Name: ultrasound-based pulse wave velocity evaluation in mice
Uploaded: 2017-02-14T13:00:00.000+00:00
Duration: 8 min 7 s
Description: Watch this Scientific Journal Video about Ultrasound-based Pulse Wave Velocity Evaluation in Mice at JoVE.com

动物实验均按照欧盟指令（2010/63 / UE）和意法（D.Lvo二千〇一十四分之二十六）进行，它遵循实验室动物护理的原则。本地伦理委员会批准批准了研究。 1.成像过程<ol><li>鼠标放置在1升/分钟的纯氧气填充有2.5％的异氟醚麻醉诱导室中。通过反应迟钝到脚趾捏核实麻醉深度。 </li><li>放置在温度控制板上的动物以仰卧姿势。滋润动物的眼睛眼药，以避免它们干涸。通过将鼠标的鼻子中的专用鼻锥体供给麻醉气体流（1.5％异氟烷）。如果需要的话，从壳体调整异氟烷的百分比情况下，根据所研究的动物。修复在40℃的电路板温度。 </li><li>涂层用导电膏中的动物的四肢和磁带它们嵌入在所述ECG电极板。测量体温用直肠探头凡士林润滑。检查所有的生理测量（ECG和呼吸信号以及温度）是否正确取得并显示。 </li><li>从脱毛霜和声耦合胶衣其腹部化学清除头发。 </li><li>放置（13-24 MHz）的超声探头在机械手臂。 </li><li>固定探针平行于动物美国和调整，以获得腹主动脉纵向图像与位于聚焦区感兴趣区域的位置。 </li><li> 收集解剖信息。 <ol><li>点击按钮，允许高帧频心电门控采集9，选择帧速率采集等于700 FPS和开始采集。注意:在这种方式与单个心动周期容器的解剖图像可以获取。 </li></ol></li><li> 收集流速信息。&lt;/ STRONG&gt; <ol><li>使用相同的扫描投影，点击PW多普勒按钮，将样品体积在容器的中心，并获取图像确保电影回放不大于3秒短。获得这些数据保持角度修正尽可能小，从壳体调整它到外壳中获得的美国突起的基础上。 </li></ol></li><li>从温度控制板上卸下的动物，等待完全恢复。 注:在我们的经验，这大约需要10分钟。不要让动物无人看管，直到它已经恢复了足够的意识，以保持胸骨斜卧。 </li></ol> 2.后处理<ol><li>出口B模式和PW多普勒图像作为DICOM文件并保存在个人计算机上。变换PW多普勒DICOM文件.TIFF图像。 </li><li> 处理B模式图像。 <ol><li>导入使用专用的图形用户界面（GUI）中相应的DICOM文件。 </li><li>要初始化轮廓，贴近容器远处的墙上（单点击启动它，然后双击截至吧）和线接近双击近壁。平行于接近远处墙上的行会自动出现。申请通过按下"ANALYSE"按钮的单个帧上的算法。 </li><li>检查结果。如果该边缘已被正确识别（ 即 ，初始化点的进化已经检测到两个后部和前壁），通过点击"GO"按钮适用于整个电影圈的算法。如果边缘没有正确识别，点击"清除轮廓"清除它们，并通过重复点2.2.2重新初始化它们。 注:该算法是基于边缘检测和轮廓跟踪技术，并已详细10先前已经描述。 </li><li>通过按下"记录"按钮，获得最终结果和保存的科尔esponding其中包含有关单个心动周期的瞬时直径值.MAT文件。 </li></ol></li><li>打开了LND-V回路实现GUI。 </li><li> 为了启动这导致单拍平均速度曲线PW多普勒图像处理点击"VELOCITY"按钮。 <ol><li>标识PW多普勒跟踪和定位相应于一个速度值按"白线"按钮等于零的行。 </li><li>通过使用"速度"和"时间"按钮（在校准面板），分别执行速度校正和时间校准。按下这些按钮允许一个画一条线，其长度相当于插入的校准因子。 </li><li>手动选择使用"ROI PHYSIO"按钮包含生理信号的投资回报率。 </li><li>手动选择按"ROI SIGNAL"按钮包含PW多普勒跟踪一个投资回报率。 </li><li> CLI对"ANALYSE"按钮，CK检查信封标识。如果结果不理想，改变阈值（通过键入"速度阈值"可编辑的文本字段的新值），并再次按下"ANALYSE"按钮。调整阈值从个别情况，这取决于图象的质量。按"拟订一项"按钮。 </li><li>找到心电信号的R峰，并通过单击"更新"按钮，相应的分割速度包络信号。选择不受噪音通过点击"选择BEATS"键损坏或设在吸气阶段节拍。以这种方式，获得了单拍平均速度波形。 </li></ol></li><li>使用快速傅立叶变换方法来内插选定节拍在频域中，使它们都构成相同的数量的点的，如在参考11详细描述。只需按下自动RET执行此操作PC键盘一旦节拍上瓮键已经被选中。如果"平均速度"复选框被选中的单次搏动平均流速信号是通过将最大速度曲线由两个，假设到抛物线速度分布12来实现的。按"确定"按钮。 </li><li>点击"直径"按钮。插在时域中的单节拍直径波形，以便获得具有相同的采样频率为按"INTERPOLATE"按钮单拍速度信号的单拍直径信号。点击"确定"按钮。 注意:为了有单拍直径和平均具有相同的采样频率和相同数量的数据点速度曲线，它们在频域中进行内插。 </li><li>选择"二阶导数"的方法作为对齐方式（显示直径和速度波形图上方），点击"更新"按钮操ñ。两条曲线将被自动时间对齐使用二阶导数方法14。 </li><li>通过绘制针对单拍单拍直径值的自然对数平均流速值建立最终的LND-V循环。当两个波形对准这是自动完成的。注意:包含5％和90％的单拍的最大值之间分平均速度曲线被自动定位和在这些点的线性内插被施加到评估循环的线性部分的斜率。 </li><li>根据以下等式7 PWV计算 <img alt="式（1）" src="/files/ftp_upload/54362/54362eq1.jpg" /></li></ol>

