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Bulk thermal ablation, including radiofrequency ablation (RFA) as well as microwave and ultrasound (US) ablation, is an important approach to tumor treatment. To avoid incomplete treatments and cancer recurrence while reducing morbidity, a real-time monitoring and control approach, capable of providing consistent thermal ablation in minimum time, is needed. Echo decorrelation imaging has been successfully...
An effective imaging modality to delineate the ablated region after microwave ablation (MWA) therapy is crucial to yield promising treatment outcomes. Ultrasound B mode imaging is widely used to guide the ablation needle. However, the image quality suffers from relatively low imaging contrast due to the similar echogenicity between the ablated and surrounding liver tissue. In this study, we applied...
We have designed and implemented an ultrasonic imaging research platform that performs all signal processing, including beamforming and image processing, using software on a GPU. An operating software is developed on a PC that can control RF data acquisition hardware to accommodate ultrasound images of various formats. Beamforming methods that include conventional scan line based imaging, scan line-based...
In this paper we propose a computer-aided diagnosis system for the breast lesion classification. Our approach is based on quantitative ultrasound and deep learning. We used the Nakagami imaging to create parametric maps of breast lesions that illustrate tissue scattering properties. For this task the sliding window technique was applied. The Nakagami parameter was calculated using the maximum likelihood...
Cervical spine pathoanatomy is typically evaluated by static radiographs, CT or MRI; however, these modalities are unable to directly measure the dynamic performance of the spine that account for its functionality. We have developed an ultrasound based technique that provides a non-invasive, realtime, quantitative, textitin-vivo image of the C-spine that allows for assessment of the dynamic motion...
Previous work has shown that the degree of anisotropy in tissue can be assessed using Acoustic Radiation Force Impulse (ARFI) imaging performed with a geometrically asymmetric excitation. In this work, we investigate the clinical relevance of mechanical anisotropy in Duchenne muscular dystrophy (DMD). Anisotropy assessment was performed using relative elasticity (RE) and relative viscosity (RV) parameters...
Ultrafast imaging based on plane wave (PW) / diverging wave (DW) is an active area of research in ultrasound acquisitions because of its capacity of reaching high frame rate. Beamforming of received echoes in Fourier domain provides comparable image quality but lower computational complexity with respect to the conventional DAS approach [Zhang et al., UFFC, 2016]. However, the current state-of-the-art...
Multi-planar reformatting (MPR) in 3-D ultrasound imaging provides the viewer with planar cross-sectional images extracted from the 3-D data. To produce the MPR imaging from the acquired 3-D volume data, the 3-D scan conversion (SC), which transforms the acquired data in the 3-D polar coordinate system to the 3-D Cartesian coordinate system, is performed for display. Direct 3-D SC and separable 3-D...
Multi-line transmission (MLT) is a recently developed method for high frame rate cardiac ultrasound imaging. However, a potential pitfall of this method is the presence of artifacts due to cross-talk between the MLT beams. Low complexity adaptive beamforming (LCA) is a high resolution adaptive beamforming method that chooses a weighting function out of a predefined set of apodization functions assembled...
Ultrafast ultrasound has contributed to a renewed interested in vector Doppler. Sampling RF signals at a rate 4 times the carrier frequency is the standard procedure since this rule complies with the Nyquist sampling theorem, regardless of the transducer bandwidth. RF acquisition with a high-performance multi-channel system generates massive datasets, especially in 3-D ultrafast ultrasound. The objective...
The point spread function (PSF), namely the response of an ultrasound system to a point source, is a powerful measure of the quality of an imaging system. The lack of an analytical formulation inhibits many applications ranging from apodization optimization, array-design, and deconvolution algorithms. We propose to fill this gap through a general PSF derivation that is flexible with respect to the...
Carotid atherosclerotic plaque is a major contributor to cerebrovascular disease. Noninvasive quantitative ultrasound (QUS) evaluation of plaque morphology is requisite for comprehensive risk assessment. System and setting dependencies, however, limit current grayscale analyses. Here, integrated backscatter (IB) and attenuation coefficient (AC) were calculated in-vivo and compared with pathology scores...
Minimally invasive procedures such as microwave ablation (MWA) are growing in popularity as a substitute for surgical resection of hepatocellular carcinomas. Ultrasound electrode displacement elastography (EDE) has demonstrated the potential to provide a feasible non-ionizing approach for monitoring the region of thermal necrosis. We present results on a comparison of the contrast, signal-to-noise...
Quasi-static elastography is a widely applied ultrasound method in which RF data acquired in tissue at different states of deformation are correlated to estimate displacements and strain (displacement gradient). A recent development is the introduction of ultrafast plane-wave imaging where element data are beam-formed after collection to reconstruct the image lines. Several beam-forming strategies...
In Duchenne muscular dystrophy (DMD), muscle fiber necrosis and subsequent progressive replacement of muscle by fibrous tissue and fat impacts the degree of anisotropy (DoA) in mechanical properties. Mechanical DoA can be assessed in skeletal muscle using Viscoelastic Response (VisR) ultrasound. We hypothesize that in vivo VisR DoA measures in the rectus femoris (RF) muscles of boys with DMD statistically...
We are investigating backscatter-based quantitative ultrasound parameters to detect premature cervical remodeling ultimately leading to spontaneous preterm birth. This work systematically assesses the ex vivo human cervix microstructure and the effects of cervical ripening based on parameters derived from the acoustic backscatter coefficients (BSCs).
Contrast enhanced ultrasound (CEUS) has shown great promise in quantifying myocardial perfusion and ventricular flow. More recently high frame-rate contrast enhanced echocardiography (HFR CE), based on pulse inversion (PI) and diverging waves, has shown to significantly improve the image contrast over standard CEUS [M. Toulemonde, IUS 2016]. Both contrast pulse sequences and spatial compounding involve...
The nonlinear shear modulus was found to exhibit higher contrast than shear modulus for the detection of breast lesions (Bernal, Chamming's et al. 2016) and may thus serve as a potential diagnostic index of tissue pathology. Such nonlinear elastic constant of soft tissues has been demonstrated to be effectively estimated by combining ultrasound elastography and supersonic shear imaging based on acoustoelastic...
Contrast enhanced ultrasound (CEUS) imaging offers great opportunities for new ultrasound applications by improving the contrast between blood and tissue using microbubbles. However, the low signal-to-noise ratio (SNR) due to the low mechanical index (MI) requirement can be an issue in practice. Multiplane wave (MW) imaging is a technique recently proposed to increase the SNR for compounding plane...
Coded excitation with complementary Golay codes has been demonstrated to increase the signal-to-noise ratio (SNR) and penetration of diverging wave (DW) coherent compounding for high frame rate cardiac imaging (Zhao et al., PMB 2017). However, the effective gain in frame rate of the Golay coded system is compromised by a factor of 2 because two complementary codes are transmitted. The objectives of...
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