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Parasaram V, Civale J, Bamber JC, Robinson SP, Jamin Y, Harris E. Preclinical Three-Dimensional Vibrational Shear Wave Elastography for Mapping of Tumour Biomechanical Properties In Vivo. Cancers (Basel) 2022; 14:4832. [PMID: 36230755 PMCID: PMC9564290 DOI: 10.3390/cancers14194832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/06/2022] [Accepted: 09/23/2022] [Indexed: 11/16/2022] Open
Abstract
Preclinical investigation of the biomechanical properties of tissues and their treatment-induced changes are essential to support drug-discovery, clinical translation of biomarkers of treatment response, and studies of mechanobiology. Here we describe the first use of preclinical 3D elastography to map the shear wave speed (cs), which is related to tissue stiffness, in vivo and demonstrate the ability of our novel 3D vibrational shear wave elastography (3D-VSWE) system to detect tumour response to a therapeutic challenge. We investigate the use of one or two vibrational sources at vibrational frequencies of 700, 1000 and 1200 Hz. The within-subject coefficients of variation of our system were found to be excellent for 700 and 1000 Hz and 5.4 and 6.2%, respectively. The relative change in cs measured with our 3D-VSWE upon treatment with an anti-vascular therapy ZD6126 in two tumour xenografts reflected changes in tumour necrosis. U-87 MG drug vs vehicle: Δcs = −24.7 ± 2.5 % vs 7.5 ± 7.1%, (p = 0.002) and MDA-MB-231 drug vs vehicle: Δcs = −12.3 ± 2.7 % vs 4.5 ± 4.7%, (p = 0.02). Our system enables rapid (<5 min were required for a scan length of 15 mm and three vibrational frequencies) 3D mapping of quantitative tumour viscoelastic properties in vivo, allowing exploration of regional heterogeneity within tumours and speedy recovery of animals from anaesthesia so that longitudinal studies (e.g., during tumour growth or following treatment) may be conducted frequently.
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Affiliation(s)
| | | | | | | | | | - Emma Harris
- Division of Radiotherapy and Imaging, Centre for Cancer Imaging, Institute of Cancer Research, London SM2 5NG, UK
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Layek K, Basak B, Samanta S, Maity SP, Barui A. Stiffness prediction on elastography images and neuro-fuzzy based segmentation for thyroid cancer detection. APPLIED OPTICS 2022; 61:49-59. [PMID: 35200805 DOI: 10.1364/ao.445226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 11/29/2021] [Indexed: 06/14/2023]
Abstract
The elastography method detects metastatic changes by measuring the stiffness of tissues. Estimation of elasticities from elastography images facilitates more precise identification of the metastatic region and detection of the same. In this study, an automated segmentation algorithm is proposed that calculates pixel-wise elasticity values to detect thyroid cancer from elastography images. This intensity to elasticity conversion is achieved by constructing a fuzzy inference system using an adaptive neuro-fuzzy inference system supported by two meta-heuristic algorithms: genetic algorithm and particle swarm optimization. Pixels of the input color images (red, green, and blue) are replaced by equivalent elasticity values (in kilo Pascal) and are stored in a two-dimensional array to form an "elasticity matrix." The elasticity matrix is then segmented into three regions, namely, suspicious, near-suspicious, and non-suspicious, based on the elasticity measures, where the threshold limits are calculated using the fuzzy entropy maximization method optimized by the differential evolution algorithm. Segmentation performances are evaluated by Kappa and the dice similarity co-efficient, and average values achieved are 0.94±0.11 and 0.93±0.12, respectively. Sensitivity and specificity values achieved by the proposed method are 86.35±0.34% and 97.67±0.40%, respectively, showing an overall accuracy of 93.50±0.42%. Results justify the importance of pixel stiffness for segmentation of thyroid nodules in elastography images.
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Zvietcovich F, Larin KV. Wave-based optical coherence elastography: The 10-year perspective. PROGRESS IN BIOMEDICAL ENGINEERING (BRISTOL, ENGLAND) 2022; 4:012007. [PMID: 35187403 PMCID: PMC8856668 DOI: 10.1088/2516-1091/ac4512] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
After 10 years of progress and innovation, optical coherence elastography (OCE) based on the propagation of mechanical waves has become one of the major and the most studied OCE branches, producing a fundamental impact in the quantitative and nondestructive biomechanical characterization of tissues. Preceding previous progress made in ultrasound and magnetic resonance elastography; wave-based OCE has pushed to the limit the advance of three major pillars: (1) implementation of novel wave excitation methods in tissues, (2) understanding new types of mechanical waves in complex boundary conditions by proposing advance analytical and numerical models, and (3) the development of novel estimators capable of retrieving quantitative 2D/3D biomechanical information of tissues. This remarkable progress promoted a major advance in answering basic science questions and the improvement of medical disease diagnosis and treatment monitoring in several types of tissues leading, ultimately, to the first attempts of clinical trials and translational research aiming to have wave-based OCE working in clinical environments. This paper summarizes the fundamental up-to-date principles and categories of wave-based OCE, revises the timeline and the state-of-the-art techniques and applications lying in those categories, and concludes with a discussion on the current challenges and future directions, including clinical translation research.
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Affiliation(s)
- Fernando Zvietcovich
- University of Houston, Biomedical Engineering, Houston, TX, United States, 77204
| | - Kirill V. Larin
- University of Houston, Biomedical Engineering, Houston, TX, United States, 77204,
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Dayavansha EGS, Gross GJ, Ehrman MC, Grimm PD, Mast TD. Reconstruction of shear wave speed in tissue-mimicking phantoms from aliased pulse-echo imaging of high-frequency wavefields. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021; 150:4128. [PMID: 34972294 DOI: 10.1121/10.0008901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Accepted: 11/09/2021] [Indexed: 06/14/2023]
Abstract
Quantitative elasticity estimation in medical and industrial applications may benefit from advancements in reconstruction of shear wave speed with enhanced resolution. Here, shear wave speed is reconstructed from pulse-echo ultrasound imaging of elastic waves induced by high-frequency (>400 Hz), time-harmonic mechanical excitation. Particle displacement in shear wavefields is mapped from measured interframe phase differences with compensation for timing of multiple scan lines, then processed by spatial Fourier analysis to estimate the predominant wave speed and analyzed by algebraic wavefield inversion to reconstruct wave speed maps. Reconstructions of shear wave speed from simulated wavefields illustrate the accuracy and spatial resolution available with both methods, as functions of signal-to-noise ratio and sizes of windows used for Fourier analysis or wavefield smoothing. The methods are applied to shear wavefields with frequencies up to six times the Nyquist rate, thus extending the frequency range measurable by a given imaging system. Wave speed measurements in tissue-mimicking phantoms are compared with supersonic shear imaging and mechanical tensile testing, demonstrating feasibility of the wavefield measurement and wave speed reconstruction methods employed.
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Affiliation(s)
| | - Gary J Gross
- The Procter & Gamble Company, Mason, Ohio 45040, USA
| | | | - Peter D Grimm
- Department of Biomedical Engineering, University of Cincinnati, Cincinnati, Ohio 45267, USA
| | - T Douglas Mast
- Department of Biomedical Engineering, University of Cincinnati, Cincinnati, Ohio 45267, USA
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Lee HK, Kong D, Choi K, Mislati R, Doyley MM. A Robust and Fast Method for 2-D Shear Wave Speed Calculation. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:2351-2360. [PMID: 33625981 DOI: 10.1109/tuffc.2021.3061916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We developed a new method, called the tangent plane method (TPM), for more efficiently and accurately estimating 2-D shear wave speed (SWS) from any direction of wave propagation. In this technique, we estimate SWS by solving the Eikonal equation because this approach is more robust to noise. To further enhance the performance, we computed the tangent plane of the arrival time surface. To evaluate the approach, we performed simulations and also conducted phantom studies. Simulation studies showed that TPM was more robust to noise than the conventional methods such as 2-D cross correlation (CC) and the distance method. The contrast/CNR for an inclusion (69 kPa; manufacturer provided stiffness) of a phantom is 0.54/4.17, 0.54/1.82, and 0.46/1.22. SWS results [mean and standard deviation (SD)] were 4.41 ± 0.49, 4.62 ± 0.85, and 3.66 ± 0.99 m/s, respectively, while the manufacturer's reported value (mean and range) is 4.81 ± 0.49 m/s. This shows that TPM has the higher CNR and lower SD than other methods. To increase the computation speed, an iterative version of TPM (ITPM) was also developed, which calculated the time-of-flight iteratively. ITPM reduced the computation time to 3.6%, i.e., from 748 to 27 s. In vivo case analysis demonstrated the feasibility of using the conventional ultrasound scanner for the proposed 2-D SWS algorithms.
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Basavarajappa L, Rijal G, Hoyt K. Multifocused Ultrasound Therapy for Controlled Microvascular Permeabilization and Improved Drug Delivery. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:961-968. [PMID: 32976098 PMCID: PMC8034541 DOI: 10.1109/tuffc.2020.3026697] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Focused ultrasound (FUS) exposure of micro-bubble (MB) contrast agents can transiently increase microvascular permeability allowing anticancer drugs to extravasate into a targeted tumor tissue. Either fixed or mechanically steered in space, most studies to date have used a single element focused transducer to deliver the ultrasound (US) energy. The goal of this study was to investigate various multi-FUS strategies implemented on a programmable US scanner (Vantage 256, Verasonics Inc.) equipped with a linear array for image guidance and a 128-element therapy transducer (HIFUPlex-06, Sonic Concepts). The multi-FUS strategies include multi-FUS with sequential excitation (multi-FUS-SE) and multi-FUS with temporal sequential excitation (multi-FUS-TSE) and were compared to single-FUS and sham treatment. This study was performed using athymic mice implanted with breast cancer cells ( N = 20 ). FUS therapy experiments were performed for 10 min after a solution containing MBs (Definity, Lantheus Medical Imaging Inc.) and near-infrared (NIR, surrogate drug) dye were injected via the tail vein. The fluorescent signal was monitored using an in vivo optical imaging system (Pearl Trilogy, LI-COR) to quantify intratumoral dye accumulation at baseline and again at 0.1, 24, and 48 h after receiving US therapy. Animals were then euthanized for ex vivo dye extraction analysis. At 48 h, fluorescent tracer accumulation within the tumor space for the multi-FUS-TSE therapy group animals was found to be 67.3%, 50.3%, and 36.2% higher when compared to sham, single-FUS, and multi-FUS-SE therapy group measures, respectively. Also, dye extraction and fluorescence measurements from excised tumor tissue found increases of 243.2%, 163.1%, and 68.1% for the multi-FUS-TSE group compared to sham, single-FUS, and multi-FUS-SE therapy group measures, respectively. In summary, experimental results revealed that for a multi-FUS sequence, increased microvascular permeability was considerably influenced by both the spatial and temporal aspects of the applied US therapy.
