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Liang M, Liu J, Guo C, Zong Y, Wan M. Velocity field estimation in transcranial small vessel using super-resolution ultrasound imaging velocimetry. Ultrasonics 2023; 132:107016. [PMID: 37094521 DOI: 10.1016/j.ultras.2023.107016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 04/11/2023] [Accepted: 04/13/2023] [Indexed: 05/03/2023]
Abstract
Based on the diameter and position information of small vessels obtained by transcranial super-resolution imaging using 3 MHz low-frequency chirp plane waves, a Gaussian-like non-linear compression was adopted to compress the blood flow signals in spatiotemporal filtering (STF) data to a precise region, and then estimate the blood flow velocity field inside the region over the adjacent time intervals using ultrasound imaging velocimetry (UIV). Imaging parameters, such as the mechanical index (MI), frame rate, and microbubble (MB) concentration, are critical during the estimation of velocity fields over a short time at high MB contrast agent concentrations. These were optimized through experiments and algorithms, in which dividing the connected domain was proposed to calculate MB cluster spot centroid spacing (SCS) and the spot-to-flow area ratio (SFAR) to determine the suitable MB concentration. The results of the in vitro experiments showed that the estimation of the small vessel flow velocity field was consistent with the theoretical results; the velocity field resolution for vessels with diameters of 0.5 mm and 0.3 mm was 36 μm and 21 μm, and the error between the mean velocity and the theoretical value was 0.7 % and 0.67 %, respectively.
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Affiliation(s)
- Meiling Liang
- College of Life Sciences and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Jiacheng Liu
- College of Life Sciences and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Chao Guo
- College of Life Sciences and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Yujin Zong
- College of Life Sciences and Technology, Xi'an Jiaotong University, Xi'an, China.
| | - Mingxi Wan
- College of Life Sciences and Technology, Xi'an Jiaotong University, Xi'an, China.
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Rowland EM, Riemer K, Lichtenstein K, Tang MX, Weinberg PD. Non-invasive Assessment by B-Mode Ultrasound of Arterial Pulse Wave Intensity and Its Reduction During Ventricular Dysfunction. Ultrasound Med Biol 2023; 49:473-488. [PMID: 36335055 DOI: 10.1016/j.ultrasmedbio.2022.09.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/12/2022] [Accepted: 09/24/2022] [Indexed: 06/16/2023]
Abstract
Arterial pulse waves contain clinically useful information about cardiac performance, arterial stiffness and vessel tone. Here we describe a novel method for non-invasively assessing wave properties, based on measuring changes in blood flow velocity and arterial wall diameter during the cardiac cycle. Velocity and diameter were determined by tracking speckles in successive B-mode images acquired with an ultrafast scanner and plane-wave transmission. Blood speckle was separated from tissue by singular value decomposition and processed to correct biases in ultrasound imaging velocimetry. Results obtained in the rabbit aorta were compared with a conventional analysis based on blood velocity and pressure, employing measurements obtained with a clinical intra-arterial catheter system. This system had a poorer frequency response and greater lags but the pattern of net forward-traveling and backward-traveling waves was consistent between the two methods. Errors in wave speed were also similar in magnitude, and comparable reductions in wave intensity and delays in wave arrival were detected during ventricular dysfunction. The non-invasive method was applied to the carotid artery of a healthy human participant and gave a wave speed and patterns of wave intensity consistent with earlier measurements. The new system may have clinical utility in screening for heart failure.
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Affiliation(s)
- Ethan M Rowland
- Department of Bioengineering, Imperial College London, London, UK
| | - Kai Riemer
- Department of Bioengineering, Imperial College London, London, UK
| | | | - Meng-Xing Tang
- Department of Bioengineering, Imperial College London, London, UK
| | - Peter D Weinberg
- Department of Bioengineering, Imperial College London, London, UK.
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Zhou X, Zhou X, Leow CH, Tang MX. Measurement of Flow Volume in the Presence of Reverse Flow with Ultrasound Speckle Decorrelation. Ultrasound Med Biol 2019; 45:3056-3066. [PMID: 31378548 PMCID: PMC6863465 DOI: 10.1016/j.ultrasmedbio.2019.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 06/19/2019] [Accepted: 07/01/2019] [Indexed: 05/28/2023]
Abstract
Direct measurement of volumetric flow rate in the cardiovascular system with ultrasound is valuable but has been a challenge because most current 2-D flow imaging techniques are only able to estimate the flow velocity in the scanning plane (in-plane). Our recent study demonstrated that high frame rate contrast ultrasound and speckle decorrelation (SDC) can be used to accurately measure the speed of flow going through the scanning plane (through-plane). The volumetric flow could then be calculated by integrating over the luminal area, when the blood vessel was scanned from the transverse view. However, a key disadvantage of this SDC method is that it cannot distinguish the direction of the through-plane flow, which limited its applications to blood vessels with unidirectional flow. Physiologic flow in the cardiovascular system could be bidirectional due to its pulsatility, geometric features, or under pathologic situations. In this study, we proposed a method to distinguish the through-plane flow direction by inspecting the flow within the scanning plane from a tilted transverse view. This method was tested on computer simulations and experimental flow phantoms. It was found that the proposed method could detect flow direction and improved the estimation of the flow volume, reducing the overestimation from over 100% to less than 15% when there was flow reversal. This method showed significant improvement over the current SDC method in volume flow estimation and can be applied to a wider range of clinical applications where bidirectional flow exists.
