Article
Engineering, Civil
Baiju M. Nair, Arun Kumar, Rajendar Bahl
Summary: This article examines the LR ambiguity resolution using two parallel arrays, focusing on a second-order nulling beamformer to address the axisymmetry issue. The study compares different methods and evaluates performance in correlated noise conditions. Experimental results confirm the effectiveness of cardioid-based beamformers in achieving higher rejection ratios for the azimuth ambiguity.
IEEE JOURNAL OF OCEANIC ENGINEERING
(2022)
Article
Computer Science, Information Systems
Atiqa Kayani, Graeme K. Woodward, Zubair Khalid, Ijaz Haider Naqvi
Summary: This article evaluates and compares the multiuser downlink ergodic sum spectral efficiency (ESSE) using different combinations of analog and digital beamforming techniques when users are closely-spaced. The authors derive an analytical expression characterizing the loss of per-user ergodic spectral efficiency relative to fully digital beamforming for any given combination of hybrid beamforming. They also quantify the angle-of-departure separation across multiple users to minimize the ESSE loss due to closely-spaced terminals. The results demonstrate that an extra RF chain can compensate for most of the loss in ESSE.
Article
Acoustics
Xiuwen Zhang, Qing Wang
Summary: In this study, we proposed a novel CPWC-based adaptive beamforming algorithm, THR-PCF + RCM-MV, which combined the threshold phase coherence factor (THR-PCF) with the reconstructed covariance matrix minimum variance (RCM-MV) to achieve high-resolution and high-contrast images. Simulation, phantom, and in-vivo experiments demonstrated that the proposed method improved contrast ratio (CR), contrast noise ratio (CNR), speckle signal-to-noise ratio (s_SNR), generalized contrast-to-noise ratio (GCNR), and the full width at half maximum (FWHM) compared to the traditional adaptive methods. The results also showed enhanced image quality in both near and far fields, indicating the potential of our new method for clinical applications.
Article
Engineering, Aerospace
Zijiao Tian, Andrew Finelli, Benny Milgrom, Kaipei Yang, Yaakov Bar-Shalom, Peter Willett
Summary: This article presents an effective method to enhance the resolution for two closely-spaced targets. By jointly estimating the positions and intensities of the targets based on the original frame and the offset frame, it determines whether the targets can be resolved or not using a hypothesis test. Simulations show that adding offset to the image provides more information and enhances the resolution probability compared to frames without offset.
IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS
(2023)
Article
Acoustics
Emily D. Golightly, Brian E. Anderson, Adam D. Kingsley, Rylee Russell, Rebekah Higgins
Summary: Time reversal is a process of recording and playing back sound in reverse at the same location. This paper focuses on using scatterers to achieve super resolution in time reversal focusing. It demonstrates that the increased path length due to diffraction can lead to a decrease in effective wave speed, resulting in super resolution. It also highlights the importance of accounting for the longer path length traveled around scatterers for achieving super resolution.
Article
Engineering, Biomedical
Hao Zhang, Yunhao Zhu, Bowen Zhou, Songde Liu, Nianan He, Chao Tian
Summary: In this study, a multibeam MV (MB-MV) beamformer based on the conventional MV was proposed to enhance the image quality in ring array ultrasound imaging. Simulations, phantom experiments, and in vivo human experiments were conducted to compare MB-MV with DAS and spatial smoothing (SS) MV beamformers. The results showed that the MB-MV method achieved significant improvement in terms of image resolution and contrast ratio compared to the other methods.
PHYSICS IN MEDICINE AND BIOLOGY
(2023)
Review
Chemistry, Multidisciplinary
Ge Zhang, Chen Liao, Jun-Rui Hu, Hai-Man Hu, Yu-Meng Lei, Sevan Harput, Hua-Rong Ye
Summary: Super-resolution ultrasound localization microscopy (SR-ULM) has revolutionized ultrasound imaging by resolving microvascular structures below the diffraction limit. This review discusses nanodroplet-based SR-ULM techniques, their imaging mechanisms, preclinical applications, and challenges in clinical translation. SR-ULM is a promising technology for microvasculature imaging that can provide valuable diagnostic and prognostic information for various pathologies and enable personalized treatment monitoring.