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Application of the novel estimation method by shear wave elastography using vibrator to human skeletal muscle. Sci Rep 2020; 10:22248. [PMID: 33335237 PMCID: PMC7747727 DOI: 10.1038/s41598-020-79215-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 12/02/2020] [Indexed: 12/28/2022] Open
Abstract
In recent years, non-invasive measurement of tissue stiffness (hardness) using ultrasound elastography has attracted considerable attention. It has been used to evaluate muscle stiffness in the fields of rehabilitation, sports, and orthopedics. However, ultrasonic diagnostic devices with elastography systems are expensive and clinical use of such devices has been limited. In this study, we proposed a novel estimation method for vibration-based shear wave elastography measurement of human skeletal muscle, then determined its reproducibility and reliability. The coefficient of variation and correlation coefficient were used to determine reproducibility and reliability of the method by measuring the shear wave velocities in konjac phantom gels and agar phantom gels, as well as skeletal muscle. The intra-day, day-to-day, and inter-operator reliabilities were good when measuring the shear wave velocities in phantom gels. The intra-day and day-to-day reliabilities were good when measuring the shear wave velocities in skeletal muscle. The findings confirmed adequate reproducibility and reliability of the novel estimation method for vibration-based shear wave elastography. Therefore, the proposed measurement method may be a useful tool for evaluation of muscle stiffness.
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Pasyar P, Masjoodi S, Montazeriani Z, Makkiabadi B. A digital viscoelastic liver phantom for investigation of elastographic measurements. Comput Biol Med 2020; 127:104078. [PMID: 33126121 DOI: 10.1016/j.compbiomed.2020.104078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 10/12/2020] [Accepted: 10/20/2020] [Indexed: 12/16/2022]
Abstract
To develop elastography imaging technologies and implement image reconstruction algorithms, testing is done with phantoms. Although the validation step is usually taken using real data and physical phantoms, their geometry as well as composition, biomechanical parameters, and details of applying stress cannot be modified readily. Such considerations have gained increasing importance with the growth of elastography techniques as one of the non-invasive medical imaging modalities, which can map the elastic properties and stiffness of soft tissues. In this article, we develop a digital viscoelastic phantom using computed tomography (CT) imaging data and several application software tools based on illustrations of normal liver anatomy so as to investigate the biomechanics of elastography via finite element modeling (FEM). Here we discuss how to create this phantom step by step, demonstrate typical shear wave elastography (SWE) experiments of applying transient stress to the liver model, and calculate quantitative measurements. In particular, shear wave velocities are investigated through a parametric study designed based on tissue stiffness and distance from the applied stress. According to the results of FEM analysis, low errors were obtained for shear wave velocity estimation for both mechanical stress (~2-5%) and acoustic radiation force (~3-7%). Results show that our model is a powerful framework and benchmark for simulating and implementing different algorithms in shear wave elastography, which can serve as a guide for upcoming researches and assist scientists to optimize their subsequent experiments in terms of design.
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Affiliation(s)
- Pezhman Pasyar
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran.
| | - Sadegh Masjoodi
- Institute for Cognitive and Brain Science, Shahid Beheshti University, Tehran, Iran
| | - Zahra Montazeriani
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
| | - Bahador Makkiabadi
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
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9
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Tai H, Khairalseed M, Hoyt K. 3-D H-Scan Ultrasound Imaging and Use of a Convolutional Neural Network for Scatterer Size Estimation. ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:2810-2818. [PMID: 32653207 PMCID: PMC7484237 DOI: 10.1016/j.ultrasmedbio.2020.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 05/25/2020] [Accepted: 06/01/2020] [Indexed: 05/29/2023]
Abstract
H-Scan ultrasound (US) is a new imaging technology that estimates the relative size of acoustic scattering objects and structures. The purpose of this study was to introduce a three-dimensional (3-D) H-scan US imaging approach for scatterer size estimation in volume space. Using a programmable research scanner (Vantage 256, Verasonics Inc, Kirkland, WA, USA) equipped with a custom volumetric imaging transducer (4 DL7, Vermon, Tours, France), raw radiofrequency (RF) data was collected for offline processing to generate H-scan US volumes. A deep convolutional neural network (CNN) was modified and used to achieve voxel mapping from the input H-scan US image to underlying scatterer size. Preliminary studies were conducted using homogeneous gelatin-based tissue-mimicking phantom materials embedded with acoustic scatterers of varying size (15 to 250 μm) and concentrations (0.1 to 1%). Two additional phantoms were embedded with 63 or 125 µm-sized microspheres and used to test CNN estimation accuracy. In vitro results indicate that 3-D H-scan US imaging can visualize the spatial distribution of acoustic scatterers of varying size at different concentrations (R2 > 0.85, p < 0.03). The result of scatterer size estimation reveals that a CNN can achieve an average mapping accuracy of 93.3%. Overall, our preliminary in vitro findings reveal that 3-D H-scan US imaging allows the visualization of tissue scatterer patterns and incorporation of a CNN can be used to help estimate size of the acoustic scattering objects.
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Affiliation(s)
- Haowei Tai
- Department of Electrical and Computer Engineering, University of Texas at Dallas, Richardson, TX, USA
| | - Mawia Khairalseed
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX, USA
| | - Kenneth Hoyt
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX, USA; Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Electrical and Computer Engineering, University of Texas at Dallas, Richardson, TX, USA.
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10
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Yang H, Carrascal CA, Xie H, Shamdasani V, Anthony BW. 2-D Ultrasound Shear Wave Elastography With Multi-Sphere-Source External Mechanical Vibration: Preliminary Phantom Results. ULTRASOUND IN MEDICINE & BIOLOGY 2020; 46:2505-2519. [PMID: 32513435 DOI: 10.1016/j.ultrasmedbio.2020.03.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 03/11/2020] [Accepted: 03/12/2020] [Indexed: 06/11/2023]
Abstract
Ultrasound shear wave elastography (SWE) imaging is emerging as a quantitative and non-invasive tissue characterization modality. Shear wave generation using external mechanical vibration (EMV) has received extensive research interest over acoustic radiation force impulse (ARFI) because of its low cost and potential for portability. In this paper, we propose an EMV concept with multiple spherical sources that can be easily reconfigured in three configurations to induce unique shear wave propagation patterns. We introduce two design embodiments of this concept bench test design for proof of concept and a clinically deployable design. The latter is designed to incorporate size, ergonomics, portability and power consumption considerations and constraints. Experimental validation on elasticity phantoms using both EMV designs demonstrates shear wave generation and elasticity reconstruction comparable in performance to ElastQ, a commercial ARFI-based shear elastography technology from Philips. In addition, the local displacement amplitude induced by EMV is 10 times greater than that induced by ARFI at the same given depth. Finally, the multiple configurations of the presented EMV design would allow exploration of advanced elastography methods such as tissue anisotropic elasticity.
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Affiliation(s)
- Heng Yang
- Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | | | - Hua Xie
- Philips Research North America, Cambridge, Massachusetts, USA
| | | | - Brian W Anthony
- Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
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11
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Chen PY, Yang TH, Kuo LC, Shih CC, Huang CC. Characterization of Hand Tendons Through High-Frequency Ultrasound Elastography. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2020; 67:37-48. [PMID: 31478846 DOI: 10.1109/tuffc.2019.2938147] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Tendon stiffness plays an important role in the tendon healing process, and many studies have indicated that measuring the shear wave velocity (SWV) on tendons relates to their stiffness. Because the thickness of hand tendons is a few millimeters, high-resolution imaging is required for visualizing hand tissues. However, the resolution of current ultrasound elastography systems is insufficient. In this study, a high-frequency (HF) ultrasound elastography system is proposed for measuring the SWVs of hand tendons. The HF ultrasound elastography system uses an external vibrator to create shear waves on hand tendons. Then, it uses a 40-MHz HF ultrasound array transducer with ultrafast ultrasound imaging technology to measure the SWV for characterizing hand tendons. A handheld device that combines a transducer and a vibrator allows the user to scan hand tissues. The biases of HF ultrasound elastography were measured in gelatin phantom experiments and were less than 6% compared to standard mechanical testing approach. Human experiments showed the ability to use HF ultrasound elastography to distinguish different SWVs of hand tendons. The SWVs were 0.73 ± 0.65 m/s and 1 ± 0.54 m/s for flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP), respectively, and 0.52 ± 0.14 m/s and 4.02 ± 0.77 m/s for extensor tendon under stretch and contraction conditions, respectively. The simplicity and convenience of the HF ultrasound elastography system for measuring hand tendon stiffness make it a promising tool for evaluating the severity of hand injuries and the performance of rehabilitation after hand injuries.
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Zvietcovich F, Ge GR, Mestre H, Giannetto M, Nedergaard M, Rolland JP, Parker KJ. Longitudinal shear waves for elastic characterization of tissues in optical coherence elastography. BIOMEDICAL OPTICS EXPRESS 2019; 10:3699-3718. [PMID: 31360610 PMCID: PMC6640829 DOI: 10.1364/boe.10.003699] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 05/30/2019] [Accepted: 06/11/2019] [Indexed: 05/10/2023]
Abstract
In dynamic optical coherence elastography (OCE), surface acoustic waves are the predominant perturbations. They constrain the quantification of elastic modulus to the direction of wave propagation only along the surface of tissues, and disregard elasticity gradients along depth. Longitudinal shear waves (LSW), on the other hand, can be generated at the surface of the tissue and propagate through depth with desirable properties for OCE: (1) LSW travel at the shear wave speed and can discriminate elasticity gradients along depth, and (2) the displacement of LSW is longitudinally polarized along the direction of propagation; therefore, it can be measured by a phase-sensitive optical coherence tomography system. In this study, we explore the capabilities of LSW generated by a circular glass plate in contact with a sample using numerical simulations and tissue-mimicking phantom experiments. Results demonstrate the potential of LSW in detecting an elasticity gradient along axial and lateral directions simultaneously. Finally, LSW are used for the elastography of ex vivo mouse brain and demonstrate important implications in in vivo and in situ measurements of local elasticity changes in brain and how they might correlate with the onset and progression of degenerative brain diseases.