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Affiliation(s)
- Xiaowei Zhou
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Xinhuan Zhou
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Chee Hau Leow
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Meng-Xing Tang
- Department of Bioengineering, Imperial College London, London, United Kingdom.
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Gates PE, Gurung A, Mazzaro L, Aizawa K, Elyas S, Strain WD, Shore AC, Shandas R. Measurement of Wall Shear Stress Exerted by Flowing Blood in the Human Carotid Artery: Ultrasound Doppler Velocimetry and Echo Particle Image Velocimetry. Ultrasound Med Biol 2018; 44:1392-1401. [PMID: 29678322 PMCID: PMC5960638 DOI: 10.1016/j.ultrasmedbio.2018.02.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 01/22/2018] [Accepted: 02/26/2018] [Indexed: 05/15/2023]
Abstract
Vascular endothelial cells lining the arteries are sensitive to wall shear stress (WSS) exerted by flowing blood. An important component of the pathophysiology of vascular diseases, WSS is commonly estimated by centerline ultrasound Doppler velocimetry (UDV). However, the accuracy of this method is uncertain. We have previously validated the use of a novel, ultrasound-based, particle image velocimetry technique (echo PIV) to compute 2-D velocity vector fields, which can easily be converted into WSS data. We compared WSS data derived from UDV and echo PIV in the common carotid artery of 27 healthy participants. Compared with echo PIV, time-averaged WSS was lower using UDV (28 ± 35%). Echo PIV revealed that this was due to considerable spatiotemporal variation in the flow velocity profile, contrary to the assumption that flow is steady and the velocity profile is parabolic throughout the cardiac cycle. The largest WSS underestimation by UDV was found during peak systole (118 ± 16%) and the smallest during mid-diastole (4.3± 46%). The UDV method underestimated WSS for the accelerating and decelerating systolic measurements (68 ± 30% and 24 ± 51%), whereas WSS was overestimated for end-diastolic measurements (-44 ± 55%). Our data indicate that UDV estimates of WSS provided limited and largely inaccurate information about WSS and that the complex spatiotemporal flow patterns do not fit well with traditional assumptions about blood flow in arteries. Echo PIV-derived WSS provides detailed information about this important but poorly understood stimulus that influences vascular endothelial pathophysiology.
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Affiliation(s)
- Phillip E Gates
- National Institute of Health Research (NIHR) Exeter Clinical Research Facility and Diabetes and Vascular Medicine Research Centre, University of Exeter Medical School, Exeter, United Kingdom
| | - Arati Gurung
- Department of Bioengineering, University of Colorado Denver, Aurora, Colorado, USA
| | - Luciano Mazzaro
- Department of Bioengineering, University of Colorado Denver, Aurora, Colorado, USA
| | - Kuni Aizawa
- National Institute of Health Research (NIHR) Exeter Clinical Research Facility and Diabetes and Vascular Medicine Research Centre, University of Exeter Medical School, Exeter, United Kingdom
| | - Salim Elyas
- National Institute of Health Research (NIHR) Exeter Clinical Research Facility and Diabetes and Vascular Medicine Research Centre, University of Exeter Medical School, Exeter, United Kingdom
| | - William D Strain
- National Institute of Health Research (NIHR) Exeter Clinical Research Facility and Diabetes and Vascular Medicine Research Centre, University of Exeter Medical School, Exeter, United Kingdom
| | - Angela C Shore
- National Institute of Health Research (NIHR) Exeter Clinical Research Facility and Diabetes and Vascular Medicine Research Centre, University of Exeter Medical School, Exeter, United Kingdom
| | - Robin Shandas
- Department of Bioengineering, University of Colorado Denver, Aurora, Colorado, USA.
