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Gu O, He B, Xiong L, Zhang Y, Li Z, Lang X. Reconstructive interpolation for pulse wave estimation to improve local PWV measurement of carotid artery. Med Biol Eng Comput 2024; 62:1459-1473. [PMID: 38252371 DOI: 10.1007/s11517-023-03008-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Accepted: 12/21/2023] [Indexed: 01/23/2024]
Abstract
Ultrasonic transit time (TT)-based local pulse wave velocity (PWV) measurement is defined as the distance between two beam positions on a segment of common carotid artery (CCA) divided by the TT in the pulse wave propagation. However, the arterial wall motions (AWMs) estimated from ultrasonic radio frequency (RF) signals with a limited number of frames using the motion tracking are typically discrete. In this work, we develop a method involving motion tracking combined with reconstructive interpolation (MTRI) to reduce the quantification errors in the estimated PWs, and thereby improve the accuracy of the TT-based local PWV measurement for CCA. For each beam position, normalized cross-correlation functions (NCCFs) between the reference (the first frame) and comparison (the remaining frames) RF signals are calculated. Thereafter, the reconstructive interpolation is performed in the neighborhood of the NCCFs' peak to identify the interpolation-deduced peak locations, which are more exact than the original ones. According to which, the improved AWMs are obtained to calculate their TT along a segment of the CCA. Finally, the local PWV is measured by applying a linear regression fit to the time-distance result. In ultrasound simulations based on the pulse wave propagation models of young, middle-aged, and elderly groups, the MTRI method with different numbers of interpolated samples was used to estimate AWMs and local PWVs. Normalized root mean squared errors (NRMSEs) between the estimated and preset values of the AWMs and local PWVs were calculated and compared with ones without interpolation. The means of the NRMSEs for the AWMs and local PWVs based on the MTRI method with one interpolated sample decrease from 1.14% to 0.60% and 7.48% to 4.61%, respectively. Moreover, Bland-Altman analysis and coefficient of variation were used to validate the performance of the MTRI method based on the measured local PWVs of 30 healthy subjects. In conclusion, the reconstructive interpolation for the pulse wave estimation improves the accuracy and repeatability of the carotid local PWV measurement.
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Affiliation(s)
- Ouyang Gu
- Department of Electronic Engineering, Information School, Yunnan University, Kunming, 650091, Yunnan, China
| | - Bingbing He
- Department of Electronic Engineering, Information School, Yunnan University, Kunming, 650091, Yunnan, China.
| | - Li Xiong
- Department of Electronic Engineering, Information School, Yunnan University, Kunming, 650091, Yunnan, China
| | - Yufeng Zhang
- Department of Electronic Engineering, Information School, Yunnan University, Kunming, 650091, Yunnan, China
| | - Zhiyao Li
- Department of Ultrasound, the Third Affiliated Hospital of Kunming Medical College, Kunming, 650118, China
| | - Xun Lang
- Department of Electronic Engineering, Information School, Yunnan University, Kunming, 650091, Yunnan, China
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Ekroll IK, Saris AECM, Avdal J. FLUST: A fast, open source framework for ultrasound blood flow simulations. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 238:107604. [PMID: 37220679 DOI: 10.1016/j.cmpb.2023.107604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 05/08/2023] [Accepted: 05/14/2023] [Indexed: 05/25/2023]
Abstract
BACKGROUND AND OBJECTIVE Ultrasound based blood velocity estimation is a continuously developing frontier, where the vast number of possible acquisition setups and velocity estimators makes it challenging to assess which combination is better suited for a given imaging application. FLUST, the Flow-Line based Ultrasound Simulation Tool, may be used to address this challenge, providing a common platform for evaluation of velocity estimation schemes on in silico data. However, the FLUST approach had some limitations in its original form, including reduced robustness for phase sensitive setups and the need for manual selection of integrity parameters. In addition, implementation of the technique and therefore also documentation of signal integrity was left to potential users of the approach. METHODS In this work, several improvements to the FLUST technique are proposed and investigated, and a robust, open source simulation framework developed. The software supports several transducer types and acquisition setups, in addition to a range of different flow phantoms. The main goal of this work is to offer a robust, computationally cheap and user-friendly framework to simulate ultrasound data from stationary blood velocity fields and thereby facilitate design and evaluation of estimation schemes, including acquisition design, velocity estimation and other post-processing steps. RESULTS The technical improvements proposed in this work resulted in reduced interpolation errors, reduced variability in signal power, and also automatic selection of spatial and temporal discretization parameters. Results are presented illustrating the challenges and the effectiveness of the solutions. The integrity of the improved simulation framework is validated in an extensive study, with results indicating that speckle statistics, spatial and temporal correlation and frequency content all correspond well with theoretical predictions. Finally, an illustrative example shows how FLUST may be used throughout the design and optimization process of a velocity estimator. CONCLUSIONS The FLUST framework is available as a part of the UltraSound ToolBox (USTB), and the results in this paper demonstrate that it can be used as an efficient and reliable tool for the development and validation of ultrasound-based velocity estimation schemes.
