The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Cardiac function has traditionally been studied using pressure-volume (PV) loop analysis. PV loops can be used to derive functional indices such as end-systolic pressure volume relationship (ESPVR)—a measure of myocardial contractility, end-diastolic pressure volume relationship (EDPVR) — a measure of myocardial compliance and relaxation time constant (τ) — a measure of left ventricular relaxation...
Although 3D ultrasound plays an increasingly important role, 2D echocardiography remains the main clinical imaging modality for cardiac function assessment in daily practice. This requires precise delineation of the myocardium at end diastole (ED) and systole (ES). Because of intrinsic high variability in image quality, manual interactions are still needed. In this study, we investigate a machine...
Microembolization during PCI for acute myocardial infarction can cause microvascular obstruction (MVO). MVO severely limits the success of reperfusion therapies and is linked to worse prognosis, including death. A recent clinical trial showed that adjunct short pulse MB+US therapy prior to and following PCI in first STEMI patients, improved angiographic recanalization prior to PCI and ejection fraction...
Time delay estimation using cross correlation between successive RF lines is an established method to estimate tissue velocity. We have applied this method on our system using 10 MHz transducers sutured to the epicardium to measure the myocardial contraction pattern at high spatial and temporal resolution. In this setup, the myocardial tissue velocity will generally increase with the depth, as the...
Fast cardiac imaging requires a reduction of the number of transmit events. This is typically achieved through multi-line-transmission (MLT) and/or multi-line-acquisition (MLA) techniques. However, restricting the field-of-view (FOV) to the anatomically relevant domain, e.g. the myocardium, can increase frame rate (FR) further. Using computer simulations, we previously proposed an anatomical scan...
Cardiac pathologies are often characterized by important changes of myocardial properties such as the myocardial stiffness, re-organization of muscle fiber structure, modification of the microcirculation flow, all of which remain challenging to assess quantitatively and non-invasively in vivo. Over the last decade, the advent of software-based systems has enabled the implementation of ultrafast ultrasound...
Myocardial deformation imaging at a high frame rate (HFR) has the potential to gain new insights in cardiac mechanics by resolving short-lived mechanical events during the cardiac cycle. In order to achieve such high frame rate, our lab recently proposed to combine multi-line transmit with ‘anatomical imaging’ i.e. imaging only the anatomically relevant spatial domain (e.g. the myocardium). Although...
Tissue Doppler Imaging (TDI) is an excellent tool for early detection of myocardial dysfunction, as well as for prognosis and follow-up of the myocardial function after surgical treatment. However, since it exploits the same principles of color flow imaging, TDI requires to balance frame rate with field of view. A novel TDI technique based on multiline transmission (MLT), i.e. the simultaneous transmission...
ARFI displacements have been shown to share an inverse relationship with shear wave speed — based estimates of tissue elasticity. Both ARFI and shear wave elasticity imaging (SWEI) have been used to track the stiffening and softening of myocardium through the cardiac cycle in open-chest, intracardiac, and Langendorff preparations. In transthoracic imaging, induced shear waves have been observed during...
Increased myocardial stiffness is characteristic of many diseases, leads to a loss of diastolic function, and is a cause of diastolic heart failure (DHF). Methods to estimate myocardial stiffness include Shear Wave Elastography (SWE). Currently, ultrasound-based cardiac SWE includes acoustic radiation force (ARF)-based methods; however, the in vivo generation and detection of the shear waves in myocardium...
Strain imaging is gaining traction as a means to assess cardiac function by tracking the cyclic deformation of the myocardium. Compared to traditional measures such as ejection fraction, global myocardial strain has been shown to be an earlier and more sensitive measure of overall ventricular function. Similarly, regional myocardial strain has been shown to be useful for identifying ischemia and myocardial...
Arrhythmias can be treated by ablating the heart tissue in the regions of abnormal conduction, e.g. activating too early or with a different speed. The key of the treatment then lies in the location of these areas. In current clinical practice, 3-D electroanatomic maps can be created during the procedure by probing the heart with a specific catheter. However, it is a time-consuming and invasive procedure...
Myocardial elastance, derived from pressure-volume (PV) loops in the left ventricle (LV), can be used to assess LV function and myocardial performance. This method requires an invasive intracardiac pressure-volume catheter to be inserted in the LV, limiting the method's utility in clinical screening and monitoring. Strain echocardiography and cardiac acoustic radiation force impulse (ARFI) imaging...
Investigating myocardial dynamics through the assessment of mechanical properties of heart is a challenging problem in a murine model as the heart rate is high. The objective of this study was to compare displacements estimated using radiofrequency (RF) signals with Cardiac Elastography (CE) and Speckle Tracking Echocardiography (STE) for quantifying myocardial dynamics.
High speed ultrasound imaging is a new imaging method particularly applicable to cardiology. At Duke we have developed a real time high speed imaging system capable of producing up to 2500 images per second while maintaining the live imaging feature so essential in clinical scanning. For high speed 2D the Duke system, T5, uses 96 transmitters and 96 receivers at 32:1 parallel processing in conjunction...
Given the limited spatiotemporal resolution of 3D echocardiography, simultaneous assessment of all ventricular myocardial segments can clinically be performed using multi-plane acquisitions (MP) — i.e. biplane (BP) or triplane (TP). However, the wider field of view of MP impairs spatiotemporal resolution, thus hindering the performance of e.g. speckle tracking. Multi Line Transmit (MLT) beam forming...
Speckle tracking echocardiography (STE) is a well-established method to assess regional cardiac function. Traditionally, the left ventricular (LV) walls are divided into 18 segments (6 LV walls each with 3 segments) and the deformation parameters are measured for each of the segments. However, usually, segmental deformation curves are obtained by taking the average of an underlying strain field that...
Myocardial fibrosis is recognized as a physio-pathologic substrate of main cardiovascular syndromes such as myocardial infraction or heart failure. Knowing that fibrosis leads to increased myocardial stiffness, elastography techniques, such as shear wave imaging, has been showed to detect for the detection Fibrotic Tissue (FT) (Liver, arteries, …). However, its application on the heart still remain...
Contrast enhanced ultrasound (CEUS) has shown great promise in quantifying myocardial perfusion and ventricular flow. More recently high frame-rate contrast enhanced echocardiography (HFR CE), based on pulse inversion (PI) and diverging waves, has shown to significantly improve the image contrast over standard CEUS [M. Toulemonde, IUS 2016]. Both contrast pulse sequences and spatial compounding involve...
Left intraventricular blood vortices could provide important information on cardiovascular health. However they are not explicitly measured in current-day commercial systems. Additionally, the slow frame rates (typically <30Hz) of 2D cardiac Doppler imaging do not enable adequate sampling of the intraventricular blood dynamics. Finally, current imaging modes do not allow simultaneous estimation...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.