Name: transthoracic speckle tracking echocardiography for the quantitative assessment of left ventricular myocardial deformation
Uploaded: 2016-10-20T15:00:00
Description: Watch this Scientific Journal Video about Transthoracic Speckle Tracking Echocardiography for the Quantitative Assessment of Left Ventricular Myocardial Deformation at JoVE.com

The authors thank the echocardiographic study subject for volunteering in the video as well as Witten/Herdecke University and HELIOS Research Center (HRC-ID 000416 assigned to Kai O. Hensel) for funding.

The protocol content has been ethically approved by the Witten/Herdecke University Ethics Committee.
1. Technical Requirements
<ol>
	<li>Utilize an echocardiography device featuring speckle tracking technology equipped with an adequate sector array tissue harmonic imaging transducer.</li>
	<li>During image acquisition, record and connect a standard 3-lead EKG directly to the echocardiography device in order to synchronize echocardiographic motion images to electromechanical activity. This is mandatory for timing...

<ol>
	<li>Leischik, R., Dworrak, B., Hensel, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intraobserver+and+interobserver+reproducibility+for+radial,+circumferential+and+longitudinal+strain+echocardiography.">Intraobserver and interobserver reproducibility for radial, circumferential and longitudinal strain echocardiography.</a> Open Cardiovasc. Med. J. 8, 102-109 (2014).</li><li>Smiseth, O. A., Torp, H., Opdahl, A., Haugaa, K. H., Urheim, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Myocardial+strain+imaging:+how+useful+is+it+in+clinical+decision+making?.">Myocardial strain imaging: how useful is it in clinical decision making?.</a> Eur Heart J. , (2015).</li><li>Opdahl, A., Helle-Valle, T., Skulstad, H., Smiseth, O. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strain,+strain+rate,+torsion,+and+twist:+echocardiographic+evaluation.">Strain, strain rate, torsion, and twist: echocardiographic evaluation.</a> Curr. Cardiol. Rep. 17, 568 (2015).</li><li>Kukulski, T., 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=Identification+of+acutely+ischemic+myocardium+using+ultrasonic+strain+measurements.+A+clinical+study+in+patients+undergoing+coronary+angioplasty.">Identification of acutely ischemic myocardium using ultrasonic strain measurements. A clinical study in patients undergoing coronary angioplasty.</a> J. Am. Coll. Cardiol. 41, 810-819 (2003).</li><li>Suffoletto, M. S., Dohi, K., Cannesson, M., Saba, S., Gorcsan, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+speckle-tracking+radial+strain+from+routine+black-and-white+echocardiographic+images+to+quantify+dyssynchrony+and+predict+response+to+cardiac+resynchronization+therapy.">Novel speckle-tracking radial strain from routine black-and-white echocardiographic images to quantify dyssynchrony and predict response to cardiac resynchronization therapy.</a> Circulation. 113, 960-968 (2006).</li><li>Hensel, K. O., 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=Subclinical+Alterations+of+Cardiac+Mechanics+Present+Early+in+the+Course+of+Pediatric+Type+1+Diabetes+Mellitus:+A+Prospective+Blinded+Speckle+Tracking+Stress+Echocardiography+Study.">Subclinical Alterations of Cardiac Mechanics Present Early in the Course of Pediatric Type 1 Diabetes Mellitus: A Prospective Blinded Speckle Tracking Stress Echocardiography Study.</a> J Diabetes Res. 2016, 2583747 (2016).</li><li>Kalam, K., Otahal, P., Marwick, T. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prognostic+implications+of+global+LV+dysfunction:+a+systematic+review+and+meta-analysis+of+global+longitudinal+strain+and+ejection+fraction.">Prognostic implications of global LV dysfunction: a systematic review and meta-analysis of global longitudinal strain and ejection fraction.</a> Heart. 100, 1673-1680 (2014).</li><li>Hensel, K. O., Grimmer, F., Jenke, A. C., Wirth, S., Heusch, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+influence+of+real-time+blood+glucose+levels+on+left+ventricular+myocardial+strain+and+strain+rate+in+pediatric+patients+with+type+1+diabetes+mellitus+-+a+speckle+tracking+echocardiography+study.">The influence of real-time blood glucose levels on left ventricular myocardial strain and strain rate in pediatric patients with type 1 diabetes mellitus - a speckle tracking echocardiography study.</a> BMC Cardiovasc. Disord. 15, 175 (2015).</li><li>Kurt, M., Tanboga, I. H., Aksakal, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two-Dimensional+Strain+Imaging:+Basic+principles+and+Technical+Consideration.">Two-Dimensional Strain Imaging: Basic principles and Technical Consideration.</a> Eurasian J Med. 46, 126-130 (2014).</li><li>Cameli, M., Lisi, M., Righini, F. M., Mondillo, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+echocardiographic+techniques+to+assess+left+atrial+size,+anatomy+and+function.">Novel echocardiographic techniques to assess left atrial size, anatomy and function.</a> Cardiovasc. Ultrasound. 10 (4), (2012).</li><li>Pellikka, P. A., Nagueh, S. F., Elhendy, A. A., Kuehl, C. A., Sawada, S. