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Wang Y, Zheng C, Wang Y, Feng S, Liu M, Peng H. An adaptive beamformer based on dynamic phase coherence factor for pixel-based medical ultrasound imaging. Technol Health Care 2023; 31:747-770. [PMID: 36314178 DOI: 10.3233/thc-220450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Pixel-based beamforming realizes dynamic focusing at the pixel level with a focused beam by assuming that the received signals are composed of spherical pulses. Far-focused pixel-based (FPB) imaging was proposed to avoid artifacts around the focal depth. However, the contrast improvement is limited. OBJECTIVE We propose an adaptive weighting method based on dynamic phase coherence factor (DPCF) to improve the image contrast while preserving the speckle pattern. METHODS The phase variation is dynamically estimated based on the noise energy proportion of echo signals and it is used to calculate phase coherence weights for suppressing interference and preserving desired signals. A depth-dependent parameter is designed for DPCF to enhance the performance of noise and clutter suppression in the far-field region. We further use the subarray averaging technique to smooth the speckle texture. RESULTS The proposed method was evaluated on simulated, phantom experimental, and in vivo data. Results show that, compared with the phase coherence factor (PCF) based method, DPCF respectively leads to average CR improvements by more than 60% and 24% in simulation and experiment, while obtaining an improved speckle signal-to-noise ratio. CONCLUSIONS The proposed method is a potentially valuable approach to obtaining high-quality ultrasound images in clinical applications.
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Affiliation(s)
- Yadan Wang
- School of Mechanical Engineering, Hefei University of Technology, Hefei, Anhui, China
| | - Chichao Zheng
- Department of Biomedical Engineering, Hefei University of Technology, Hefei, Anhui, China
| | - Yuanguo Wang
- Department of Biomedical Engineering, Hefei University of Technology, Hefei, Anhui, China
| | - Shuai Feng
- Materials and Facilities Service Division, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Mingzhou Liu
- School of Mechanical Engineering, Hefei University of Technology, Hefei, Anhui, China
| | - Hu Peng
- Department of Biomedical Engineering, Hefei University of Technology, Hefei, Anhui, China
- Anhui Province Key Laboratory of Measuring Theory and Precision Instrument, Hefei University of Technology, Hefei, Anhui, China
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Song H, Kang J, Boctor EM. A novel design framework of synthetic radial aperture focusing for volumetric transrectal ultrasound imaging. JOURNAL OF COMPUTATIONAL DESIGN AND ENGINEERING 2022; 9:1852-1865. [PMID: 36268473 PMCID: PMC9563629 DOI: 10.1093/jcde/qwac083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 04/19/2022] [Accepted: 05/14/2022] [Indexed: 06/16/2023]
Abstract
In this paper, we present a novel design framework of synthetic radial aperture focusing for three-dimensional (3D) transrectal ultrasound imaging (TRUS-rSAF), in which multiple transmittance/reception events at different scanning angles are synthesized to reconstruct a radial plane in the target volume, securing high spatial resolution and texture uniformity. A theory-based design approach has not been available to push the envelope of the 3D rSAF technique. Herein, a closed-form analytical description of the TRUS-rSAF method is presented for the first time, effectively delineating spatial resolution and grating lobe positions in the radial dimension of a TRUS transducer. We demonstrate a solid optimization workflow based on the theoretical foundation to improve its spatiotemporal resolution, grating lobe artifacts, and signal-to-noise ratio. A specific design criterion was considered to outperform a clinical 3D TRUS imaging as a reference (TRUS-REF), where each radial plane is reconstructed with a single transmittance/reception event using a motorized actuator. The optimized TRUS-rSAF method significantly enhanced spatial resolution up to 50% over the TRUS-REF method while providing clinically effective temporal resolution (2-8 volume/sec) with negligible grating lobe artifacts. The results indicate that the proposed design approach would enable a novel TRUS imaging solution in clinics.