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Affiliation(s)
- Ingvild Kinn Ekroll
- CIUS and the Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Norway.
| | - Anne E C M Saris
- Medical Ultrasound Imaging Center, Department of Medical Imaging, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jørgen Avdal
- CIUS and the Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Norway; Department of Health Research, SINTEF Digital, Norway
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3
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Hasegawa H, Omura M, Nagaoka R, Saito K. Two-Dimensional Wavenumber Analysis Implemented in Ultrasonic Vector Doppler Method with Focused Transmit Beams. SENSORS (BASEL, SWITZERLAND) 2022; 22:9787. [PMID: 36560161 PMCID: PMC9781179 DOI: 10.3390/s22249787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/05/2022] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
The multi-angle Doppler method was introduced for the estimation of velocity vectors by measuring axial velocities from multiple directions. We have recently reported that the autocorrelation-based velocity vector estimation could be ameliorated significantly by estimating the wavenumbers in two dimensions. Since two-dimensional wavenumber estimation requires a snapshot of an ultrasonic field, the method was first implemented in plane wave imaging. Although plane wave imaging is predominantly useful for examining blood flows at an extremely high temporal resolution, it was reported that the contrast in a B-mode image obtained with a few plane wave emissions was lower than that obtained with focused beams. In this study, the two-dimensional wavenumber analysis was first implemented in a framework with focused transmit beams. The simulations showed that the proposed method achieved an accuracy in velocity estimation comparable to that of the method with plane wave imaging. Furthermore, the performances of the methods implemented in focused beam and plane wave imaging were compared by measuring human common carotid arteries in vivo. Image contrasts were analyzed in normal and clutter-filtered B-mode images. The method with focused beam imaging achieved a better contrast in normal B-mode imaging, and similar velocity magnitudes and angles were obtained by both the methods with focused beam and plane wave imaging. In contrast, the method with plane wave imaging gave a better contrast in a clutter-filtered B-mode image and smaller variances in velocity magnitudes than those with focused beams.
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Affiliation(s)
- Hideyuki Hasegawa
- Faculty of Engineering, University of Toyama, Toyama 930-8555, Japan
| | - Masaaki Omura
- Faculty of Engineering, University of Toyama, Toyama 930-8555, Japan
| | - Ryo Nagaoka
- Faculty of Engineering, University of Toyama, Toyama 930-8555, Japan
| | - Kozue Saito
- Department of Neurology, Stroke Center, Nara Medical University, Nara 634-8522, Japan
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Slart RHJA, Reijnen MMPJ. Carotid plaque stenosis, metabolism and flow dynamics: Important determinants of atherosclerotic risk? J Nucl Cardiol 2022; 29:578-580. [PMID: 32910416 DOI: 10.1007/s12350-020-02311-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 07/24/2020] [Indexed: 10/23/2022]
Affiliation(s)
- Riemer H J A Slart
- Medical Imaging Center, Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9700 RB, Groningen, The Netherlands.
