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Hu Z, Liao S, Zhou J, Chen Q, Wu R. Elastic parameter identification of three-dimensional soft tissue based on deep neural network. J Mech Behav Biomed Mater 2024; 155:106542. [PMID: 38631100 DOI: 10.1016/j.jmbbm.2024.106542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/04/2024] [Accepted: 04/09/2024] [Indexed: 04/19/2024]
Abstract
In the field of virtual surgery and deformation simulation, the identification of elastic parameters of human soft tissues is a critical technology that directly affects the accuracy of deformation simulation. Current research on soft tissue deformation simulation predominantly assumes that the elasticity of tissues is fixed and already known, leading to the difficulty in populating with the elasticity measured or identified from specific tissues of real patients. Existing elasticity modeling efforts struggle to be implemented on irregularly structured soft tissues, failing to adapt to clinical surgical practices. Therefore, this paper proposes a new method for identifying human soft tissue elastic parameters based on the finite element method and the deep neural network, UNet. This method requires only the full-field displacement data of soft tissues under external loads to predict their elastic distribution. The performance and validity of the algorithm are assessed using test data and clinical data from rhinoplasty surgeries. Experiments demonstrate that the method proposed in this paper can achieve an accuracy of over 99% in predicting elastic parameters. Clinical data validation shows that the predicted elastic distribution can reduce the error in finite element deformation simulations by more than 80% at the maximum compared to the error with traditional uniform elastic parameters, effectively enhancing the computational accuracy in virtual surgery simulations and soft tissue deformation modeling.
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Affiliation(s)
- Ziyang Hu
- School of Computer Science and Engineering, Central South University, Changsha, 410083, Hunan, China
| | - Shenghui Liao
- School of Computer Science and Engineering, Central South University, Changsha, 410083, Hunan, China.
| | - Jianda Zhou
- The Third Xiangya Hospital, Central South University, Changsha, 410083, Hunan, China
| | - Qiuyang Chen
- School of Computer Science and Engineering, Central South University, Changsha, 410083, Hunan, China
| | - Renzhong Wu
- School of Computer Science and Engineering, Central South University, Changsha, 410083, Hunan, China
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Kamezawa C, Cramer A, Krull W, Yashiro W, Hyodo K, Gupta R. Dynamic X-ray elastography using a pulsed photocathode source. Sci Rep 2021; 11:24128. [PMID: 34916531 PMCID: PMC8677743 DOI: 10.1038/s41598-021-03221-y] [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: 06/14/2021] [Accepted: 10/20/2021] [Indexed: 11/24/2022] Open
Abstract
X-ray absorption of breast cancers and surrounding healthy tissue can be very similar, a situation that sometimes leads to missed cancers or false-positive diagnoses. To increase the accuracy of mammography and breast tomosynthesis, we describe dynamic X-ray elastography using a novel pulsed X-ray source. This new imaging modality provides both absorption and mechanical properties of the imaged material. We use a small acoustic speaker to vibrate the sample while a synchronously pulsed cold cathode X-ray source images the mechanical deformation. Using these stroboscopic images, we derive two-dimensional stiffness maps of the sample in addition to the conventional X-ray image. In a breast phantom composed of ZrO2 powder embedded in gel, dynamic elastography derived stiffness maps were able to discriminate a hard inclusion from surrounding material with a contrast-to-noise ratio (CNR) of 4.5. The CNR on the corresponding absorption image was 1.1. This demonstrates the feasibility of dynamic X-ray elastography with a synchronously pulsed X-ray source.
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Affiliation(s)
- Chika Kamezawa
- Department of Materials Structure Science, SOKENDAI (The Graduate University for Advanced Studies), 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
- Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
- Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577, Japan
| | - Avilash Cramer
- Massachusetts Institute of Technology, Cambridge, 02139, USA
- Harvard Medical School, Boston, 20115, USA
| | | | - Wataru Yashiro
- Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577, Japan
| | - Kazuyuki Hyodo
- Department of Materials Structure Science, SOKENDAI (The Graduate University for Advanced Studies), 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
- Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Rajiv Gupta
- Harvard Medical School, Boston, 20115, USA.
- Massachusetts General Hospital, Boston, 02114, USA.
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Sahin Ediz S, Atalay B, Aydin Canturk I, Kabaalioglu A. Assessment of the optic nerve, optic disc, and perineural area using shear-wave elastography in patients with multiple sclerosis. Int J Clin Pract 2021; 75:e14736. [PMID: 34392588 DOI: 10.1111/ijcp.14736] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 04/18/2021] [Accepted: 08/10/2021] [Indexed: 11/27/2022] Open
Abstract
PURPOSE To observe and describe the stiffness changes of the optic nerve in the patients with multiple sclerosis (MS) with or without optic neuritis and healthy adults via shear wave elastography (SWE). METHODS 70 optic nerves from 35 patients with MS and 60 optic nerves from 30 healthy subjects were included prospectively in the study. The optic nerve (ON), optic disc (OD), and perineural area were evaluated with SWE and optic nerve sheat diameter (ONSD) was measured by ultrasound. RESULTS The mean age of patients was 39.68 ± 9.99 years. There was no statistically significant difference between the groups in terms of ONSD, SWE ON, SWE OD, and SWE perineural area levels (P > .05). In the MS group; No statistically significant difference was found between patients with and without optic neuritis for the mean age, gender distribution, duration of MS, types of MS, ONSD, SWE ON, SWE OD, SWE perineural area, and Expanded Disability Status Scale (EDSS) scores (P > .05). No statistically significant difference in terms of ONSD, SWE ON, SWE OD, and SWE perineural area between the MS patients with or without optic neuritis and the control group (P > .05). CONCLUSION Shear wave elastography measurements of the optic nerve, optic disc, and perineural area do not contribute to the evaluation of optic neuritis in a patient with MS.
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Affiliation(s)
- Suna Sahin Ediz
- Department of Radiology, Kartal Dr. Lutfi Kirdar City Hospital, University of Health Sciences, Istanbul, Turkey
| | - Basak Atalay
- Department of Radiology, Goztepe Education and Research Hospital, Medeniyet University, Istanbul, Turkey
| | - Ilknur Aydin Canturk
- Department of Neurology, Goztepe Education and Research Hospital, Medeniyet University, Istanbul, Turkey
| | - Adnan Kabaalioglu
- Department of Radiology, Koc University Hospital, Koc University, Istanbul, Turkey
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Esaki M, Yamamura T, Nakamura M, Maeda K, Sawada T, Mizutani Y, Ishikawa E, Suzuki H, Kuno T, Yamada K, Hasegawa I, Ishikawa T, Kakushima N, Furukawa K, Ohno E, Kawashima H, Hirooka Y, Fujishiro M. Endoscopic Ultrasound Elastography as a Novel Diagnostic Method for the Assessment of Hardness and Depth of Invasion in Colorectal Neoplasms. Digestion 2021; 102:701-713. [PMID: 33207360 DOI: 10.1159/000511589] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/13/2020] [Indexed: 02/04/2023]
Abstract
INTRODUCTION We aimed to compare the efficacy of endoscopic ultrasound elastography (EUS-EG) with that of magnifying chromoendoscopy (MCE) and endoscopic ultrasonography (EUS) for the diagnosis of the depth of invasion in colorectal neoplasms. This is an important clinical issue as the depth of invasion is associated with the risk of metastasis. METHODS Consecutive patients with suspected superficial colorectal neoplasms, evaluated by MCE, EUS, and EUS-EG, for whom endoscopic submucosal dissection was considered, were enrolled in 2018 (derivation study) and in 2019-2020 (validation study). The primary clinical endpoint was the diagnostic yield differentiating intramucosal and shallow submucosal neoplasms from deep submucosal (dSM) and advanced colorectal cancers. In addition, inter- and intra-observer agreements of the elastic score of colorectal neoplasm (ES-CRN) were evaluated by 2 expert and 2 non-expert endoscopists. RESULTS Thirty-one (33 lesions) and 50 (55 lesions) patients were enrolled in the derivation and validation studies, respectively. Sensitivity, specificity, positive, and negative predictive values, and accuracy of assessment of the depth of submucosal or deeper invasion in the derivation and validation groups were as follows: EUS-EG, 100/88.2/86.7/100/93.3% and 77.8/86.1/73.7/88.6/83.3%; MCE, 66.7/94.4/90.9/77.3/81.8% and 84.2/91.4/84.2/91.4/88.9%; and EUS, 93.3/77.8/77.8/93.3/84.8% and 89.5/65.7/58.6/92.0/74.1%, respectively. For the 2 expert endoscopists, interobserver agreement for the ES-CRN (first and second assessments) in the derivation group was 0.84 and 0.78, respectively; these values were 0.73 and 0.49, respectively, for the 2 non-expert endoscopists. DISCUSSION/CONCLUSION All 3 modalities presented similar diagnostic yield. Inter- and intra-observer agreements of the ES-CRN were substantial, even for non-expert endoscopists. Therefore, EUS-EG may be a useful modality in determining the depth of invasion in colorectal neoplasms.