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Affiliation(s)
- Hyunwoo Song
- Department of Computer Science, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
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Xie HW, Guo H, Zhou GQ, Nguyen NQ, Prager RW. Improved ultrasound image quality with pixel-based beamforming using a Wiener-filter and a SNR-dependent coherence factor. ULTRASONICS 2022; 119:106594. [PMID: 34628298 DOI: 10.1016/j.ultras.2021.106594] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 09/18/2021] [Accepted: 09/18/2021] [Indexed: 06/13/2023]
Abstract
Pixel-based beamforming generates focused data by assuming that the waveforms received on a linear transducer array are composed of spherical pulses. It does not take into account the spatiotemporal spread in the data from the length of the excitation pulse or from the transfer functions of the transducer elements. As a result, these beamformers primarily have impacts on lateral, rather than axial, resolution. This paper proposes an efficient method to improve the axial resolution for pixel-based beamforming. We extend our field pattern analysis and show that the received waveforms should be passed through a Wiener filter before being used in the coherent pixel-based beamformer. This filter is designed based on signals echoed from a single scatterer at the transmit focus. The beamformer output is then combined with a coherence factor, that is adaptive to the signal-to-noise ratio, to improve the image contrast and suppress artifacts that have arisen during the filtering process. We validate the proposed method and compare it with other beamforming strategies using a series of experiments, including simulation, phantom and in vivo studies. It is shown to offer significant improvements in axial resolution and contrast over coherent pixel-based beamforming, as well as other spatial filters derived from synthetic aperture imaging. The method also demonstrates robustness to modeling errors in the experimental data. Overall, the imaging results show that the proposed approach has the potential to be of value in clinical applications.
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Affiliation(s)
- Hui-Wen Xie
- The School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Hao Guo
- The School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Guang-Quan Zhou
- The School of Biological Science and Medical Engineering, Southeast University, Nanjing, China.
| | - Nghia Q Nguyen
- Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK; Cambridge University - Nanjing Centre of Technology and Innovation, Nanjing, China
| | - Richard W Prager
- Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK; Cambridge University - Nanjing Centre of Technology and Innovation, Nanjing, China
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Zheng C, Wang Y, Qiu W, Zhang C, Peng H. Ultrasound far-focused pixel-based imaging using Wiener postfilter scaled by adjustable zero-cross factor. ULTRASONICS 2021; 115:106417. [PMID: 33964600 DOI: 10.1016/j.ultras.2021.106417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 02/04/2021] [Accepted: 02/28/2021] [Indexed: 06/12/2023]
Abstract
Synthetic aperture (SA) imaging can provide a uniform lateral resolution but an insufficient signal-to-noise ratio (SNR). SA method with bidirectional pixel-based focusing (SA-BiPBF) has the ability to obtain a higher quality image than conventional SA imaging. In this paper, an enhanced SA-BiPBF named full aperture received far-focused pixel-based (FrFPB) is firstly proposed to obtain a high resolution image. An adjustable zero-cross factor scaled Wiener postfilter (AZFsW) is then implemented in FrFPB for improving contrast ratio (CR). The adjustable zero-cross factor is calculated using the polarity of echo signals sequence with an adjustable coefficient σ to estimate the signal coherence, and it is combined with Wiener postfilter to obtain a good capability of noise reduction and background speckle pattern preservation. Simulation and experiments have been conducted to evaluate the imaging performance of the proposed methods. Results show that FrFPB can obviously improve the resolution in comparison with SA-BiPBF, and contrast-to-noise ratio (CNR) and speckle signal-to-noise ratio (sSNR) are retained. In addition, AZFsW can achieve a much higher CR than SA-BiPBF. When σ is 0.6, the CR improvement is 96.7% in simulation, 78.7% in phantom experiment, and 49.2% in in-vivo experiment. To evaluate the imaging performance of AZFsW, coherence factor, conventional Wiener postfilter, and scaled Wiener postfilter are implemented. The imaging results show that when σ is in the range of [0.6, 0.7], AZFsW exhibits a satisfying comprehensive imaging performance.
