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Ultrafast 3D Doppler imaging can provide volumetric high frame rate and high resolution mapping of the vascular anatomy and function [1]. Current approach relies on the use of matrix arrays connected to high count of electronics channel which remain complex and costly. Row Column Addressed (RCA) approaches have been proposed as a low complexity alternative to matrix probe for imaging of blood flows...
Pulmonary embolism (PE) is the third-leading cause of death from cardiovascular disease. Currently, PE is treated via catheter-delivered, ultrasound-enhanced thrombolysis using side-fired, low-intensity ultrasound energy (0.5 W/cm2) at ∼2 MHz to reduce the required dose of thrombolytic drugs because of the enhanced drug penetration into the clot. However, several clinical studies have shown that the...
Echocardiography is the most used modality for the evaluation of cardiac function. To obtain a time-resolved volumetric quantification of cardiac motion, ultrafast 3-D imaging is required. Ultrafast ultrasound imaging with diverging waves has demonstrated its potential for clinical 2-D echocardiography. It has been shown that MoCo (motion compensation) strategies based on a triangle transmit arrangement...
Phase-change contrast agents (PCCAs) provide advantages over conventional microbubble contrast agents, including increased circulation time and the ability to extravasate from leaky tumor vasculature. Additionally, PCCAs can be vaporized into echogenic microbubbles for diagnostic ultrasound imaging. Previous studies have demonstrated that the vaporization threshold of PCCAs is higher in vivo than...
Irregular patterns of microcalcifications in the breast may indicate a malignant cancer tumor. The gold standard for early detection is X-ray mammography. However, high density of connective tissue of the breast can limit detection. Improved suppression of the connective tissue can be achieved with ultrasound. However detecting the weak signals from microcalcifications in a highly echoic background...
Persistent occlusion following venous thrombosis is associated with an increased risk of post-thrombotic syndrome. Venous recanalization may prevent this complication. Ultrasonic histotripsy has been shown to fractionate thrombus through a cavitation cloud generated by an external transducer and restore the flow [1]. In this study, we aimed at demonstrating that thrombotrispy can be performed with...
Several challenges limit the use of Pulsed Wave (PW) Doppler to assess blood flow in the coronary arteries. The transit time effect causes spectral broadening in regions with high blood velocities such as coronary stenoses, leading to overestimation of maximum velocities. In this work we use a modified commercial 3D ultrasound imaging system to perform trans-thoracic, 3D high frame-rate imaging of...
A dual beam vector Doppler method was proposed (DOI: 10.1016/j.ultrasmedbio.2009.11.004), in which one beam is continuously tracked perpendicular to the flow direction, and the second one is used to perform velocity measurements with known Doppler angle. Since two consecutive transmission (TX) and reception (RX) events (one for each beam) are needed, the effective Doppler pulse repetition frequency...
Echocardiography is one of the most widely spread modality for non-invasive 2-D imaging of the heart. However, to fully observe and quantify left ventricular function and morphology, 3-D imaging is required. The observation of the whole left ventricle remains limited by the temporal resolution of conventional 3-D echocardiography. Indeed, the only way to get wide-angle volumetric images is to merge...
Subharmonic aided pressure estimation (SHAPE) uses ultrasound contrast agents (UCAs) to estimate hydrostatic pressure by transmitting at one frequency, receiving at its subharmonic frequency and then monitoring the subharmonic amplitude variations. The subharmonic response of the UCAs has an inverse linear relationship with the ambient pressure. In order to optimize SHAPE, we studied the impact of...
Microbubble and its cavitation combined with ultrasound have been explored to improve the theranostics of vascular diseases. Inspiring achievements have been obtained in molecular imaging, drug delivery, and thrombolysis by using microbubbles. However, microbubbles flow along the vessel axis in the blood laminar flow, preventing the microbubbles from contacting with the targeting endothelium. Hence,...
Ultrafast imaging based on diverging wave (DW) is an active area of research in ultrasound sectorial acquisition because of its capacity of reaching high frame rate. Recently, we have introduced a 3D Fourier-based formalism for the reconstruction of 3D sectorial images with DW insonifications and validated with numerical simulations [Zhang et al. IUS 2016]. The proposed method can provide comparable...
Objective myocardial deformation assessment during stress tests could help clinicians to better diagnose myocardial ischemia. However, the use of conventional focused echocardiography is compromised at increased heart rates due to its limited lateral field of view and frame rate. Ultrafast echocardiography using coherent compounding of diverging waves improves temporal resolution while maintaining...
Real-time dynamic monitoring of cavitation is essential for the safety and efficiency of high intensity focused ultrasound (HIFU) therapy. Unlike pulse-echo imaging, which can only be of use while HIFU is turned off, passive acoustic mapping (PAM) can enable monitoring of cavitation during HIFU exposure. But the conventional used PAM has low resolution and interference artifacts. For this, a unique...
Sonothrombolysis with microbubbles (STL) is being explored as a promising therapeutic alternative in ischemic stroke. The objective of this study is to better understand the impact of STL +/-rt-PA on the acoustic properties of blood clot in vitro.
The emergence of ultrafast imaging allows new insights into cardiac deformation/motion analysis that could enable new advancements in clinical diagnosis. Several studies showed that a good compromise between the temporal and the spatial resolution can be obtained by transmitting multiple focused beams simultaneously, method referred in literature as MLT (multi line transmit). However, previous investigations...
The emergence of ultrafast imaging allowed new insights into cardiac deformation/motion analysis that enabled new advancements in clinical diagnosis. Several studies showed that a good compromise between the temporal and the spatial resolution can be obtained by transmitting multiple focused beams (MLT) simultaneously. However, the current implementation of MLT in 3D cannot be used in dynamic conditions...
Acoustically-activated nanodroplets facilitate localized drug delivery after vaporization with improved in vivo stability, drug payload, and minimal interference outside of the ultrasound focal zone compared with microbubbles. They are new acoustic mediators to induce blood-brain barrier (BBB) opening for drug delivery to the brain, with promising potential of extravasation to enhance targeted delivery...
Nanomedicines recently gain great attention for their cancer targeting abilities and multi-functionality. Active targeting of nanoparticles with external stimuli-responsive property would improve the therapeutic efficacy and reduce harmful side effects because therapeutic effects are concentrated at the combined area of both drug and external stimuli.
Depth-resolved intravascular photoacoustic imaging has been shown to successfully image lipid in atherosclerotic plaques. During IVPA imaging, the level of laser irradiation and corresponding thermal dose depends on the imaging parameters (number of A-lines per frame, frame rate, pullback speed, pulse energy). It is unclear what level of laser irradiation will cause inadvertent tissue damage — the...
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