- Biomedical Photonic Imaging Group, University of Twente, Enschede, The Netherlands.
| | - Michel M P J Reijnen
- Multi-Modality Medical Imaging Group, Technical Medical Centre, University of Twente, Enschede, The Netherlands
- Department of Surgery, Rijnstate, Arnhem, The Netherlands
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Hasegawa H, Omura M, Nagaoka R. On the Investigation of Autocorrelation-Based Vector Doppler Method With Plane Wave Imaging. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2022; 69:1301-1311. [PMID: 35171769 DOI: 10.1109/tuffc.2022.3152186] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Although color flow imaging is one of the representative applications of the Doppler method, it can estimate only the velocity component in the direction of ultrasonic propagation, that is, the axial velocity component. The vector Doppler method with high-frame-rate plane wave imaging overcomes such a limitation by estimating the blood flow velocity vectors using the axial velocities obtained by emitting plane waves in multiple directions. The autocorrelation technique can be used for the estimation of the axial velocity using the phase shift of an ultrasonic echo signal between two transmit-receive events. The technique also requires the frequency of the received echo signal. Although the center frequency of the emitted ultrasonic signal is commonly used in the estimation of axial velocities, the center frequency should be estimated from the received signals. In this study, a method for the estimation of the center frequency designed particularly for the high-frame-rate plane wave imaging was developed. The proposed method estimates the wavenumbers of the received signal in lateral and vertical directions to estimate the wavenumber in the axial direction, from which the center frequency was estimated. The beam steering angle was also estimated from the wavenumbers in the two directions. The effect of the proposed method was validated in simulations. The absolute bias error (ABE) and root-mean squared error in estimated velocity vectors obtained by plane wave imaging with three beam steering angles (-15°, 0°, and 15°) were reduced from 9.27% and 14.80% to 1.15% and 8.75%, respectively, by the proposed method. The applicability of the proposed method to in vivo measurements was also demonstrated using the in vivo recordings of human common carotid arteries. Physiologically consistent blood flow velocity distributions were obtained with respect to three subjects using the proposed method.
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6
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Acoustic-Field Beamforming-Based Generalized Coherence Factor for Handheld Ultrasound. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12020560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
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.
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Baun J. Emerging Technology: Ultrasound Vector Flow Imaging—A Novel Approach to Arterial Hemodynamic Quantification. JOURNAL OF DIAGNOSTIC MEDICAL SONOGRAPHY 2021. [DOI: 10.1177/87564793211036013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Accurate, reliable, and easily obtainable quantification of peripheral arterial hemodynamic states has long been a holy grail of vascular ultrasound. While conventional Doppler modalities have been relied upon for decades to provide velocity, directionality, and flow volume data for integration into patient management schema, they carry limitations in accurately and reproducibly quantifying complex arterial hemodynamic patterns. Advances in ultrasound imaging architecture, such as virtual beamforming, integration of “big data” capabilities, and the use of enhanced digital signal processing methods have opened the door for a novel approach to arterial hemodynamic mapping and quantification—ultrasound vector flow imaging (VFI). This article presents an overview of the technological underpinnings of VFI, compares it with conventional pulsed wave and color Doppler methods, and describes the potential clinical benefits of this emerging vascular ultrasound modality.
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Affiliation(s)
- Jim Baun
- Sonography Scholar Emeritus, Toledo, OH, USA
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8
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Hu CL, Wu GZ, Chang CC, Li ML. Acoustic-Field Beamforming for Low-Power Portable Ultrasound. ULTRASONIC IMAGING 2021; 43:175-185. [PMID: 33957822 DOI: 10.1177/01617346211013473] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
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.