<ol>
	<li>Zaragoza, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+Models+of+Cardiovascular+Diseases.">Animal Models of Cardiovascular Diseases.</a> J Biomed Biotechnol. 2011, 497-841 (2011).</li><li>Laurent, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expert+consensus+document+on+arterial+stiffness:+methodological+issues+and+clinical+applications.">Expert consensus document on arterial stiffness: methodological issues and clinical applications.</a> Eur Heart J. 27, 2588-2605 (2006).</li><li>Wang, Y. X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increased+aortic+stiffness+assessed+by+pulse+wave+velocity+in+apolipoprotein+E-deficient+mice.">Increased aortic stiffness assessed by pulse wave velocity in apolipoprotein E-deficient mice.</a> Am. J. Physiol. Heart Circ. Physiol. 278, 428-434 (2000).</li><li>Mitchell, G. F., Pfeffer, M. A., Finn, P. V., Pfeffer, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+techniques+for+measuring+pulse-wave+velocity+in+the+rat.">Comparison of techniques for measuring pulse-wave velocity in the rat.</a> J Appl Physiol. 82 (1), 203-210 (1997).</li><li>Parczyk, M., Herold, V., Klug, G., Bauer, W. R., Rommel, E., Jakob, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regional+in+vivo+transit+time+measurements+of+aortic+pulse+wave+velocity+in+mice+with+high-field+CMR+at+17.6+Tesla.">Regional in vivo transit time measurements of aortic pulse wave velocity in mice with high-field CMR at 17.6 Tesla.</a> J Cardiovasc Magn Reson. 12, 72 (2010).</li><li>Hartley, C. J., Taffet, G. E., Michael, L. H., Pham, T. T., Entman, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Noninvasive+determination+of+pulse-wave+velocity+in+mice.">Noninvasive determination of pulse-wave velocity in mice.</a> Am J Physiol. 273 (1), 494-500 (1997).</li><li>Feng, J., Khir, A. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determination+of+wave+speed+and+wave+separation+in+the+arteries+using+diameter+and+velocity.">Determination of wave speed and wave separation in the arteries using diameter and velocity.</a> J Biomech. 43 (3), 455-462 (2010).</li><li>Borlotti, A., Khir, A. W., Rietzschel, E. R., De Buyzere, M. L., Vermeersch, S., Segers, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Noninvasive+determination+of+local+pulse+wave+velocity+and+wave+intensity:+changes+with+age+and+gender+in+the+carotid+and+femoral+arteries+of+healthy+human.">Noninvasive determination of local pulse wave velocity and wave intensity: changes with age and gender in the carotid and femoral arteries of healthy human.</a> J Appl Physiol. 113 (5), 727-735 (2012).</li><li>Ch&#233;rin, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrahigh+frame+rate+retrospective+ultrasound+microimaging+and+blood+flow+visualization+in+mice+in+vivo.">Ultrahigh frame rate retrospective ultrasound microimaging and blood flow visualization in mice in vivo.</a> Ultrasound Med Biol. 32 (5), 683-691 (2006).</li><li>Gemignani, V., Faita, F., Ghiadoni, L., Poggianti, E., Demi, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+system+for+real-time+measurement+of+the+brachial+artery+diameter+in+B-mode+ultrasound+images.">A system for real-time measurement of the brachial artery diameter in B-mode ultrasound images.</a> IEEE Trans Med Imaging. 26 (3), 393-404 (2006).</li><li>Di Lascio, N., Stea, F., Kusmic, C., Sicari, R., Faita, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Non-invasive+assessment+of+pulse+wave+velocity+in+mice+by+means+of+ultrasound+images.">Non-invasive assessment of pulse wave velocity in mice by means of ultrasound images.</a> Atherosclerosis. 237 (1), 31-37 (2014).</li><li>Nichols, W. W., O'Rourke, M. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> McDonald's Blood Flow in Arteries: Theoretical, Experimental, and Clinical Principles. , 215-358 (1998).</li><li>Williams, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Noninvasive+ultrasonic+measurement+of+regional+and+local+pulse+wave+velocity+in+mice.">Noninvasive ultrasonic measurement of regional and local pulse wave velocity in mice.</a> Ultrasound Med Biol. 33 (9), 1368-1375 (2007).</li><li>Penny, D. 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作者什么都没有透露。

