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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...
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...
Patients with a 70–99% stenosed carotid artery will undergo surgery to prevent rupture of the plaque. However, the degree of stenosis does not determine the vulnerability of the plaque, since vulnerability depends on the plaque's morphology, mechanical properties and the force acting on the plaque. Mechanical models of the carotid artery can improve decision-making of the surgeon by quantifying and...
Acoustic Angiography enables high resolution and high SNR imaging of microbubble contrast agents. The technique relies on pulsing and receiving at two widely separated acoustic bandwidths to reject signal from the tissue. To date this technique has been used to evaluate microvasculature within tumors and kidneys, but has not been used to visualize in vivo blood flow within heart, or liver. These targets...
Cardiovascular diseases are the leading cause of death globally. Such diseases may affect the left ventricular function, which in turn is closely related to the left ventricular stiffness. Estimation of cardiac deformation can give information on the myocardial stiffness, and may therefore be important in assessment of cardiovascular diseases. A 3D motion estimation scheme is necessary to measure...
Automated robotic inspection systems are a way of speeding up the inspection of large components with complex geometries and reducing production bottlenecks during the non-destructive evaluation of critical parts. Such systems allow the collection of large data volumes, compared to existing inspection systems. To maximise the throughput of the non-destructive evaluation phase, it is crucial that the...
Air-coupled transducers are used to conduct fast non-contact inspections in NDT. Normally, the bandwidth of a conventional transducer can be enhanced, but with a cost to its sensitivity. However, low sensitivity is very disadvantageous in air-coupled NDT. This paper presents a methodology for improving the bandwidth of an air-coupled diaphragm transducer without sensitivity loss by connecting a number...
Phase-Contrast MRI (PC-MRI) is capable of 4D flow imaging and considered a gold standard for blood velocity measurements, but is currently cumbersome and time consuming. Ultrasound is bedside applicable, but is typically limited to a 1D velocity measurement. In this work we measure 3D blood flow velocity fields using high frame rate 3D ultrasound blood speckle tracking (BST) without contrast and compare...
3D Ultrasound systems present several technical challenges, particularly the large number of elements in a 2D array, high electrical impedance, and image acquisition time. Crossed electrode arrays address some of these issues, especially the huge reduction in number of elements. However, creating a two-way focused 3D image in real-time is difficult with these arrays because azimuth and elevation dimensions...
Radiofrequency and microwave ablation procedures are commonly used for treating hepatocellular carcinoma in patients that are not candidates for surgical resection. Ablation is a minimally invasive procedure which involves insertion of an ablation needle (electrode) into the tumor which produces localized heating to kill the surrounding cancerous cells. Ultrasound can be a valuable tool for real-time...
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...
A hybrid beamforming approach combining the strengths of diverging wave compounding (DWC) and multi-line-transmit beamforming (MLT) (i.e., multi-plane-transmit, MPT) was previously proposed by our labs for 3D imaging [1]. Although we demonstrated this approach to be superior to 3D DWC and 3D MLT, we did not account for artifacts induced by motion. The aim of this study was therefore to propose a motion...
Assessing the response of heart failure (HF) patients to Cardiac Resynchronization Therapy (CRT) currently relies on the ECG and left ventricular (LV) ejection fraction. Electromechanical Wave Imaging (EWI) is a high frame-rate (2000 Hz) ultrasound-based technique capable of non-invasively mapping the electromechanical activation in all four cardiac chambers in vivo. In this study, we aim to show...
While tissue-mimicking phantoms have been useful in the validation of ultrasonic equipment and image processing techniques, they are often restricted to simple vascular geometries due to limitations in fabrication techniques. To address this need, a novel technique has been employed to fabricate 3D-printed photo-curable poly(ethylene glycol) (PEG) hydrogel constructs containing complex, small-scale...
3D diverging wave compounding (DWC) was recently demonstrated to be capable of providing high-frame-rate imaging, but at the risk of introducing motion artifacts. As an alternative, a hybrid beamforming approach combining the features of DWC and multi-line-transmit (MLT) beamforming was proposed (i.e., multi-plane-transmit, MPT), showing some superiority when compared with 3D DWC [1]. However, in...
The design of 3D TEE transducers poses severe technical challenges: channel count, electronics integration with high and low voltages, heat dissipation, etc. We present an adult matrix TEE probe with separate transmit (Tx) and receive (Rx) arrays allowing optimization in both Tx and Rx [1]. Tx elements are directly wired out, Rx employs integrated micro-beamformers in low-voltage (1.8/5.0V) chip technology...
Achieving a high frame rate in echocardiography is highly important for quantifying the short phases of the cardiac cycle that contain valuable information for medical diagnosis. Additionally, the 3D quantitative assessment of the heart would significantly improve the current measurements used in daily clinical routine. Nevertheless, obtaining ultrafast images remains a challenge due to the trade-off...
Clinical studies using HRpQCT have revealed that cortical bone porosity is a major risk factor for fracture Not only average porosity but also pore size and local accumulation of large basic multicellular units (BMUs) have been associated with a reduction of the hip strength. However, an increase of cortical pore dimensions is poorly captured by X-ray based techniques. A previous in-silico study provided...
The estimation of Ultrasound-Contrast-Agent (UCA) kinetics from Dynamic Contrast-Enhanced Ultrasound (DCE-US) recordings has shown promise to localize prostatic malignancy. In a two-dimensional (2D) approach, UCA dispersion and velocity provide a characterization of the prostate (micro)vasculature with diagnostic value [1]. To this end, the UCA transport kinetics are modelled with strong assumptions...
Conventional 2D Doppler ultrasound is a valuable screening tool for early detection of cardiovascular disease, including aneurysm of the abdominal aorta (AA) and stenosis of the carotid artery (CA). However, vascular ultrasound screening rates remain low and vary widely among physicians, due to the need for a skilled sonographer, equipment costs and scan time. We have recently developed a low-cost...
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