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Qingfeng Zhuge - IEEE Xplore Author Profile

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The influence of the transducer lens on image reconstruction is often overlooked. Lenses usually exhibit a lower sound speed than soft biological tissues. In academic research, the exact lens sound speed and thickness are typically unknown. Here, we present a simple and nondestructive method to characterize the lens sound speed and thickness as well as the time to peak of the round-trip ultrasound...Show More
By changing the ultrasonic receiving angle in post-processing, we can obtain flow vectors from a photoacoustic experiment on a blood vessel phantom by solving the photoacoustic Doppler equation using a least-squares optimisation approach.Show More
In a recent study, we proposed a technique to correct aberration caused by the skull and reconstruct a transcranial B-mode image with a refraction-corrected synthetic aperture imaging (SAI) scheme. Given a sound speed map, the arrival times were calculated using a fast marching technique (FMT), which solves the Eikonal equation and, therefore, is computationally expensive for real-time imaging. In...Show More
Transcranial ultrasound imaging (TUI) is a diagnostic modality with numerous applications, but unfortunately, it is hindered by phase aberration caused by the skull. In this article, we propose to reconstruct a transcranial B-mode image with a refraction-corrected synthetic aperture imaging (SAI) scheme. First, the compressional sound velocity of the aberrator (i.e., the skull) is estimated using ...Show More
Transcranial ultrasound imaging is a suitable technology for diagnosis of strokes as it is safe, portable, relatively inexpensive and available in emergency medicine services, however it currently offers poor image quality due to the phase aberration caused by the human skull. In this work, we evaluate an approach for two-dimensional transcranial ultrasound imaging through the temporal window of a...Show More
Detection methods implemented in present clinical ultrasound scanners for contrast-enhanced ultrasound imaging show high sensitivity but a rather poor specificity due to pseudo-enhancement (false detection of contrast agent) produced by nonlinear wave propagation. They all require linear ultrasound propagation to detect nonlinear scattering of contrast agent microbubbles. Even at low transmit pres...Show More
The acoustic nonlinear responses of ultrasound contrast agent microbubbles (MBs) are of great interest for both diagnostic and therapeutic applications. Previously, optical and acoustical methods were developed to characterize single bubbles floating against a rigid wall. However, there is a need to develop an efficient approach for statistical measurement of single freely-floating MBs. Here we co...Show More
Ultrasound contrast agents are widely used in clinical practice. Commercial lipid-coated microbubbles mainly consist of either DSPC or DPPC. Previous research on homemade microbubbles based on these lipids showed different shell micro-structures. In this study the acoustical behavior and shell properties are characterized by microbubble spectroscopy using the Brandaris 128 high-speed camera. DPPC ...Show More
Carotid intraplaque neovascularization (IPN) has been associated with progressive atherosclerotic disease and plaque vulnerability. Therefore, its accurate quantification might allow early detection of plaque vulnerability. Contrast enhanced ultrasound (CEUS) can detect these small microvessels. To quantify IPN, we developed quantitative methods based on time intensity curve (TIC) and maximum inte...Show More
Recently we have shown that a suitable design of the excitation envelope to generate a self-demodulation signal at the subharmonic (SH) frequency can enhance the SH emission of microbubble (MB) contrast agents at 10 MHz. In this study we investigated effects of the excitation envelope on volumetric SH response of individual MB excited in the frequency range of 5-8 MHz with an acoustical set up (ac...Show More
Atherosclerosis is associated with the formation of microvessels in the arterial wall, referred to as vasa vasorum (VV). VV imaging may constitute a new intravascular ultrasound (IVUS) metric of coronary artery plaque vulnerability. The potential of nonlinear contrast IVUS to detect VV in vivo was demonstrated using a prototype transducer with dual-peak frequency response. In this study, we report...Show More
Most techniques for contrast-enhanced ultrasound imaging such as phase inversion and amplitude modulation require linear propagation to detect nonlinear scattering of contrast agent microbubbles. Waveform distortion due to nonlinear propagation impairs the ability to distinguish contrast agent microbubbles from tissue. This leads to erroneous detection of contrast agent behind any vessel or blood ...Show More
Intraplaque neovascularization (IPN) is linked to progressive atherosclerotic disease and plaque instability. Contrast enhanced ultrasound (CEUS) can detect these microvessels. Quantification of IPN may allow early detection of vulnerable plaques. We developed a semiautomatic quantification of IPN in CEUS, with motion compensation, contrast spot detection, tracking and classification, and vascular...Show More
This study intends to identify the best pulse sequences for ultrasound contrast imaging of the carotid artery by comparing a fairly exhaustive list of pulse sequences reported in literature. A good candidate must provide sensitive detection of contrast microbubbles, efficient suppression of tissue echoes and prevent artifacts. Especially the far wall artifact caused by nonlinear propagation throug...Show More
We demonstrate the feasibility of intravascular ultrasound chirp imaging. Chirp excitations were emitted with a 34 MHz single crystal intravascular transducer and compared to conventional Gaussian modulated pulses of equal peak negative pressure. The signal to noise ratio of the chirp images was increased up to 9 dB. The method shows potential for intravascular imaging of structures in and beyond ...Show More
Several studies have linked intraplaque neovascularization (IPN) with progressive atherosclerotic disease and plaque instability. An accurate quantification of IPN may allow early detection of vulnerable plaques. In this study, a dedicated motion compensation method was developed for quantification of IPN in small plaques (<;30% diameter stenosis). Motion compensation is a prerequisite to analyze ...Show More
The influence of a dynamic variation in the ambient pressure on the subharmonic response of phospholipid-coated microbubbles was investigated. The ambient pressure in water was modulated by a 2.5 kHz acoustic wave with peak amplitude of 15 kPa. We investigated the fundamental and subharmonic emission at two driving frequencies: 5 and 10 MHz. We measured that the variation in the ambient pressure o...Show More
In this study, we propose an optimized NRUS measuring and data processing protocol dedicated to small bone samples specially designed to be used in a four-point bending mechanical fatigue test. Our goal was to assess the elastic and dissipative hysteretic nonlinear parameters repeatability with the proposed protocol using several classes of materials with weak, intermediate and high nonlinear prop...Show More
The Luxembourg-Gorky effect, defined as a transfer of amplitude-modulation from one wave to a second wave, is applied to lipid-coated microbubbles tailored for nonlinear contrast ultrasound imaging. This nonlinear effect is non-classical because not created in micro-homogeneous media. A simple experimental set-up allowing the dual-frequency dual-beam insoniflcation of single bubbles was developed ...Show More
Trabecular bone tissue contains microcracks which may affect its mechanical properties as well as the whole structure. A Dynamic AcoutoElastic (DAE) method based on two acoustic waves coupling was developed to measure viscoelastic and dissipative nonlinearities in trabecular bone. The purpose of this work is to validate the technique sensitivity to monitor microdamage in human calcaneus.Show More
Dynamic AcoustoElasticity (DAE) method was first developed to assess microcracks in trabecular bone tissue. However, the method appears to offer larger applications, especially in fluids, to investigate nonlinear rheological behaviors. The purpose of this work is to validate the technique's sensitivity and to characterize the viscoelasticity in fluids, and particularly in non-Newtonian fluids whic...Show More
Bone tissue contains microcracks that may affect its mechanical properties as well as the whole trabecular structure. The relationship between crack density and bone strength is nevertheless poorly understood. Linear ultrasound techniques being almost insensitive to the level of damage, we propose a method to measure acoustic non- linearity in trabecular bone using time-of-flight modulation (TOFM)...Show More