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Affiliation(s)
- Fernando Zvietcovich
- Dept. of Electrical & Computer Engineering, University of Rochester, Rochester, NY 14627,
USA
| | - Gary R. Ge
- The Institute of Optics, University of Rochester, Rochester, NY 14627,
USA
| | - Humberto Mestre
- Center for Translational Neuromedicine, Dept. of Neurosurgery, University of Rochester, Rochester, NY 14642,
USA
| | - Michael Giannetto
- Center for Translational Neuromedicine, Dept. of Neurosurgery, University of Rochester, Rochester, NY 14642,
USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Dept. of Neurosurgery, University of Rochester, Rochester, NY 14642,
USA
| | - Jannick P. Rolland
- The Institute of Optics, University of Rochester, Rochester, NY 14627,
USA
| | - Kevin J. Parker
- Dept. of Electrical & Computer Engineering, University of Rochester, Rochester, NY 14627,
USA
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13
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Khairalseed M, Xiong F, Kim JW, Mattrey RF, Parker KJ, Hoyt K. Spatial Angular Compounding Technique for H-Scan Ultrasound Imaging. ULTRASOUND IN MEDICINE & BIOLOGY 2018; 44:267-277. [PMID: 29031985 PMCID: PMC5712267 DOI: 10.1016/j.ultrasmedbio.2017.09.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 08/23/2017] [Accepted: 09/01/2017] [Indexed: 05/12/2023]
Abstract
H-Scan is a new ultrasound imaging technique that relies on matching a model of pulse-echo formation to the mathematics of a class of Gaussian-weighted Hermite polynomials. This technique may be beneficial in the measurement of relative scatterer sizes and in cancer therapy, particularly for early response to drug treatment. Because current H-scan techniques use focused ultrasound data acquisitions, spatial resolution degrades away from the focal region and inherently affects relative scatterer size estimation. Although the resolution of ultrasound plane wave imaging can be inferior to that of traditional focused ultrasound approaches, the former exhibits a homogeneous spatial resolution throughout the image plane. The purpose of this study was to implement H-scan using plane wave imaging and investigate the impact of spatial angular compounding on H-scan image quality. Parallel convolution filters using two different Gaussian-weighted Hermite polynomials that describe ultrasound scattering events are applied to the radiofrequency data. The H-scan processing is done on each radiofrequency image plane before averaging to get the angular compounded image. The relative strength from each convolution is color-coded to represent relative scatterer size. Given results from a series of phantom materials, H-scan imaging with spatial angular compounding more accurately reflects the true scatterer size caused by reductions in the system point spread function and improved signal-to-noise ratio. Preliminary in vivo H-scan imaging of tumor-bearing animals suggests this modality may be useful for monitoring early response to chemotherapeutic treatment. Overall, H-scan imaging using ultrasound plane waves and spatial angular compounding is a promising approach for visualizing the relative size and distribution of acoustic scattering sources.
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Affiliation(s)
- Mawia Khairalseed
- Department of Bioengineering, University of Texas at Dallas, Richardson, Texas, USA; Department of Biomedical Engineering, Sudan University of Science and Technology, Khartoum, Sudan
| | - Fangyuan Xiong
- Department of Bioengineering, University of Texas at Dallas, Richardson, Texas, USA; Department of Medical Ultrasound, Tongji Hospital of the Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jung-Whan Kim
- Department of Biological Sciences, University of Texas at Dallas, Richardson, Texas, USA
| | - Robert F Mattrey
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Kevin J Parker
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York, USA
| | - Kenneth Hoyt
- Department of Bioengineering, University of Texas at Dallas, Richardson, Texas, USA; Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
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14
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Khairalseed M, Hoyt K, Ormachea J, Terrazas A, Parker KJ. H-scan sensitivity to scattering size. J Med Imaging (Bellingham) 2017; 4:043501. [PMID: 29152532 DOI: 10.1117/1.jmi.4.4.043501] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/12/2017] [Indexed: 11/14/2022] Open
Abstract
In the H-scan analysis and display, visualization of different scattering sizes and types is enabled by a matched filter approach involving different orders of Gaussian weighted Hermite functions. An important question with respect to clinical applications involves the change in H-scan outputs with respect to small changes in scatterer sizes. The sensitivity of H-scan outputs is analyzed using the theory of backscatter from a compressible sphere. Experimental corroboration is established using mono dispersed spherical scatterers in phantoms. With a 6-MHz center frequency broadband transducer, it is possible to visualize changes in scattering size in the order of 10 to [Formula: see text] in phantoms and also changes in ex vivo bovine liver tissue due to edema caused by hypotonic perfusion.
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Affiliation(s)
- Mawia Khairalseed
- University of Texas at Dallas, Department of Bioengineering, Richardson, Texas, United States.,Sudan University of Science and Technology, Department of Biomedical Engineering, Khartoum, Sudan
| | - Kenneth Hoyt
- University of Texas at Dallas, Department of Bioengineering, Richardson, Texas, United States.,University of Texas Southwestern Medical Center, Department of Radiology, Dallas, Texas, United States
| | - Juvenal Ormachea
- University of Rochester, Department of Electrical and Computer Engineering, Rochester, New York, United States
| | - Alberto Terrazas
- Tecnológico de Monterrey, Grupo de Bioinformatica, Monterrey, Nuevo León, Mexico
| | - Kevin J Parker
- University of Rochester, Department of Electrical and Computer Engineering, Rochester, New York, United States
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15
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Arroyo J, Castaneda B. Shear wave estimation by using Shear Wave Holography with normal vibration: Preliminary results. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2017; 2017:3004-3007. [PMID: 29060530 DOI: 10.1109/embc.2017.8037489] [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
Mechanical properties of soft human tissue are linked to their pathological state. One way to assess these properties is through the Young modulus measurement, which is related to the shear wave speed in the medium when considering tissues as nearly incompressible. In order to characterize its elastic properties using sonoelastography, we introduce a new technique for shear wave estimation from a static interference pattern based on Shear Wave Holography. A relation between the mathematical representation of the interference pattern and the local shear speed is derived using the Phase Derivative approach. The experimental scheme is presented, detailing the advantages of the new configuration. Homogeneous and heterogeneous elastic media were simulated, generating an interference pattern on them. The shear speed estimation algorithm was explained and applied to obtain the speed map, calculating the mean value over each medium. The technique was tested on a nearly incompressible homogeneous elastic phantom, yielding a maximum and a mean estimation error of 6% and 4.6% respectively. Overall, Shear Wave Holography using normal vibration is feasible and shows promising results in estimating shear wave speed in elastic materials.
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16
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Li GY, Cao Y. Mechanics of ultrasound elastography. Proc Math Phys Eng Sci 2017; 473:20160841. [PMID: 28413350 PMCID: PMC5378248 DOI: 10.1098/rspa.2016.0841] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 01/23/2017] [Indexed: 12/19/2022] Open
Abstract
Ultrasound elastography enables in vivo measurement of the mechanical properties of living soft tissues in a non-destructive and non-invasive manner and has attracted considerable interest for clinical use in recent years. Continuum mechanics plays an essential role in understanding and improving ultrasound-based elastography methods and is the main focus of this review. In particular, the mechanics theories involved in both static and dynamic elastography methods are surveyed. They may help understand the challenges in and opportunities for the practical applications of various ultrasound elastography methods to characterize the linear elastic, viscoelastic, anisotropic elastic and hyperelastic properties of both bulk and thin-walled soft materials, especially the in vivo characterization of biological soft tissues.
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Affiliation(s)
- Guo-Yang Li
- Department of Engineering Mechanics, Institute of Biomechanics and Medical Engineering, AML, Tsinghua University, Beijing 100084, People's Republic of China
| | - Yanping Cao
- Department of Engineering Mechanics, Institute of Biomechanics and Medical Engineering, AML, Tsinghua University, Beijing 100084, People's Republic of China
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17
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Zvietcovich F, Rolland JP, Yao J, Meemon P, Parker KJ. Comparative study of shear wave-based elastography techniques in optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:35010. [PMID: 28358943 DOI: 10.1117/1.jbo.22.3.035010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 03/15/2017] [Indexed: 05/03/2023]
Abstract
We compare five optical coherence elastography techniques able to estimate the shear speed of waves generated by one and two sources of excitation. The first two techniques make use of one piezoelectric actuator in order to produce a continuous shear wave propagation or a tone-burst propagation (TBP) of 400 Hz over a gelatin tissue-mimicking phantom. The remaining techniques utilize a second actuator located on the opposite side of the region of interest in order to create three types of interference patterns: crawling waves, swept crawling waves, and standing waves, depending on the selection of the frequency difference between the two actuators. We evaluated accuracy, contrast to noise ratio, resolution, and acquisition time for each technique during experiments. Numerical simulations were also performed in order to support the experimental findings. Results suggest that in the presence of strong internal reflections, single source methods are more accurate and less variable when compared to the two-actuator methods. In particular, TBP reports the best performance with an accuracy error < 4.1 % . Finally, the TBP was tested in a fresh chicken tibialis anterior muscle with a localized thermally ablated lesion in order to evaluate its performance in biological tissue.