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Affiliation(s)
- Masaya Esaki
- Department of Endoscopy, Nagoya University Hospital, Nagoya, Japan
| | - Takeshi Yamamura
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan,
| | - Masanao Nakamura
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Keiko Maeda
- Department of Endoscopy, Nagoya University Hospital, Nagoya, Japan
| | - Tsunaki Sawada
- Department of Endoscopy, Nagoya University Hospital, Nagoya, Japan
| | - Yasuyuki Mizutani
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Eri Ishikawa
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroto Suzuki
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Takeshi Kuno
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Kentaro Yamada
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Issei Hasegawa
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Takuya Ishikawa
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Naomi Kakushima
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Kazuhiro Furukawa
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Eizaburo Ohno
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroki Kawashima
- Department of Endoscopy, Nagoya University Hospital, Nagoya, Japan
| | - Yoshiki Hirooka
- Department of Gastroenterology and Gastroenterological Oncology, Fujita Health University School of Medicine, Toyoake, Japan
| | - Mitsuhiro Fujishiro
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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Delaunay R, Hu Y, Vercauteren T. An unsupervised learning approach to ultrasound strain elastography with spatio-temporal consistency. Phys Med Biol 2021; 66. [PMID: 34298531 PMCID: PMC8417818 DOI: 10.1088/1361-6560/ac176a] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 07/23/2021] [Indexed: 12/19/2022]
Abstract
Quasi-static ultrasound elastography (USE) is an imaging modality that measures deformation (i.e. strain) of tissue in response to an applied mechanical force. In USE, the strain modulus is traditionally obtained by deriving the displacement field estimated between a pair of radio-frequency data. In this work we propose a recurrent network architecture with convolutional long-short-term memory decoder blocks to improve displacement estimation and spatio-temporal continuity between time series ultrasound frames. The network is trained in an unsupervised way, by optimising a similarity metric between the reference and compressed image. Our training loss is also composed of a regularisation term that preserves displacement continuity by directly optimising the strain smoothness, and a temporal continuity term that enforces consistency between successive strain predictions. In addition, we propose an open-access in vivo database for quasi-static USE, which consists of radio-frequency data sequences captured on the arm of a human volunteer. Our results from numerical simulation and in vivo data suggest that our recurrent neural network can account for larger deformations, as compared with two other feed-forward neural networks. In all experiments, our recurrent network outperformed the state-of-the-art for both learning-based and optimisation-based methods, in terms of elastographic signal-to-noise ratio, strain consistency, and image similarity. Finally, our open-source code provides a 3D-slicer visualisation module that can be used to process ultrasound RF frames in real-time, at a rate of up to 20 frames per second, using a standard GPU.
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Affiliation(s)
- Rémi Delaunay
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, Gower Street, London WC1E 6BT, United Kingdom.,School of Biomedical Engineering & Imaging Sciences, King's College London, Strand, London WC2R 2LS, United Kingdom
| | - Yipeng Hu
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Tom Vercauteren
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, Gower Street, London WC1E 6BT, United Kingdom.,School of Biomedical Engineering & Imaging Sciences, King's College London, Strand, London WC2R 2LS, United Kingdom
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A Quasi-Static Quantitative Ultrasound Elastography Algorithm Using Optical Flow. SENSORS 2021; 21:s21093010. [PMID: 33923001 PMCID: PMC8123352 DOI: 10.3390/s21093010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 04/19/2021] [Accepted: 04/22/2021] [Indexed: 11/17/2022]
Abstract
Ultrasound elastography is a constantly developing imaging technique which is capable of displaying the elastic properties of tissue. The measured characteristics could help to refine physiological tissue models, but also indicate pathological changes. Therefore, elastography data give valuable insights into tissue properties. This paper presents an algorithm that measures the spatially resolved Young’s modulus of inhomogeneous gelatin phantoms using a CINE sequence of a quasi-static compression and a load cell measuring the compressing force. An optical flow algorithm evaluates the resulting images, the stresses and strains are computed, and, conclusively, the Young’s modulus and the Poisson’s ratio are calculated. The whole algorithm and its results are evaluated by a performance descriptor, which determines the subsequent calculation and gives the user a trustability index of the modulus estimation. The algorithm shows a good match between the mechanically measured modulus and the elastography result—more precisely, the relative error of the Young’s modulus estimation with a maximum error 35%. Therefore, this study presents a new algorithm that is capable of measuring the elastic properties of gelatin specimens in a quantitative way using only the image data. Further, the computation is monitored and evaluated by a performance descriptor, which measures the trustability of the results.
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Sayed AM, Naser MA, Wahba AA, Eldosoky MAA. Breast Tumor Diagnosis Using Finite-Element Modeling Based on Clinical in vivo Elastographic Data. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2020; 39:2351-2363. [PMID: 32472949 DOI: 10.1002/jum.15344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 02/21/2020] [Accepted: 04/26/2020] [Indexed: 06/11/2023]
Abstract
OBJECTIVES This study exploited finite-element modeling (FEM) to simulate breast tissue multicompression during ultrasound elastography to classify breast tumors based on their nonlinear biomechanical properties. METHODS Numeric simulations were first calculated by using 3-dimensional (3D) virtual models with an assumed tumor's geometric dimensions but with actual material properties to test and validate the FEM. Further numeric simulations were used to construct 3D models based on in vivo experimental data to verify our models. The models were designed for each individual in vivo case, emphasizing the geometry, position, and biomechanical properties of the breast tissue. At different compression levels, tissue strains were analyzed between the tumors and the background normal tissues to explore their nonlinearity and classify the tumor type. Tumor classification parameters were deduced by using a power-law relationship between the applied compressive forces and strain differences. RESULTS Classification parameters were compared between benign and malignant tumors, for which they were found to be statistically significant in classifying the tumor types (P < .05) by both the validation and verification of FEM. We compared the classification parameters between the in vivo and FEM classifications, for which they were found to be strongly correlated (R = 0.875; P < .001), with no statistical differences between their outcomes (P = .909). CONCLUSIONS Good agreement between the model outcomes and the in vivo diagnostics was reported. The implemented models were validated and verified. The introduced 3D modeling method may augment elastographic methods to preliminary classify breast tumors at an early stage.
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Affiliation(s)
- Ahmed M Sayed
- Biomedical Engineering Department, Faculty of Engineering, Helwan University, Helwan, Egypt
| | - Mohamed A Naser
- Biomedical Engineering Department, Faculty of Engineering, Minia University, Minia, Egypt
| | - Ashraf A Wahba
- Biomedical Engineering Department, Faculty of Engineering, Helwan University, Helwan, Egypt
| | - Mohamed A A Eldosoky
- Biomedical Engineering Department, Faculty of Engineering, Helwan University, Helwan, Egypt
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Niu H, Li C, Guan Y, Dang Y, Li X, Fan Z, Shen J, Ma L, Guan J. High oxygen preservation hydrogels to augment cell survival under hypoxic condition. Acta Biomater 2020; 105:56-67. [PMID: 31954189 PMCID: PMC7098391 DOI: 10.1016/j.actbio.2020.01.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 12/18/2019] [Accepted: 01/13/2020] [Indexed: 12/29/2022]
Abstract
Cell therapy is a promising approach for ischemic tissue regeneration. However, high death rate of delivered cells under low oxygen condition, and poor cell retention in tissues largely limit the therapeutic efficacy. Using cell carriers with high oxygen preservation has potential to improve cell survival. To increase cell retention, cell carriers that can quickly solidify at 37 °C so as to efficiently immobilize the carriers and cells in the tissues are necessary. Yet there lacks cell carriers with these combined properties. In this work, we have developed a family of high oxygen preservation and fast gelation hydrogels based on N-isopropylacrylamide (NIPAAm) copolymers. The hydrogels were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization of NIPAAm, acrylate-oligolactide (AOLA), 2-hydroxyethyl methacrylate (HEMA), and methacrylate-poly(ethylene glycol)-perfluorooctane (MAPEGPFC). The hydrogel solutions exhibited sol-gel temperatures around room temperature and were flowable and injectable at 4°C. They can quickly solidify (≤6 s) at 37°C to form flexible gels. These hydrogels lost 9.4~29.4% of their mass after incubation in Dulbecco's Phosphate-Buffered Saline (DPBS) for 4 weeks. The hydrogels exhibited a greater oxygen partial pressure than DPBS after being transferred from a 21% O2 condition to a 1% O2 condition. When bone marrow mesenchymal stem cells (MSCs) were encapsulated in the hydrogels and cultured under 1% O2, the cells survived and proliferated during the 14-day culture period. In contrast, the cells experienced extensive death in the control hydrogel that had low oxygen preservation capability. The hydrogels possessed excellent biocompatibility. The final degradation products did not provoke cell death even when the concentration was as high as 15 mg/ml, and the hydrogel implantation did not induce substantial inflammation. These hydrogels are promising as cell carriers for cell transplantation into ischemic tissues. STATEMENT OF SIGNIFICANCE: Stem cell therapy for ischemic tissues experiences low therapeutic efficacy largely due to poor cell survival under low oxygen condition. Using cell carriers with high oxygen preservation capability has potential to improve cell survival. In this work, we have developed a family of hydrogels with this property. These hydrogels promoted the encapsulated stem cell survival and growth under low oxygen condition.
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Affiliation(s)
- Hong Niu
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210, USA; Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Chao Li
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Ya Guan
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210, USA; Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Yu Dang
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210, USA; Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Xiaofei Li
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Zhaobo Fan
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Jie Shen
- Orthopaedic Surgery, Washington University School of Medicine, St. Louis, MO, 631310, USA
| | - Liang Ma
- Division of Dermatology, Washington University School of Medicine, St. Louis, MO, 631310, USA
| | - Jianjun Guan
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43210, USA; Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO 63130, USA.
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Zaki F, Wang Y, Wang C, Liu X. Adaptive Doppler analysis for robust handheld optical coherence elastography. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2019; 10880. [PMID: 31333279 DOI: 10.1117/12.2503809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Optical coherence tomography (OCT) allows structural and functional imaging of biological tissue with high resolution and high speed. Optical coherence elastography (OCE), a functional extension of OCT, has been used to perform mechanical characterization. A handheld fiber-optic OCE instrument allows high sensitivity virtual palpation of tissue with great convenience and flexibility and can be used in a wide range of clinical settings. Moreover, fiber-optic OCE instruments can be integrated into a needle device to access deep tissue. However, the major challenge in the development of handheld OCE instrument is non-constant motion within the tissue. In this study, a simple and effective method for temporally and spatially adaptive Doppler analysis is investigated. The adaptive Doppler analysis method strategically chooses the time interval (δt) between signals involved in Doppler analysis, to track the motion speed v(z,t) that varies as time (t) and depth (z) in a deformed sample volume under manual compression. The aim is to use an optimal time interval to achieve a large yet artifact free Doppler phase shift for motion tracking.