Article
Chemistry, Multidisciplinary
Jin Yang, Jiake Li, Xiaodong Chen, Jiaqi Xi, Huaiyu Cai, Yi Wang
Summary: The proposed GSC-CROSS approach for medical ultrasound imaging, using the cross-covariance matrix instead of the traditional covariance matrix estimation, significantly improves lateral resolution and contrast. Experimental results demonstrate the method's superiority in imaging of scattering points and cyst targets.
APPLIED SCIENCES-BASEL
(2021)
Article
Clinical Neurology
Li Yan, Chen Bai, Yu Zheng, Xiaodong Zhou, Mingxi Wan, Yujin Zong, Shanshan Chen, Yin Zhou
Summary: Super-resolution imaging technology provides higher resolution and signal-to-noise ratio in intracranial microvessel imaging compared to conventional imaging, making it suitable for imaging in large animals and serving as an important experimental basis for the clinical application of non-invasive transcranial ultrasound.
FRONTIERS IN NEUROLOGY
(2021)
Article
Acoustics
Wenping Wang, Qiong He, Ziyou Zhang, Ziliang Feng
Summary: A newly proposed adaptive beamforming method based on deep neural network and minimum variance is able to enhance image quality and accelerate beamforming process in ultrafast ultrasound imaging. Compared with traditional approaches, this method shows superior resolution and contrast performance, along with lower computational complexity and faster frame rate. It has the potential to be deployed in ultrafast ultrasound imaging systems.
Article
Acoustics
Che-Chou Shen
Summary: BB-DMAS beamforming leverages baseband spatial coherence for improved image resolution and contrast, while effectively suppressing side-lobe clutter and noise. Integration with minimum-variance beamforming can significantly enhance image resolution with low p values, maintaining speckle quality.
Article
Engineering, Civil
Jiaxin He, Shaohui He, Xiabing Liu, Jinlei Zheng
Summary: This paper presents a study on closely spaced double tunnels in Taizhou, China. It analyzes the impact of one tunnel's construction on the structural design of the other tunnel using numerical simulation. The mechanical responses of the tunnels during construction are comprehensively monitored and analyzed. The safety status of the tunnels is evaluated based on monitoring data. Design optimization proposals are made through parametric studies.
FRONTIERS OF STRUCTURAL AND CIVIL ENGINEERING
(2022)
Article
Engineering, Mechanical
Shijia Yin, Li Li, Yang Zhao, Linyong Li, Yang Yang, Zhigang Chu
Summary: This paper proposes an off-grid sparse Bayesian inference-based compressive spherical beamforming (OGSBI-CSB) method, which effectively solves the basis mismatch problem in traditional CSB and significantly improves identification accuracy, super-resolution, and resistance to noise interference for off-grid sources.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2023)
Article
Acoustics
Boudewine W. Ossenkoppele, Ben Luijten, Deep Bera, Nico De Jong, Martin D. Verweij, Ruud J. G. Van Sloun
Summary: There is an increased demand for miniature ultrasound probes with small apertures to provide high frame rate volumetric images for in-body applications. However, achieving a good lateral resolution remains a challenge. In this study, we propose the use of adaptive beamforming with deep learning (ABLE) in combination with training targets generated by a large aperture array to improve lateral resolution. We found that this method significantly enhances image quality compared to existing beamforming techniques.
ULTRASOUND IN MEDICINE AND BIOLOGY
(2023)
Article
Engineering, Biomedical
Yuanguo Wang, Yadan Wang, Mingzhou Liu, Zhengfeng Lan, Chichao Zheng, Hu Peng
Summary: This paper introduces a method to improve the imaging performance of the MV beamformer by using a covariance matrix-based adaptive weighting approach (CMSAW). The CMSAW method reduces sidelobes and incoherent clutter to enhance image resolution and noise reduction.
BIOMEDICAL ENGINEERING ONLINE
(2022)
Article
Acoustics
Lasse Thurmann Jorgensen, Marie Sand Traberg, Matthias Bo Stuart, Jorgen Arendt Jensen
Summary: In this study, the accuracy of row-column tensor velocity imaging (TVI) was quantified and compared to actual velocities using computational fluid dynamics (CFD) simulations. The results show that with a 62-channel receive array, complex 3-D flow fields can be measured at a high volume rate.
IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL
(2022)
Article
Acoustics
Tin-Quoc Nguyen, Marie Sand Traberg, Jacob Bjerring Olesen, Ramin Moshavegh, Peter Hasse Moller-Sorensen, Lars Lonn, Jorgen Arendt Jensen, Michael Bachmann Nielsen, Kristoffer Lindskov Hansen
Summary: This study compared local pressure differences estimated using vector flow imaging and direct catheterization with simulated pressure fields. The results showed a strong correlation between VFI and simulated peak pressure differences, while the catheter method exhibited no correlation. VFI pressure difference estimation was found to be feasible in phantoms and in vivo.
ULTRASOUND IN MEDICINE AND BIOLOGY
(2022)
Article
Acoustics
Sigrid H. Oygard, Melanie Audoin, Andreas Austeng, Erik V. Thomsen, Matthias B. Stuart, Jorgen A. Jensen
Summary: A ray tracing method is proposed to predict the position of the transmitted wave in order to improve the usable transmitted field-of-view (FOV) of a row-column array (RCA) with a diverging lens. The method is compared with a simpler thin lens model and shown to increase the usable transmitted FOV.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2022)
Article
Acoustics
Iman Taghavi, Sofie Bech Andersen, Carlos Armando Villagomez Hoyos, Mikkel Schou, Fredrik Gran, Kristoffer Lindskov Hansen, Michael Bachmann Nielsen, Charlotte Mehlin Sorensen, Matthias Bo Stuart, Jorgen Arendt Jensen
Summary: This study presents a new hierarchical Kalman (HK) tracker that can achieve better performance in scenarios with high concentrations of microbubbles and high localization uncertainty. The results show that the HK tracker is most similar to the ground truth in most scenarios and has the lowest root-mean-square error compared to the nearest-neighbor (NN) and Kalman (K) trackers. The HK tracker also provides more accurate vessel diameter reconstruction and better estimation of microbubble velocities. The tracking performance of the HK tracker is observed to be improved in in vivo experiments as well.
Article
Acoustics
Lars Emil Haslund, Lasse Thurmann Jorgensen, Matthias Bo Stuart, Marie Sand Traberg, Jorgen Arendt Jensen
Summary: This study presents a noninvasive method for estimating pressure gradient with higher precision than invasive catheters. The method combines a new acceleration estimation approach with the Navier-Stokes equation. The accuracy of the method is evaluated through computational fluid dynamic simulation and experimental data, and the precision is compared to invasive catheter measurements.
IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL
(2023)
Article
Acoustics
Sigrid Husebo Oygard, Martin Lind Ommen, Borislav Gueorguiev Tomov, Soren Elmin Diederichsen, Erik Vilain Thomsen, Matthias Bo Stuart, Niels Bent Larsen, Jorgen Arendt Jensen
Summary: This study demonstrates that the nonlinear relationship between voltage and emitted signal in CMUTs can be effectively addressed by using a three-pulse amplitude modulation sequence. Experimental results show that the CMUT and PZT arrays have an average contrast-to-tissue ratio (CTR) enhancement of 37.4 dB and 49.9 dB, respectively, for B-mode and CEUS images with an applied alternating current voltage of 6-60 V. Hydrophone recordings indicate that the nonlinear emissions from CMUTs do not significantly degrade the cancellation in the compounded AM signal, with only 2% of the emitted power between 26 and 60 V AC. Therefore, it is demonstrated that CMUTs can perform CEUS imaging independently of the applied excitation voltage when using a three-pulse AM sequence.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2023)
Article
Cardiac & Cardiovascular Systems
Rasmus Hvid, Matthias Bo Stuart, Jorgen Arendt Jensen, Marie Sand Traberg
Summary: This paper investigates the accuracy of blood flow velocities simulated by a geometry prescribed CFD pipeline in a dynamic heart phantom. The CFD flow patterns are compared to direct flow measurements by ultrasound VFI. The study finds that while the accuracy is high near the inlet and outlet, it is lower in locations far from these.