在这项研究中，基于对小鼠PWV评估LND-V循环的图像处理算法已被详细描述。所提出的方法是基于美国图像的处理之用，因此，可以代表现有技术6中 ，13为动脉硬度的在小鼠模型中评估一个有效的替代。事实上，相反地到其基于获取的动脉内压力信号和所需要的动物被处死侵入性的方法如图6所示 ，这种技术是完全非侵入性的，因此，可...

小鼠模型正日益用于心血管疾病的调查（CVD）和在纵向研究允许疾病发展1的不同阶段的表征中是特别使用。大动脉弹性性质与不同病理状况;从技术角度来看，动脉硬度可以通过测量脉搏波速度（PWV），其表示与该脉波在管道中容器2行进的速度进行评估。由于其临床意义，人们越来越即使是在临床前小动物模型3个测量。 不同的技术可用于在小鼠中评估PWV。侵入性方法是基于使用导管末端压力换能器。 PWV是通过在两个不同的动脉部位采集压力信号和除以两个测量之间的距离s评估由信号4之间的时移ITES。有关这类技术的主要缺点是，它们需要两个测量部位，因此，不能在纵向研究中使用之间的距离的评价动物牺牲。为了克服这一限制，可以根据不同的成像技术的非侵入性的方法，已经被开发。以前的研究已经报道通过将上速度编码磁共振成像数据5和脉冲多普勒信号6的渡越时间的方法得到的小鼠PWV评估。然而，用这些方法得到的PWV值是动脉硬化的一个区域评价。事实上，它代表一个平均值，占不同动脉的尺寸和弹性性能方面。此外，这些种类的评价的所需要的两个测量点之间的距离的评估是错误可能INF源luence最终结果。 PWV可以使用直径速度（LND-V）的环7进行评估。此方法是基于直径和流速值的选定容器中的同时评估。按照这种方法，LND-V族环通过绘制自然对数直径值获得VS平均速度值和PWV通过计算对应于早期收缩阶段所得到的循环的线性部分的斜率估算。关于实际执行这种方法，以前的作品已经报道了其在体外的建立系统7应用程序及其为颈动脉和股PWV人类8评估使用效果。 本研究的主要目的是提供一种图像处理算法的详细说明，提供了在使用Ú小鼠非侵入动脉的PWV测量仅s的图像。所提出的方法允许本地动脉硬度的由两个B模式和脉冲波多普勒（PW多普勒）的图像，并且可以对具有关键的重要性，动脉施加的处理装置的评价如腹主动脉。