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Affiliation(s)
- Farzana Zaki
- Dept. of Electrical and Computer Engineering, New Jersey Institute of Technology, University Heights, Newark, New Jersey, USA, 07102
| | - Yahui Wang
- Dept. of Electrical and Computer Engineering, New Jersey Institute of Technology, University Heights, Newark, New Jersey, USA, 07102
| | - Chizhong Wang
- Dept. of Electrical and Computer Engineering, New Jersey Institute of Technology, University Heights, Newark, New Jersey, USA, 07102
| | - Xuan Liu
- Dept. of Electrical and Computer Engineering, New Jersey Institute of Technology, University Heights, Newark, New Jersey, USA, 07102
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Otesteanu CF, Sanabria SJ, Goksel O. Robust Reconstruction of Elasticity Using Ultrasound Imaging and Multi-Frequency Excitations. IEEE TRANSACTIONS ON MEDICAL IMAGING 2018; 37:2502-2513. [PMID: 29994521 DOI: 10.1109/tmi.2018.2837390] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Biomedical parameters of tissue can be important indicators for clinical diagnosis. One such parameter that reflects tissue stiffness is elasticity, the imaging of which is called elastography. In this paper, we use displacements from harmonic excitations to solve the inverse problem of elasticity based on a finite-element method (FEM) formulation. This leads to iterative solution of nonlinear and nonconvex problems. In this paper, we show the importance and selection of viable initializations in numerical simulation studies and propose techniques for the fusion of multiple initializations for ideal reconstructions of unknown tissue as well as combining information from excitations at multiple frequencies. Results show that our method leads up to 76% decrease in root-mean-squared error (RMSE) and 9.9 dB increase in contrast-to-noise ratio (CNR) in simulations with noise, when compared to conventional iterative FEM without multiple initializations and frequencies. As the wave patterns in individually selected frequencies may introduce artifacts, a joint inverse-problem solution of multi-frequency excitations is introduced as a robust solution, where CNR improvements of up to 11.9 dB are observed. We also present the methods on a tissue-mimicking gelatin phantom study using mechanical excitation and ultrafast plane-wave ultrasound imaging, where the RMSE was improved by up to 51%. An experiment of ablation via heating an ex-vivo bovine liver shows that reconstruction artifacts are reduced with our proposed method.
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13
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Acoustic Radiation Force Based Ultrasound Elasticity Imaging for Biomedical Applications. SENSORS 2018; 18:s18072252. [PMID: 30002352 PMCID: PMC6069000 DOI: 10.3390/s18072252] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 07/03/2018] [Accepted: 07/11/2018] [Indexed: 01/02/2023]
Abstract
Pathological changes in biological tissue are related to the changes in mechanical properties of biological tissue. Conventional medical screening tools such as ultrasound, magnetic resonance imaging or computed tomography have failed to produce the elastic properties of biological tissues directly. Ultrasound elasticity imaging (UEI) has been proposed as a promising imaging tool to map the elastic parameters of soft tissues for the clinical diagnosis of various diseases include prostate, liver, breast, and thyroid gland. Existing UEI-based approaches can be classified into three groups: internal physiologic excitation, external excitation, and acoustic radiation force (ARF) excitation methods. Among these methods, ARF has become one of the most popular techniques for the clinical diagnosis and treatment of disease. This paper provides comprehensive information on the recently developed ARF-based UEI techniques and instruments for biomedical applications. The mechanical properties of soft tissue, ARF and displacement estimation methods, working principle and implementation instruments for each ARF-based UEI method are discussed.
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Zhang Z, Liu H. A 2D phase zero algorithm for estimation of displacement in ultrasound elastography based on the optimization of initial value for iteration. BIOTECHNOL BIOTEC EQ 2018. [DOI: 10.1080/13102818.2018.1456974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Affiliation(s)
- Zhihong Zhang
- Department of Computer Science, College of Computer Engineering and Applied Mathenatics, Changsha University, Changsha, PR China
| | - Huafu Liu
- Department of Computer Science, College of Computer Engineering and Applied Mathenatics, Changsha University, Changsha, PR China
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Washburn N, Onishi K, Wang JHC. Ultrasound elastography and ultrasound tissue characterisation for tendon evaluation. J Orthop Translat 2018; 15:9-20. [PMID: 30258782 PMCID: PMC6148731 DOI: 10.1016/j.jot.2018.06.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 06/04/2018] [Accepted: 06/07/2018] [Indexed: 12/16/2022] Open
Abstract
Ultrasound elastography (UE) and ultrasound tissue characterisation (UTC) are two newer modes of ultrasound (US) which have begun to attract scientific interests as ways to improve tendon characterisation. These modes of US show early promise in improved diagnostic accuracy, prediction of at-risk tendons and prognostication capability beyond conventional grey-scale US. Here, we provide a review of the literature on UE and UTC for Achilles, patellar and rotator cuff tendons. The translational potential of this article: The present literature indicates that UE and UTC could potentially increase the clinician's ability to accurately diagnose the extent of tendon pathology, including preclinical injury.
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Affiliation(s)
- Neal Washburn
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh Medical Center, Kaufman Building, 3471 Fifth Avenue, Suite 201, Pittsburgh, PA, 15213, USA
| | - Kentaro Onishi
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh Medical Center, Kaufman Building, 3471 Fifth Avenue, Suite 201, Pittsburgh, PA, 15213, USA.,Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, Kaufman Building, 3471 Fifth Avenue, Suite 1011, Pittsburgh, PA, 15213, USA
| | - James H-C Wang
- MechanoBiology Laboratory, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, 210 Lothrop Street, BST, E1640, Pittsburgh, PA 15213, USA
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16
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Fekkes S, Saris AECM, Nillesen MM, Menssen J, Hansen HHG, de Korte CL. Simultaneous Vascular Strain and Blood Vector Velocity Imaging Using High-Frequency Versus Conventional-Frequency Plane Wave Ultrasound: A Phantom Study. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2018; 65:1166-1181. [PMID: 29993371 DOI: 10.1109/tuffc.2018.2834724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Plaque strain and blood vector velocity imaging of stenosed arteries are expected to aid in diagnosis and prevention of cerebrovascular disease. Ultrafast plane wave imaging enables simultaneous strain and velocity estimation. Multiple ultrasound vendors are introducing high-frequency ultrasound probes and systems. This paper investigates whether the use of high-frequency ultrafast ultrasound is beneficial for assessing blood velocities and strain in arteries. The performance of strain and blood flow velocity estimation was compared between a high-frequency transducer (MS250, fc = 21 MHz) and a clinically utilized transducer (L12-5, fc = 9 MHz). Quantitative analysis based on straight tube phantom experiments revealed that the MS250 outperformed the L12-5 in the superficial region: low velocities near the wall were more accurately estimated and wall strains were better resolved. At greater than 2-cm echo depth, the L12-5 performed better due to the high attenuation of the MS250 probe. Qualitative comparison using a perfused patient-specific carotid bifurcation phantom confirmed these findings. Thus, in conclusion, for strain and blood velocity estimation for depths up to ~2 cm, a high-frequency probe is recommended.
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17
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Kang K, Cho Y, Yu KJ. Novel Nano-Materials and Nano-Fabrication Techniques for Flexible Electronic Systems. MICROMACHINES 2018; 9:E263. [PMID: 30424196 PMCID: PMC6187536 DOI: 10.3390/mi9060263] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/19/2018] [Accepted: 05/24/2018] [Indexed: 12/17/2022]
Abstract
Recent progress in fabricating flexible electronics has been significantly developed because of the increased interest in flexible electronics, which can be applied to enormous fields, not only conventional in electronic devices, but also in bio/eco-electronic devices. Flexible electronics can be applied to a wide range of fields, such as flexible displays, flexible power storages, flexible solar cells, wearable electronics, and healthcare monitoring devices. Recently, flexible electronics have been attached to the skin and have even been implanted into the human body for monitoring biosignals and for treatment purposes. To improve the electrical and mechanical properties of flexible electronics, nanoscale fabrications using novel nanomaterials are required. Advancements in nanoscale fabrication methods allow the construction of active materials that can be combined with ultrathin soft substrates to form flexible electronics with high performances and reliability. In this review, a wide range of flexible electronic applications via nanoscale fabrication methods, classified as either top-down or bottom-up approaches, including conventional photolithography, soft lithography, nanoimprint lithography, growth, assembly, and chemical vapor deposition (CVD), are introduced, with specific fabrication processes and results. Here, our aim is to introduce recent progress on the various fabrication methods for flexible electronics, based on novel nanomaterials, using application examples of fundamental device components for electronics and applications in healthcare systems.
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Affiliation(s)
- Kyowon Kang
- School of Electrical Engineering, Yonsei University, Seoul 03722, Korea.
| | - Younguk Cho
- School of Electrical Engineering, Yonsei University, Seoul 03722, Korea.
| | - Ki Jun Yu
- School of Electrical Engineering, Yonsei University, Seoul 03722, Korea.
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18
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Czajkowska J, Pyciński B, Juszczyk J, Pietka E. Biopsy needle tracking technique in US images. Comput Med Imaging Graph 2018; 65:93-101. [DOI: 10.1016/j.compmedimag.2017.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 06/23/2017] [Accepted: 07/18/2017] [Indexed: 11/28/2022]
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19
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Wang W, Zou W, Hu D, Wang J. Adaptive mesh refinement for elastic modulus reconstruction in elastography. Proc Inst Mech Eng H 2018; 232:215-229. [DOI: 10.1177/0954411917752026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Meshes play a crucial role in determining the accuracy of the elastic modulus reconstruction in the elastography when the finite element method is employed. In this article, we propose an adaptive mesh refinement strategy which can ensure the coincidence of the meshes with the shape of the inclusions in the observed tissue. This strategy is based on the intensity distribution of the strain image where the variance of the strain distribution in each element of the meshes is used to measure the homogeneity of the element, that is, the larger the strain variance is the more inhomogeneous the element will be and hence more detailed information will be included in this element. For more accurate reconstruction of such detailed information, mesh refinement procedure is implemented in such elements. Besides, two refinement steps are employed for the reconstruction to improve the fitness of the reconstructed image and the observed tissue. Simulation results show that the two-stage adaptive mesh refinement algorithm performs well without needing any prior information about the internal geometric shape in tissue. Not only Young’s moduli of models but also shapes of the inclusions can be reconstructed perfectly and quickly with our proposed method.
