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Myocardial strain imaging has been shown to add significant prognostic and diagnostic value to echocardiography. While the reliability of ultrasound-based strain measurement techniques has improved considerably in terms of regional consistency and inter-reader, inter-vendor agreement; most state-of-the-art strain imaging packages constrain their analyses to individual cardiac cycles. This limitation...
Biomechanical properties of the extracellular matrix (ECM) are important regulators in cell development, including proliferation, apoptosis and migration. Recent studies have shown that stiffening of the ECM resulting from deposition and crosslinking of collagen may promote invasion and migration of tumor cells. In our previous study, a laser speckle contrast shear wave (SW) imaging system was developed,...
Currently there are two main categories of adaptive beamforming applied to medical ultrasound imaging: minimum-variance-related beamforming(MV) and coherence-factor-related beamforming (CF), both of which have been applied to suppress side/granting lobe and clutter for plane-wave imaging. Unfortunately, due to low SNR/SINR, the resulting images may suffer from deficiencies: deteriorated speckle pattern,...
Contrast-enhanced ultrasound (CEUS) permits quantification and monitoring of tumor vascular changes in response to anti-angiogenic treatment with the goal of informing targeted therapy. Conventional mean-intensity-based CEUS analysis discounts additional information that may be available from the first-order speckle statistics in a CEUS image. We demonstrate that our compound speckle model for analysis...
In the Western World, the high prevalence of stenotic plaques in the carotid arteries results in many strokes and transient ischemic events. In daily clinical practice, the severity of stenosis is estimated based on the maximum velocity measured before and after the stenosis using pulsed wave Doppler. However, because of the angle dependency of Doppler techniques, novel flow imaging techniques are...
The Reference Phantom Method can be used to quantify acoustic properties of tissue by compensating for system effects using the average power spectrum from a well-characterized homogeneous medium. Widespread clinical application of the Reference Phantom Method is hindered by the need to scan the reference phantom using the same transducer, system, and system settings as used for scanning the tissue...
Mechanobiology is an emerging field of research that studies the influences on the cell behaviors by mechanical stimuli. In this research, the previously developed laser speckle contrast shear wave imaging system is implemented for monitoring the temporal and spatial changes in the stiffness of the self-designed in vitro cancer metastasis model. Results from the immunostaining with laminin and collagen...
Ultrasound imaging is a real-time and high frame rate modality suitable for the analysis of tendon dynamics, e.g. for diagnosis of carpal tunnel syndrome. Tendon displacement quantification algorithms based on speckle tracking are sensitive to underestimation due to stationary clutter present in the tendon region. In this study we propose an improved speckle tracking method based on Singular Value...
Recently a new beamformer called the Delay-Multiply-And-Sum (DMAS) beamformer was introduced in the field of medical ultrasound imaging (Matrone et al IEEE Trans. Med. Imag. 2015). Instead of summing the signals recorded by each transducer element as with the Delay-And-Sum (DAS) beamformer, the DMAS algorithm multiplies the signals pairwise before summing them. This multiplication creates an “artificial...
Ultrasound perfusion imaging with and without contrast agents continues to be a relevant problem as ultrasound systems and algorithms get more sensitive to slow blood flow. Unfortunately, there have been few phantoms to help develop these techniques. Some have used very small linear tubes, while others have adapted dialysis cartridges. Here we propose a technique based off of conventional gelatin...
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.
We have developed a modern array driver employing multi-channel arbitrary waveform generator and linear amplifiers for transmit wavefront synthesis. The system utilizes deep waveform memory that can be configured for switching between transmit patterns seamlessly thus allowing for the use of spatial and frequency diversity in image acquisition. In this paper, we present the first experimental results...
Strain and strain rate imaging can serve as noninvasive tools for quantitative assessment of regional myocardial contractility. Because of the 3D nature of cardiac motion, a 3D motion estimation scheme must be applied in order to be able to measure the full myocardial. Several method has been proposed to estimated the 3D velocity vectors field, such as 3D speckle tracking and 3D Transverse Oscillation...
The size, distribution and morphology of microcalcifications (MCs) in breasts can for some cases be considered an early indicator of breast cancer. MCs are small, hard calcium deposits in soft breast tissue and appear as point scatterers in an ultrasound image. However, detection of MCs in ultrasound images is challenging. Background speckle often obscure the MCs and thus highly affect the probability...
We have developed a modern array driver employing multi-channel arbitrary waveform generator and linear amplifiers for transmit wavefront synthesis. The system utilizes deep waveform memory that can be configured for switching between transmit patterns seamlessly thus allowing for the use of spatial and frequency diversity in image acquisition. In this paper, we present the first experimental results...
A challenge in the clinical application of shear wave elastography is the level of measurement variance or noise compared to clinically significant changes in shear wave speed. For instance, liver fibrosis staging is challenged by the relatively high variance of shear wave velocity estimates in comparison to the modulus difference between early (F1-F3) fibrosis stages. Recent work has shown that ultrasound...
In fascioscapulohumeral muscular dystrophy (FSHD) and many other neuromuscular disorders there is a need for biomarkers to diagnose, quantify and longitudinally follow muscle disease. Furthermore, the pathophysiological mechanisms leading to muscle weakness in most neuromuscular disorders are not completely understood. Speckle tracking allows to quantify muscle deformation. This dynamic information...
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...
An undesired effect, the dark region artifact (DRA), has been under-communicated in our research community. The DRA appear next to acoustically strong targets for some of the many adaptive beamformers introduced in the literature. This study investigates the DRA for a collection of adaptive beamformers and shows that this effect originates because some of the methods fail to estimate which signals...
Recently, high-frame-rate (HFR) imaging has found many applications such as fast cardiac imaging, elasticity imaging, flow velocity vector imaging, and functional imaging. In late 1990s, a HFR imaging method based on Fourier reconstruction was developed with either plane wave or limited-diffraction beam (LDB). To increase image resolution and field of view, images obtained with steered plane wave...
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