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Affiliation(s)
- Fernando Zvietcovich
- University of Rochester, Department of Electrical and Computer Engineering, Rochester, New York, United States
| | - Jannick P Rolland
- University of Rochester, The Institute of Optics, Rochester, New York, United States
| | - Jianing Yao
- University of Rochester, The Institute of Optics, Rochester, New York, United States
| | - Panomsak Meemon
- University of Rochester, The Institute of Optics, Rochester, New York, United StatescSuranaree University of Technology, School of Physics, Institute of Science, Nakhon Ratchasima, Thailand
| | - Kevin J Parker
- University of Rochester, Department of Electrical and Computer Engineering, Rochester, New York, United States
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18
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Yang W, Ziemlewicz TJ, Varghese T, Alexander ML, Rubert N, Ingle AN, Lubner MG, Hinshaw JL, Wells SA, Lee FT, Zagzebski JA. Post-Procedure Evaluation of Microwave Ablations of Hepatocellular Carcinomas Using Electrode Displacement Elastography. ULTRASOUND IN MEDICINE & BIOLOGY 2016; 42:2893-2902. [PMID: 27592561 PMCID: PMC5116412 DOI: 10.1016/j.ultrasmedbio.2016.07.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 05/02/2016] [Accepted: 07/13/2016] [Indexed: 05/04/2023]
Abstract
Microwave ablation has been used clinically as an alternative to surgical resection. However, lack of real-time imaging to assess treated regions may compromise treatment outcomes. We previously introduced electrode displacement elastography (EDE) for strain imaging and verified its feasibility in vivo on porcine animal models. In this study, we evaluated EDE on 44 patients diagnosed with hepatocellular carcinoma, treated using microwave ablation. The ablated region was identified on EDE images for 40 of the 44 patients. Ablation areas averaged 13.38 ± 4.99 cm2 on EDE, compared with 7.61 ± 3.21 cm2 on B-mode imaging. Contrast and contrast-to-noise ratios obtained with EDE were 232% and 98%, respectively, significantly higher than values measured on B-mode images (p < 0.001). This study indicates that EDE is feasible in patients and provides improved visualization of the ablation zone compared with B-mode ultrasound.
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Affiliation(s)
- Wenjun Yang
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Timothy J Ziemlewicz
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Tomy Varghese
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA; Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA.
| | - Marci L Alexander
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Nicholas Rubert
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Atul N Ingle
- Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Meghan G Lubner
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - James L Hinshaw
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Shane A Wells
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Fred T Lee
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - James A Zagzebski
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
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19
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Ormachea J, Lavarello RJ, McAleavey SA, Parker KJ, Castaneda B. Shear Wave Speed Measurements Using Crawling Wave Sonoelastography and Single Tracking Location Shear Wave Elasticity Imaging for Tissue Characterization. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2016; 63:1351-1360. [PMID: 27295662 DOI: 10.1109/tuffc.2016.2576962] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Elastography provides tissue stiffness information that attempts to characterize the elastic properties of tissue. However, there is still limited literature comparing elastographic modalities for tissue characterization. This study focuses on two quantitative techniques using different vibration sources that have not been compared to date: crawling wave sonoelastography (CWS) and single tracking location shear wave elasticity imaging (STL-SWEI). To understand each technique's performance, shear wave speed (SWS) was measured in homogeneous phantoms and ex vivo beef liver tissue. Then, the contrast, contrast-to-noise ratio (CNR), and lateral resolution were measured in an inclusion and two-layer phantoms. The SWS values obtained with both modalities were validated with mechanical measurements (MM) which serve as ground truth. The SWS results for the three different homogeneous phantoms (10%, 13%, and 16% gelatin concentrations) and ex vivo beef liver tissue showed good agreement between CWS, STL-SWEI, and MM as a function of frequency. For all gelatin phantoms, the maximum accuracy errors were 2.52% and 2.35% using CWS and STL-SWEI, respectively. For the ex vivo beef liver, the maximum accuracy errors were 9.40% and 7.93% using CWS and STL-SWEI, respectively. For lateral resolution, contrast, and CNR, both techniques obtained comparable measurements for vibration frequencies less than 300 Hz (CWS) and distances between the push beams ( ∆x ) between 3 mm and 5.31 mm (STL-SWEI). The results obtained in this study agree over an SWS range of 1-6 m/s. They are expected to agree in perfectly linear, homogeneous, and isotropic materials, but the SWS overlap is not guaranteed in all materials because each of the three methods have unique features.
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20
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Mellema DC, Song P, Kinnick RR, Urban MW, Greenleaf JF, Manduca A, Chen S. Probe Oscillation Shear Elastography (PROSE): A High Frame-Rate Method for Two-Dimensional Ultrasound Shear Wave Elastography. IEEE TRANSACTIONS ON MEDICAL IMAGING 2016; 35:2098-106. [PMID: 27076352 PMCID: PMC5495143 DOI: 10.1109/tmi.2016.2550007] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Ultrasound shear wave elastography (SWE) utilizes the propagation of induced shear waves to characterize the shear modulus of soft tissue. Many methods rely on an acoustic radiation force (ARF) "push beam" to generate shear waves. However, specialized hardware is required to generate the push beams, and the thermal stress that is placed upon the ultrasound system, transducer, and tissue by the push beams currently limits the frame-rate to about 1 Hz. These constraints have limited the implementation of ARF to high-end clinical systems. This paper presents Probe Oscillation Shear Elastography (PROSE) as an alternative method to measure tissue elasticity. PROSE generates shear waves using a harmonic mechanical vibration of an ultrasound transducer, while simultaneously detecting motion with the same transducer under pulse-echo mode. Motion of the transducer during detection produces a "strain-like" compression artifact that is coupled with the observed shear waves. A novel symmetric sampling scheme is proposed such that pulse-echo detection events are acquired when the ultrasound transducer returns to the same physical position, allowing the shear waves to be decoupled from the compression artifact. Full field-of-view (FOV) two-dimensional (2D) shear wave speed images were obtained by applying a local frequency estimation (LFE) technique, capable of generating a 2D map from a single frame of shear wave motion. The shear wave imaging frame rate of PROSE is comparable to the vibration frequency, which can be an order of magnitude higher than ARF based techniques. PROSE was able to produce smooth and accurate shear wave images from three homogeneous phantoms with different moduli, with an effective frame rate of 300 Hz. An inclusion phantom study showed that increased vibration frequencies improved the accuracy of inclusion imaging, and allowed targets as small as 6.5 mm to be resolved with good contrast (contrast-to-noise ratio ≥ 19 dB) between the target and background.
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Affiliation(s)
- Daniel C. Mellema
- Mayo Graduate School and the Department of Radiology, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - Pengfei Song
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - Randall R. Kinnick
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - Matthew W. Urban
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - James F. Greenleaf
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - Armando Manduca
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
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21
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Rojas R, Ormachea J, Salo A, Rodríguez P, Parker KJ, Castaneda B. Crawling Waves Speed Estimation Based on the Dominant Component Analysis Paradigm. ULTRASONIC IMAGING 2015; 37:341-355. [PMID: 25628096 DOI: 10.1177/0161734614568651] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A novel method for estimating the shear wave speed from crawling waves based on the amplitude modulation-frequency modulation model is proposed. Our method consists of a two-step approach for estimating the stiffness parameter at the central region of the material of interest. First, narrowband signals are isolated in the time dimension to recover the locally strongest component and to reject distortions from the ultrasound data. Then, the shear wave speed is computed by the dominant component analysis approach and its spatial instantaneous frequency is estimated by the discrete quasi-eigenfunction approximations method. Experimental results on phantoms with different compositions and operating frequencies show coherent speed estimations and accurate inclusion locations.
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Affiliation(s)
- Renán Rojas
- Sección de Electricidad y Electrónica, Pontificia Universidad Católica del Perú, Lima, Peru
| | - Juvenal Ormachea
- Sección de Electricidad y Electrónica, Pontificia Universidad Católica del Perú, Lima, Peru
| | - Arthur Salo
- Department of Biomedical Engineering, University of Rochester, Rochester, NY, USA
| | - Paul Rodríguez
- Sección de Electricidad y Electrónica, Pontificia Universidad Católica del Perú, Lima, Peru
| | - Kevin J Parker
- Department of Electrical & Computer Engineering, University of Rochester, Rochester, NY, USA
| | - Benjamin Castaneda
- Sección de Electricidad y Electrónica, Pontificia Universidad Católica del Perú, Lima, Peru
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22
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Barry CT, Hazard C, Hah Z, Cheng G, Partin A, Mooney RA, Chuang KH, Cao W, Rubens DJ, Parker KJ. Shear wave dispersion in lean versus steatotic rat livers. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2015; 34:1123-9. [PMID: 26014333 DOI: 10.7863/ultra.34.6.1123] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
OBJECTIVES The precise measurement of fat accumulation in the liver, or steatosis, is an important clinical goal. Our previous studies in phantoms and mouse livers support the hypothesis that, starting with a normal liver, increasing accumulations of microsteatosis and macrosteatosis will increase the lossy viscoelastic properties of shear waves in a medium. This increase results in an increased dispersion (or slope) of the shear wave speed in the steatotic livers. METHODS In this study, we moved to a larger animal model, lean versus obese rat livers ex vivo, and a higher-frequency imaging system to estimate the shear wave speed from crawling waves. RESULTS The results showed elevated dispersion in the obese rats and a separation of the lean versus obese liver parameters in a 2-dimensional parameter space of the dispersion (slope) and shear wave speed at a reference frequency of 150 Hz. CONCLUSIONS We have confirmed in 3 separate studies the validity of our dispersion hypothesis in animal models.