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Affiliation(s)
- Wenxia Wang
- School of Electronic and Information Engineering, Soochow University, Suzhou, China
- College of Information Engineering, Henan University of Science and Technology, Luoyang, China
| | - Wei Zou
- School of Electronic and Information Engineering, Soochow University, Suzhou, China
| | - Danfeng Hu
- School of Electronic and Information Engineering, Soochow University, Suzhou, China
| | - Jiajun Wang
- School of Electronic and Information Engineering, Soochow University, Suzhou, China
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20
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Stromer J, Ladani L. Examination of a spectral-based ultrasonic analysis method for materials characterization and evaluation. Biomed Signal Process Control 2018. [DOI: 10.1016/j.bspc.2017.10.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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21
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Han M, Wan J, Zhao Y, Zhou X, Wan M. Nakagami-m Parametric Imaging for Atherosclerotic Plaque Characterization Using the Coarse-to-Fine Method. ULTRASOUND IN MEDICINE & BIOLOGY 2017; 43:1275-1289. [PMID: 28392001 DOI: 10.1016/j.ultrasmedbio.2017.01.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 11/15/2016] [Accepted: 01/30/2017] [Indexed: 06/07/2023]
Abstract
The Nakagami model was used to analyze the statistical differences in ultrasound backscattered signals between different plaque types. To improve image resolution, Nakagami-m parametric imaging using the coarse-to-fine method based on the maximum likelihood estimation (CTF-BOW) was proposed for atherosclerotic plaque characterization. Simulation results confirmed that the CTF-BOW method significantly outperforms the sliding window method in precision, smoothness and resolution. Preliminary in vivo results (n = 45) indicated that the ranges of the m parameters for calcified, mixed and echolucent plaques are, respectively, 0.2852-0.5225, 0.6532-0.8784 and 0.8908-1.4011, with no overlap. Results revealed that the CTF-BOW method significantly improves image resolution without sacrificing accuracy and can distinguish between calcified, mixed and echolucent plaques. Moreover, it was found that the parameter m is related to the composition of the plaque, indicating that Nakagami-m parametric imaging has the potential to characterize plaques.
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Affiliation(s)
- Meng Han
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Jinjin Wan
- Science and Technology on Electro-optical Control Laboratory, Luoyang, China
| | - Yongfeng Zhao
- Department of Ultrasound, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Xiaodong Zhou
- Department of Ultrasound, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Mingxi Wan
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Department of Biomedical Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China.
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22
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Chaudhry A, Kim N, Unnikrishnan G, Nair S, Reddy JN, Righetti R. Effect of Interstitial Fluid Pressure on Ultrasound Axial Strain and Axial Shear Strain Elastography. ULTRASONIC IMAGING 2017; 39:137-146. [PMID: 27694129 DOI: 10.1177/0161734616671713] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Ultrasound elastography is an imaging modality that has been used to diagnose tumors of the breast, thyroid, and prostate. Both axial strain elastography and axial shear strain elastography (ASSE) have shown significant potentials to differentiate between benign and malignant tumors. Elevated interstitial fluid pressure (IFP) is a characteristic of many malignant tumors and a major barrier in targeted drug delivery therapies. This parameter, however, has not received significant attention in ultrasound elastography and, in general, in most diagnostic imaging modalities yet. In this paper, we investigate the effect of an underlying IFP contrast on ultrasound axial strain and axial shear strain imaging using finite element analysis. Our results show that an underlying contrast in IFP creates a new contrast mechanism in both the axial strain and axial shear strain elastographic images. This information might be important for a better interpretation of elastographic images of tumors.
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Affiliation(s)
- Anuj Chaudhry
- 1 Department of Electrical & Computer Engineering, Texas A&M University, College Station, TX, USA
| | - Namhee Kim
- 2 Department of Mechanical Engineering, Texas A&M University, College Station, TX, USA
| | - Ginu Unnikrishnan
- 2 Department of Mechanical Engineering, Texas A&M University, College Station, TX, USA
| | - Sanjay Nair
- 1 Department of Electrical & Computer Engineering, Texas A&M University, College Station, TX, USA
| | - J N Reddy
- 2 Department of Mechanical Engineering, Texas A&M University, College Station, TX, USA
| | - Raffaella Righetti
- 1 Department of Electrical & Computer Engineering, Texas A&M University, College Station, TX, USA
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23
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Liu C, Zhou Y. Improvement of Lesion Detection by Complete Angular Compound Ultrasonic Elastography. ULTRASONIC IMAGING 2017; 39:19-32. [PMID: 26809674 DOI: 10.1177/0161734615627419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Quasi-static ultrasound elastography is an emerging diagnostic imaging modality for determining the stiffness of pathologically changed soft tissues, which do not show significant differences in acoustic impedance for B-mode imaging. Although some methods were applied to improve the signal-to-noise ratio (SNRe) and contrast-to-noise ratio (CNRe) of the constructed elastogram, nonuniform strain distribution at the internal boundary of a hard inclusion, even with the uniform displacement on the surface, is an inherent mechanical effect and results in distortion at the detected lesion boundary. To overcome such stress concentrations, a new elastographic modality was proposed, where the elastograms from different angles throughout 360° were compounded. The strain field and subsequent ultrasound images were calculated using the finite element method (FEM) and Field II, respectively, from which the elastograms were constructed. The performance of complete angular compound elastography with varied interval angles, lesion sizes, and ratios of Young's moduli of the lesion to the background was simulated and compared with that of conventional axial strain elastography. It is found that viewing the lesion from only about 10 angles (interval of 36°) would significantly improve the image quality of elastogram (increasing SNRe by at least 13% and CNRe by at least 5.8 dB), reduce the lesion distortion in the lateral direction, and enhance the sensitivity, resolution, and accuracy of lesion detection. A preliminary phantom study showed similar improvements. Altogether, complete angular compound elastography improves the elastogram quality and reduces the mechanical effects in lesion detection.
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Affiliation(s)
- Chenhui Liu
- 1 School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
| | - Yufeng Zhou
- 1 School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
- 2 Key Laboratory of Modern Acoustics, Nanjing University, Nanjing, China
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24
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Xu X, Chung Y, Brooks AD, Shih WH, Shih WY. Development of array piezoelectric fingers towards in vivo breast tumor detection. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:124301. [PMID: 28040934 PMCID: PMC5148765 DOI: 10.1063/1.4971325] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 11/21/2016] [Indexed: 06/06/2023]
Abstract
We have investigated the development of a handheld 4 × 1 piezoelectric finger (PEF) array breast tumor detector system towards in vivo patient testing, particularly, on how the duration of the DC applied voltage, the depression depth of the handheld unit, and breast density affect the PEF detection sensitivity on 40 patients. The tests were blinded and carried out in four phases: with DC voltage durations 5, 3, 2, to 0.8 s corresponding to scanning a quadrant, a half, a whole breast, and both breasts within 30 min, respectively. The results showed that PEF detection sensitivity was unaffected by shortening the applied voltage duration from 5 to 0.8 s nor was it affected by increasing the depression depth from 2 to 6 mm. Over the 40 patients, PEF detected 46 of the 48 lesions (46/48)-with the smallest lesion detected being 5 mm in size. Of 28 patients (some have more than one lesion) with mammography records, PEF detected 31/33 of all lesions (94%) and 14/15 of malignant lesions (93%), while mammography detected 30/33 of all lesions (91%) and 12/15 of malignant lesions (80%), indicating that PEF could detect malignant lesions not detectable by mammography without significantly increasing false positives. PEF's detection sensitivity is also shown to be independent of breast density, suggesting that PEF could be a potential tool for detecting breast cancer in young women and women with dense breasts.
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Affiliation(s)
- Xin Xu
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania 19104, USA
| | - Youngsoo Chung
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania 19104, USA
| | - Ari D Brooks
- Department of Surgery, College of Medicine, Drexel University, Philadelphia, Pennsylvania 19104, USA
| | - Wei-Heng Shih
- Department of Materials Science and Engineering, Drexel University, Philadelphia, Pennsylvania 19104, USA
| | - Wan Y Shih
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania 19104, USA
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25
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Fekkes S, Swillens AES, Hansen HHG, Saris AECM, Nillesen MM, Iannaccone F, Segers P, de Korte CL. 2-D Versus 3-D Cross-Correlation-Based Radial and Circumferential Strain Estimation Using Multiplane 2-D Ultrafast Ultrasound in a 3-D Atherosclerotic Carotid Artery Model. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2016; 63:1543-1553. [PMID: 27576246 DOI: 10.1109/tuffc.2016.2603189] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Three-dimensional (3-D) strain estimation might improve the detection and localization of high strain regions in the carotid artery (CA) for identification of vulnerable plaques. This paper compares 2-D versus 3-D displacement estimation in terms of radial and circumferential strain using simulated ultrasound (US) images of a patient-specific 3-D atherosclerotic CA model at the bifurcation embedded in surrounding tissue generated with ABAQUS software. Global longitudinal motion was superimposed to the model based on the literature data. A Philips L11-3 linear array transducer was simulated, which transmitted plane waves at three alternating angles at a pulse repetition rate of 10 kHz. Interframe (IF) radio-frequency US data were simulated in Field II for 191 equally spaced longitudinal positions of the internal CA. Accumulated radial and circumferential displacements were estimated using tracking of the IF displacements estimated by a two-step normalized cross-correlation method and displacement compounding. Least-squares strain estimation was performed to determine accumulated radial and circumferential strain. The performance of the 2-D and 3-D methods was compared by calculating the root-mean-squared error of the estimated strains with respect to the reference strains obtained from the model. More accurate strain images were obtained using the 3-D displacement estimation for the entire cardiac cycle. The 3-D technique clearly outperformed the 2-D technique in phases with high IF longitudinal motion. In fact, the large IF longitudinal motion rendered it impossible to accurately track the tissue and cumulate strains over the entire cardiac cycle with the 2-D technique.