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Affiliation(s)
- Chichao Zheng
- Department of Biomedical Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Yazhong Wang
- Department of Biomedical Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Wenqian Qiu
- Department of Ultrasound, The First Affiliated Hospital of Anhui Medical University, Hefei, 230022, China
| | - Chaoxue Zhang
- Department of Ultrasound, The First Affiliated Hospital of Anhui Medical University, Hefei, 230022, China.
| | - Hu Peng
- Department of Biomedical Engineering, Hefei University of Technology, Hefei, 230009, China
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Lag-Based Filtered-Delay Multiply and Sum Beamformer Combined with Two Phase-Related Factors for Medical Ultrasound Imaging. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2020; 2020:1503791. [PMID: 32908575 PMCID: PMC7474785 DOI: 10.1155/2020/1503791] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 07/20/2020] [Indexed: 11/23/2022]
Abstract
A novel adaptive beamformer named filtered-delay multiply and sum (F-DMAS) has recently been proposed. Compared to the delay and sum (DAS) beamforming algorithm, F-DMAS can efficiently improve the resolution and contrast. However, the DAS can still be seen in the expansion of DMAS. Therefore, we rearrange the pair-wised signals in terms of lag in DMAS and then synthesize a lot of new signals. Thanks to the relationship between the spatial coherence and lag, these new signals can be thought of as sorted by the spatial coherence. Thus, we apply two phase-related factors, the polarity-based factor (PF) and the sign coherence factor (SCF), which are evaluated based on new signals, to weight the output of DMAS. The two approaches are consequently referred to as LAG-DMAS-PF and LAG-DMAS-SCF, respectively. The results show that, compared to F-DMAS and DAS, our proposed methods can improve the resolution and contrast to some extent without increasing too much computational complexity. In the comparison between LAG-DMAS-PF and LAG-DMAS-SCF, the latter has better performance, but the former can better protect image details.
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Nguyen NQ, Prager RW. Ultrasound Pixel-Based Beamforming With Phase Alignments of Focused Beams. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2017; 64:937-946. [PMID: 28358679 DOI: 10.1109/tuffc.2017.2685198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We previously developed unified pixel-based (PB) beamforming to generate high-resolution sonograms, based on field pattern analysis. In this framework, we found that the transmit waveshape away from the focus could be characterized by two spherical pulses. These correspond to the maximal and minimal distances from the imaging point to the active aperture. The beamformer uses this model to select the highest energy signals from backscattered data. A spatiotemporal interpolation formula is used to provide a smooth transition in regions near the focal depth where there is no dominant reflected pulse. In this paper, we show that the unified PB approach is less robust at lower center frequencies. The interpolated data is suboptimal for a longer transmit waveshape. As a result, the spatial resolution at the focal depth is lower than that in other regions. By further exploring the field pattern, we propose a beamformer that is more robust to variations in beamwidth. The new method, named coherent PB beamforming, aligns and compounds the pulse data directly in the transition regions. In simulation and phantom studies, the coherent PB approach is shown to outperform the unified PB approach in spatial resolution. It helps regain optimal resolution at the focal depth while still maintaining good image quality in other regions. We also demonstrate the new method on in vivo data where its improvements over the unified PB method are demonstrated on scanned objects with a more complicated structure.
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Nguyen NQ, Prager RW. High-Resolution Ultrasound Imaging With Unified Pixel-Based Beamforming. IEEE TRANSACTIONS ON MEDICAL IMAGING 2016; 35:98-108. [PMID: 26731794 DOI: 10.1109/tmi.2015.2456982] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
This paper describes the development and evaluation of a new beamforming strategy based on pixel-based focusing for ultrasound linear array systems. We first implement conventional pixel-based beamforming in which the transmitted wave is assumed as spherical and diverging from the centre of the transmit subaperture. This assumed wave-shape is only valid within a limited angle on each side of the beam and this restricts the number of different subaperture positions from which data can be combined to improve image quality. By analyzing the field patterns, we propose a new unified pixel-based beamforming algorithm that better adapts to the non-spherical wave-shape of the transmit beam. This approach enables us to select the best-possible signal from each transducer waveform for data superposition. In simulations and a phantom study, we show that the unified pixel-based beamformer offers significant improvements in image quality compared to other delay-and-sum methods but at a higher computational cost. The new algorithm also demonstrates robust performance in a limited in vivo study. Overall, the results show that it is potentially of value in clinical applications.