CARDIOVASCULAR ENGINEERING AND TECHNOLOGY
(2023)
Article
Acoustics
Jorgen Arendt Jensen, Borislav Gueorguiev Tomov, Lars Emil Haslund, Nathalie Sarup Panduro, Charlotte Mehlin Sorensen
Summary: Synthetic aperture (SA) can be used for both anatomic and functional imaging, providing information on tissue motion and blood velocity. This article proposes the development of a single, universal sequence for linear array SA imaging, which can generate high-quality linear and nonlinear B-mode images as well as accurate motion and flow estimates for varying blood velocities and super-resolution images.
IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL
(2023)
Article
Acoustics
Lasse Thurmann Jorgensen, Sebastian Kazmarek Praesius, Matthias Bo Stuart, Jorgen Arendt Jensen
Summary: This work presents a beamforming procedure that reduces the number of operations for synthetic aperture imaging. It uses the approximation that image values along the elevation direction of the low-resolution volume are constant. The proposed method consists of two stages: cross-sectional beamforming and extrapolation. The proposed beamformer achieves significantly faster volumetric imaging with negligible difference in image quality.
IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL
(2023)
Article
Medicine, General & Internal
Stinne Byrholdt Sogaard, Sofie Bech Andersen, Iman Taghavi, Mikkel Schou, Christina Christoffersen, Jens Christian Brings Jacobsen, Hans Martin Kjer, Carsten Gundlach, Amy Mcdermott, Jorgen Arendt Jensen, Michael Bachmann Nielsen, Charlotte Mehlin Sorensen
Summary: Super-resolution ultrasound (SRUS) imaging was used to investigate the changes in renal blood vessel density and tortuosity in a type 2 diabetes rat model, with promising results for monitoring and prognosing diabetic kidney disease (DKD) in the future.
Article
Acoustics
Mudabbir Tufail Bhatti, Borislav Gueorguiev Tomov, Soren Elmin Diederichsen, Matthias Bo Stuart, Erik Vilain Thomsen, Jorgen Arendt Jensen
Summary: Coded excitation has the potential to enhance image quality and penetration depth, but the increase in operating temperature poses a challenge. This study investigates the ability of CMUTs to handle coded excitation and finds that CMUTs can generate coded excitation signals more effectively at lower temperatures compared to PZT probes.
Proceedings Paper
Acoustics
Lars Emil Haslund, Matthias Bo Stuart, Marie Sand Traberg, Jorgen Arendt Jensen
Summary: This study validates a newly developed non-invasive ultrasound method for estimating pressure gradients, showing that it provides more accurate and precise results compared to micro-tip catheters. The ultrasound procedure is convenient and quick, making it suitable for patients who are not recommended for catheterization.
2022 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IEEE IUS)
(2022)
Proceedings Paper
Acoustics
Georgios Papageorgiou, Mairead Butler, Andrew Mobberley, Weiping Lu, Julian Keanie, Daniel Good, Kevin Gallagher, Alan McNeill, Vassilis Sboros
Summary: In this study, we present preliminary results on cancer detection and localization using super-resolution ultrasound imaging data. Our analysis demonstrates the feasibility of discriminating between healthy and tumorous regions using SRUI data, despite the limited number of patients.
2022 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IEEE IUS)
(2022)
Proceedings Paper
Acoustics
Sebastian Kazmarek Praesius, Matthias Bo Stuart, Mikkel Schou, Bernd Dammann, Hans Henrik Brandenborg Sorensen, Jorgen Arendt Jensen
Summary: The SURE method of super-resolution ultrasound imaging allows non-invasive visualization of vessels in a few seconds. In this study, the feasibility of real-time processing using a NVIDIA GeForce RTX 3090 GPU was explored. The results showed that SURE images can now be acquired and displayed in a matter of seconds, enabling immediate diagnosis of patients.
2022 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IEEE IUS)
(2022)
Proceedings Paper
Acoustics
Mostafa Amin-Naji, Iman Taghavi, Stinne Byrholdt Sogaard, Sofie Bech Andersen, Charlotte Mehlin Sorensen, Matthias Bo Stuart, Jorgen Arendt Jensen
Summary: This study presents a new approach for super-resolution ultrasound imaging using erythrocytes as targets. By combining trajectories from different velocities and applying image fusion methods, the enhanced intensity maps are demonstrated.
MEDICAL IMAGING 2022: ULTRASONIC IMAGING AND TOMOGRAPHY
(2022)