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26
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Shaswary E, Xu Y, Tavakkoli J. Performance study of a new time-delay estimation algorithm in ultrasonic echo signals and ultrasound elastography. ULTRASONICS 2016; 69:11-18. [PMID: 27010697 DOI: 10.1016/j.ultras.2016.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Revised: 01/14/2016] [Accepted: 03/03/2016] [Indexed: 06/05/2023]
Abstract
Time-delay estimation has countless applications in ultrasound medical imaging. Previously, we proposed a new time-delay estimation algorithm, which was based on the summation of the sign function to compute the time-delay estimate (Shaswary et al., 2015). We reported that the proposed algorithm performs similar to normalized cross-correlation (NCC) and sum squared differences (SSD) algorithms, even though it was significantly more computationally efficient. In this paper, we study the performance of the proposed algorithm using statistical analysis and image quality analysis in ultrasound elastography imaging. Field II simulation software was used for generation of ultrasound radio frequency (RF) echo signals for statistical analysis, and a clinical ultrasound scanner (Sonix® RP scanner, Ultrasonix Medical Corp., Richmond, BC, Canada) was used to scan a commercial ultrasound elastography tissue-mimicking phantom for image quality analysis. The statistical analysis results confirmed that, in overall, the proposed algorithm has similar performance compared to NCC and SSD algorithms. The image quality analysis results indicated that the proposed algorithm produces strain images with marginally higher signal-to-noise and contrast-to-noise ratios compared to NCC and SSD algorithms.
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Affiliation(s)
- Elyas Shaswary
- Department of Physics, Ryerson University, Toronto, Ontario, Canada
| | - Yuan Xu
- Department of Physics, Ryerson University, Toronto, Ontario, Canada
| | - Jahan Tavakkoli
- Department of Physics, Ryerson University, Toronto, Ontario, Canada.
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27
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Ophir J, Alam SK, Garra BS, Kallel F, Konofagou EE, Krouskop T, Merritt CRB, Righetti R, Souchon R, Srinivasan S, Varghese T. Elastography: Imaging the elastic properties of soft tissues with ultrasound. J Med Ultrason (2001) 2016; 29:155. [PMID: 27277961 DOI: 10.1007/bf02480847] [Citation(s) in RCA: 165] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2002] [Accepted: 09/13/2002] [Indexed: 01/30/2023]
Abstract
Elastography is a method that can ultimately generate several new kinds of images, called elastograms. As such, all the properties of elastograms are different from the familiar properties of sonograms. While sonograms convey information related to the local acoustic backscatter energy from tissue components, elastograms relate to its local strains, Young's moduli or Poisson's ratios. In general, these elasticity parameters are not directly correlated with sonographic parameters, i.e. elastography conveys new information about internal tissue structure and behavior under load that is not otherwise obtainable. In this paper we summarize our work in the field of elastography over the past decade. We present some relevant background material from the field of biomechanics. We then discuss the basic principles and limitations that are involved in the production of elastograms of biological tissues. Results from biological tissues in vitro and in vivo are shown to demonstrate this point. We conclude with some observations regarding the potential of elastography for medical diagnosis.
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Affiliation(s)
- Jonathan Ophir
- The University of Texas Medical School at Houston, Houston, TX, USA.,Department of ECE, The University of Houston, Houston, TX, USA
| | - S Kaisar Alam
- The University of Texas Medical School at Houston, Houston, TX, USA.,Riverside Research Institute, New York, NY, USA
| | - Brian S Garra
- Fletcher Allen Medical Center, University of Vermont, Burlington, VT, USA
| | - Faouzi Kallel
- The University of Texas Medical School at Houston, Houston, TX, USA
| | - Elisa E Konofagou
- The University of Texas Medical School at Houston, Houston, TX, USA.,Brigham and Women's Hospital, Boston, MA, USA
| | | | | | - Raffaella Righetti
- The University of Texas Medical School at Houston, Houston, TX, USA.,Department of ECE, The University of Houston, Houston, TX, USA
| | - Remi Souchon
- l'Institut National de la Sante et de la Recherche Médicale (INSERM) Unité 556, Lyon, France
| | - Seshadri Srinivasan
- The University of Texas Medical School at Houston, Houston, TX, USA.,Department of ECE, The University of Houston, Houston, TX, USA
| | - Tomy Varghese
- The University of Texas Medical School at Houston, Houston, TX, USA.,University of Wisconsin, Madison, WI, USA
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28
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Witzenburg CM, Barocas VH. A nonlinear anisotropic inverse method for computational dissection of inhomogeneous planar tissues. Comput Methods Biomech Biomed Engin 2016; 19:1630-46. [PMID: 27140845 DOI: 10.1080/10255842.2016.1176154] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Quantification of the mechanical behavior of soft tissues is challenging due to their anisotropic, heterogeneous, and nonlinear nature. We present a method for the 'computational dissection' of a tissue, by which we mean the use of computational tools both to identify and to analyze regions within a tissue sample that have different mechanical properties. The approach employs an inverse technique applied to a series of planar biaxial experimental protocols. The aggregated data from multiple protocols provide the basis for (1) segmentation of the tissue into regions of similar properties, (2) linear analysis for the small-strain behavior, assuming uniform, linear, anisotropic behavior within each region, (3) subsequent nonlinear analysis following each individual experimental protocol path and using local linear properties, and (4) construction of a strain energy data set W(E) at every point in the material by integrating the differential stress-strain functions along each strain path. The approach has been applied to simulated data and captures not only the general nonlinear behavior but also the regional differences introduced into the simulated tissue sample.
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Affiliation(s)
- Colleen M Witzenburg
- a Department of Mechanical Engineering , University of Minnesota , Minneapolis , MN , USA
| | - Victor H Barocas
- b Department of Biomedical Engineering , University of Minnesota , Minneapolis , MN , USA
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29
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Chaudhry A, Yazdi IK, Kongari R, Tasciotti E, Righetti R. A New Class of Phantom Materials for Poroelastography Imaging Techniques. ULTRASOUND IN MEDICINE & BIOLOGY 2016; 42:1230-8. [PMID: 26806439 DOI: 10.1016/j.ultrasmedbio.2015.12.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 11/17/2015] [Accepted: 12/14/2015] [Indexed: 05/20/2023]
Abstract
Poroelastography is an elastographic technique used to image the temporal mechanical behavior of tissues. One of the major challenges in determining experimental potentials and limitations of this technique has been the lack of complex and realistic controlled phantoms that could be used to corroborate the limited number of theoretical and simulation studies available in the literature as well as to predict its performance in complex experimental situations and in a variety of conditions. In the study described here, we propose and analyze a new class of phantom materials for temporal elastography imaging. The results indicate that, by using polyacrylamide, we can generate inhomogeneous elastographic phantoms with controlled fluid content and fluid flow properties, while maintaining mechanical and ultrasonic properties similar to those of soft tissues.
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Affiliation(s)
- Anuj Chaudhry
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas, USA
| | - Iman K Yazdi
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, Texas, USA; Department of Biomedical Engineering, University of Houston, Houston, Texas, USA
| | - Rohit Kongari
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | - Ennio Tasciotti
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, Texas, USA
| | - Raffaella Righetti
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas, USA.
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30
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Shin B, Gopaul D, Fienberg S, Kwon HJ. Application of Eshelby's Solution to Elastography for Diagnosis of Breast Cancer. ULTRASONIC IMAGING 2016; 38:115-136. [PMID: 25761705 DOI: 10.1177/0161734615573030] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Eshelby's solution is the analytical method that can derive the elastic field within and around an ellipsoidal inclusion embedded in a matrix. Since breast tumor can be regarded as an elastic inclusion with different elastic properties from those of surrounding matrix when the deformation is small, we applied Eshelby's solution to predict the stress and strain fields in the breast containing a suspicious lesion. The results were used to investigate the effectiveness of strain ratio (SR) from elastography in representing modulus ratio (MR) that may be the meaningful indicator of the malignancy of the lesion. This study showed that SR significantly underestimates MR and is varied with the shape and the modulus of the lesion. Based on the results from Eshelby's solution and finite element analysis (FEA), we proposed a surface regression model as a polynomial function that can predict the MR of the lesion to the matrix. The model has been applied to gelatin-based phantoms and clinical ultrasound images of human breasts containing different types of lesions. The results suggest the potential of the proposed method to improve the diagnostic performance of breast cancer using elastography.
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Affiliation(s)
- Bonghun Shin
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Darindra Gopaul
- Radiation Oncology, Grand River Regional Cancer Centre, Kitchener, Ontario, Canada
| | | | - Hyock Ju Kwon
- Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario, Canada
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31
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Witzenburg CM, Dhume RY, Lake SP, Barocas VH. Automatic Segmentation of Mechanically Inhomogeneous Tissues Based on Deformation Gradient Jump. IEEE TRANSACTIONS ON MEDICAL IMAGING 2016; 35:29-41. [PMID: 26168433 PMCID: PMC4739827 DOI: 10.1109/tmi.2015.2453316] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Variations in properties, active behavior, injury, scarring, and/or disease can all cause a tissue's mechanical behavior to be heterogeneous. Advances in imaging technology allow for accurate full-field displacement tracking of both in vitro and in vivo deformation from an applied load. While detailed strain fields provide some insight into tissue behavior, material properties are usually determined by fitting stress-strain behavior with a constitutive equation. However, the determination of the mechanical behavior of heterogeneous soft tissue requires a spatially varying constitutive equation (i.e., one in which the material parameters vary with position). We present an approach that computationally dissects the sample domain into many homogeneous subdomains, wherein subdomain boundaries are formed by applying a betweenness based graphical analysis to the deformation gradient field to identify locations with large discontinuities. This novel partitioning technique successfully determined the shape, size and location of regions with locally similar material properties for: (1) a series of simulated soft tissue samples prescribed with both abrupt and gradual changes in anisotropy strength, prescribed fiber alignment, stiffness, and nonlinearity, (2) tissue analogs (PDMS and collagen gels) which were tested biaxially and speckle tracked (3) and soft tissues which exhibited a natural variation in properties (cadaveric supraspinatus tendon), a pathologic variation in properties (thoracic aorta containing transmural plaque), and active behavior (contracting cardiac sheet). The routine enables the dissection of samples computationally rather than physically, allowing for the study of small tissues specimens with unknown and irregular inhomogeneity.