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Affiliation(s)
- Christopher T Barry
- Departments of Surgery (C.T.B., K.-H.C.), Pathology and Laboratory Medicine (R.A.M., W.C.), and Radiology (D.J.R.), University of Rochester Medical Center, Rochester, New York USA; GE Global Research, Niskayuna, New York USA (C.H.); Department of Electrical and Computer Engineering (Z.H., A.P., K.J.P.), University of Rochester, Rochester, New York USA; and GE Global Research, Shanghai, China (G.C.)
| | - Christopher Hazard
- Departments of Surgery (C.T.B., K.-H.C.), Pathology and Laboratory Medicine (R.A.M., W.C.), and Radiology (D.J.R.), University of Rochester Medical Center, Rochester, New York USA; GE Global Research, Niskayuna, New York USA (C.H.); Department of Electrical and Computer Engineering (Z.H., A.P., K.J.P.), University of Rochester, Rochester, New York USA; and GE Global Research, Shanghai, China (G.C.)
| | - Zaegyoo Hah
- Departments of Surgery (C.T.B., K.-H.C.), Pathology and Laboratory Medicine (R.A.M., W.C.), and Radiology (D.J.R.), University of Rochester Medical Center, Rochester, New York USA; GE Global Research, Niskayuna, New York USA (C.H.); Department of Electrical and Computer Engineering (Z.H., A.P., K.J.P.), University of Rochester, Rochester, New York USA; and GE Global Research, Shanghai, China (G.C.)
| | - Gang Cheng
- Departments of Surgery (C.T.B., K.-H.C.), Pathology and Laboratory Medicine (R.A.M., W.C.), and Radiology (D.J.R.), University of Rochester Medical Center, Rochester, New York USA; GE Global Research, Niskayuna, New York USA (C.H.); Department of Electrical and Computer Engineering (Z.H., A.P., K.J.P.), University of Rochester, Rochester, New York USA; and GE Global Research, Shanghai, China (G.C.)
| | - Alexander Partin
- Departments of Surgery (C.T.B., K.-H.C.), Pathology and Laboratory Medicine (R.A.M., W.C.), and Radiology (D.J.R.), University of Rochester Medical Center, Rochester, New York USA; GE Global Research, Niskayuna, New York USA (C.H.); Department of Electrical and Computer Engineering (Z.H., A.P., K.J.P.), University of Rochester, Rochester, New York USA; and GE Global Research, Shanghai, China (G.C.)
| | - Robert A Mooney
- Departments of Surgery (C.T.B., K.-H.C.), Pathology and Laboratory Medicine (R.A.M., W.C.), and Radiology (D.J.R.), University of Rochester Medical Center, Rochester, New York USA; GE Global Research, Niskayuna, New York USA (C.H.); Department of Electrical and Computer Engineering (Z.H., A.P., K.J.P.), University of Rochester, Rochester, New York USA; and GE Global Research, Shanghai, China (G.C.)
| | - Kuang-Hsiang Chuang
- Departments of Surgery (C.T.B., K.-H.C.), Pathology and Laboratory Medicine (R.A.M., W.C.), and Radiology (D.J.R.), University of Rochester Medical Center, Rochester, New York USA; GE Global Research, Niskayuna, New York USA (C.H.); Department of Electrical and Computer Engineering (Z.H., A.P., K.J.P.), University of Rochester, Rochester, New York USA; and GE Global Research, Shanghai, China (G.C.)
| | - Wenqing Cao
- Departments of Surgery (C.T.B., K.-H.C.), Pathology and Laboratory Medicine (R.A.M., W.C.), and Radiology (D.J.R.), University of Rochester Medical Center, Rochester, New York USA; GE Global Research, Niskayuna, New York USA (C.H.); Department of Electrical and Computer Engineering (Z.H., A.P., K.J.P.), University of Rochester, Rochester, New York USA; and GE Global Research, Shanghai, China (G.C.)
| | - Deborah J Rubens
- Departments of Surgery (C.T.B., K.-H.C.), Pathology and Laboratory Medicine (R.A.M., W.C.), and Radiology (D.J.R.), University of Rochester Medical Center, Rochester, New York USA; GE Global Research, Niskayuna, New York USA (C.H.); Department of Electrical and Computer Engineering (Z.H., A.P., K.J.P.), University of Rochester, Rochester, New York USA; and GE Global Research, Shanghai, China (G.C.)
| | - Kevin J Parker
- Departments of Surgery (C.T.B., K.-H.C.), Pathology and Laboratory Medicine (R.A.M., W.C.), and Radiology (D.J.R.), University of Rochester Medical Center, Rochester, New York USA; GE Global Research, Niskayuna, New York USA (C.H.); Department of Electrical and Computer Engineering (Z.H., A.P., K.J.P.), University of Rochester, Rochester, New York USA; and GE Global Research, Shanghai, China (G.C.).
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23
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Zhao H, Song P, Meixner DD, Kinnick RR, Callstrom MR, Sanchez W, Urban MW, Manduca A, Greenleaf JF, Chen S. External vibration multi-directional ultrasound shearwave elastography (EVMUSE): application in liver fibrosis staging. IEEE TRANSACTIONS ON MEDICAL IMAGING 2014; 33:2140-8. [PMID: 25020066 PMCID: PMC4216646 DOI: 10.1109/tmi.2014.2332542] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Shear wave speed can be used to assess tissue elasticity, which is associated with tissue health. Ultrasound shear wave elastography techniques based on measuring the propagation speed of the shear waves induced by acoustic radiation force are becoming promising alternatives to biopsy in liver fibrosis staging. However, shear waves generated by such methods are typically very weak. Therefore, the penetration may become problematic, especially for overweight or obese patients. In this study, we developed a new method called external vibration multi-directional ultrasound shearwave elastography (EVMUSE), in which external vibration from a loudspeaker was used to generate a multi-directional shear wave field. A directional filter was then applied to separate the complex shear wave field into several shear wave fields propagating in different directions. A 2-D shear wave speed map was reconstructed from each individual shear wave field, and a final 2-D shear wave speed map was constructed by compounding these individual wave speed maps. The method was validated using two homogeneous phantoms and one multi-purpose tissue-mimicking phantom. Ten patients undergoing liver magnetic resonance elastography (MRE) were also studied with EVMUSE to compare results between the two methods. Phantom results showed EVMUSE was able to quantify tissue elasticity accurately with good penetration. In vivo EVMUSE results were well correlated with MRE results, indicating the promise of using EVMUSE for liver fibrosis staging.
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Affiliation(s)
- Heng Zhao
- Mayo Clinic College of Medicine, Rochester, MN 55905 USA. He is now with Sonavation Inc., Palm Beach Gardens, FL 33410 USA
| | - Pengfei Song
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - Duane D. Meixner
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - Randall R. Kinnick
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - Matthew R. Callstrom
- Department of Radiology, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - William Sanchez
- Department of Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - Matthew W. Urban
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - Armando Manduca
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - James F. Greenleaf
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
| | - Shigao Chen
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905 USA
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24
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Hah Z, Partin A, Parker KJ. Shear wave speed and dispersion measurements using crawling wave chirps. ULTRASONIC IMAGING 2014; 36:277-290. [PMID: 24658144 DOI: 10.1177/0161734614527581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This article demonstrates the measurement of shear wave speed and shear speed dispersion of biomaterials using a chirp signal that launches waves over a range of frequencies. A biomaterial is vibrated by two vibration sources that generate shear waves inside the medium, which is scanned by an ultrasound imaging system. Doppler processing of the acquired signal produces an image of the square of vibration amplitude that shows repetitive constructive and destructive interference patterns called "crawling waves." With a chirp vibration signal, successive Doppler frames are generated from different source frequencies. Collected frames generate a distinctive pattern which is used to calculate the shear speed and shear speed dispersion. A special reciprocal chirp is designed such that the equi-phase lines of a motion slice image are straight lines. Detailed analysis is provided to generate a closed-form solution for calculating the shear wave speed and the dispersion. Also several phantoms and an ex vivo human liver sample are scanned and the estimation results are presented.
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Affiliation(s)
- Zaegyoo Hah
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY, USA
| | - Alexander Partin
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY, USA
| | - Kevin J Parker
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY, USA
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25
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Song P, Manduca A, Zhao H, Urban MW, Greenleaf JF, Chen S. Fast shear compounding using robust 2-D shear wave speed calculation and multi-directional filtering. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:1343-55. [PMID: 24613636 PMCID: PMC4011964 DOI: 10.1016/j.ultrasmedbio.2013.12.026] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 12/18/2013] [Accepted: 12/23/2013] [Indexed: 05/03/2023]
Abstract
A fast shear compounding method was developed in this study using only one shear wave push-detect cycle, such that the shear wave imaging frame rate is preserved and motion artifacts are minimized. The proposed method is composed of the following steps: 1. Applying a comb-push to produce multiple differently angled shear waves at different spatial locations simultaneously; 2. Decomposing the complex shear wave field into individual shear wave fields with differently oriented shear waves using a multi-directional filter; 3. Using a robust 2-D shear wave speed calculation to reconstruct 2-D shear elasticity maps from each filter direction; and 4. Compounding these 2-D maps from different directions into a final map. An inclusion phantom study showed that the fast shear compounding method could achieve comparable performance to conventional shear compounding without sacrificing the imaging frame rate. A multi-inclusion phantom experiment showed that the fast shear compounding method could provide a full field-of-view, 2-D and compounded shear elasticity map with three types of inclusions clearly resolved and stiffness measurements showing excellent agreement to the nominal values.
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Affiliation(s)
- Pengfei Song
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN, USA; Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Armando Manduca
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Heng Zhao
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Matthew W Urban
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - James F Greenleaf
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Shigao Chen
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN, USA.
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26
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Partin A, Hah Z, Barry CT, Rubens DJ, Parker KJ. Elasticity estimates from images of crawling waves generated by miniature surface sources. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:685-94. [PMID: 23972485 PMCID: PMC3931766 DOI: 10.1016/j.ultrasmedbio.2013.05.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 05/23/2013] [Accepted: 05/24/2013] [Indexed: 05/24/2023]
Abstract
We describe a surface-based approach to the generation of shear wave interference patterns, called crawling waves (CrW), within a medium and derive local estimates of biomechanical properties of tissue. In previous experiments, elongated bars operating as vibration sources were used to generate CrW propagation in samples. In the present study, however, a pair of miniature circular vibration sources was applied to the overlying skin to generate the CrW within the medium. The shape and position of the miniature sources make this configuration more applicable for in vivo implementation. A modified ultrasound imaging system is used to display the CrW propagation. A shear speed mapping algorithm is developed using a detailed analysis of the CrW. The proposed setup is applied to several biomaterials including a homogeneous phantom, an inhomogeneous phantom and an ex vivo human liver. The data are analyzed using the mapping algorithm to reveal the biomechanical properties of the biomaterials.
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Affiliation(s)
- Alexander Partin
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York, USA
| | - Zaegyoo Hah
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York, USA
| | - Christopher T Barry
- Department of Surgery, University of Rochester Medical Center, Rochester, New York, USA
| | - Deborah J Rubens
- Department of Radiology, University of Rochester Medical Center, Rochester, New York, USA
| | - Kevin J Parker
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York, USA.