<table><tbody><tr><td>VEVO2100</td><td>FUJIFILM VisualSonics Inc, Toronto, Canada</td><td></td><td>micro-ultrasound equipment</td></tr><tr><td>MS250 Ultrasound Probe</td><td>FUJIFILM VisualSonics Inc, Toronto, Canada</td><td></td><td>micro-ultrasound probe</td></tr><tr><td>EKV Software</td><td>FUJIFILM VisualSonics Inc, Toronto, Canada</td><td></td><td>Software</td></tr><tr><td>Matlab R2015a&amp;nbsp;</td><td>MathWorks Inc, Natick, MA, USA</td><td></td><td>Software</td></tr><tr><td>Conductive Paste</td><td>Chosen by the operator</td><td></td><td>Laboratory material</td></tr><tr><td>Petroleum Jelly</td><td>Chosen by the operator</td><td></td><td>Laboratory material</td></tr><tr><td>Depilatory Cream</td><td>Chosen by the operator</td><td></td><td>Laboratory material</td></tr><tr><td>Acoustic Coupling Gel&amp;nbsp;</td><td>Chosen by the operator</td><td></td><td>Laboratory material</td></tr><tr><td>Developed Matlab Software</td><td></td><td></td><td>The authors are willing to collaborate with those researchers who are interested in the software and to make the software available under their supervision</td></tr></tbody></table>

ultrasound-based pulse wave velocity evaluation in mice

动脉硬度可通过计算脉搏波速度（PWV）， 即 ，与该脉波在管道容器行进的速度进行评价。该参数在它被用于评估在与特定基因型/治疗血管功能的改变或用于表征心血管疾病进展小啮齿动物模型中被越来越多的研究。这个协议描述这导致仅使用超声（US）图像小鼠非侵入动脉的PWV测量的图像处理算法。所提出的技术已被用来评估腹主动脉PWV小鼠，并评估其与年龄相关的变化。 腹主动脉美国扫描是从用装有高频美国探针的特定美国设备气态麻醉下的小鼠获得。 B型和脉搏波的多普勒（PW多普勒）图像，以便分别获得直径和平均血流速度瞬时值，分析。为了这个目的，边缘检测和轮廓跟踪技术使用。单拍平均直径和速度波形是时间对齐和组合，以实现对直径速度（LND-V）的循环。 PWV值从环路，其对应于早期收缩相位的线性部分的斜率获得的。 用本方法，解剖和功能信息有关鼠标腹主动脉可以非侵入性地实现。要求美国图像的处理而已，它可以表示为在小鼠的不同动脉部位的弹性特性方面的非侵入性特征的有用工具。本技术的应用可以很容易地扩展到其他血管区，如颈内动脉，因此提供了可能性，以获得一个多站点动脉僵硬度评估。

所提出的方法已被应用到小鼠腹主动脉在先前的研究11。下图显示了真实影像小鼠所描述的方法的应用程序的结果。这些数据是从一个单一的动物（野生型小鼠13周龄，应变:C57BL6，重量33 g）在特别地， 图1表示美国图像的分析的结果。适用于具有高帧率心电门控模式提供直径波形获得的B型图像边缘检测和轮廓跟踪技术;另一方面，对PW-多普勒?...

Watch this Scientific Journal Video about Ultrasound-based Pulse Wave Velocity Evaluation in Mice at JoVE.com

Ultrasound-based Pulse Wave Velocity Evaluation in Mice

动脉硬度表示可以被认为是对动脉僵硬度的替代索引在心血管疾病和脉搏波速度（PWV）的关键因素。这个协议描述了用于基于可应用于在不同的动脉部位的超声波图像处理小鼠计算的PWV的图像处理算法。

基于超声脉搏波速度评价小鼠

Arterial stiffness can be evaluated by calculating pulse wave velocity (PWV), i.e., the speed with which the pulse wave travels in a conduit vessel. This ...

ultrasound-based-pulse-wave-velocity-evaluation-in-mice

Research

JoVE Journal

Medicine

13.0K 次观看.  Scuola Superiore Sant'Anna. 动脉硬度表示可以被认为是对动脉僵硬度的替代索引在心血管疾病和脉搏波速度（PWV）的关键因素。这个协议描述了用于基于可应用于在不同的动脉部位的超声波图像处理小鼠计算的PWV的图像处理算法。 