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Affiliation(s)
- Chang-Lin Hu
- Industrial Technology Research Institute, Hsinchu
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu
| | - Guo-Zua Wu
- Industrial Technology Research Institute, Hsinchu
| | | | - Meng-Lin Li
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu
- Brain Research Center, National Tsing Hua University, Hsinchu
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9
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He B, Zhang Y, Zhang K, Chen J, Zhang J, Liang H. Optimum Speckle Tracking Based on Ultrafast Ultrasound for Improving Blood Flow Velocimetry. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:494-509. [PMID: 32746230 DOI: 10.1109/tuffc.2020.3012344] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Speckle tracking using optimum comparison frames (STO) is proposed to improve the blood flow velocity profile (BFVP) estimation based on ultrafast ultrasound with coherent plane-wave compounding. The optimum comparison frames are as far as possible from the reference frame image while possessing a speckle correlation above a given threshold. The correlation thresholds for different kernel sizes are determined via an experiment based on a vascular-mimicking phantom. In in vitro experiments with different peak velocities of the flow ranging from 0.38 to 1.18 m/s, the proposed STO method with three kernel sizes ( 0.46 × 0.46 , 0.31 × 0.69 , and 0.92 × 0.92 mm2) is used for the BFVP estimations. The normalized root mean square errors (NRMSEs) between the estimated and theoretical BFVPs are calculated and compared with the results based on the speckle tracking using adjacent-frame images. For the three kernel sizes, the mean relative decrements in the STO-based NRMSEs are 46.6%, 44.7%, and 52.9%, and the standard deviations are 36.8%, 37.6%, and 35.9%, respectively. The STO method is also validated by in vivo experiments using rabbit iliac arteries with contrast agents. With parabolic curves fitting to the mean velocity estimates, the average relative increments for the STO-based R2 (coefficients of determination) are 7.22% and 6.25% for kernel sizes of 0.46 × 0.46 and 0.31 × 0.69 mm2, respectively. In conclusion, the STO method improves the BFVP measurement accuracy, whereby accurate diagnosis information can be acquired for clinical applications.
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10
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Nguyen TQ, Traberg MS, Olesen JB, Heerwagen ST, Brandt AH, Bechsgaard T, Pedersen BL, Moshavegh R, Lönn L, Jensen JA, Nielsen MB, Hansen KL. Flow Complexity Estimation in Dysfunctional Arteriovenous Dialysis Fistulas using Vector Flow Imaging. ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:2493-2504. [PMID: 32595057 DOI: 10.1016/j.ultrasmedbio.2020.05.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 05/25/2020] [Accepted: 05/31/2020] [Indexed: 06/11/2023]
Abstract
Non-invasive assessment is preferred for monitoring arteriovenous dialysis fistulas (AVFs). Vector concentration assesses flow complexity, which may correlate with stenosis severity. We determined whether vector concentration could assess stenosis severity in dysfunctional AVFs. Vector concentration was estimated in four stenotic phantoms at different pulse repetition frequencies. Spectral Doppler peak velocity and vector concentration were measured in 12 patients with dysfunctional AVFs. Additionally, 5 patients underwent digital subtraction angiography (DSA). In phantoms, vector concentration exhibited an inverse relationship with stenosis severity and was less affected by aliasing in severe stenoses. In nine stenoses of 5 patients undergoing DSA, vector concentration correlated strongly with stenosis severity (first stenosis: r = -0.73, p = 0.04; other stenoses; r = -0.69, p = 0.02) and mid-stenotic diameter (first stenosis: r = 0.87, p = 0.006; other stenoses: r = 0.70, p = 0.02) as opposed to peak velocities (p > 0.05). Vector concentration is less affected by aliasing in severe stenoses and correlates with DSA in patients with dysfunctional AVF.