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Kang J, Chang JH, Wilson BC, Veilleux I, Bai Y, DaCosta R, Kim K, Ha S, Lee JG, Kim JS, Lee SG, Kim SM, Lee HJ, Ahn YB, Han S, Yoo Y, Song TK. A prototype hand-held tri-modal instrument for in vivo ultrasound, photoacoustic, and fluorescence imaging. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:034901. [PMID: 25832265 DOI: 10.1063/1.4915146] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Multi-modality imaging is beneficial for both preclinical and clinical applications as it enables complementary information from each modality to be obtained in a single procedure. In this paper, we report the design, fabrication, and testing of a novel tri-modal in vivo imaging system to exploit molecular/functional information from fluorescence (FL) and photoacoustic (PA) imaging as well as anatomical information from ultrasound (US) imaging. The same ultrasound transducer was used for both US and PA imaging, bringing the pulsed laser light into a compact probe by fiberoptic bundles. The FL subsystem is independent of the acoustic components but the front end that delivers and collects the light is physically integrated into the same probe. The tri-modal imaging system was implemented to provide each modality image in real time as well as co-registration of the images. The performance of the system was evaluated through phantom and in vivo animal experiments. The results demonstrate that combining the modalities does not significantly compromise the performance of each of the separate US, PA, and FL imaging techniques, while enabling multi-modality registration. The potential applications of this novel approach to multi-modality imaging range from preclinical research to clinical diagnosis, especially in detection/localization and surgical guidance of accessible solid tumors.
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Affiliation(s)
- Jeeun Kang
- Department of Electronic Engineering, Sogang University, Seoul 121-742, South Korea
| | - Jin Ho Chang
- Department of Electronic Engineering, Sogang University, Seoul 121-742, South Korea
| | - Brian C Wilson
- Princess Margaret Cancer Centre/University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Israel Veilleux
- Princess Margaret Cancer Centre/University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Yanhui Bai
- Princess Margaret Cancer Centre/University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Ralph DaCosta
- Princess Margaret Cancer Centre/University Health Network, Toronto, Ontario M5G 1L7, Canada
| | - Kang Kim
- Center for Ultrasound Molecular Imaging and Therapeutics, Department of Medicine, University of Pittsburgh School of Medicine and Heart and Vascular Institute, University of Pittsburgh Medical Center (UPMC), Pittsburgh, Pennsylvania 15213, USA
| | - Seunghan Ha
- Center for Ultrasound Molecular Imaging and Therapeutics, Department of Medicine, University of Pittsburgh School of Medicine and Heart and Vascular Institute, University of Pittsburgh Medical Center (UPMC), Pittsburgh, Pennsylvania 15213, USA
| | - Jong Gun Lee
- GE Ultrasound Korea, Seongnam 462-807, South Korea
| | | | | | - Sun Mi Kim
- Department of Radiology, Seoul National University of Bundang Hospital, Kyonggi-do, South Korea
| | - Hak Jong Lee
- Department of Radiology, Seoul National University of Bundang Hospital, Kyonggi-do, South Korea
| | - Young Bok Ahn
- Department of Electronic Engineering, Konkuk University, Seoul 143-701, South Korea
| | - Seunghee Han
- Sogang Institute of Advanced Technology, Sogang University, Seoul 121-742, South Korea
| | - Yangmo Yoo
- Department of Electronic Engineering, Sogang University, Seoul 121-742, South Korea
| | - Tai-Kyong Song
- Department of Electronic Engineering, Sogang University, Seoul 121-742, South Korea
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