视频: Ultrasound-based Pulse Wave Velocity Evaluation in Mice

Transthoracic Echocardiography in Mice

In recent years, murine models have become the primary avenue for studying the molecular mechanisms of cardiac dysfunction resulting from changes in gene expression. Transgenic and gene targeting methods can be used to generate mice with altered cardiac size and function,1-3 and as a result, in vivo techniques are needed to evaluate their cardiac phenotype. Transthoracic echocardiography, pulse wave Doppler (PWD), and tissue Doppler imaging (TDI) can be used to provide dimensional measurements of the mouse heart and to quantify the degree of cardiac systolic and diastolic performance. Two-dimensional imaging is used to detect abnormal anatomy or movements of the left ventricle, whereas M-mode echo is used for quantification of cardiac dimensions and contractility.4,5 In addition, PWD is used to quantify localized velocity of turbulent flow,6 whereas TDI is used to measure the velocity of myocardial motion.7 Thus, transthoracic echocardiography offers a comprehensive method for the noninvasive evaluation of cardiac function in mice.

Transthoracic echocardiography offers a noninvasive method for the evaluation of cardiac function in mice. A combination of ultrasound and Doppler imaging modalities can be used to obtain dimensional measurements of the heart and intracardiac blood flow, which together provide an assessment of cardiac systolic and diastolic performance.

经胸超声心动图在小鼠

In recent years, murine models have become the primary avenue for studying the molecular mechanisms of cardiac dysfunction resulting from changes in gene ...

科研

医学

High-frequency High-resolution Echocardiography: First Evidence on Non-invasive Repeated Measure of Myocardial Strain, Contractility, and Mitral Regurgitation in the Ischemia-reperfused Murine Heart

Ischemia-reperfusion (IR) was surgically performed in murine hearts which were then subjected to repeated imaging to monitor temporal changes in functional parameters of key clinical significance. Two-dimensional movies were acquired at high frame rate (8 kHz) and were utilized to estimate high-quality myocardial strain. Two-dimensional elastograms (strain images), as well as strain profiles, were visualized. Results were powerful in quantitatively assessing IR-induced changes in cardiac events including left-ventricular (LV) contraction, LV relaxation and isovolumetric phases of both pre-IR and post-IR beating hearts in intact mice. In addition, compromised sector-wise wall motion and anatomical deformation in the infarcted myocardium were visualized.  The elastograms were uniquely able to provide information on the following parameters in addition to standard physiological indices that are known to be affected by myocardial infarction in the mouse: internal diameters of mitral valve orifice and aorta, effective regurgitant orifice, myocardial strain (circumferential as well as radial), turbulence in blood flow pattern as revealed by the color Doppler movies and velocity profiles, asynchrony in LV sector, and changes in the length and direction of vectors demonstrating slower and asymmetrical wall movement. This work emphasizes on the visual demonstration of how such analyses are performed. 

High-frequency High-resolution Echocardiography: First Evidence on Non-invasive Repeated Measure of Myocardial Strain, Contractility, and Mitral Regurgitation in the Ischemia-reperfused Murine Heart 

High frequency Doppler ultrasound is a novel technology for assessing regional myocardial function. This work presents first evidence demonstrating applicability of this versatile imaging platform for the repeated measure of myocardial strain, dp/dt, and mitral regurgitation in the ischemia-reperfused (IR) murine heart.

高频超声心动图：非侵入性的反复测量小鼠心脏缺血再灌注心肌劳损，收缩力，二尖瓣关闭不全的第一个证据

Ischemia-reperfusion (IR) was surgically performed in murine hearts which were then subjected to repeated imaging to monitor temporal changes in ...