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Affiliation(s)
- Colleen M. Witzenburg
- University of Minnesota, Minneapolis, MN 55455 USA and is now with the University of Virginia, Charlottesville, VA 22908 USA
| | | | - Spencer P. Lake
- University of Minnesota, Minneapolis, MN 55455 USA as is now with Washington University, St. Louis, MO 63130 USA
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Yu X, Guo Y, Huang SM, Li ML, Lee WN. Beamforming effects on generalized Nakagami imaging. Phys Med Biol 2015; 60:7513-31. [DOI: 10.1088/0031-9155/60/19/7513] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Wang W, Hu D, Wang J, Zou W. Strain estimation by a Fourier Series-based extrema tracking algorithm for elastography. ULTRASONICS 2015; 62:278-291. [PMID: 26096883 DOI: 10.1016/j.ultras.2015.05.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 05/26/2015] [Accepted: 05/31/2015] [Indexed: 06/04/2023]
Abstract
In this paper, a new strain estimator using extrema tracking based on Fourier Series expansion (ETBFS) is proposed for ultrasonic elastography. In this method, the extremum is determined by solving an equation constructed by obtaining the first order derivative of the Fourier Series expansion and setting it to zero. Unlike other tracking algorithms, the ETBFS method can locate the extrema of radio frequency (RF) signals exactly between two adjacent sampling points and achieve a sub-sample accuracy without additional explicit interpolation. The correspondence between the located extrema in the pre- and post-compressed RF signal segments are constructed with a fine matching technique, with which the displacements and strains are estimated. Experimental results on a finite-element-modeling (FEM) simulation phantom show that the new proposed method can provide a more accurate displacement estimation than the standard cross-correlation (CC)-based method and the scale-invariant keypoints tracking (SIKT) algorithm. Moreover, performance analysis in terms of elastographic signal-to-noise ratio (SNRe), elastographic contrast-to-noise ratio (CNRe) and the real-versus-estimated strain error (RESE) also indicate that the dynamic range of the strain filter and its sensitivity can be improved with this new method.
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Affiliation(s)
- Wenxia Wang
- School of Electronic and Information Engineering, Soochow University, Suzhou 215006, PR China; College of Information Engineering, Henan University of Science and Technology, Luoyang 471023, PR China
| | - Danfeng Hu
- School of Electronic and Information Engineering, Soochow University, Suzhou 215006, PR China
| | - Jiajun Wang
- School of Electronic and Information Engineering, Soochow University, Suzhou 215006, PR China.
| | - Wei Zou
- School of Electronic and Information Engineering, Soochow University, Suzhou 215006, PR China
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Nahiyan A, Hasan MK. Hybrid algorithm for elastography to visualize both solid and fluid-filled lesions. ULTRASOUND IN MEDICINE & BIOLOGY 2015; 41:1058-1078. [PMID: 25701523 DOI: 10.1016/j.ultrasmedbio.2014.11.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 11/02/2014] [Accepted: 11/08/2014] [Indexed: 06/04/2023]
Abstract
We propose a novel strain estimation technique that can produce reliable strain images of both solid and fluid-filled lesions. In our method, a kernel-based correlation coefficient technique and a speckle tracking-based strain estimation technique are combined into a single algorithm. The elegance of our algorithm is that fluid-filled lesions are first automatically identified by three selection criteria, and strain in those parts is estimated using the kernel-based correlation coefficient technique. Strain where fluid-filled lesions have not been detected is estimated using a speckle tracking-based algorithm, and then these two estimates are merged to form the final image. Any speckle tracking algorithm can be used in our proposed technique; however, we used a modified version of the direct average spectral strain estimation technique to describe our algorithm. We modified the direct average spectral strain estimation algorithm to track smaller strain variation and to facilitate strain calculation from multiple frames. We describe the performance of our proposed hybrid algorithm using in vivo patient data. Both the solid and fluid-filled lesions are clearly visible in the strain images produced by our proposed approach and are of better quality in terms of contrast-to-noise ratio and border sharpness than the strain images generated by other reported techniques. We also validate the performance of our proposed multiframe technique using experimental phantom data and in vivo patient data. The results reveal that the quality of the strain image can be improved using the multiframe technique compared with its dual-frame counterpart.
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Affiliation(s)
- Adib Nahiyan
- Department of Electrical and Electronic Engineering, Bangladesh University of Engineering and Technology, Dhaka, Bangladesh
| | - Md Kamrul Hasan
- Department of Electrical and Electronic Engineering, Bangladesh University of Engineering and Technology, Dhaka, Bangladesh.
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Selvan S, Shenbagadevi S, Suresh S. Computer-Aided Diagnosis of Breast Elastography and B-Mode Ultrasound. ADVANCES IN INTELLIGENT SYSTEMS AND COMPUTING 2015. [DOI: 10.1007/978-81-322-2135-7_24] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Dominguez-Muñoz JE, Iglesias-Garcia J, Castiñeira Alvariño M, Luaces Regueira M, Lariño-Noia J. EUS elastography to predict pancreatic exocrine insufficiency in patients with chronic pancreatitis. Gastrointest Endosc 2015; 81:136-42. [PMID: 25088920 DOI: 10.1016/j.gie.2014.06.040] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 06/26/2014] [Indexed: 02/08/2023]
Abstract
BACKGROUND Diagnosis of pancreatic exocrine insufficiency (PEI) is hindered by methodological difficulties of pancreatic function tests. The probability of PEI in chronic pancreatitis (CP) increases as pancreatic fibrosis develops. Pancreatic fibrosis in CP may be quantified by EUS elastography. OBJECTIVE To evaluate whether EUS-elastography can predict PEI in patients with CP. DESIGN Prospective, observational study. SETTING Department of Gastroenterology, University Hospital of Santiago de Compostela, Spain. PATIENTS Patients diagnosed with CP based on EUS and magnetic resonance imaging and MRCP findings. INTERVENTIONS Diagnosis of PEI was based on the (13)C-mixed triglyceride breath test. EUS-elastography was performed with PENTAX echoendoscopes and Hitachi-Preirus US platform. Two areas were selected for elastographic evaluation: area A corresponds to the pancreatic parenchyma and area B to a soft peripancreatic reference area. The quotient B/A (strain ratio [SR]) was considered the elastographic result. MAIN OUTCOME MEASUREMENTS Pancreatic SR in CP patients with and without PEI. RESULTS A total of 115 patients with CP (mean age, 50.2 years, range, 21-81; 92 male) of different etiologies were included; 35 patients (30.4%) had PEI. Pancreatic SR was higher in patients with PEI (4.89; 95% confidence interval, 4.36-5.41) than in those with a normal breath test result (2.99; 95% confidence interval, 2.82-3.16) (P < .001). A direct relationship was found between the SR and the probability of PEI, which increases from 4.2% in patients with an SR less than 2.5 to 92.8% in those with an SR greater than >5.5. LIMITATIONS Single-center study. CONCLUSIONS The degree of pancreatic fibrosis as measured by EUS-guided elastography allows quantification of the probability of PEI in patients with CP.
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Affiliation(s)
- J Enrique Dominguez-Muñoz
- Department of Gastroenterology and Hepatology, University Hospital of Santiago de Compostela, Santiago de Compostela, Spain; Foundation for Research in Digestive Diseases (FIENAD), University Hospital of Santiago de Compostela, Santiago de Compostela, Spain
| | - Julio Iglesias-Garcia
- Department of Gastroenterology and Hepatology, University Hospital of Santiago de Compostela, Santiago de Compostela, Spain; Foundation for Research in Digestive Diseases (FIENAD), University Hospital of Santiago de Compostela, Santiago de Compostela, Spain
| | - Margarita Castiñeira Alvariño
- Foundation for Research in Digestive Diseases (FIENAD), University Hospital of Santiago de Compostela, Santiago de Compostela, Spain
| | - Maria Luaces Regueira
- Foundation for Research in Digestive Diseases (FIENAD), University Hospital of Santiago de Compostela, Santiago de Compostela, Spain
| | - Jose Lariño-Noia
- Department of Gastroenterology and Hepatology, University Hospital of Santiago de Compostela, Santiago de Compostela, Spain; Foundation for Research in Digestive Diseases (FIENAD), University Hospital of Santiago de Compostela, Santiago de Compostela, Spain
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Leineweber MJ, Westborn J, Cochran A, Choi J, Gao Y. Averaging improves strain images of the biceps brachii using quasi-static ultrasound elastography. Br J Radiol 2014; 87:20130624. [PMID: 24758309 DOI: 10.1259/bjr.20130624] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE Quasi-static ultrasound elastography is a technique for measuring tissue deformation (strain) under externally applied loading and can be used to identify the presence of abnormalities. The objective of this study was to demonstrate the efficacy of averaging strain images from repeated compression cycles in mitigating user-induced error using quasi-static ultrasound elastography. METHODS Freehand compressions were performed with an ultrasound transducer on the biceps brachii of nine participants (five males and four females), as well as with a custom automated compression system. Sets of strain images from the freehand techniques were averaged to create single representative images and compared against strain images from the automated compressions using both qualitative and quantitative metrics. RESULTS Significant improvements in intra-operator repeatability and interoperator reproducibility can be achieved by averaging strain images from four to eight repeated compressions. The resulting strain images did not lose significant image data compared with strain images from single automated compressions. CONCLUSION Averaging is introduced as a feasible and appropriate technique to improve strain image quality without sacrificing important image data. ADVANCES IN KNOWLEDGE Simple averaging of multiple freehand elastography measures can achieve a similar degree of accuracy, repeatability and reproducibility as that of more awkward and expensive automated methods. The resulting elastograms can be used to obtain a more accurate and complete diagnosis without additional cost to the doctor or the patient.