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Barry CT, Hah Z, Partin A, Mooney RA, Chuang KH, Augustine A, Almudevar A, Cao W, Rubens DJ, Parker KJ. Mouse liver dispersion for the diagnosis of early-stage Fatty liver disease: a 70-sample study. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:704-13. [PMID: 24412179 DOI: 10.1016/j.ultrasmedbio.2013.10.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 10/15/2013] [Accepted: 10/21/2013] [Indexed: 05/08/2023]
Abstract
The accumulation of fat droplets within the liver is an important marker of liver disease. This study assesses gradations of steatosis in mouse livers using crawling waves, which are interfering patterns of shear waves introduced into the liver by external sources. The crawling waves are detected by Doppler ultrasound imaging techniques, and these are analyzed to estimate the shear wave speed as a function of frequency between 200 and 360 Hz. In a study of 70 mice with progressive increases in steatosis from 0% to >60%, increases in steatosis are found to increase the dispersion, or frequency dependence, of shear wave speed. This finding confirms an earlier, smaller study and points to the potential of a scoring system for steatosis based on shear wave dispersion.
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Affiliation(s)
- Christopher T Barry
- Department of Surgery, University of Rochester Medical Center, Rochester, New York, USA
| | - Zaegyoo Hah
- Department of Electrical & Computer Engineering, University of Rochester, Rochester, New York, USA
| | - Alexander Partin
- Department of Electrical & Computer Engineering, University of Rochester, Rochester, New York, USA
| | - Robert A Mooney
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, New York, USA
| | - Kuang-Hsiang Chuang
- Department of Surgery, University of Rochester Medical Center, Rochester, New York, USA
| | - Alicia Augustine
- Department of Public Health Services, University of Rochester Medical Center, Rochester, New York, USA
| | - Anthony Almudevar
- Department of Biostatistics and Computational Biology, University of Rochester Medical Center, Rochester, New York, USA
| | - Wenqing Cao
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, New York, USA
| | - Deborah J Rubens
- Department of Biostatistics and Computational Biology, University of Rochester Medical Center, Rochester, New York, USA; Department of Radiology, University of Rochester Medical Center, Rochester, New York, USA
| | - Kevin J Parker
- Department of Electrical & Computer Engineering, University of Rochester, Rochester, New York, USA.
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Tzschätzsch H, Ipek-Ugay S, Guo J, Streitberger KJ, Gentz E, Fischer T, Klaua R, Schultz M, Braun J, Sack I. In vivotime-harmonic multifrequency elastography of the human liver. Phys Med Biol 2014; 59:1641-54. [DOI: 10.1088/0031-9155/59/7/1641] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Doyley MM, Parker KJ. Elastography: general principles and clincial applications. ACTA ACUST UNITED AC 2014; 9:1-11. [PMID: 24459461 DOI: 10.1016/j.cult.2013.09.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- M M Doyley
- University of Rochester, Department of Electrical and Computer Engineering, Hopeman, Engineering Building 343, Box 270126, Rochester, NY 14627, USA
| | - K J Parker
- University of Rochester, Department of Electrical and Computer Engineering, Hopeman, Engineering Building 343, Box 270126, Rochester, NY 14627, USA
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Good DW, Stewart GD, Hammer S, Scanlan P, Shu W, Phipps S, Reuben R, McNeill AS. Elasticity as a biomarker for prostate cancer: a systematic review. BJU Int 2013; 113:523-34. [DOI: 10.1111/bju.12236] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Daniel W. Good
- Edinburgh Urological Cancer Group; University of Edinburgh; Edinburgh UK
- Department of Urology; Western General Hospital; Edinburgh UK
| | - Grant D. Stewart
- Edinburgh Urological Cancer Group; University of Edinburgh; Edinburgh UK
- Department of Urology; Western General Hospital; Edinburgh UK
| | - Steven Hammer
- School of Engineering and Physical Sciences; Heriot-Watt University; Edinburgh UK
| | - Paul Scanlan
- School of Engineering and Physical Sciences; Heriot-Watt University; Edinburgh UK
| | - Wenmiao Shu
- School of Engineering and Physical Sciences; Heriot-Watt University; Edinburgh UK
| | - Simon Phipps
- Edinburgh Urological Cancer Group; University of Edinburgh; Edinburgh UK
- Department of Urology; Western General Hospital; Edinburgh UK
| | - Robert Reuben
- School of Engineering and Physical Sciences; Heriot-Watt University; Edinburgh UK
| | - Alan S. McNeill
- Edinburgh Urological Cancer Group; University of Edinburgh; Edinburgh UK
- Department of Urology; Western General Hospital; Edinburgh UK
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Kim JG, Aowlad Hossain ABM, Shin JH, Lee SY. Calculation of strain images of a breast-mimicking phantom from 3D CT image data. Med Phys 2012; 39:5469-78. [PMID: 22957614 DOI: 10.1118/1.4742902] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Elastography is a medical imaging modality to visualize the elasticity of soft tissues. Ultrasound and MRI have been exclusively used for elastography of soft tissues since they can sensitize the tissues' minute displacements of an order of μm. It is known that ultrasound and MRI elastography show cancerous tissues with much higher contrast than conventional ultrasound and MRI. To evaluate possibility of combining elastography with x-ray imaging, we have calculated strain images of a breast-mimicking phantom from its 3D CT image data. METHODS We first simulated the x-ray elastography using a FEM model which incorporated both the elasticity and x-ray attenuation behaviors of breast tissues. After validating the x-ray elastography scheme by simulation, we made a breast-mimicking phantom that contained a hard inclusion against soft background. With a micro-CT, we took 3D images of the phantom twice, changing the compressing force to the phantom. From the two 3D phantom images taken with two different compression ratios, we calculated the displacement vector maps that represented the compression-induced pixel displacements. In calculating the displacement vectors, we tracked the movements of image feature patterns from the less-compressed-phantom images to the more-compressed-phantom images using the 3D image correlation technique. We obtained strain images of the phantom by differentiating the displacement vector maps. RESULTS The FEM simulation has shown that x-ray strain imaging is possible by tracking image feature patterns in the 3D CT images of the breast-mimicking phantom. The experimental displacement and strain images of a breast-mimicking phantom, obtained from the 3D micro-CT images taken with 0%-3% compression ratios, show behaviors similar to the FEM simulation results. The contrast and noise performance of the strain images improves as the phantom compression ratio increases. CONCLUSIONS We have experimentally shown that we can improve x-ray strain image quality by applying 3D image correlation to the two sets of 3D CT images taken with different compression ratios. But, we need further investigations to evaluate the strain imaging performance considering the noise and decorrelation effects as well as the extra dose caused by two scans.
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Affiliation(s)
- Jae G Kim
- Department of Biomedical Engineering, Kyung Hee University, 1 Seochun, Yongin-si, Gyeonggi-do, South Korea
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Ødegaard S, Nesje LB, Lærum OD, Kimmey MB. High-frequency ultrasonographic imaging of the gastrointestinal wall. Expert Rev Med Devices 2012; 9:263-273. [DOI: 10.1586/erd.12.6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
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Walsh J, An L, Mills B, Hah Z, Moalem J, Miller M, Giampoli E, Parker K, Rubens D. Quantitative Crawling Wave Sonoelastography of Benign and Malignant Thyroid Nodules. Otolaryngol Head Neck Surg 2012; 147:233-8. [DOI: 10.1177/0194599812443339] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Objective The purpose of this study is to determine if crawling wave elastography, a novel sonoelastography technique, can be used to provide quantitative measurements of thyroid tissue shear velocity (a measure of tissue stiffness) and distinguish between benign and malignant thyroid nodules. Study Design Diagnostic test assessment. Setting Academic university. Subjects and Methods Fresh thyroid specimens (n = 20) with 44 regions of interest were imaged ex vivo with crawling wave sonoelastography over a 9-month period in 2010 at a single institution. Using the sonoelastography technique, shear velocity estimations and contrast-to-noise ratios were calculated. The higher the shear velocity (SV) and contrast-to-noise ratio (CNR), the greater the tissue stiffness. Histological diagnosis was correlated with shear velocity and contrast-to-noise ratio values. Results Both the shear velocity and contrast-to-noise values of papillary thyroid carcinoma (n = 10, CNR = 5.29, SV = 2.45 m/s) were significantly higher than benign nodules (n = 22, CNR = −0.41, SV = 1.90 m/s). There is a maximum sensitivity and specificity of 100% and 90.9%, respectively, for differentiating papillary thyroid carcinoma from benign nodules using contrast-to-noise ratio values. There is a maximum sensitivity and specificity of 83.3% and 72.7%, respectively, for differentiating papillary thyroid carcinoma from benign nodules using shear velocity values. Insufficient samples were obtained for comparison with other histological types. Conclusion Crawling wave sonoelastography can provide quantitative estimations of shear velocity, thereby depicting the elastic properties of thyroid nodules. The shear velocity and contrast-to-noise ratio can differentiate between benign thyroid nodules and papillary thyroid carcinoma with high specificity and sensitivity.
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Affiliation(s)
- Jonathan Walsh
- Department of Otolaryngology, University of Rochester, Rochester, New York, USA
| | - Liwei An
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York, USA
| | - Brad Mills
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York, USA
| | - Zaegyoo Hah
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York, USA
| | - Jacob Moalem
- Department of Surgery, University of Rochester, Rochester, New York, USA
| | - Matthew Miller
- Department of Otolaryngology, University of Rochester, Rochester, New York, USA
| | - Ellen Giampoli
- Department of Pathology, University of Rochester, Rochester, New York, USA
| | - Kevin Parker
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York, USA
| | - Deborah Rubens
- Department of Radiology, University of Rochester, Rochester, New York, USA
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Aowlad Hossain ABM, Cho MH, Lee SY. A Simulation study on iterative shear velocity image reconstruction for ultrasound transient elastography. Biomed Eng Lett 2012. [DOI: 10.1007/s13534-012-0048-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Abstract
Elastography is emerging as an imaging modality that can distinguish normal versus diseased tissues via their biomechanical properties. This paper reviews current approaches to elastography in three areas--quasi-static, harmonic and transient--and describes inversion schemes for each elastographic imaging approach. Approaches include first-order approximation methods; direct and iterative inversion schemes for linear elastic; isotropic materials and advanced reconstruction methods for recovering parameters that characterize complex mechanical behavior. The paper's objective is to document efforts to develop elastography within the framework of solving an inverse problem, so that elastography may provide reliable estimates of shear modulus and other mechanical parameters. We discuss issues that must be addressed if model-based elastography is to become the prevailing approach to quasi-static, harmonic and transient elastography: (1) developing practical techniques to transform the ill-posed problem with a well-posed one; (2) devising better forward models to capture the complex mechanical behavior of soft tissues and (3) developing better test procedures to evaluate the performance of modulus elastograms.
