scholarly journals Acoustic-Field Beamforming-Based Generalized Coherence Factor for Handheld Ultrasound

2022 ◽  
Vol 12 (2) ◽  
pp. 560
Author(s):  
Chang-Lin Hu ◽  
Chien-Ju Li ◽  
I-Cheng Cheng ◽  
Peng-Zhi Sun ◽  
Brian Hsu ◽  
...  
Keyword(s):  
Image Quality ◽  
Acoustic Field ◽  
Contrast Ratio ◽  
Electricity Consumption ◽  
Adaptive Beamforming ◽  
Coherence Factor ◽  
In Vivo Testing ◽  
Handheld Ultrasound ◽  
Diagnostic Applications

Handheld ultrasound devices have been widely used for diagnostic applications. The use of the acoustic-field beamforming (AFB) method has been proposed for handheld ultrasound to reduce electricity consumption and avoid battery and unwanted heat issues. However, the image quality, such as the contrast ratio and contrast-to-noise-ratio, are poorer with this technique than with the conventional delay-and-sum method. To address the problems associated with the worse image quality in AFB imaging, in this paper we propose the use of an AFB-based generalized coherence factor (GCF) technique, in which the GCF weighting developed for adaptive beamforming is extended to AFB. Simulation data, experimental results, and in vivo testing verified the efficacy of our proposed AFB-based GCF technique.

scholarly journals A United Sign Coherence Factor Beamformer for Coherent Plane-Wave Compounding with Improved Contrast

2020 ◽  
Vol 10 (7) ◽  
pp. 2250 ◽  
Author(s):  
Chen Yang ◽  
Yang Jiao ◽  
Tingyi Jiang ◽  
Yiwen Xu ◽  
Yaoyao Cui
Keyword(s):  
Image Quality ◽  
Plane Wave ◽  
Contrast Ratio ◽  
Spatial Coherence ◽  
Frame Rate ◽  
In Vivo Studies ◽  
Angular Dimension ◽  
One Dimensional ◽  
Coherence Factor

In this study, we present a united sign coherence factor beamformer for coherent plane-wave compounding (CPWC). CPWC is capable of reaching an image quality comparable to the conventional B-mode with a much higher frame rate. Conventional coherence factor (CF) based beamformers for CPWC are based on one-dimensional (1D) frameworks, either in the spatial coherence dimension or angular coherence dimension. Both 1D frameworks do not take into account the coherence information of the dimensions of each other. In order to take full advantage of the radio-frequency (RF) data, this paper proposes a united framework containing both spatial and angular information for CPWC. A united sign coherence factor beamformer (uSCF), which combines the conventional sign coherence factor (SCF) and the united framework, is introduced in the paper as well. The proposed beamformer is compared with the conventional 1D SCF beamformers (spatial and angular dimension beamformers) using simulation, phantom and in vivo studies. In the in vivo images, the proposed method improves the contrast ratio (CR) and generalized contrast-to-noise ratio (gCNR) by 197% and 20% over CPWC. Compared with other 1D methods, uSCF also shows an improved contrast and lateral resolution on all datasets.

Comparative investigation of coherence factor weighting methods for an annular array photoacoustic microscope

2021 ◽  
Author(s):  
Riku Suzuki ◽  
Ryo Shintate ◽  
Takuro Ishii ◽  
Yoshifumi Saijo
Keyword(s):  
Image Quality ◽  
Noise Suppression ◽  
Contrast Ratio ◽  
Comparative Investigation ◽  
Phase Coherence ◽  
Annular Array ◽  
Coherence Factor ◽  
Array Transducer ◽  
Weighting Methods

Abstract To achieve fine visualization of the peripheral microvascular networks, we have developed a photoacoustic (PA) microscope equipped with a four-channel annular array transducer. The quality of PA images processed with Delay-and-Sum (DAS) method is degraded by off-axis signals. Thus, to achieve higher image quality for the PA microscope, this study evaluated the efficacy of the five coherence factor weighting methods: coherence factor, sign coherence factor, phase coherence factor, circular coherence factor, and vector coherence factor. Using PA signals acquired from a 100 µm microtube and the skin microvessels, we generated PA images with DAS and one of the weighting methods, and quantitatively evaluated the image quality by calculating the sharpness, contrast ratio, and contrast-to-noise ratio. The results showed the phase coherence factor and the vector coherence factor methods were more effective to clearly visualize the microvascular structure, in terms of vessel sharpening and noise suppression performances, than the other methods.

scholarly journals Neighborhood Singular Value Decomposition Filter and Application in Adaptive Beamforming for Coherent Plane-Wave Compounding

