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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...
Plane-wave imaging plays a highly significant role o wing to the special demand for high frame rate, however, its po or image quality hinders its application in ultrasound industrie s. Many scholars have attempted to give a wide variety of soluti ons to improve the image quality, however, each of them has li mitations or compromises. In this study, we improve the spatio -temporally smoothed factor...
Recently we demonstrated non-contact excitation of broadband mechanical waves in soft media for transient elastography. Using US from an air-coupled transducer focused on an air/medium interface, this method (called “acoustic micro-tapping”, or AμT) provides sufficient radiation force to launch a transient displacement. Combined with ultrafast phase sensitive OCT, AμT-OCT can track propagating mechanical...
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...
Capacitive micro-machined ultrasonic transducers (CMUTs) offer several advantages over conventional piezoelectric transducers in terms of acoustic performance and circuit integration capability. In this study, we focus on the potential of CMUTs for the high receiving sensitivity which is strongly required for photoacoustic imaging applications. We propose an advanced CMUT cell design with an ultra-narrow...
In this work, a new method for extracting palm vein pattern is proposed. The procedure uses as input the 3D ultrasound images of a portion of the hand volume acquired with a fast and reliable system recently proposed. The method detects low brightness areas in B-mode images and then selects the vectors that specify the centers of mass of these dark regions (centroids). Vein patterns are defined whenever...
We have developed a new, fast and simple 3D imaging approach referred to as Simultaneous Azimuth and Fresnel Elevation (SAFE) compounding. The principle behind this technique is to perform conventional plane wave compounding with the bottom set of electrodes, while implementing a reconfigurable Fresnel elevation lens with the top electrodes. While a Fresnel lens would usually result in unacceptable...
Acoustic droplet vaporization (ADV) has shown a great potential in extravascular tumor-targeting theranostics. The mechanical perturbations produced during ADV process (e.g. initial volume expansion, cavitation, and movement of the bubble) on the nearby cells could cause cell dysfunction with irreversible cell membrane damage or facilitate drug delivery due to sonoporation. A confocal acousto-optical...
Because conventional geophysical measurements cannot directly measure the microstructure or pore fluids of rocks, new measurement approaches are needed as well as one that can select regions of interest. The aim of this study is to utilize the nonlinear interaction of two co-propagating longitudinal waves to characterize induced viscoelastic changes occurring in the rock microstructure. Our experimental...
Coupling between surface acoustic waves (SAW) and arrays of mechanical resonators has appeared early in SAW history as a potential means to slow down wave propagation through mass-loading, in particular by creating corrugations on the substrate surface. This concept has been revisited over the past few years in the context of locally-resonant phononic crystals where pillars deposited on a homogeneous...
This paper reports on the investigation of 1 μm thick films of 20% Scandium-doped Aluminum Nitride (ScAlN) for the making of piezoelectric MEMS laterally vibrating resonators (LVRs). The ScAlN films, which can be sputter-deposited such as undoped Aluminum Nitride (AlN) films, were used to demonstrate high performance resonators. These devices showed quality factor (Qs) in excess of 1000 in air centered...
Noninvasive electrical brain imaging in humans often suffers from poor spatial resolution due to the uncertain spread of electric fields through the head. To overcome this limitation, we propose 4D transcranial acoustoelectric brain imaging (tABI) for mapping current densities at a spatial resolution confined to the ultrasound (US) focus. Acoustoelectric (AE) imaging exploits an interaction between...
Ultrasonic standing waves (USWs) particle sorting has shown great potential to develop diverse applications in biotechnology and medical research due to its ability to offer non-contact, label-free particle manipulation. Currently, most reported on-chip acoustic particle sorters rely on high Q-value materials and elaborate geometry designs, which make these devices not easy to build and unsuited for...
In this paper, we present a front-end integrated circuit (IC) for an ultrasound neurostimulation system, to be interfaced with a 16×16 2D CMUT array to realize an ultrasound field pattern (USFP) using quantized phases and amplitudes. The IC uses a pulse width modulation (PWM) technique with a three-level pulse to generate excitation signals having multi-level quantized amplitudes. For a programmable...
An original method to measure the acoustic properties of porous Pb(Zr0.53Ti0.47)O3 (PZT) backings at high-frequencies (HF, i.e. between 15 and 25 MHz), was developed. To this end, a piezoelectric PZT-based thick film was deposited onto the porous ceramic backing and directly used to generate an acoustic signal in water. Here, the considered signal is the one that was generated in water, reflected...
This paper introduces the use of artificial neural networks (ANNs) as a method to guide the design of high-performance MEMS resonators and applies it to the prediction of spurious modes (SMs) in the proximity of the series resonance of aluminum nitride (AlN) contour-mode MEMS resonators (CMRs). ANN enables both fast and accurate prediction of spurious modes, hence facilitating the MEMS designer in...
As the medical ultrasound signals are not stationary, the radiation pattern of the corresponding input data does not have a specific shape. Thus, their reconstruction using adaptive beamformer (BF) become indispensable in order to improve the quality of the image. Generalized Side Lobe Canceller (GSC) is a robust realization against clutter and interference, resulting from an elegant representation...
We present a new technique for photoacoustic (PA) image formation, termed ‘F-Mode’, which capitalizes on variations in the power spectrum of PA signals to produce images with object specific contrast. The technique is applied to a PA dataset by calculating the signal power spectrum at each scan location, segmenting it into discrete frequency bands, and then forming an image representing the spatial...
Carotid plaque vulnerability is difficult to characterize from B-mode ultrasound imaging alone. However, elastographic characterization of plaque mechanical properties may aid in the assessment of vulnerability. As an initial step to understand the complex wave propagation that can occur in plaques, we have developed simulation models that incorporate different shear moduli (μ) of the arterial wall,...
Driven by the need for high data-rates and improved cell coverage, mobile phone filters are required to process increasingly high RF power levels. The simultaneous demand for smaller filter footprints makes designing a filter for high-power performance a challenge. We report a method for simulating the self-heating effects of high input powers on a surface acoustic wave (SAW) filter. We also report...
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