Murine Echocardiography and Ultrasound Imaging

Rodent models of cardiac pathophysiology represent a valuable research tool to investigate mechanism of disease as well as test new therapeutics.1 Echocardiography provides a powerful, non-invasive tool to serially assess cardiac morphometry and function in a living animal.2 However, using this technique on mice poses unique challenges owing to the small size and rapid heart rate of these animals.3 Until recently, few ultrasound systems were capable of performing quality echocardiography on mice, and those generally lacked the image resolution and frame rate necessary to obtain truly quantitative measurements. Newly released systems such as the VisualSonics Vevo2100 provide new tools for researchers to carefully and non-invasively investigate cardiac function in mice. This system generates high resolution images and provides analysis capabilities similar to those used with human patients. Although color Doppler has been available for over 30 years in humans, this valuable technology has only recently been possible in rodent ultrasound.4,5 Color Doppler has broad applications for echocardiography, including the ability to quickly assess flow directionality in vessels and through valves, and to rapidly identify valve regurgitation. Strain analysis is a critical advance that is utilized to quantitatively measure regional myocardial function.6 This technique has the potential to detect changes in pathology, or resolution of pathology, earlier than conventional techniques. Coupled with the addition of three-dimensional image reconstruction, volumetric assessment of whole-organs is possible, including visualization and assessment of cardiac and vascular structures. Murine-compatible contrast imaging can also allow for volumetric measurements and tissue perfusion assessment.

This video demonstrates use of a rail-mounted high-frequency ultrasound probe to perform echocardiography on an anesthetized mouse. The methods describe both conventional two-dimensional and M-mode measurements of cardiac function in addition to newer, more powerful tools such as color Doppler, strain analysis, as well as general and targeted contrast imaging.

小鼠超声心动图和超声成像

Rodent models of cardiac pathophysiology represent a valuable research tool to investigate mechanism of disease as well as test new therapeutics.1  ...

Pulse Wave Velocity Testing in the Baltimore Longitudinal Study of Aging

Carotid-femoral pulse wave velocity is considered the gold standard for measurements of central arterial stiffness obtained through noninvasive methods1.&#160;Subjects are placed in the supine position and allowed to rest quietly for at least 10 min prior to the start of the exam. The proper cuff size is selected and a blood pressure is obtained using an oscillometric device. Once a resting blood pressure has been obtained, pressure waveforms are acquired from the right femoral and right common carotid arteries. The system then automatically calculates the pulse transit time between these two sites (using the carotid artery as a surrogate for the descending aorta). Body surface measurements are used to determine the distance traveled by the pulse wave between the two sampling sites. This distance is then divided by the pulse transit time resulting in the pulse wave velocity. The measurements are performed in triplicate and the average is used for analysis.

Pulse wave velocity (PWV) measurement assesses arterial stiffness by a tonometry-based system that measures the speed with which arterial pressure wave travels along the arterial tree, typically approximating the time that it takes this wave to travel from the descending aorta (using the carotid artery as a surrogate) to the femoral artery. Carotid-femoral PWV increases two- to threefold across the adult lifespan.

脉搏波传导速度测试老化的巴尔的摩纵向研究中

Carotid-femoral pulse wave velocity is considered the gold standard for measurements of central arterial stiffness obtained through noninvasive ...

Assessment of Right Ventricular Structure and Function in Mouse Model of Pulmonary Artery Constriction by Transthoracic Echocardiography

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, the RV is significantly affected in pulmonary diseases such as pulmonary artery hypertension (PAH). In addition, the RV is remarkably sensitive to cardiac pathologies, including left ventricular (LV) dysfunction, valvular disease or RV infarction4. To understand the role of RV in the pathogenesis of cardiac diseases, a reliable and noninvasive method to access the RV structurally and functionally is essential.
A noninvasive trans-thoracic echocardiography (TTE) based methodology was established and validated for monitoring dynamic changes in RV structure and function in adult mice. To impose RV stress, we employed a surgical model of pulmonary artery constriction (PAC) and measured the RV response over a 7-day period using a high-frequency ultrasound microimaging system. Sham operated mice were used as controls. Images were acquired in lightly anesthetized mice at baseline (before surgery), day 0 (immediately post-surgery), day 3, and day 7 (post-surgery). Data was analyzed offline using software.
Several acoustic windows (B, M, and Color Doppler modes), which can be consistently obtained in mice, allowed for reliable and reproducible measurement of RV structure (including RV wall thickness, end-diastolic&#160;and end-systolic dimensions), and function (fractional area change, fractional shortening, PA peak velocity, and peak pressure gradient) in normal mice and following PAC.
Using this method, the pressure-gradient resulting from PAC was accurately measured in real-time using Color Doppler mode and was comparable to direct pressure measurements performed with a Millar high-fidelity microtip catheter. Taken together, these data demonstrate that RV measurements obtained from various complimentary views using echocardiography are reliable, reproducible and can provide insights regarding RV structure and function. This method will enable a better understanding of the role of RV cardiac dysfunction.

