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Dimmock R, Zhang Y, Butt GF, Rauz S, Huang Z, Yang Y. Characterizing Biomechanics of Limbal Niche Using Vibrational Optical Coherence Elastography. JOURNAL OF BIOPHOTONICS 2024:e202400172. [PMID: 39340174 DOI: 10.1002/jbio.202400172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2024] [Revised: 08/05/2024] [Accepted: 08/22/2024] [Indexed: 09/30/2024]
Abstract
The limbal niche is an adult source of epithelial stem cells which regenerate the cornea epithelium. The architecture and biomechanical properties of the limbus have previously been demonstrated to change due to aging and disease. This study aims to non-destructively and simultaneously quantify these limbal niche properties, along with their age-related changes. A lab-built vibrational optical coherence elastography (OCE) device consisting of a phase-sensitive optical coherence tomography (OCT) with a vibrational stimulator has been used to collect structural images and the depth-resolved elasticity of human corneoscleral tissues (aged 4-96 years old). The limbal palisades of Vogt (POV) were delineated well in OCT images which were validated by histology. The POVs have been spatially mapped with simultaneous elasticity measurements in cross-sections, showing tissue stiffness distributions across the undulations. A significant influence of age on the dimensions of the POVs was explored. The elastic modulus within the limbal niches for the ≥65-year-old group was significantly higher than that of the <65-year-old group.
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Affiliation(s)
- Ryan Dimmock
- School of Pharmacy and Bioengineering, Keele University, Stoke-on-Trent, UK
| | - Yilong Zhang
- School of Science and Engineering, University of Dundee, Dundee, UK
| | - Gibran F Butt
- Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
| | - Saaeha Rauz
- Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
| | - Zhihong Huang
- School of Science and Engineering, University of Dundee, Dundee, UK
| | - Ying Yang
- School of Pharmacy and Bioengineering, Keele University, Stoke-on-Trent, UK
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2
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Luo J, Zhang Y, Ai S, Shi G, Han X, Wang Y, Zhao Y, Yang H, Li Y, He X. Two-dimensional elastic distribution imaging of the sclera using acoustic radiation force optical coherence elastography. JOURNAL OF BIOPHOTONICS 2024; 17:e202300368. [PMID: 38010344 DOI: 10.1002/jbio.202300368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/23/2023] [Accepted: 11/15/2023] [Indexed: 11/29/2023]
Abstract
The scleral elasticity is closely related with many ocular diseases, but the relevant research is still insufficient. Here, we utilized optical coherence elastography to carefully study biomechanical properties of the sclera at different positions and under different intraocular pressures. Meanwhile, elastic wave velocity and Young's modulus of each position were obtained using a phase velocity algorithm. Accordingly, the two-dimensional elasticity distribution image was achieved by mapping the Young's modulus values to the corresponding structure based on the relationship between the position and its Young's modulus. Therefore, elastic information in regions-of-interest can be read and compared directly from the scleral structure, indicating that our method may be a very useful tool to evaluate the elasticity of sclera and provide intuitive and reliable proof for diagnosis and research.
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Affiliation(s)
- Jiahui Luo
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, PR China
| | - Yubao Zhang
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, PR China
| | - Sizhu Ai
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, PR China
| | - Gang Shi
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, PR China
| | - Xiao Han
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, PR China
| | - Yidi Wang
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, PR China
| | - Yanzhi Zhao
- Eye Center, Second Affiliated Hospital of Nanchang University, Nanchang, PR China
| | - Hongwei Yang
- Eye Center, Second Affiliated Hospital of Nanchang University, Nanchang, PR China
| | - Yingjie Li
- Department of Ophthalmology, Nanchang First Hospital, Nanchang, PR China
| | - Xingdao He
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, PR China
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3
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Petrescu A, Voigt JU. [Echocardiography with high frame rates in the clinical practice : Principles, applications and perspectives]. Herz 2023; 48:339-351. [PMID: 37530782 DOI: 10.1007/s00059-023-05199-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/16/2023] [Indexed: 08/03/2023]
Abstract
Continuous developments in cardiovascular imaging, software and hardware have led to technological advancements that open new ways for assessing myocardial mechanics, hemodynamics, and function. Through new scan modalities, echocardiographic scanners can nowadays achieve very high frame rates up to 5000 frames s-1 which enables a wide variety of new applications, including shear wave elastography, ultrafast speckle tracking, the visualization of intracardiac blood flow and myocardial perfusion imaging. This review provides an overview of these advances and demonstrates possible applications and their potential added value in the clinical practice.