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Gurung A, Gates PE, Mazzaro L, Fulford J, Zhang F, Barker AJ, Hertzberg J, Aizawa K, Strain WD, Elyas S, Shore AC, Shandas R. Echo Particle Image Velocimetry for Estimation of Carotid Artery Wall Shear Stress: Repeatability, Reproducibility and Comparison with Phase-Contrast Magnetic Resonance Imaging. Ultrasound Med Biol 2017; 43:1618-1627. [PMID: 28501327 DOI: 10.1016/j.ultrasmedbio.2017.03.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 02/17/2017] [Accepted: 03/27/2017] [Indexed: 06/07/2023]
Abstract
Measurement of hemodynamic wall shear stress (WSS) is important in investigating the role of WSS in the initiation and progression of atherosclerosis. Echo particle image velocimetry (echo PIV) is a novel ultrasound-based technique for measuring WSS in vivo that has previously been validated in vitro using the standard optical PIV technique. We evaluated the repeatability and reproducibility of echo PIV for measuring WSS in the human common carotid artery. We measured WSS in 28 healthy participants (18 males and 10 females, mean age: 56 ± 12 y). Echo PIV was highly repeatable, with an intra-observer variability of 1.0 ± 0.1 dyn/cm2 for peak systolic (maximum), 0.9 dyn/cm2 for mean and 0.5 dyn/cm2 for end-diastolic (minimum) WSS measurements. Likewise, echo PIV was reproducible, with a low inter-observer variability (max: 2.0 ± 0.2 dyn/cm2, mean: 1.3 ± 0.1 dyn/cm2, end-diastolic: 0.7 dyn/cm2) and more variable inter-scan (test-retest) variability (max: 7.1 ± 2.3 dyn/cm2, mean: 2.9 ± 0.4 dyn/cm2, min: 1.5 ± 0.1 dyn/cm2). We compared echo PIV with the reference method, phase-contrast magnetic resonance imaging (PC-MRI); echo PIV-based WSS measurements agreed qualitatively with PC-MRI measurements (r = 0.89, p < 0.05). Significant differences were observed in some WSS measurements (echo PIV vs. PC-MRI): WSS at peak systole: 21 ± 7.0 dyn/cm2 vs. 15 ± 5.0 dyn/cm2; time-averaged WSS: 8.9 ± 3.0 dyn/cm2 vs. 7.1 ± 3.0 dyn/cm2 (p < 0.05); WSS at end diastole: 3.8 ± 2.8 dyn/cm2 vs. 3.9 ± 2 dyn/cm2 (p > 0.05). For the first time, we report that echo PIV can measure WSS with good repeatability and reproducibility in adult humans with a broad age range. Echo PIV is feasible in humans and offers an easy-to-use, ultrasound-based, quantitative technique for measuring WSS in vivo in humans with good repeatability and reproducibility.
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Affiliation(s)
- Arati Gurung
- Department of Bioengineering, University of Colorado Denver, Aurora, Colorado, USA
| | - Phillip E Gates
- Diabetes and Vascular Medicine, University of Exeter Medical School, Exeter, UK
| | - Luciano Mazzaro
- Department of Bioengineering, University of Colorado Denver, Aurora, Colorado, USA
| | - Jonathan Fulford
- Diabetes and Vascular Medicine, University of Exeter Medical School, Exeter, UK
| | - Fuxing Zhang
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado, USA
| | - Alex J Barker
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado, USA
| | - Jean Hertzberg
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, Colorado, USA
| | - Kunihiko Aizawa
- Diabetes and Vascular Medicine, University of Exeter Medical School, Exeter, UK
| | - William D Strain
- Diabetes and Vascular Medicine, University of Exeter Medical School, Exeter, UK
| | - Salim Elyas
- Diabetes and Vascular Medicine, University of Exeter Medical School, Exeter, UK
| | - Angela C Shore
- Diabetes and Vascular Medicine, University of Exeter Medical School, Exeter, UK
| | - Robin Shandas
- Department of Bioengineering, University of Colorado Denver, Aurora, Colorado, USA.
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Leow CH, Bazigou E, Eckersley RJ, Yu ACH, Weinberg PD, Tang MX. Flow Velocity Mapping Using Contrast Enhanced High-Frame-Rate Plane Wave Ultrasound and Image Tracking: Methods and Initial in Vitro and in Vivo Evaluation. Ultrasound Med Biol 2015; 41:2913-2925. [PMID: 26275971 DOI: 10.1016/j.ultrasmedbio.2015.06.012] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Revised: 04/22/2015] [Accepted: 06/16/2015] [Indexed: 06/04/2023]
Abstract
Ultrasound imaging is the most widely used method for visualising and quantifying blood flow in medical practice, but existing techniques have various limitations in terms of imaging sensitivity, field of view, flow angle dependence, and imaging depth. In this study, we developed an ultrasound imaging velocimetry approach capable of visualising and quantifying dynamic flow, by combining high-frame-rate plane wave ultrasound imaging, microbubble contrast agents, pulse inversion contrast imaging and speckle image tracking algorithms. The system was initially evaluated in vitro on both straight and carotid-mimicking vessels with steady and pulsatile flows and in vivo in the rabbit aorta. Colour and spectral Doppler measurements were also made. Initial flow mapping results were compared with theoretical prediction and reference Doppler measurements and indicate the potential of the new system as a highly sensitive, accurate, angle-independent and full field-of-view velocity mapping tool capable of tracking and quantifying fast and dynamic flows.
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Affiliation(s)
- Chee Hau Leow
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Eleni Bazigou
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Robert J Eckersley
- Department of Biomedical Engineering, King's College London, London, United Kingdom
| | - Alfred C H Yu
- Medical Engineering Program, University of Hong Kong, Pokfulam, Hong Kong
| | - Peter D Weinberg
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Meng-Xing Tang
- Department of Bioengineering, Imperial College London, London, United Kingdom.
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