2020 ◽  
Vol 10 (16) ◽  
pp. 5595
Author(s):  
Shuai Feng ◽  
Yadan Wang ◽  
Chichao Zheng ◽  
Zhihui Han ◽  
Hu Peng
Keyword(s):  
Image Quality ◽  
Singular Value Decomposition ◽  
Plane Wave ◽  
Adaptive Beamforming ◽  
Singular Value ◽  
Adaptive Weighting ◽  
Coherence Factor ◽  
Noise Ratio ◽  
Value Decomposition ◽  
Suppress Noise

Coherent plane-wave compounding (CPWC) is widely used in medical ultrasound imaging, in which plane-waves tilted at multiple angles are used to reconstruct ultrasound images. CPWC helps to achieve a balance between frame rate and image quality. However, the image quality of CPWC is limited due to sidelobes and noise interferences. Filtering techniques and adaptive beamforming methods are commonly used to suppress noise and sidelobes. Here, we propose a neighborhood singular value decomposition (NSVD) filter to obtain high-quality images in CPWC. The NSVD filter is applied to adaptive beamforming by combining with adaptive weighting factors. The NSVD filter is advantageous because of its singular value decomposition (SVD) and smoothing filters, performing the SVD processing in neighboring regions while using a sliding rectangular window to filter the entire imaging region. We also tested the application of NSVD in adaptive beamforming. The NSVD filter was combined with short-lag spatial coherence (SLSC), coherence factor (CF), and generalized coherence factor (GCF) to enhance performances of adaptive beamforming methods. The proposed methods were evaluated using simulated and experimental datasets. We found that NSVD can suppress noise and achieve improved contrast (contrast ratio (CR), contrast-to-noise ratio (CNR) and generalized CNR (gCNR)) compared to CPWC. When the NSVD filter is used, adaptive weighting methods provide higher CR, CNR, gCNR and speckle signal-to-noise ratio (sSNR), indicating that NSVD is able to improve the imaging performance of adaptive beamforming in noise suppression and speckle pattern preservation.

Acoustic-Field Beamforming for Low-Power Portable Ultrasound

2021 ◽  
pp. 016173462110134
Author(s):  
Chang-Lin Hu ◽  
Guo-Zua Wu ◽  
Chih-Chi Chang ◽  
Meng-Lin Li
Keyword(s):  
Power Consumption ◽  
Low Power ◽  
Acoustic Field ◽  
Emergency Rooms ◽  
Digital To Analog Converter ◽  
Large Power ◽  
Analog To Digital ◽  
Portable Ultrasound ◽  
Diagnostic Applications

Portable ultrasound has been extensively used for diagnostic applications in health monitoring, emergency rooms, and ambulances. However, these handheld ultrasound systems may suffer from heat and battery issues attributed to the large power consumption of the transmitter. Additionally, the largest portion of the direct current (DC) power consumption can be attributed to the amplifier in the digital-to-analog converter (DAC) of the transmitter and to the analog-to-digital converter (ADC) of the receiver. Therefore, the number of transmit/receive channels in a portable ultrasound instrument is one of the crucial design factors regarding heat and battery related issues. To address these problems, we propose an acoustic-field beamforming (AFB) technique for low-power portable ultrasound systems with a single receive and five transmit channels. Finally, the simulation, experimental, and in vivo results verified the feasibility of this approach.

scholarly journals 2-D Minimum Variance Based Plane Wave Compounding with Generalized Coherence Factor in Ultrafast Ultrasound Imaging

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4099 ◽  
Author(s):  
Yanxing Qi ◽  
Yuanyuan Wang ◽  
Jinhua Yu ◽  
Yi Guo
Keyword(s):  
Plane Wave ◽  
Ultrasound Imaging ◽  
Contrast Ratio ◽  
Minimum Variance ◽  
Frame Rate ◽  
In Vivo Studies ◽  
Coherence Factor ◽  
Wave Imaging ◽  
Phantom Experiments

Plane wave compounding (PWC) is an effective modality for ultrafast ultrasound imaging. It can provide higher resolution and better noise reduction than plane wave imaging (PWI). In this paper, a novel beamformer integrating the two-dimensional (2-D) minimum variance (MV) with the generalized coherence factor (GCF) is proposed to maintain the high resolution and contrast along with a high frame rate for PWC. To specify, MV beamforming is adopted in both the transmitting aperture and the receiving one. The subarray technique is therefore upgraded into the sub-matrix division. Then, the output of each submatrix is used to adaptively compute the GCF using a 2-D fast Fourier transform (FFT). After the 2-D MV beamforming and the 2-D GCF weighting, the final output can be obtained. Results of simulations, phantom experiments, and in vivo studies confirm the advantages of the proposed method. Compared with the delay-and-sum (DAS) beamformer, the full width at half maximum (FWHM) is 90% smaller and the contrast ratio (CR) improvement is 154% in simulations. The over-suppression of desired signals, which is a typical drawback of the coherence factor (CF), can be effectively avoided. The robustness against sound velocity errors is also enhanced.