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Affiliation(s)
- Tin-Quoc Nguyen
- Department of Diagnostic Radiology, Rigshospitalet, Copenhagen, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.
| | - Marie Sand Traberg
- Center for Fast Ultrasound Imaging, Department of Health Technology, Technical University of Denmark, Lyngby, Denmark
| | - Jacob Bjerring Olesen
- Center for Fast Ultrasound Imaging, Department of Health Technology, Technical University of Denmark, Lyngby, Denmark; BK Medical, Herlev, Denmark
| | | | | | - Thor Bechsgaard
- Department of Radiology, Odense University Hospital, Odense C, Denmark
| | | | - Ramin Moshavegh
- Center for Fast Ultrasound Imaging, Department of Health Technology, Technical University of Denmark, Lyngby, Denmark; BK Medical, Herlev, Denmark
| | - Lars Lönn
- Department of Diagnostic Radiology, Rigshospitalet, Copenhagen, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen Arendt Jensen
- Center for Fast Ultrasound Imaging, Department of Health Technology, Technical University of Denmark, Lyngby, Denmark
| | - Michael Bachmann Nielsen
- Department of Diagnostic Radiology, Rigshospitalet, Copenhagen, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Kristoffer Lindskov Hansen
- Department of Diagnostic Radiology, Rigshospitalet, Copenhagen, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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11
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Hendriks GAGM, Hansen HHG, De Korte CL, Chen C. Optimization of transmission and reconstruction parameters in angular displacement compounding using plane wave ultrasound. Phys Med Biol 2020; 65:085007. [PMID: 32109889 DOI: 10.1088/1361-6560/ab7b2f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In ultrasound elastography, plane-wave acquisitions and angular displacement compounding (ADC) are often used and combined to allow high frame rates and to improve accuracy of lateral displacement estimates, respectively. This study investigates the performance of displacement and strain estimation for ADC as a function of; the main-to-grating-lobe-amplitude ratio which decreases as a function of steering angle; plane-wave acquisition and Delay-and-Sum (DaS)-related parameters; and grating-lobe filter cut-off frequency. Three experiments were conducted with a block phantom to test ADC performance for displacement fields of varying complexity: a lateral transducer shift, phantom rotation and phantom deformation. Experiments were repeated for four linear array transducers (pitch-to-lambda ratios between 0.6 and 1.4). Best ADC performance was found for steering angles that resulted in a theoretically derived main-to-grating-lobe-amplitude ratio of 1.7 dB for pure lateral translation and 6 dB for predominately lateral strain or rotation. Temporal filtering to reduce grating lobe signal or shifting of the receive aperture to receive angles below or above the optimal angle, as dictated by the main-to-grating-lobe-amplitude ratio, did not improve results. The accuracy of lateral displacement and strain estimates was improved by apodization in transmission and a dedicated F-number in DaS (0.75) allowing incidence angles within ± 33° in the active aperture. ADC with the optimized settings as found in this study improves the accuracy of displacements and strain estimates up to 80.7% compared to non-ADC. Compared to ADC settings described in current literature, our optimization improved the accuracy by 11.9% to 75.3% for lateral displacement and strain, and by 89.3% to 96.2% for rotation. The accuracy of ADC in rotation seemed to depend highly on plane-wave and DaS-related parameters which may explain the major improvement compared to settings in current literature. The overall improvement by optimized ADC was statistically significant compared to non-ADC (p = 0.003) and literature (p = 0.002).
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Affiliation(s)
- Gijs A G M Hendriks
- Medical UltraSound Imaging Center (MUSIC), Department of Radiology and Nuclear Medicine, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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12
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Saris AECM, Hansen HHG, Fekkes S, Menssen J, Nillesen MM, de Korte CL. In Vivo Blood Velocity Vector Imaging Using Adaptive Velocity Compounding in the Carotid Artery Bifurcation. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:1691-1707. [PMID: 31079874 DOI: 10.1016/j.ultrasmedbio.2019.03.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 03/06/2019] [Accepted: 03/10/2019] [Indexed: 06/09/2023]
Abstract
Visualization and quantification of blood flow are considered important for early detection of atherosclerosis and patient-specific diagnosis and intervention. As conventional Doppler imaging is limited to 1-D velocity estimates, 2-D and 3-D techniques are being developed. We introduce an adaptive velocity compounding technique that estimates the 2-D velocity vector field using predominantly axial displacements estimated by speckle tracking from dual-angle plane wave acquisitions. Straight-vessel experiments with a 7.8-MHz linear array transducer connected to a Verasonics Vantage ultrasound system revealed that the technique performed with a maximum velocity magnitude bias and angle bias of -3.7% (2.8% standard deviation) and -0.16° (0.41° standard deviation), respectively. In vivo, complex flow patterns were visualized in two healthy and three diseased carotid arteries and quantified using a vector complexity measure that increased with increasing wall irregularity. This measure could potentially be a relevant clinical parameter which might aid in early detection of atherosclerosis.