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=American+Society+of+Echocardiography+recommendations+for+performance,+interpretation,+and+application+of+stress+echocardiography.">American Society of Echocardiography recommendations for performance, interpretation, and application of stress echocardiography.</a> J. Am. Soc. Echocardiogr. 20, 1021-1041 (2007).</li><li>Lang, R. M., 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=Recommendations+for+cardiac+chamber+quantification+by+echocardiography+in+adults:+an+update+from+the+American+Society+of+Echocardiography+and+the+European+Association+of+Cardiovascular+Imaging.">Recommendations for cardiac chamber quantification by echocardiography in adults: an update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging.</a> J. Am. Soc. Echocardiogr. 28, 1-39 (2015).</li><li>Curtis, J. P., 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=The+association+of+left+ventricular+ejection+fraction,+mortality,+and+cause+of+death+in+stable+outpatients+with+heart+failure.">The association of left ventricular ejection fraction, mortality, and cause of death in stable outpatients with heart failure.</a> J. Am. Coll. Cardiol. 42, 736-742 (2003).</li><li>Liebson, P. 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=Echocardiographic+correlates+of+left+ventricular+structure+among+844+mildly+hypertensive+men+and+women+in+the+Treatment+of+Mild+Hypertension+Study+(TOMHS).">Echocardiographic correlates of left ventricular structure among 844 mildly hypertensive men and women in the Treatment of Mild Hypertension Study (TOMHS).</a> Circulation. 87, 476-486 (1993).</li><li>Hensel, K. O., Jenke, A., Leischik, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Speckle-tracking+and+tissue-Doppler+stress+echocardiography+in+arterial+hypertension:+a+sensitive+tool+for+detection+of+subclinical+LV+impairment.">Speckle-tracking and tissue-Doppler stress echocardiography in arterial hypertension: a sensitive tool for detection of subclinical LV impairment.</a> Biomed Res Int. , 472562 (2014).</li><li>Gorcsan, J., Tanaka, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Echocardiographic+assessment+of+myocardial+strain.">Echocardiographic assessment of myocardial strain.</a> J. Am. Coll. Cardiol. 58, 1401-1413 (2011).</li><li>Holmes, A. A., Taub, C. C., Garcia, M. J., Shan, J., Slovut, D. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increased+Apical+Rotation+in+Severe+Aortic+Stenosis+is+Associated+with+Reduced+Survival:+A+Speckle-Tracking.">Increased Apical Rotation in Severe Aortic Stenosis is Associated with Reduced Survival: A Speckle-Tracking.</a> J. Am. Soc. Echocardiogr. , (2015).</li><li>Auger, D., 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=Effect+of+cardiac+resynchronization+therapy+on+the+sequence+of+mechanical+activation+assessed+by+two-dimensional+radial+strain+imaging.">Effect of cardiac resynchronization therapy on the sequence of mechanical activation assessed by two-dimensional radial strain imaging.</a> Am. J. Cardiol. 113, 982-987 (2014).</li><li>To, A. 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=Strain-time+curve+analysis+by+speckle+tracking+echocardiography+in+cardiac+resynchronization+therapy:+Insight+into+the+pathophysiology+of+responders+vs.+non-responders.">Strain-time curve analysis by speckle tracking echocardiography in cardiac resynchronization therapy: Insight into the pathophysiology of responders vs. non-responders.</a> Cardiovasc. Ultrasound. 14 (14), (2016).</li><li>Seo, Y., 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=Three-dimensional+propagation+imaging+of+left+ventricular+activation+by+speckle-tracking+echocardiography+to+predict+responses+to+cardiac+resynchronization+therapy.">Three-dimensional propagation imaging of left ventricular activation by speckle-tracking echocardiography to predict responses to cardiac resynchronization therapy.</a> J. Am. Soc. Echocardiogr. 28, 606-614 (2015).</li><li>Trache, T., Stobe, S., Tarr, A., Pfeiffer, D., Hagendorff, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+agreement+between+3D,+standard+2D+and+triplane+2D+speckle+tracking:+effects+of+image+quality+and+3D+volume+rate.">The agreement between 3D, standard 2D and triplane 2D speckle tracking: effects of image quality and 3D volume rate.</a> Echo Res Pract. 1, 71-83 (2014).</li><li>Sanchez, A. A., 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=Effects+of+frame+rate+on+two-dimensional+speckle+tracking-derived+measurements+of+myocardial+deformation+in+premature+infants.">Effects of frame rate on two-dimensional speckle tracking-derived measurements of myocardial deformation in premature infants.</a> Echocardiography. 32, 839-847 (2015).</li><li>Hensel, K. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Non-ischemic+diabetic+cardiomyopathy+may+initially+exhibit+a+transient+subclinical+phase+of+hyperdynamic+myocardial+performance.">Non-ischemic diabetic cardiomyopathy may initially exhibit a transient subclinical phase of hyperdynamic myocardial performance.</a> Medical Hypotheses. 94, 7-10 (2016).</li></ol>

