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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,...
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...
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...
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.
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...
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...
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. In this presentation, we demonstrate that our compound...
Cardiac malformations develop in the first trimester of pregnancy and early detection of abnormalities is important to plan delivery and treatment. Recent reports indicate that blood flow patterns play a significant role in the development of the heart. Our aim is to investigate if vector flow imaging using blood speckle tracking can add useful information to the conventional ultrasound examination...
Uterine peristaltic movement plays an important role for the success of embryo implantation. This is especially relevant in the context of assistive reproduction technology. Unfortunately, the lack of tools for quantitative analysis limits our understanding of the uterine activity. Recently, strain analysis by ultrasound speckle tracking has gained attention for assessment of the uterine activity...
Quality assessment of ultrasound images is difficult since image quality is subjective to the human observer. Nevertheless, image quality metrics are imperative when benchmarking different beamforming techniques. However, if we do not know how a beamformer alters an image, a quality metric might give an incorrect measurement of the image quality. Using the standard Delay-And-Sum (DAS) beamformer as...
Coherence-based methods have been shown to improve image quality by suppressing spurious lobes. However, when imaging a diffuse medium, such methods lead to a high variance of speckle amplitudes (i.e. granular appearance) which could limit their applicability for direct clinical imaging. The granular pattern may however be beneficial for speckle tracking echocardiography (STE), given the higher contrast...
Mechanical dyssynchrony caused by left bundle branch block (LBBB) negatively affects cardiac performance and can be treated by cardiac resynchronization therapy. Cardiac strain derived from ultrasound (US) images can be used to quantify and visualise this dyssynchrony at a regional level. Speckle tracking echocardiography is the most commonly used technique, however commercially available methods...
Inside tortuous vasculatures such as aneurysms, flow patterns are inherently 3D in nature and would vary spatiotemporally in different phases of a pulse cycle. At present, it is difficult to consistently visualize such complex flow using color Doppler imaging. 4D flow imaging may be a potential solution, but existing clinical 3D scanners have hitherto yielded mediocre visualization of 3D flow volumes,...
Cardiac strain estimation from ultrasound images is an efficient tool for the diagnosis of cardiac diseases. This study focuses on cardiac amyloidosis (CA), a pathology characterized by nonspecific early symptoms such as increased wall thickness. Recent clinical studies have demonstrated that patients with CA present an apex-to-base gradient longitudinal strain pattern, i.e., a normal strain in apex...
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