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Affiliation(s)
- M J Leineweber
- 1 Mechanical and Aerospace Engineering Department, Cornell University, Ithaca, NY, USA
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Kashif AS, Lotz TF, McGarry MD, Pattison AJ, Chase JG. Silicone breast phantoms for elastographic imaging evaluation. Med Phys 2014; 40:063503. [PMID: 23718614 DOI: 10.1118/1.4805096] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Breast cancer is a major public health issue for women, and early detection significantly increases survival rate. Currently, there is increased research interest in elastographic soft-tissue imaging techniques based on the correlation between pathology and mechanical stiffness. Anthropomorphic breast phantoms are critical for ex vivo validation of emerging elastographic technologies. This research develops heterogeneous breast phantoms for use in testing elastographic imaging modalities. METHODS Mechanical property estimation of eight different elastomers is performed to determine storage moduli (E') and damping ratios (ζ) using a dynamic mechanical analyzer. Dynamic compression testing was carried out isothermally at room temperature over a range of 4-50 Hz. Silicone compositions with physiologically realistic storage modulus were chosen for mimicking skin adipose, cancerous tumors, and pectoral muscles and 13 anthropomorphic breast phantoms were constructed for ex vivo trials of digital image elastotomography (DIET) breast cancer screening system. A simpler fabrication was used to assess the possibility of multiple tumor detection using magnetic resonance elastography (MRE). RESULTS Silicone materials with ranges of storage moduli (E') from 2 to 570 kPa and damping ratios (ζ) from 0.03 to 0.56 were identified. The resulting phantoms were tested in two different elastographic breast cancer diagnostic modalities. A significant contrast was successfully identified between healthy tissues and cancerous tumors both in MRE and DIET. CONCLUSIONS The phantoms presented promise aid to researchers in elastographic imaging modalities for breast cancer detection and provide a foundation for silicone based phantom materials for mimicking soft tissues of other human organs.
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Affiliation(s)
- Amer S Kashif
- Centre for Bioengineering, Department of Mechanical Engineering, University of Canterbury, Christchurch 8041, New Zealand
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Obst SJ, Newsham-West R, Barrett RS. In vivo measurement of human achilles tendon morphology using freehand 3-D ultrasound. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:62-70. [PMID: 24139914 DOI: 10.1016/j.ultrasmedbio.2013.08.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 07/17/2013] [Accepted: 08/12/2013] [Indexed: 06/02/2023]
Abstract
This study investigated the accuracy of phantom volume and length measurements and the reliability of in vivo Achilles tendon (AT) volume, length and cross-sectional area measurements obtained using freehand 3-D ultrasound. Participants (n = 13) were scanned on consecutive days under active and passive loading conditions. In vivo AT length was evaluated using a two-point method and an approach that accounted for AT curvature (centroid method). Three-dimensional ultrasound provided accurate measures of phantom volume and length (mean difference = 0.05 mL and 0.2 mm, respectively) and reliable in vivo measures of AT volume, length and average cross-sectional area, with all intra-class correlations coefficients greater than 0.98. The mean minimally detectable changes for in vivo AT volume, two-point length and centroid length were 0.2 mL, 1.5 mm and 2.0 mm, respectively. Two-point AT length underestimated centroid AT length by 0.7 mm, suggesting that the effect of curvature on in vivo AT length is negligible.
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Affiliation(s)
- Steven J Obst
- School of Rehabilitation Sciences and Centre for Musculoskeletal Research, Griffith Health Institute, Griffith University, Southport, Queensland, Australia.
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41
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Albocher U, Barbone P, Richards M, Oberai A, Harari I. Approaches to accommodate noisy data in the direct solution of inverse problems in incompressible plane-strain elasticity. INVERSE PROBLEMS IN SCIENCE AND ENGINEERING 2014; 22:1307-1328. [PMID: 25383085 PMCID: PMC4222193 DOI: 10.1080/17415977.2013.872100] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We apply the adjoint weighted equation method (AWE) to the direct solution of inverse problems of incompressible plane strain elasticity. We show that based on untreated noisy displacements, the reconstruction of the shear modulus can be very poor. We link this poor performance to loss of coercivity of the weak form when treating problems with discontinuous coefficients. We demonstrate that by smoothing the displacements and appending a regularization term to the AWE formulation, a dramatic improvement in the reconstruction can be achieved. With these improvements, the advantages of the AWE method as a direct solution approach can be extended to a wider range of problems.
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Affiliation(s)
- U. Albocher
- Faculty of Engineering, Tel Aviv University, 69978 Ramat Aviv, Israel
| | - P.E. Barbone
- Department of Mechanical Engineering, Boston University, Boston, MA 02215, USA
| | - M.S. Richards
- Department of Surgery, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA
| | - A.A. Oberai
- Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - I. Harari
- Faculty of Engineering, Tel Aviv University, 69978 Ramat Aviv, Israel
- Corresponding author.
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Hussain MA, Alam F, Rupa SA, Awwal R, Lee SY, Hasan MK. Lesion edge preserved direct average strain estimation for ultrasound elasticity imaging. ULTRASONICS 2014; 54:137-146. [PMID: 23806339 DOI: 10.1016/j.ultras.2013.05.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2012] [Revised: 05/09/2013] [Accepted: 05/20/2013] [Indexed: 06/02/2023]
Abstract
Elasticity imaging techniques with built-in or regularization-based smoothing feature for ensuring strain continuity are not intelligent enough to prevent distortion or lesion edge blurring while smoothing. This paper proposes a novel approach with built-in lesion edge preservation technique for high quality direct average strain imaging. An edge detection scheme, typically used in diffusion filtering is modified here for lesion edge detection. Based on the extracted edge information, lesion edges are preserved by modifying the strain determining cost function in the direct-average-strain-estimation (DASE) method. The proposed algorithm demonstrates approximately 3.42-4.25 dB improvement in terms of edge-mean-square-error (EMSE) than the other reported regularized or average strain estimation techniques in finite-element-modeling (FEM) simulation with almost no sacrifice in elastographic-signal-to-noise-ratio (SNRe) and elastographic-contrast-to-noise-ratio (CNRe) metrics. The efficacy of the proposed algorithm is also tested for the experimental phantom data and in vivo breast data. The results reveal that the proposed method can generate a high quality strain image delineating the lesion edge more clearly than the other reported strain estimation techniques that have been designed to ensure strain continuity. The computational cost, however, is little higher for the proposed method than the simpler DASE and considerably higher than that of the 2D analytic minimization (AM2D) method.
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Affiliation(s)
- Mohammad Arafat Hussain
- Department of Electrical and Electronic Engineering, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh
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Song S, Huang Z, Nguyen TM, Wong EY, Arnal B, O’Donnell M, Wang RK. Shear modulus imaging by direct visualization of propagating shear waves with phase-sensitive optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2013; 18:121509. [PMID: 24213539 PMCID: PMC4019419 DOI: 10.1117/1.jbo.18.12.121509] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 10/17/2013] [Indexed: 05/12/2023]
Abstract
We propose an integrated method combining low-frequency mechanics with optical imaging to map the shear modulus within the biological tissue. Induced shear wave propagating in tissue is tracked in space and time using phase-sensitive optical coherence tomography (PhS-OCT). Local estimates of the shear-wave speed obtained from tracking results can image the local shear modulus. A PhS-OCT system remotely records depth-resolved, dynamic mechanical waves at an equivalent frame rate of ∼47 kHz with the high spatial resolution. The proposed method was validated by examining tissue-mimicking phantoms made of agar and light scattering material. Results demonstrate that the shear wave imaging can accurately map the elastic moduli of these phantoms.
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Affiliation(s)
- Shaozhen Song
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195
- University of Dundee, School of Engineering, Physics and Mathematics, Dundee DD1 4HN, Scotland, UK
| | - Zhihong Huang
- University of Dundee, School of Engineering, Physics and Mathematics, Dundee DD1 4HN, Scotland, UK
| | - Thu-Mai Nguyen
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195
| | - Emily Y. Wong
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195
| | - Bastien Arnal
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195
| | - Matthew O’Donnell
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195
| | - Ruikang K. Wang
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195
- University of Washington, Department of Ophthalmology, 325 9th Avenue, Seattle, Washington 98104
- Address all correspondence to: Ruikang K. Wang, University of Washington, Department of Bioengineering, 3720 15th Avenue NE, Seattle, Washington 98195. Tel: 206 6165025; Fax: 206-685-3300; E-mail:
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Dutta D, Mahmoud AM, Leers SA, Kim K. Motion Artifact Reduction in Ultrasound Based Thermal Strain Imaging of Atherosclerotic Plaques Using Time Series Analysis. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2013; 60:1660-1668. [PMID: 24808628 PMCID: PMC4010158 DOI: 10.1109/tuffc.2013.2748] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Large lipid pools in vulnerable plaques, in principle, can be detected using US based thermal strain imaging (US-TSI). One practical challenge for in vivo cardiovascular application of US-TSI is that the thermal strain is masked by the mechanical strain caused by cardiac pulsation. ECG gating is a widely adopted method for cardiac motion compensation, but it is often susceptible to electrical and physiological noise. In this paper, we present an alternative time series analysis approach to separate thermal strain from the mechanical strain without using ECG. The performance and feasibility of the time-series analysis technique was tested via numerical simulation as well as in vitro water tank experiments using a vessel mimicking phantom and an excised human atherosclerotic artery where the cardiac pulsation is simulated by a pulsatile pump.