Right ventricle (RV) dysfunction is critical to the pathogenesis of cardiovascular disease, yet limited methodologies are available for its evaluation. Recent advances in ultrasound imaging provide a noninvasive and accurate option for longitudinal RV study. Herein, we detail a step-by-step echocardiographic method using a murine model of RV pressure overload.

右心室结构和功能的肺动脉缩窄经胸超声小鼠模型的评估

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, ...

Measuring Ascending Aortic Stiffness In Vivo in Mice Using Ultrasound

We present a protocol for measuring in vivo aortic stiffness in mice using high-resolution ultrasound imaging. Aortic diameter is measured by ultrasound and aortic blood pressure is measured invasively with a solid-state pressure catheter. Blood pressure is raised then lowered incrementally by intravenous infusion of vasoactive drugs phenylephrine and sodium nitroprusside. Aortic diameter is measured for each pressure step to characterize the pressure-diameter relationship of the ascending aorta. Stiffness indices derived from the pressure-diameter relationship can be calculated from the data collected. Calculation of arterial compliance is described in this protocol.
This technique can be used to investigate mechanisms underlying increased aortic stiffness associated with cardiovascular disease and aging. The technique produces a physiologically relevant measure of stiffness compared to ex vivo approaches because physiological influences on aortic stiffness are incorporated in the measurement. The primary limitation of this technique is the measurement error introduced from the movement of the aorta during the cardiac cycle. This motion can be compensated by adjusting the location of the probe with the aortic movement as well as making multiple measurements of the aortic pressure-diameter relationship and expanding the experimental group size.

Measuring Ascending Aortic Stiffness In Vivo in Mice Using Ultrasound

We describe a technique for measuring aortic stiffness from its pressure-diameter relationship in vivo in mice. Aortic diameter is recorded by ultrasound and aortic pressure is measured invasively with a solid-state pressure catheter. Blood pressure is changed incrementally and the resulting diameter is measured.

测量升主动脉刚度<em&gt;在体内</em&gt;小鼠使用超声

We present a protocol for measuring in vivo aortic stiffness in mice using high-resolution ultrasound imaging. Aortic diameter is measured by ultrasound ...

Ultrasound Based Assessment of Coronary Artery Flow and Coronary Flow Reserve Using the Pressure Overload Model in Mice

Transthoracic Doppler echocardiography (TTDE) is a clinically useful, noninvasive tool for studying coronary artery flow velocity and coronary flow reserve (CFR) in humans. Reduced CFR is accompanied by marked intramyocardial and pericoronary fibrosis and is used as an indication of the severity of dysfunction. This study explores, step-by-step, the real-time changes measured in the coronary flow velocity, CFR and systolic to diastolic peak velocity (S/D) ratio in the setting of an aortic banding model in mice. By using a Doppler transthoracic imaging technique that yields reproducible and reliable data, the method assesses changes in flow in the septal coronary artery (SCA), for a period of over two weeks in mice, that previously either underwent aortic banding or thoracotomy. 
During imaging, hyperemia in all mice was induced by isoflurane, an anesthetic that increased coronary flow velocity when compared with resting flow. All images were acquired by a single imager. Two ratios, (1) CFR, the ratio between hyperemic and baseline flow velocities, and (2) systolic (S) to diastolic (D) flow were determined, using a proprietary software and by two independent observers. Importantly, the observed changes in coronary flow preceded LV dysfunction as evidenced by normal LV mass and fractional shortening (FS). 
The method was benchmarked against the current gold standard of coronary assessment, histopathology. The latter technique showed clear pathologic changes in the coronary artery in the form of peri-coronary fibrosis that correlated to the flow changes as assessed by echocardiography. 
The study underscores the value of using a non-invasive technique to monitor coronary circulation in mouse hearts. The method minimizes redundant use of research animals and demonstrates that advanced ultrasound-based indices, such as CFR and S/D ratios, can serve as viable diagnostic tools in a variety of investigational protocols including drug studies and the study of genetically modified strains.

Coronary flow reserve (CFR) is useful for assessment of myocardial oxygen demand and evaluation of cardiovascular risk. This study establishes a step-by-step transthoracic Doppler echocardiographic (TTDE) method for longitudinal monitoring of the changes in CFR, as measured from coronary artery in mice, under the experimental pressure overload of aortic banding.