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Affiliation(s)
- Anne E C M Saris
- Medical Ultrasound Imaging Centre (MUSIC), Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Hendrik H G Hansen
- Medical Ultrasound Imaging Centre (MUSIC), Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Stein Fekkes
- Medical Ultrasound Imaging Centre (MUSIC), Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jan Menssen
- Medical Ultrasound Imaging Centre (MUSIC), Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Maartje M Nillesen
- Medical Ultrasound Imaging Centre (MUSIC), Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Chris L de Korte
- Medical Ultrasound Imaging Centre (MUSIC), Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands; Physics of Fluid Group, MESA+ Institute for Nanotechnology, and MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
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13
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Liu Z, He Q, Luo J. Spatial Angular Compounding With Affine-Model-Based Optical Flow for Improvement of Motion Estimation. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2019; 66:701-716. [PMID: 30703018 DOI: 10.1109/tuffc.2019.2895374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Tissue motion estimation is an essential step for ultrasound elastography. Our previous study has shown that the affine-model-based optical flow (OF) method outperforms the normalized cross-correlation-based block matching (BM) method in motion estimation. However, the quality of lateral estimation using OF is still low due to inherent limitation of ultrasound imaging. BM-based spatial angular compounding (SAC) has been developed to obtain better motion estimation. In this paper, OF-based SAC (OF-SAC) is proposed to further improve the performance of lateral (and axial) estimation, and it is compared with BM-based SAC (BM-SAC). Plane wave as well as focused wave is transmitted in both simulations and phantom experiments on a linear array. In order to compare the performance quantitatively, the root-mean-square error (RMSE) of axial/lateral displacement and strain, and signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of axial/lateral strain are used as the evaluation criteria in the simulations. In the phantom experiments, the SNR and CNR are used to assess the quality of axial/lateral strain. The results show that for both OF and BM, SAC improves the performance of motion estimation, regardless of using plane or focused wave transmission. More importantly, OF-SAC is shown to outperform BM-SAC with lower RMSE, higher SNR, and higher CNR. In addition, preliminary in vivo experiments on the carotid artery of a healthy human subject also prove the superiority of OF-SAC. These results suggest that OF-SAC is preferred for both axial and lateral motion estimation to BM-SAC.
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Nie L, Cowell DMJ, Carpenter TM, Mclaughlan JR, Cubukcu AA, Freear S. High-Frame-Rate Contrast-Enhanced Echocardiography Using Diverging Waves: 2-D Motion Estimation and Compensation. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2019; 66:359-371. [PMID: 30575531 DOI: 10.1109/tuffc.2018.2887224] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Combining diverging ultrasound waves and microbubbles could improve contrast-enhanced echocardiography (CEE), by providing enhanced temporal resolution for cardiac function assessment over a large imaging field of view. However, current image formation techniques using coherent summation of echoes from multiple steered diverging waves (DWs) are susceptible to tissue and microbubble motion artifacts, resulting in poor image quality. In this study, we used correlation-based 2-D motion estimation to perform motion compensation for CEE using DWs. The accuracy of this motion estimation method was evaluated with Field II simulations. The root-mean-square velocity errors were 5.9% ± 0.2% and 19.5% ± 0.4% in the axial and lateral directions, when normalized to the maximum value of 62.8 cm/s which is comparable to the highest speed of blood flow in the left ventricle (LV). The effects of this method on image contrast ratio (CR) and contrast-to-noise ratio (CNR) were tested in vitro using a tissue mimicking rotating disk with a diameter of 10 cm. Compared against the control without motion compensation, a mean increase of 12 dB in CR and 7 dB in CNR were demonstrated when using this motion compensation method. The motion correction algorithm was tested in vivo on a CEE data set acquired with the Ultrasound Array Research Platform II performing coherent DW imaging. Improvement of the B-mode and contrast-mode image quality with cardiac motion and blood flow-induced microbubble motion was achieved. The results of motion estimation were further processed to interpret blood flow in the LV. This allowed for a triplex cardiac imaging technique, consisting of B mode, contrast mode, and 2-D vector flow imaging with a high frame rate of 250 Hz.
