic stress that demands a highly coordinated neurovascular response in order to match oxygen delivery to metabolic ...

Quantification of Levator Ani Hiatus Enlargement by Magnetic Resonance Imaging in Males and Females with Pelvic Organ Prolapse

Here we present a protocol to examine the levator ani hiatus in males and females with pelvic organ prolapse, during the Valsalva maneuver and while evacuating acoustic gel, using a horizontally oriented 1.5 T magnetic resonance (MR) scanner. On midsagittal images, the vertical distance of pelvic organs is measured in millimeters relative to the hymen plane (female) and to the lower border of the symphysis pubis (male), preceded by - (above) or + ( below) signs. On axial images, the levator ani area is calculated in square centimeters with a free-hand tracing method from three key images, passing through the midsymphysis (level I), tangential to the lower border of the symphysis (level II), and at the maximal anterior rectal wall bulging (level III). Areas at rest and strained are compared to find evidence of a percentage of increase. The purpose is to provide objective evidence of the maximal extent of pelvic organs descent and hiatus enlargement without the interference of foreign objects or the examiner&#39;s proximity, so as to overcome the limitations of pelvic examination and transperineal sonography (i.e., subjectivity and sex-related limitations [female only]).

Here we present a protocol to standardize the measurement of the levator ani hiatus size&#160;by magnetic resonance imaging. The purpose is to extract biomechanical inferences from image analysis by comparing resting and straining values in patients of both sexes with pelvic prolapse, using consistent anatomical bony landmarks.

男性和女性盆腔器官脱垂的磁共振成像对左旋的定量研究

Here we present a protocol to examine the levator ani hiatus in males and females with pelvic organ prolapse, during the Valsalva maneuver and while ...