Significance of the technique with respect to alternative methods
The current gold standard for the echocardiographic assessment of LV systolic function is the LV ejection fraction (EF)13. However, determination of EF is based on a simplistic approach that is closely correlated to the radial component of myocardial contraction but does not take into consideration the important longitudinal and circumferential planes. Hence, EF oversimplifies the three-dimensional co...

Scientific and clinical scenarios in cardiovascular medicine are more and more addressed by continuous variables and cutoff values rather than simplistic &#34;yes or no&#34; algorithms. Imaging techniques have evolved to be able to assess cardiac function in ever increasing detail. Speckle tracking echocardiography (STE) is an emerging diagnostic tool for the quantitative evaluation of myocardial performance. While conventional echocardiography is limited by subjective image interpretation and a strong dependence on the individual examiner&#39;s expertise, STE has been introduced as a reproducible and more objective method to quantify global and regional systolic and diastolic function1,2.
Left ventricular (LV) myocardial deformation &#8212; longitudinal and circumferential shortening as well as radial thickening in systole and vice versa in diastole &#8212; can be described measuring the parameters strain (&#949;) and strain rate (SR). &#949; is a dimensionless percent change in myocardial length. SR is a time derivate of &#949;3. These important indices of myocardial function have been shown to be able to identify myocardial ischemia4, predict response to cardiac resynchronization therapy5 and to detect subclinical myocardial dysfunction while conventional echocardiographic parameters still remain normal6. In a systematic meta-analysis, global longitudinal &#949;, the most frequently used quantitative LV systolic function parameter, has been shown to have superior prognostic value for the prediction of major adverse cardiac events then LV ejection fraction (EF), the current gold standard for the assessment of LV systolic function7. Even very subtle alterations such as the effect of short term metabolic changes on myocardial mechanics in asymptomatic patients can be detected utilizing STE8.
Technically, STE uses greyscale 2D or 3D B-mode motion images recorded in standard echocardiography views. Several consecutive cardiac cycles are recorded in apical 4-, 3- and 2-chamber views to measure longitudinal deformation and in the parasternal short axis view for circumferential and radial deformation9. Moreover, by capturing the short axis view at the level of the mitral valve, the papillary muscles and the apex, LV torsion can be assessed3. Subsequently to image acquisition and storage as digital loops, myocardial deformation is measured on an off-line work station or on the ultrasound device itself. The software detects unique myocardial pixel patterns in the recorded greyscale images, so-called &#34;speckles&#34; and traces them throughout the analyzed cardiac cycle. Vectors are measured and deformation parameters are subsequently calculated. This way regional and global myocardial deformation can be assessed in systole and diastole for both the left and right ventricle and atrium10.