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Fekkes S, Saris AECM, Nillesen MM, Menssen J, Hansen HHG, de Korte CL. Simultaneous Vascular Strain and Blood Vector Velocity Imaging Using High-Frequency Versus Conventional-Frequency Plane Wave Ultrasound: A Phantom Study. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2018; 65:1166-1181. [PMID: 29993371 DOI: 10.1109/tuffc.2018.2834724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Plaque strain and blood vector velocity imaging of stenosed arteries are expected to aid in diagnosis and prevention of cerebrovascular disease. Ultrafast plane wave imaging enables simultaneous strain and velocity estimation. Multiple ultrasound vendors are introducing high-frequency ultrasound probes and systems. This paper investigates whether the use of high-frequency ultrafast ultrasound is beneficial for assessing blood velocities and strain in arteries. The performance of strain and blood flow velocity estimation was compared between a high-frequency transducer (MS250, fc = 21 MHz) and a clinically utilized transducer (L12-5, fc = 9 MHz). Quantitative analysis based on straight tube phantom experiments revealed that the MS250 outperformed the L12-5 in the superficial region: low velocities near the wall were more accurately estimated and wall strains were better resolved. At greater than 2-cm echo depth, the L12-5 performed better due to the high attenuation of the MS250 probe. Qualitative comparison using a perfused patient-specific carotid bifurcation phantom confirmed these findings. Thus, in conclusion, for strain and blood velocity estimation for depths up to ~2 cm, a high-frequency probe is recommended.
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A PSF-Shape-Based Beamforming Strategy for Robust 2D Motion Estimation in Ultrafast Data. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8030429] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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17
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Wei S, Yang M, Zhou J, Sampson R, Kripfgans OD, Fowlkes JB, Wenisch TF, Chakrabarti C. Low-Cost 3-D Flow Estimation of Blood With Clutter. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2017; 64:772-784. [PMID: 28362605 DOI: 10.1109/tuffc.2017.2676091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Volumetric flow rate estimation is an important ultrasound medical imaging modality that is used for diagnosing cardiovascular diseases. Flow rates are obtained by integrating velocity estimates over a cross-sectional plane. Speckle tracking is a promising approach that overcomes the angle dependency of traditional Doppler methods, but suffers from poor lateral resolution. Recent work improves lateral velocity estimation accuracy by reconstructing a synthetic lateral phase (SLP) signal. However, the estimation accuracy of such approaches is compromised by the presence of clutter. Eigen-based clutter filtering has been shown to be effective in removing the clutter signal; but it is computationally expensive, precluding its use at high volume rates. In this paper, we propose low-complexity schemes for both velocity estimation and clutter filtering. We use a two-tiered motion estimation scheme to combine the low complexity sum-of-absolute-difference and SLP methods to achieve subpixel lateral accuracy. We reduce the complexity of eigen-based clutter filtering by processing in subgroups and replacing singular value decomposition with less compute-intensive power iteration and subspace iteration methods. Finally, to improve flow rate estimation accuracy, we use kernel power weighting when integrating the velocity estimates. We evaluate our method for fast- and slow-moving clutter for beam-to-flow angles of 90° and 60° using Field II simulations, demonstrating high estimation accuracy across scenarios. For instance, for a beam-to-flow angle of 90° and fast-moving clutter, our estimation method provides a bias of -8.8% and standard deviation of 3.1% relative to the actual flow rate.
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