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Affiliation(s)
- Debaditya Dutta
- Center for Ultrasound Molecular Imaging and Therapeutics – Department of Medicine, University of Pittsburgh and UPMC, Pittsburgh, PA, USA
- Heart and Vascular Institute, University of Pittsburgh and UPMC, Pittsburgh, PA, USA
| | - Ahmed M. Mahmoud
- Center for Ultrasound Molecular Imaging and Therapeutics – Department of Medicine, University of Pittsburgh and UPMC, Pittsburgh, PA, USA
- Heart and Vascular Institute, University of Pittsburgh and UPMC, Pittsburgh, PA, USA
- Department of Biomedical Engineering and Systems, Cairo University, Giza, Egypt
| | - Steven A. Leers
- Heart and Vascular Institute, University of Pittsburgh and UPMC, Pittsburgh, PA, USA
| | - Kang Kim
- Center for Ultrasound Molecular Imaging and Therapeutics – Department of Medicine, University of Pittsburgh and UPMC, Pittsburgh, PA, USA
- Heart and Vascular Institute, University of Pittsburgh and UPMC, Pittsburgh, PA, USA
- Department of Bioengineering, University of Pittsburgh and UPMC, Pittsburgh, PA, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh and UPMC, Pittsburgh, PA, USA
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Fuzzy-based classification of breast lesions using ultrasound echography and elastography. Ultrasound Q 2013; 28:159-67. [PMID: 22902839 DOI: 10.1097/ruq.0b013e318262594a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Common breast lesions have different elasticity properties. Segmentation of contours of breast lesions from elastography and B mode images by incorporating variational level set method is involved in the proposed work. After segmentation, strain and shape features, such as differences in area, perimeter, and contour and width to height difference and solidity, as well as texture features like contrast, entropy, standard deviation, dissimilarity, homogeneity and energy, are estimated. A nonlinear fuzzy inference system is applied for classifying the breast lesions as benign cyst, benign solid mass, or malignant solid mass. Detection of malignant solid masses is our primary objective. A classification accuracy of 83% is obtained. One hundred percent sensitivity is reported. It can be concluded that the proposed fuzzy-based classification technique can be used as an aid for the automated detection of breast lesions.
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Ishihara S, Sugimura K, Cox SJ, Bonnet I, Bellaïche Y, Graner F. Comparative study of non-invasive force and stress inference methods in tissue. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2013; 36:9859. [PMID: 23615875 DOI: 10.1140/epje/i2013-13045-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 02/01/2013] [Accepted: 03/19/2013] [Indexed: 06/02/2023]
Abstract
In the course of animal development, the shape of tissue emerges in part from mechanical and biochemical interactions between cells. Measuring stress in tissue is essential for studying morphogenesis and its physical constraints. For that purpose, a possible new approach is force inference (up to a single prefactor) from cell shapes and connectivity. It is non-invasive and can provide space-time maps of stress in a whole tissue, unlike existing methods. To validate this approach, three force-inference methods, which differ in their approach of treating indefiniteness in an inverse problem between cell shapes and forces, were compared. Tests using two artificial and two experimental data sets consistently indicate that our Bayesian force inference, by which cell-junction tensions and cell pressures are simultaneously estimated, performs best in terms of accuracy and robustness. Moreover, by measuring the stress anisotropy and relaxation, we cross-validated the force inference and the global annular ablation of tissue, each of which relies on different prefactors. A practical choice of force-inference methods in different systems of interest is discussed.
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Affiliation(s)
- S Ishihara
- Graduate School of Arts and Sciences, The University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo, Japan.
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Duenwald-Kuehl S, Kobayashi H, Lakes R, Vanderby R. Time-dependent ultrasound echo changes occur in tendon during viscoelastic testing. J Biomech Eng 2013; 134:111006. [PMID: 23387788 DOI: 10.1115/1.4007745] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The viscoelastic behavior of tendons has been extensively studied in vitro. A noninvasive method by which to acquire mechanical data would be highly beneficial, as it could lead to the collection of viscoelastic data in vivo. Our lab has previously presented acoustoelasticity as an alternative ultrasound-based method of measuring tendon stress and strain by reporting a relationship between ultrasonic echo intensity (B mode ultrasound image brightness) and mechanical behavior of tendon under pseudoelastic in vitro conditions [Duenwald, S., Kobayashi, H., Frisch, K., Lakes, R., and Vanderby Jr, R., 2011, "Ultrasound Echo is Related to Stress and Strain in Tendon," J. Biomech., 44(3), pp. 424-429]. Viscoelastic properties of the tendons were not examined in that study, so the presence of time-dependent echo intensity changes has not been verified. In this study, porcine flexor tendons were subjected to relaxation and cyclic testing while ultrasonic echo response was recorded. We report that time- and strain history-dependent mechanical properties during viscoelastic testing are manifested in ultrasonic echo intensity changes. We also report that the patterns of the echo intensity changes do not directly mimic the patterns of viscoelastic load changes, but the intensity changed in a repeatable (and therefore predictable) fashion. Although mechanisms need further elucidation, viscoelastic behavior can be anticipated from echo intensity changes. This phenomenon could potentially lead to a more extensive characterization of in vivo tissue behavior.
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Affiliation(s)
- Sarah Duenwald-Kuehl
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI 53706, USA
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Wang S, Larin KV, Li J, Vantipalli S, Manapuram RK, Aglyamov S, Emelianov S, Twa MD. A focused air-pulse system for optical-coherence-tomography-based measurements of tissue elasticity. LASER PHYSICS LETTERS 2013; 10:075605. [PMID: 29805349 PMCID: PMC5969524 DOI: 10.1088/1612-2011/10/7/075605] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Accurate non-invasive assessment of tissue elasticity in vivo is required for early diagnostics of many tissue abnormalities. We have developed a focused air-pulse system that produces a low-pressure and short-duration air stream, which can be used to excite transient surface waves (SWs) in soft tissues. System characteristics were studied using a high-resolution analog pressure transducer to describe the excitation pressure. Results indicate that the excitation pressure provided by the air-pulse system can be easily controlled by the air source pressure, the angle of delivery, and the distance between the tissue surface and the port of the air-pulse system. Furthermore, we integrated this focused air-pulse system with phase-sensitive optical coherence tomography (PhS-OCT) to make non-contact measurements of tissue elasticity. The PhS-OCT system is used to assess the group velocity of SW propagation, which can be used to determine Young's modulus. Pilot experiments were performed on gelatin phantoms with different concentrations (10%, 12% and 14% w/w). The results demonstrate the feasibility of using this focused air-pulse system combined with PhS-OCT to estimate tissue elasticity. This easily controlled non-contact technique is potentially useful to study the biomechanical properties of ocular and other tissues in vivo.
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Affiliation(s)
- Shang Wang
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, TX 77204, USA
| | - K V Larin
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, TX 77204, USA
- Department of Mechanical Engineering, University of Houston, N207 Engineering Building 1, Houston, TX 77204, USA
- Institute of Optics and Biophotonics, Saratov State University, Saratov 410012, Russia
| | - Jiasong Li
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, TX 77204, USA
| | - S Vantipalli
- College of Optometry, University of Houston, 505 J Davis Armistead Building, TX 77204, USA
| | - R K Manapuram
- Department of Mechanical Engineering, University of Houston, N207 Engineering Building 1, Houston, TX 77204, USA
| | - S Aglyamov
- Department of Biomedical Engineering, The University of Texas at Austin, 107 W Dean Keeton Street, Austin, TX 78712, USA
| | - S Emelianov
- Department of Biomedical Engineering, The University of Texas at Austin, 107 W Dean Keeton Street, Austin, TX 78712, USA
| | - M D Twa
- College of Optometry, University of Houston, 505 J Davis Armistead Building, TX 77204, USA
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Cardoso FM, Moraes MC, Furuie SS. Realistic IVUS image generation in different intraluminal pressures. ULTRASOUND IN MEDICINE & BIOLOGY 2012; 38:2104-2119. [PMID: 23062368 DOI: 10.1016/j.ultrasmedbio.2012.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 08/01/2012] [Accepted: 08/10/2012] [Indexed: 06/01/2023]
Abstract
Intravascular ultrasound (IVUS) phantoms are important to calibrate and evaluate many IVUS imaging processing tasks. However, phantom generation is never the primary focus of related works; hence, it cannot be well covered, and is usually based on more than one platform, which may not be accessible to investigators. Therefore, we present a framework for creating representative IVUS phantoms, for different intraluminal pressures, based on the finite element method and Field II. First, a coronary cross-section model is selected. Second, the coronary regions are identified to apply the properties. Third, the corresponding mesh is generated. Fourth, the intraluminal force is applied and the deformation computed. Finally, the speckle noise is incorporated. The framework was tested taking into account IVUS contrast, noise and strains. The outcomes are in line with related studies and expected values. Moreover, the framework toolbox is freely accessible and fully implemented in a single platform.
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Affiliation(s)
- Fernando Mitsuyama Cardoso
- Biomedical Engineering Laboratory, Department of Telecommunication and Control Engineering, School of Engineering, University of Sao Paulo, Sao Paulo, Brazil.
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Azar RZ, Dickie K, Pelissier L. Real-time 1-D/2-D transient elastography on a standard ultrasound scanner using mechanically induced vibration. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2012; 59:2167-2177. [PMID: 23143567 DOI: 10.1109/tuffc.2012.2443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Transient elastography has been well established in the literature as a means of assessing the elasticity of soft tissue. In this technique, tissue elasticity is estimated from the study of the propagation of the transient shear waves induced by an external or internal source of vibration. Previous studies have focused mainly on custom single-element transducers and ultrafast scanners which are not available in a typical clinical setup. In this work, we report the design and implementation of a transient elastography system on a standard ultrasound scanner that enables quantitative assessment of tissue elasticity in real-time. Two new custom imaging modes are introduced that enable the system to image the axial component of the transient shear wave, in response to an externally induced vibration, in both 1-D and 2-D. Elasticity reconstruction algorithms that estimate the tissue elasticity from these transient waves are also presented. Simulation results are provided to show the advantages and limitations of the proposed system. The performance of the system is also validated experimentally using a commercial elasticity phantom.
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Affiliation(s)
- Reza Zahiri Azar
- Department of Research and Development, Ultrasonix Medical Corporation, Richmond, BC, Canada.
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