<table border="0" cellpadding="0" cellspacing="0" width="1299">
	<colgroup>
		<col />
		<col span="2" />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:373px;">Phillips iE33 ultrasound system</td>
			<td style="width:155px;">Philips Healthcare</td>
			<td style="width:155px;"></td>
			<td style="width:619px;">http://www.umiultrasound.com/ultrasound-machine/philips/ie33</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:373px;"> 
			S5-1 broadband sector array transducer&#160;</td>
			<td style="width:155px;">Philips Healthcare</td>
			<td style="width:155px;"></td>
			<td>5-1 MHz, http://www.usa.philips.com/healthcare/product/HC989605412081/s5-1</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">QLAB Advanced Quantification Software Version 10.5</td>
			<td style="width:155px;">Philips Healthcare</td>
			<td style="width:155px;"></td>
			<td>Q-App: Automated Cardiac Motion Quantification (aCMQ), www.philips.com/QLAB-cardiology</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Xcelera R3.3L1 (Version 3.3.1.1103)&#160;</td>
			<td style="width:155px;">Philips Healthcare</td>
			<td style="width:155px;"></td>
			<td>http://www.usa.philips.com/healthcare/product/HC830038/xcelera-r41-cardiology-information-management-system</td>
		</tr>
	</tbody>
</table>

transthoracic speckle tracking echocardiography for the quantitative assessment of left ventricular myocardial deformation

The value of conventional echocardiography is limited by differences in inter-individual image interpretation and therefore largely dependent on the examiners&#39; expertise. Speckle tracking Echocardiography (STE) is a promising but technically challenging method that can be used to quantitatively assess regional and global systolic and diastolic myocardial performance. Myocardial strain and strain rate can be measured in all three dimensions&#160;&#8212; radial, circumferential, longitudinal &#8212; of myocardial deformation. Standard cross-sectional two-dimensional B-mode images are recorded and subsequently postprocessed by automated continuous frame-by-frame tracking and motion analysis of speckles within the myocardium. Images are recorded as digital loops and synchronized to a 3-lead EKG for timing purposes. Longitudinal deformation is assessed in the apical 4-, 3-, and 2-chamber views. Circumferential and radial deformation are measured in the parasternal short axis plane.
Optimal image quality and accurate tissue tracking are paramount for the correct determination of myocardial performance parameters. Utilizing transthoracic STE in a healthy volunteer, the present article is a detailed outline of the essential steps and potential pitfalls of quantitative echocardiographic myocardial deformation analysis.

The principle parameters for the quantitative assessment of myocardial performance are &#949; and SR. Technically, all cardiac chambers can be analyzed using STE. However, since speckle tracking methodology has been mostly used to study the LV, the focus of this article is on LV myocardial mechanics. Generally, longitudinal &#949; and SR are the most commonly assessed LV deformation parameters. Longitudinal &#949; and SR describe systolic shortening (and diastolic lengthening) of the myoc...

Watch this Scientific Journal Video about Transthoracic Speckle Tracking Echocardiography for the Quantitative Assessment of Left Ventricular Myocardial Deformation at JoVE.com

Transthoracic Speckle Tracking Echocardiography for the Quantitative Assessment of Left Ventricular Myocardial Deformation

Speckle tracking echocardiography is an emerging diagnostic imaging technique for the quantitative assessment of global and regional myocardial performance. Standard view echocardiographic motion images are recorded and deformation parameters are subsequently measured by automated continuous frame-by-frame tracking and motion analysis of speckles within the B-mode images of the myocardium.