冠脉流量和冠状动脉血流储备用小鼠压力超负荷基于模型的超声评估

Transthoracic Doppler echocardiography (TTDE) is a clinically useful, noninvasive tool for studying coronary artery flow velocity and coronary flow ...

Assessment of Cardiac Morphological and Functional Changes in Mouse Model of Transverse Aortic Constriction by Echocardiographic Imaging

Transverse aortic constriction (TAC) in mice has been used as a valuable model to study mechanisms of cardiac hypertrophy and heart failure1. A reliable noninvasive method is essential to assess real-time cardiac morphological and functional changes in animal models of heart disease. Transthoracic echocardiography represents an important tool for noninvasive assessment of cardiac structure and function2. Here we used a high-resolution ultrasound imaging system to monitor myocardial remodeling and heart failure progression over time in a mouse model of TAC. B-mode, M-mode, and Doppler imaging were used to precisely assess cardiac hypertrophy, ventricular dilatation, and functional deterioration in mice following TAC. Color and pulse wave (PW) Doppler imaging was used to noninvasively measure pressure gradient across the aortic constriction created by TAC and to assess transmitral blood flow in mice. Thus transthoracic echocardiographic imaging provides comprehensive noninvasive measurements of cardiac dimensions and function in mouse models of heart disease.

The goal of this protocol is to noninvasively assess cardiac structural and functional changes in a mouse model of heart disease created by transverse aortic constriction, using B- and M-mode echocardiography and color/pulse wave Doppler imaging.

在横向主动脉缩窄的小鼠模型和心脏形态学评估功能改变通过超声心动图成像

Transverse aortic constriction (TAC) in mice has been used as a valuable model to study mechanisms of cardiac hypertrophy and heart failure1. A reliable ...

Echocardiographic Approaches and Protocols for Comprehensive Phenotypic Characterization of Valvular Heart Disease in Mice

The aim of this manuscript and accompanying video is to provide an overview of the methods and approaches used for imaging heart valve function in rodents, with detailed descriptions of the appropriate methods for anesthesia, the echocardiographic windows used, the imaging planes and probe orientations for image acquisition, the methods for data analysis, and the limitations of emerging technologies for the evaluation of cardiac and valvular function. Importantly, we also highlight several future areas of research in cardiac and heart valve imaging that may be leveraged to gain insights into the pathogenesis of valve disease in preclinical animal models. We propose that using a systematic approach to evaluating cardiac and heart valve function in mice can result in more robust and reproducible data, as well as facilitate the discovery of previously underappreciated phenotypes in genetically-altered and/or physiologically-stressed mice.

This protocol provides a detailed description of the echocardiographic approach for comprehensive phenotyping of heart and heart valve function in mice.

超声心动图方法和协议心脏瓣膜疾病的综合表型特征小鼠

The aim of this manuscript and accompanying video is to provide an overview of the methods and approaches used for imaging heart valve function in ...

Measurement of Pulse Propagation Velocity, Distensibility and Strain in an Abdominal Aortic Aneurysm Mouse Model

An abdominal aortic aneurysm (AAA) is defined as a localized dilation of the abdominal aorta that exceeds the maximal intraluminal diameter (MILD) by 1.5 times of its original size. Clinical and experimental studies have shown that small aneurysms may rupture, while a subpopulation of large aneurysms may remain stable. Thus, in addition to the measurement of intraluminal diameter of the aorta, knowledge of structural traits of the vessel wall may provide important information to assess the stability of the AAA. Aortic stiffening has recently emerged as a reliable tool to determine early changes in the vascular wall. Pulse propagation velocity (PPV) along with the distensibility and radial strain are highly useful ultrasound-based methods relevant for assessing aortic stiffness. The primary purpose of this protocol is to provide a comprehensive technique for the use of ultrasound imaging system to acquire images and analyze the structural and functional properties of the aorta as determined by MILD, PPV, distensibility and radial strain.

This manuscript describes a detailed protocol for using high frequency ultrasound imaging to measure luminal diameter, pulse propagation velocity, distensibility and radial strain on a mouse model of abdominal aortic aneurysm.

腹部主动脉瘤小鼠模型中脉冲传播速度、失散性和应变的测量

An abdominal aortic aneurysm (AAA) is defined as a localized dilation of the abdominal aorta that exceeds the maximal intraluminal diameter (MILD) by 1.5 ...