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Affiliation(s)
- M M Doyley
- University of Rochester, Department of Electrical and Computer Engineering, Hopeman Engineering Building 413, Box 270126, Rochester, NY 14627, USA.
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Hazard C, Hah Z, Rubens D, Parker K. Integration of crawling waves in an ultrasound imaging system. Part 1: system and design considerations. ULTRASOUND IN MEDICINE & BIOLOGY 2012; 38:296-311. [PMID: 22178166 PMCID: PMC3254834 DOI: 10.1016/j.ultrasmedbio.2011.10.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 10/06/2011] [Accepted: 10/29/2011] [Indexed: 05/04/2023]
Abstract
An ultrasound system (GE Logiq 9) was modified to produce a synthetic crawling wave using shear wave displacements generated by the radiation force of focused beams formed at the left and the right edge of the region of interest (ROI). Two types of focusing, normal and axicon, were implemented. Baseband (IQ) data was collected to determine the left and right displacements, which were then used to calculate an interference pattern. By imposing a variable delay between the two pushes, the interference pattern moves across the ROI to produce crawling waves. Also temperature and pressure measurements were made to assess the safety issues. The temperature profiles measured in a veal liver along the focal line showed the maximum temperature rise less than 0.8°C, and the pressure measurements obtained in degassed water and derated by 0.3 dB/cm/MHz demonstrate that the system can operate within FDA safety guidelines.
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Barry CT, Mills B, Hah Z, Mooney RA, Ryan CK, Rubens DJ, Parker KJ. Shear wave dispersion measures liver steatosis. ULTRASOUND IN MEDICINE & BIOLOGY 2012; 38:175-82. [PMID: 22178165 PMCID: PMC3428716 DOI: 10.1016/j.ultrasmedbio.2011.10.019] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 10/18/2011] [Accepted: 10/21/2011] [Indexed: 05/08/2023]
Abstract
Crawling waves, which are interfering shear wave patterns, can be generated in liver tissue over a range of frequencies. Some important biomechanical properties of the liver can be determined by imaging the crawling waves using Doppler techniques and analyzing the patterns. We report that the dispersion of shear wave velocity and attenuation, that is, the frequency dependence of these parameters, are strongly correlated with the degree of steatosis in a mouse liver model, ex vivo. The results demonstrate the possibility of assessing liver steatosis using noninvasive imaging methods that are compatible with color Doppler scanners and, furthermore, suggest that liver steatosis can be separated from fibrosis by assessing the dispersion or frequency dependence of shear wave propagations.
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Affiliation(s)
| | - Bradley Mills
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY, USA
| | - Zaegyoo Hah
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY, USA
| | - Robert A. Mooney
- School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Charlotte K. Ryan
- School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Deborah J. Rubens
- School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Kevin J. Parker
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY, USA
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Hah Z, Hazard C, Mills B, Barry C, Rubens D, Parker K. Integration of crawling waves in an ultrasound imaging system. Part 2: signal processing and applications. ULTRASOUND IN MEDICINE & BIOLOGY 2012; 38:312-23. [PMID: 22178168 PMCID: PMC3254836 DOI: 10.1016/j.ultrasmedbio.2011.10.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 09/23/2011] [Accepted: 10/16/2011] [Indexed: 05/04/2023]
Abstract
This paper introduces methods to generate crawling wave interference patterns from the displacement fields generated from radiation force pushes on a GE Logiq 9 scanner. The same transducer and system provides both the pushing pulses to generate the shear waves and the tracking pulses to measure the displacements. Acoustic power and system limitations result in largely impulsive displacement fields. Measured displacements from pushes on either side of a region-of-interest (ROI) are used to calculate continuously varying interference patterns. This technique is explained along with a brief discussion of the conventional mechanical source-driven crawling waves for comparison. We demonstrate the method on three example cases: a gelatin-based phantom with a cylindrical inclusion, an oil-gelatin phantom and mouse livers. The oil-gelatin phantom and the mouse livers demonstrate not only shear speed estimation, but the frequency dependence of the shear wave speeds.
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Affiliation(s)
- Zaegyoo Hah
- University of Rochester, Department of Electrical and Computer Engineering, Rochester, NY 14627, USA.
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Hoyt K, Hah Z, Hazard C, Parker KJ. Experimental validation of acoustic radiation force induced shear wave interference patterns. Phys Med Biol 2011; 57:21-30. [PMID: 22127377 DOI: 10.1088/0031-9155/57/1/21] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A novel elasticity imaging system founded on the use of acoustic radiation forces from a dual beam arrangement to generate shear wave interference patterns is described. Acquired pulse-echo data and correlation-based techniques were used to estimate the resultant deformation and to visualize tissue viscoelastic response. The use of normal versus axicon focal configurations was investigated for effects on shear wave generation. Theoretical models were introduced and shown in simulation to accurately predict shear wave propagation and interference pattern properties. In a tissue-mimicking phantom, experimental results are in congruence with theoretical predictions. Using dynamic acoustic radiation force excitation, results confirm that shear wave interference patterns can be produced remotely in a particular tissue region of interest (ROI). Overall, preliminary results are encouraging and the system described may prove feasible for interrogating the viscoelastic properties of normal and diseased tissue types.
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Affiliation(s)
- Kenneth Hoyt
- Department of Radiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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Wells PNT, Liang HD. Medical ultrasound: imaging of soft tissue strain and elasticity. J R Soc Interface 2011; 8:1521-49. [PMID: 21680780 PMCID: PMC3177611 DOI: 10.1098/rsif.2011.0054] [Citation(s) in RCA: 276] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2011] [Accepted: 05/23/2011] [Indexed: 02/06/2023] Open
Abstract
After X-radiography, ultrasound is now the most common of all the medical imaging technologies. For millennia, manual palpation has been used to assist in diagnosis, but it is subjective and restricted to larger and more superficial structures. Following an introduction to the subject of elasticity, the elasticity of biological soft tissues is discussed and published data are presented. The basic physical principles of pulse-echo and Doppler ultrasonic techniques are explained. The history of ultrasonic imaging of soft tissue strain and elasticity is summarized, together with a brief critique of previously published reviews. The relevant techniques-low-frequency vibration, step, freehand and physiological displacement, and radiation force (displacement, impulse, shear wave and acoustic emission)-are described. Tissue-mimicking materials are indispensible for the assessment of these techniques and their characteristics are reported. Emerging clinical applications in breast disease, cardiology, dermatology, gastroenterology, gynaecology, minimally invasive surgery, musculoskeletal studies, radiotherapy, tissue engineering, urology and vascular disease are critically discussed. It is concluded that ultrasonic imaging of soft tissue strain and elasticity is now sufficiently well developed to have clinical utility. The potential for further research is examined and it is anticipated that the technology will become a powerful mainstream investigative tool.
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Affiliation(s)
- Peter N T Wells
- School of Engineering, Cardiff University, Queen's Buildings, The Parade, Cardiff CF24 3AA, UK.
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An L, Mills B, Hah Z, Mao S, Yao J, Joseph J, Rubens DJ, Strang J, Parker KJ. Crawling wave detection of prostate cancer: preliminary in vitro results. Med Phys 2011; 38:2563-71. [PMID: 21776792 DOI: 10.1118/1.3569578] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The focus of this article is to develop signal and imaging processing methods to derive an accurate estimation of local tissue elasticity using the crawling wave (CrW) sonoelastography method. The task is to reduce noise and to improve the contrast of the elasticity map. METHODS The protocol of the CrW approach was first tested on heterogeneous elastic phantoms as a model of prostate cancers. Then, the contrast-to-noise ratio of the estimation was calculated iteratively with various sequences of algorithms to determine the optimal signal processing settings. Finally, the optimized signal processing was applied to ex vivo prostate cancer detection. The comparison of the segmented elasticity map and the histology tumor outline was made by quadrants to evaluate the diagnostic performance of the protocol. Furthermore, the CrW approach was combined with amplitude-sonoelastography to achieve a higher specificity. RESULTS This study demonstrated the feasibility of the proposed approach for clinical applications. In the application to ex vivo prostate cancer detection, the established approach was tested on 43 excised prostate glands. The combination of the CrW approach and amplitude-sonoelastography achieved an accuracy of over 80% for finding tumors larger than 4 mm in diameter. The elasticity values and contrast found by the CrW approach were in agreement with the previous results derived from mechanical testing. CONCLUSIONS Crawling waves can be applied to detect prostate cancer with accuracy approaching 80% and can quantify the stiffness or shear modulus of both cancerous and noncancerous tissues. The technique therefore shows promise for guiding biopsies to suspect regions that are otherwise difficult to identify.
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Affiliation(s)
- Liwei An
- University of Rochester, Rochester, New York 14627, USA
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Lin K, McLaughlin JR, Thomas A, Parker K, Castaneda B, Rubens DJ. Two-dimensional shear wave speed and crawling wave speed recoveries from in vitro prostate data. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2011; 130:585-98. [PMID: 21786924 PMCID: PMC3155598 DOI: 10.1121/1.3596472] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 02/21/2011] [Accepted: 05/10/2011] [Indexed: 05/12/2023]
Abstract
The crawling wave experiment was developed to capture a shear wave induced moving interference pattern that is created by two harmonic vibration sources oscillating at different but almost the same frequencies. Using the vibration sonoelastography technique, the spectral variance image reveals a moving interference pattern. It has been shown that the speed of the moving interference pattern, i.e., the crawling wave speed, is proportional to the shear wave speed with a nonlinear factor. This factor can generate high-speed artifacts in the crawling wave speed images that do not actually correspond to increased stiffness. In this paper, an inverse algorithm is developed to reconstruct both the crawling wave speed and the shear wave speed using the phases of the crawling wave and the shear wave. The feature for the data is the application to in vitro prostate data, while the features for the algorithm include the following: (1) A directional filter is implemented to obtain a wave moving in only one direction; and (2) an L(1) minimization technique with physics inspired constraints is employed to calculate the phase of the crawling wave and to eliminate jump discontinuities from the phase of the shear wave. The algorithm is tested on in vitro prostate data measured at the Rochester Center for Biomedical Ultrasound and University of Rochester. Each aspect of the algorithm is shown to yield image improvement. The results demonstrate that the shear wave speed images can have less artifacts than the crawling wave images. Examples are presented where the shear wave speed recoveries have excellent agreement with histology results on the size, shape, and location of cancerous tissues in the glands.