The value of conventional echocardiography is limited by differences in inter-individual image interpretation and therefore largely dependent on the ...

The overall goal of this tutorial is to describe how transthoracic speckle tracking echocardiography is performed in a healthy volunteer. This method can be used to quantitatively assess both segmental and global myocardial deformation. The main advantage of this technique is that it is more sensitive than conventional echocardiography, especially for the detection of subtle alterations.Detecting subclinical dysfunction in asymptomatic patients is one example of its incremental value in myocardial imaging. Though this method is mainly utilized to measure left ventricular function, it can also be applied to assess the myocardial performance of the left atrium or the right heart. Generally, individuals new to this method might struggle because it requires impeccable image quality.Furthermore, post-processing can be time-consuming at first. Begin by acquiring an echocardiography device featuring speckle tracking technology, or STE, equipped with an adequate sector array tissue harmonic imaging transducer. Escort the subject into the testing room and connect them to a standard three-lead electrocardiogram, or EKG.Then plug the EKG wires directly into the echocardiography device in order to synchronize echocardiographic motion images to electromechanical activity. Unfreeze the ultrasound image to start detecting the EKG signal. Ask the patient to lie on their left side with their left arm stretched above the head, so that they are in a left lateral decubitus position.In order to optimize image quality and guarantee accurate assessment of myocardial deformation, adjust the frame rate between 60 to 80 frames per second using the adjust frame rate option. Capture standard apical four-three-and two-chamber views by positioning the transducer at the apex of the heart near the apical impulse, in order to assess longitudinal strain and strain rate. Aim towards the right shoulder, and angulate the transducer until all anatomical structures of interest become visible.Next, place the probe at the left parasternal border at the second or third intercostal space, and angulate until you obtain a cross-sectional, perpendicular view of the left ventricle. Finally, record images in the parasternal short axis view at the level of the mitral valve, the papillary muscles, and the apex, to detect circumferential and radial strain, and strain rate. Begin post-processing by opening the quantitative echocardiography analysis software.Click file and open, and choose the desired echocardiographic study data. Select a patient, and pick an echocardiographic plane to analyze. Next, click the Q icon in the right, lower corner of the selected image, and press the aCMQ button on the left.Choose the cardiac cycle of the highest image quality by using the green QRS skip keys at the bottom of the screen. Use the keyboard space bar to play and pause the loop. Select a region of interest, or ROI, to be analyzed by confirming the echocardiographic view on the left side of the screen.In this case, the parasternal, short axis view at the level of the mitral valve. Then, have the software automatically detect the timing of end diastole, and suggest an ROI which automatically divides the myocardium into six segments. Start the speckle tracking analysis by pressing the compute button on the left side of the screen.Click strain rate below the graphs to visualize segmental and global strain rate. Visually verify the tracking quality suggested by the software. If necessary, manually reposition the entire ROI by clicking edit on the left side of the screen.Move each segment margin as well as the endocardial and epicardial borders individually with the cursor. Utilize a dot in the center of the ROI for orientation when moving the ROI in its entirety. In the apical four-three-and two-chamber view, have the software automatically determine a possible ROI by dividing the myocardium into seven segments.If necessary, manually reposition the entire ROI by clicking edit on the left side of the screen. Move each segment margin as well as the endocardial and epicardial borders individually with the cursor. Utilize an orthogonal line pointing toward the apex for orientation when moving the ROI in its entirety.Additionally, if ROI redefinition is necessary, click draw on the left, and start out tagging the endocardial border at three reference points, the two opposing insertion points of the atrioventricular valve, and the left ventricular wall, starting with the basal inferosepta part of the valve, finishing with the center of the apex. Display segmental and global strain and strain rate by clicking the preferences button at the bottom left corner of the screen. Select the desired wave form and display options from this menu.Verify the tracking quality. If manual repositioning of the ROI is not sufficient to achieve appropriate overall speckle tracking quality, redefine the ROI, or select a different cardiac cycle, and reanalyze the data. Once optimal quality of the speckle tracking has been achieved, save and export the data for subsequent statistical analyses by clicking save at the bottom left corner of the screen.Furthermore, export cine-loops and still frames as illustrations by clicking export at the bottom left corner of the screen, and select the desired format and file directory. Here, a correct, STE-derived longitudinal strain assessment is shown. Note that optimal image quality and adequate tissue coverage of the region of interest are essential for adequate strain analysis.In contrast, this example demonstrates poor tissue tracking quality in the apical and mid-lateral segments, which results in the misinterpretation of myocardial deformation. Furthermore, a well-performed radial strain analysis is shown here, which reflects the systolic myocardial thickening. In contrast, incorrect tissue tracking of the anteroseptal myocardial segments results in inaccurate radial strain values in an asymptomatic, healthy patient.While attempting this procedure, it's important to minimize artifacts, and always optimize echocardiographic image quality. Once mastered, this technique can be done within a few minutes for each echocardiogaphic plane if it's performed properly. In addition, novel echocardiographic devices provide the possibility to assess measurements instantly at the patient's bedside.Following this procedure, speckle tracking can be combined with pharmacological or ergometer stress testing to unmask wall motion abnormalities that might remain undiscovered.