Synthesis, Properties, and in vivo Testing of Biogenic Ferrihydrite Nanoparticles

2020 ◽  
Vol 84 (11) ◽  
pp. 1366-1369
Author(s):  
S. V. Stolyar ◽  
V. P. Ladygina ◽  
A. V. Boldyreva ◽  
O. A. Kolenchukova ◽  
A. M. Vorotynov ◽  
...  
Keyword(s):  
Synthesis Properties ◽  
In Vivo Testing

Aspiration Revisited: Prospective Evaluation of a Physiologically Pressurized Model With Animal Correlation and Broader Applicability to Filler Complications

2021 ◽  
Author(s):  
Hyoung-Jin Moon ◽  
Won Lee ◽  
Ji-Soo Kim ◽  
Eun-Jung Yang ◽  
Hema Sundaram
Keyword(s):  
Normal Saline ◽  
False Negative ◽  
Vascular Complications ◽  
Filler Injection ◽  
Negative Results ◽  
Needle Position ◽  
False Negative Results ◽  
In Vivo Testing

Abstract Background Aspiration testing before filler injection is controversial. Some believe that aspiration can help prevent inadvertent intravascular injection, while others cite false-negative results and question its value given that the needle position always changes somewhat during injection procedures. Objectives To test the relation of false-negative results to the viscosity of the material within the needle lumen and determine whether a less viscous material within the needle lumen could decrease the incidence of false-negative results. Methods In vitro aspiration tests were performed using 30-G and 27-G needle gauges, two cross-linked hyaluronic acid fillers, normal saline bags pressurized at 140 and 10 mmHg to mimic human arterial and venous pressures, and three needle lumen conditions (normal saline, air, and filler). Testing was repeated three times under each study condition (72 tests in total). For in vivo correlation, aspiration tests were performed on femoral arteries and central auricular veins in three rabbits (4–5 aspirations per site, 48 tests in total). Results In vitro and in vivo testing using 30-G needles containing filler both showed false-negative results on aspiration testing. In vitro and in vivo testing using needles containing saline or air showed positive findings. Conclusions False-negative results from aspiration testing may be reduced by pre-filling the needle lumen with saline rather than a filler. The pressurized system may help overcome challenges of animal models with intravascular pressures significantly different from those of humans. The adaptability of this system to mimic various vessel pressures may facilitate physiologically relevant studies of vascular complications.

scholarly journals Effective decellularisation of human saphenous veins for biocompatible arterial tissue engineering applications: Bench optimisation and feasibility in vivo testing

2021 ◽  
Vol 12 ◽  
pp. 204173142098752
Author(s):  
Nadiah S Sulaiman ◽  
Andrew R Bond ◽  
Vito D Bruno ◽  
John Joseph ◽  
Jason L Johnson ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Mechanical Strength ◽  
Vascular Tissue ◽  
Sodium Dodecyl ◽  
Host Cells ◽  
Replacement Model ◽  
In Vivo Testing ◽  
Vascular Scaffolds

Human saphenous vein (hSV) and synthetic grafts are commonly used conduits in vascular grafting, despite high failure rates. Decellularising hSVs (D-hSVs) to produce vascular scaffolds might be an effective alternative. We assessed the effectiveness of a detergent-based method using 0% to 1% sodium dodecyl sulphate (SDS) to decellularise hSV. Decellularisation effectiveness was measured in vitro by nuclear counting, DNA content, residual cell viability, extracellular matrix integrity and mechanical strength. Cytotoxicity was assessed on human and porcine cells. The most effective SDS concentration was used to prepare D-hSV grafts that underwent preliminary in vivo testing using a porcine carotid artery replacement model. Effective decellularisation was achieved with 0.01% SDS, and D-hSVs were biocompatible after seeding. In vivo xeno-transplantation confirmed excellent mechanical strength and biocompatibility with recruitment of host cells without mechanical failure, and a 50% patency rate at 4-weeks. We have developed a simple biocompatible methodology to effectively decellularise hSVs. This could enhance vascular tissue engineering toward future clinical applications.

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