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Affiliation(s)
- Kui Lin
- Westerngeco, 10001 Richmond Avenue, Houston, Texas 77042, USA.
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Li Y, Snedeker JG. Elastography: modality-specific approaches, clinical applications, and research horizons. Skeletal Radiol 2011; 40:389-97. [PMID: 20352427 DOI: 10.1007/s00256-010-0918-0] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 02/24/2010] [Accepted: 02/24/2010] [Indexed: 02/02/2023]
Abstract
Manual palpation has been used for centuries to provide a relative indication of tissue health and disease. Engineers have sought to make these assessments increasingly quantitative and accessible within daily clinical practice. Since many of the developed techniques involve image-based quantification of tissue deformation in response to an applied force (i.e., "elastography"), such approaches fall squarely within the domain of the radiologist. While commercial elastography analysis software is becoming increasingly available for clinical use, the internal workings of these packages often remain a "black box," with limited guidance on how to usefully apply the methods toward a meaningful diagnosis. The purpose of the present review article is to introduce some important approaches to elastography that have been developed for the most widely used clinical imaging modalities (e.g., ultrasound, MRI), to provide a basic sense of the underlying physical principles, and to discuss both current and potential (musculoskeletal) applications. The article also seeks to provide a perspective on emerging approaches that are rapidly developing in the research laboratory (e.g., optical coherence tomography, fibered confocal microscopy), and which may eventually gain a clinical foothold.
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Affiliation(s)
- Yufei Li
- Department of Orthopaedics, University Hospital Balgrist, Forchstrasse 340, 8008, Zurich, Switzerland
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Hoyt K. Theoretical Analysis of Shear Wave Interference Patterns by Means of Dynamic Acoustic Radiation Forces. THE INTERNATIONAL JOURNAL OF MULTIPHYSICS 2011; 5:9-24. [PMID: 21980318 PMCID: PMC3185381 DOI: 10.1260/1750-9548.5.1.9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Acoustic radiation forces associated with high intensity focused ultrasound stimulate shear wave propagation allowing shear wave speed and shear viscosity estimation of tissue structures. As wave speeds are meters per second, real time displacement tracking over an extend field-of-view using ultrasound is problematic due to very high frame rate requirements. However, two spatially separated dynamic external sources can stimulate shear wave motion leading to shear wave interference patterns. Advantages are shear waves can be imaged at lower frame rates and local interference pattern spatial properties reflect tissue's viscoelastic properties. Here a theoretical analysis of shear wave interference patterns by means of dynamic acoustic radiation forces is detailed. Using a viscoelastic Green's function analysis, tissue motion due to a pair of focused ultrasound beams and associated radiation forces are presented. Overall, this paper theoretically demonstrates shear wave interference patterns can be stimulated using dynamic acoustic radiation forces and tracked using conventional ultrasound imaging.
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Affiliation(s)
- Kenneth Hoyt
- Departments of Radiology and Biomedical Engineering, Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Parker KJ, Doyley MM, Rubens DJ. Imaging the elastic properties of tissue: the 20 year perspective. Phys Med Biol 2010; 56:R1-R29. [PMID: 21119234 DOI: 10.1088/0031-9155/56/1/r01] [Citation(s) in RCA: 250] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
After 20 years of innovation in techniques that specifically image the biomechanical properties of tissue, the evolution of elastographic imaging can be viewed from its infancy, through a proliferation of approaches to the problem to incorporation on research and then clinical imaging platforms. Ultimately this activity has culminated in clinical trials and improved care for patients. This remarkable progression represents a leading example of translational research that begins with fundamentals of science and engineering and progresses to needed improvements in diagnostic and monitoring capabilities applied to major categories of disease, surgery and interventional procedures. This review summarizes the fundamental principles, the timeline of developments in major categories of elastographic imaging, and concludes with recent results from clinical trials and forward-looking issues.
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Affiliation(s)
- K J Parker
- Department of Electrical and Computer Engineering, University of Rochester, Hopeman Engineering Building, Box 270126, Rochester, NY 14627, USA.
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Bharat S, Varghese T. Radiofrequency electrode vibration-induced shear wave imaging for tissue modulus estimation: a simulation study. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2010; 128:1582-5. [PMID: 20968329 PMCID: PMC2981108 DOI: 10.1121/1.3466880] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Revised: 06/25/2010] [Accepted: 06/30/2010] [Indexed: 05/20/2023]
Abstract
Quasi-static electrode displacement elastography, used for in-vivo imaging of radiofrequency ablation-induced lesions in abdominal organs such as the liver and kidney, is extended in this paper to dynamic vibrational perturbations of the ablation electrode. Propagation of the resulting shear waves into adjoining regions of tissue can be tracked and the shear wave velocity used to quantify the shear (and thereby Young's) modulus of tissue. The algorithm used utilizes the time-to-peak displacement data (obtained from finite element analyses) to calculate the speed of shear wave propagation in the material. The simulation results presented illustrate the feasibility of estimating the Young's modulus of tissue and is promising for characterizing the stiffness of radiofrequency-ablated thermal lesions and surrounding normal tissue.
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Hah Z, Hazard C, Cho YT, Rubens D, Parker K. Crawling waves from radiation force excitation. ULTRASONIC IMAGING 2010; 32:177-189. [PMID: 20718246 DOI: 10.1177/016173461003200305] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Crawling waves are generated by an interference of two oscillating waves traveling in opposite directions, with a progressive movement resulting from a frequency difference or a phase difference between the sources. While the idea has been applied to numerous applications, all the previous reports used mechanical sources to vibrate the medium. It is shown, through experiments and simulation, that crawling waves can be generated from focused beams that produce radiation force excitation within the tissue. Some examples are also shown.
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Affiliation(s)
- Zaegyoo Hah
- University of Rochester, Department of Electrical and Computer Engineering, Rochester, NY 14627, USA.
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Lin K, McLaughlin J, Renzi D, Thomas A. Shear wave speed recovery in sonoelastography using crawling wave data. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2010; 128:88-97. [PMID: 20649204 PMCID: PMC2921425 DOI: 10.1121/1.3442575] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The crawling wave experiment, in which two harmonic sources oscillate at different but nearby frequencies, is a development in sonoelastography that allows real-time imaging of propagating shear wave interference patterns. Previously the crawling wave speed was recovered and used as an indicator of shear stiffness; however, it is shown in this paper that the crawling wave speed image can have artifacts that do not represent a change in stiffness. In this paper, the locations and shapes of some of the artifacts are exhibited. In addition, a differential equation is established that enables imaging of the shear wave speed, which is a quantity strongly correlated with shear stiffness change. The full algorithm is as follows: (1) extract the crawling wave phase from the spectral variance data; (2) calculate the crawling wave phase wave speed; (3) solve a first-order PDE for the phase of the wave emanating from one of the sources; and (4) compute and image the shear wave speed on a grid in the image plane.
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Affiliation(s)
- Kui Lin
- Rensselaer Polytechnic Institute, Troy, New York 12180, USA
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Rubert N, Bharat S, DeWall RJ, Andreano A, Brace C, Jiang J, Sampson L, Varghese T. Electrode displacement strain imaging of thermally-ablated liver tissue in an in vivo animal model. Med Phys 2010; 37:1075-82. [PMID: 20384243 DOI: 10.1118/1.3301603] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
PURPOSE Percutaneous thermal ablation is increasingly being used to destroy hepatic tumors in situ. The success of ablative techniques is highly dependent on adequate ablation zone monitoring, and ultrasound-based strain imaging could become a convenient and cost-effective means to delineate ablation zone boundaries. This study investigates in vivo electrode displacement-based strain imaging for monitoring hepatic ablation procedures that are difficult to perform with conventional elastography. METHODS a In our method, minute displacements (less than a millimeter) are applied to the unconstrained end of the ablation electrode, resulting in localized tissue deformation within the ablation zone that provides the mechanical stimuli required for strain imaging. This article presents electrode displacement strain images of radiofrequency ablation zones created in porcine liver in vivo (n = 13). RESULTS Cross-sectional area measurements from strain images of these ablation zones were obtained using manual and automated segmentation. Area measurements from strain images were highly correlated with areas measured on histopathology images, quantitated using linear regression (R = 0.894, P < 0.001 and R = 0.828, P < 0.001, respectively). CONCLUSIONS This study further demonstrates that electrode displacement elastography is capable of providing high-contrast images using widely available commercial ultrasound systems which may potentially be used to assess the extent of thermal ablation zones.
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Affiliation(s)
- N Rubert
- Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53706, USA
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Hoyt K, Kneezel T, Castaneda B, Parker KJ. Quantitative sonoelastography for the in vivo assessment of skeletal muscle viscoelasticity. Phys Med Biol 2008; 53:4063-80. [PMID: 18612176 DOI: 10.1088/0031-9155/53/15/004] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A novel quantitative sonoelastography technique for assessing the viscoelastic properties of skeletal muscle tissue was developed. Slowly propagating shear wave interference patterns (termed crawling waves) were generated using a two-source configuration vibrating normal to the surface. Theoretical models predict crawling wave displacement fields, which were validated through phantom studies. In experiments, a viscoelastic model was fit to dispersive shear wave speed sonoelastographic data using nonlinear least-squares techniques to determine frequency-independent shear modulus and viscosity estimates. Shear modulus estimates derived using the viscoelastic model were in agreement with that obtained by mechanical testing on phantom samples. Preliminary sonoelastographic data acquired in healthy human skeletal muscles confirm that high-quality quantitative elasticity data can be acquired in vivo. Studies on relaxed muscle indicate discernible differences in both shear modulus and viscosity estimates between different skeletal muscle groups. Investigations into the dynamic viscoelastic properties of (healthy) human skeletal muscles revealed that voluntarily contracted muscles exhibit considerable increases in both shear modulus and viscosity estimates as compared to the relaxed state. Overall, preliminary results are encouraging and quantitative sonoelastography may prove clinically feasible for in vivo characterization of the dynamic viscoelastic properties of human skeletal muscle.
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Affiliation(s)
- Kenneth Hoyt
- Department of Radiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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