transthoracic-speckle-tracking-echocardiography-for-quantitative

Research

JoVE Journal

Medicine

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.

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

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.

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 ...

Ultrasonic Assessment of Myocardial Microstructure

Echocardiography is a widely accessible imaging modality that is commonly used to noninvasively characterize and quantify changes in cardiac structure and function. Ultrasonic assessments of cardiac tissue can include analyses of backscatter signal intensity within a given region of interest. Previously established techniques have relied predominantly on the integrated or mean value of backscatter signal intensities, which may be susceptible to variability from aliased data from low frame rates and time delays for algorithms based on cyclic variation. Herein, we describe an ultrasound-based imaging algorithm that extends from previous methods, can be applied to a single image frame&#160;and accounts for the full distribution of signal intensity values derived from a given myocardial sample. When applied to representative mouse and human imaging data, the algorithm distinguishes between subjects with and without exposure to chronic afterload resistance. The algorithm offers an enhanced surrogate measure of myocardial microstructure and can be performed using open-access image analysis software.

Echocardiography is commonly used to noninvasively characterize and quantify changes in cardiac structure and function. We describe an ultrasound-based imaging algorithm that offers an enhanced surrogate measure of myocardial microstructure and can be performed using open-access image analysis software.

Echocardiography is a widely accessible imaging modality that is commonly used to noninvasively characterize and quantify changes in cardiac structure and ...

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.

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

Myocardial Infarction and Functional Outcome Assessment in Pigs

Introduction of newly discovered cardiovascular therapeutics into first-in-man trials depends on a strictly regulated ethical and legal roadmap. One important prerequisite is a good understanding of all safety and efficacy aspects obtained in a large animal model that validly reflect the human scenario of myocardial infarction (MI). Pigs are widely used in this regard since their cardiac size, hemodynamics, and coronary anatomy are close to that of humans. Here, we present an effective protocol for using the porcine MI model using a closed-chest coronary balloon occlusion of the left anterior descending artery (LAD), followed by reperfusion. This approach is based on 90 min of myocardial ischemia, inducing large left ventricle infarction of the anterior, septal and inferoseptal walls. Furthermore, we present protocols for various measures of outcome that provide a wide range of information on the heart, such as cardiac systolic and diastolic function, hemodynamics, coronary flow velocity, microvascular resistance, and infarct size. This protocol can be easily tailored to meet study specific requirements for the validation of novel cardioregenerative biologics at different stages (i.e. directly after the acute ischemic insult, in the subacute setting or even in the chronic MI once scar formation has been completed). This model therefore provides a useful translational tool to study MI, subsequent adverse remodeling, and the potential of novel cardioregenerative agents.

This protocol describes the porcine myocardial infarction (MI) model using a 90 min closed-chest coronary balloon occlusion of the left anterior descending artery (LAD), followed by reperfusion. Furthermore, the protocol for several outcome parameters, such as cardiac function, hemodynamics, microvascular resistance, and infarct size, are also presented.

Introduction of newly discovered cardiovascular therapeutics into first-in-man trials depends on a strictly regulated ethical and legal roadmap. One ...

A Murine Model of Myocardial Ischemia-reperfusion Injury through Ligation of the Left Anterior Descending Artery

Acute or chronic myocardial infarction (MI) are cardiovascular events resulting in high morbidity and mortality. Establishing the pathological mechanisms at work during MI and developing effective therapeutic approaches requires methodology to reproducibly simulate the clinical incidence and reflect the pathophysiological changes associated with MI. Here, we describe a surgical method to induce MI in mouse models that can be used for short-term ischemia-reperfusion (I/R) injury as well as permanent ligation. The major advantage of this method is to facilitate location of the left anterior descending artery (LAD) to allow for accurate ligation of this artery to induce ischemia in the left ventricle of the mouse heart. Accurate positioning of the ligature on the LAD increases reproducibility of infarct size and thus produces more reliable results. Greater precision in placement of the ligature will improve the standard surgical approaches to simulate MI in mice, thus reducing the number of experimental animals necessary for statistically relevant studies and improving our understanding of the mechanisms producing cardiac dysfunction following MI. This mouse model of MI is also useful for the preclinical testing of treatments targeting myocardial damage following MI.

We introduce a surgical method to induce experimental ischemia/reperfusion (I/R) injury to simulate myocardial infarction (MI) in mouse models that allows for more clarity in positioning of the ligation on the left anterior descending artery (LAD) to increase the reproducibility of MI experiments in mice.

Acute or chronic myocardial infarction (MI) are cardiovascular events resulting in high morbidity and mortality. Establishing the pathological mechanisms ...

Murine Echocardiography of Left Atrium, Aorta, and Pulmonary Artery

The present methodology teaches the investigator how to measure and use the LAV as a surrogate of chronic elevations in Left Ventricular diastolic pressure through echocardiography, as well as to obtain measurements of the Aorta and PA diameter in mice.
Mice older than 10 d of age can be analyzed using the present technique. The technique is composed of 3 main steps: set-up, image acquisition, and image analysis. The set-up step consists of getting the mouse anesthetized with 1% isoflurane, shaving it, and taping it in a supine position to a heated EKG board where the image acquisition will take place. The image acquisition step consists of learning to identify the cardiac structures and obtaining all the required images with its correspondent probe and axis in order to be able to calculate volumes and diameters. The image analysis step consists of measuring the previously acquired images with the aid of computer software.
Advantages of the proposed technique include a fast (15 min) procedure that would allow the researcher to evaluate interventions in a non-invasive, non-terminal approach and therefore follow the same mouse over time; each mouse can be used as its own control. This fact plus having the same operator perform all the acquisition and analysis for the entire experiment minimizes the limitation of operator-dependency. The present methodology is useful for mouse researchers in cardiovascular and pulmonary medicine.

The following protocol describes the methodology for the acquisition and analysis of echocardiographic images used to obtain the Left Atrial Volume (LAV), Aorta (Ao) diameter, and Pulmonary Artery (PA) diameter in mice. This technique is a non-invasive, non-terminal procedure that allows assessment of the cardiopulmonary function.

The present methodology teaches the investigator how to measure and use the LAV as a surrogate of chronic elevations in Left Ventricular diastolic ...

Technique of Minimally Invasive Transverse Aortic Constriction in Mice for Induction of Left Ventricular Hypertrophy

Transverse aortic constriction (TAC) in mice is one of the most commonly used surgical techniques for experimental investigation of pressure overload-induced left ventricular hypertrophy (LVH) and its progression to heart failure. In the majority of the reported investigations, this procedure is performed with intubation and ventilation of the animal which renders it demanding and time-consuming and adds to the surgical burden to the animal. The aim of this protocol is to describe a simplified technique of minimally invasive TAC without intubation and ventilation of mice. Critical steps of the technique are emphasized in order to achieve low mortality and high efficiency in inducing LVH.
Male C57BL/6 mice (10-week-old, 25-30 g, n=60) were anesthetized with a single intraperitoneal injection of a mixture of ketamine and xylazine. In a spontaneously breathing animal following a 3-4 mm upper partial sternotomy, a segment of 6/0 silk suture threaded through the eye of a ligation aid was passed under the aortic arch and tied over a blunted 27-gauge needle. Sham-operated animals underwent the same surgical preparation but without aortic constriction. The efficacy of the procedure in inducing LVH is attested by a significant increase in the heart/body weight ratio. This ratio is obtained at days 3, 7, 14 and 28 after surgery (n = 6 - 10 in each group and each time point). Using our technique, LVH is observed in TAC compared to sham animals from day 7 through day 28. Operative and late (over 28 days) mortalities are both very low at 1.7%.
In conclusion, our cost-effective technique of minimally invasive TAC in mice carries very low operative and post-operative mortalities and is highly efficient in inducing LVH. It simplifies the operative procedure and reduces the strain put on the animal. It can be easily performed by following the critical steps described in this protocol.

The aim of this protocol is to describe step-by-step the technique of minimally invasive transverse aortic constriction (TAC) in mice. By elimination of intubation and ventilation which are mandatory for the commonly used standard procedure, minimally invasive TAC simplifies the operative procedure and reduces the strain put on the animal.

Transverse aortic constriction (TAC) in mice is one of the most commonly used surgical techniques for experimental investigation of pressure ...

Morphological and Functional Assessment of the Right Ventricle Using 3D Echocardiography

Traditionally, it was believed that the right side of the heart has a minor role in circulation; however, more and more data suggest that right ventricular (RV) function has strong diagnostic and prognostic power in various cardiovascular disorders. Due to its complex morphology and function, assessment of the RV by conventional two-dimensional echocardiography is limited: the everyday clinical practice usually relies on simple linear dimensions and functional measures. Three-dimensional (3D) echocardiography overcame these limitations by providing volumetric quantification of the RV free of geometrical assumptions. Here, we offer a step-by-step guide to obtain and analyze 3D echocardiographic data of the RV using the leading commercially available software. We will quantify 3D RV volumes and ejection fraction. Several technical aspects may help to improve the quality of RV acquisition and analysis as well, which we present in a practical manner. We review the current opportunities and the limiting factors of this method and also highlight the potential applications of 3D RV assessment in current clinical practice.

Here, we provide a step-by-step acquisition and analysis protocol for the 3D volumetric assessment of the right ventricle, mainly focusing on the practical aspects that maximize the feasibility of this technique.

Traditionally, it was believed that the right side of the heart has a minor role in circulation; however, more and more data suggest that right ...

Echocardiographic Characterization of Left Ventricular Structure, Function, and Coronary Flow in Neonate Mice

Echocardiography is a non-invasive procedure that enables the evaluation of structural and functional parameters in animal models of cardiovascular disease and is used to assess the impact of potential treatments in preclinical studies. Echocardiographic studies are usually conducted in young adult mice (i.e., 4-6 weeks of age). The evaluation of early neonatal cardiovascular function is not usually performed because of the small size of the mouse pups and the associated technical difficulties. One of the most important challenges is that the short length of the pups&#39; limbs prevents them from reaching the electrodes in the echocardiography platform. Body temperature is the other challenge, as pups are very susceptible to changes in temperature. Therefore, it is important to establish a practical guide for performing echocardiographic studies in small mouse pups to help researchers detect early pathological changes and study the progression of cardiovascular disease over time. The current work describes a protocol for performing echocardiography in mouse pups at the early age of 7 days old. The echocardiographic characterization of cardiac morphology, function, and coronary flow in neonatal mice is also described.

The present protocol describes the echocardiographic assessment of left ventricular morphology, function, and coronary blood flow in 7-day old neonate mice.

Echocardiography is a non-invasive procedure that enables the evaluation of structural and functional parameters in animal models of cardiovascular ...