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Affiliation(s)
- Aniela Petrescu
- Abteilung für Kardiologie, Universitätsmedizin Mainz, Mainz, Deutschland
| | - Jens-Uwe Voigt
- Department of Cardiology, University Hospital Leuven, University of Leuven, Herestraat 49, 3000, Leuven, Belgien.
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Regnault G, Kirby MA, Wang RK, Shen TT, O’Donnell M, Pelivanov I. Possible depth-resolved reconstruction of shear moduli in the cornea following collagen crosslinking (CXL) with optical coherence tomography and elastography. BIOMEDICAL OPTICS EXPRESS 2023; 14:5005-5021. [PMID: 37791258 PMCID: PMC10545180 DOI: 10.1364/boe.497970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/10/2023] [Accepted: 08/16/2023] [Indexed: 10/05/2023]
Abstract
Corneal collagen crosslinking (CXL) is commonly used to prevent or treat keratoconus. Although changes in corneal stiffness induced by CXL surgery can be monitored with non-contact dynamic optical coherence elastography (OCE) by tracking mechanical wave propagation, depth dependent changes are still unclear if the cornea is not crosslinked through the whole depth. Here, phase-decorrelation measurements on optical coherence tomography (OCT) structural images are combined with acoustic micro-tapping (AµT) OCE to explore possible reconstruction of depth-dependent stiffness within crosslinked corneas in an ex vivo human cornea sample. Experimental OCT images are analyzed to define the penetration depth of CXL into the cornea. In a representative ex vivo human cornea sample, crosslinking depth varied from ∼100 µm in the periphery to ∼150 µm in the cornea center and exhibited a sharp in-depth transition between crosslinked and untreated areas. This information was used in an analytical two-layer guided wave propagation model to quantify the stiffness of the treated layer. We also discuss how the elastic moduli of partially CXL-treated cornea layers reflect the effective engineering stiffness of the entire cornea to properly quantify corneal deformation.
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Affiliation(s)
- Gabriel Regnault
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Mitchell A. Kirby
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Department of Ophthalmology, University of Washington, Seattle, WA, USA
| | - Tueng T. Shen
- Department of Ophthalmology, University of Washington, Seattle, WA, USA
- School of Medicine, University of Washington, Seattle, WA, USA
| | - Matthew O’Donnell
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Ivan Pelivanov
- Department of Bioengineering, University of Washington, Seattle, WA, USA
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5
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Regnault G, Kirby MA, Wang RK, Shen TT, O’Donnell M, Pelivanov I. Possible depth-resolved reconstruction of shear moduli in the cornea following collagen crosslinking (CXL) with optical coherence tomography and elastography. ARXIV 2023:arXiv:2306.15018v1. [PMID: 37426451 PMCID: PMC10327230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Corneal collagen crosslinking (CXL) is commonly used to prevent or treat keratoconus. Although changes in corneal stiffness induced by CXL surgery can be monitored with non-contact dynamic optical coherence elastography (OCE) by tracking mechanical wave propagation, depth dependent changes are still unclear if the cornea is not crosslinked through the whole depth. Here, phase-decorrelation measurements on optical coherence tomography (OCT) structural images are combined with acoustic micro-tapping (A$\mu$T) OCE to explore possible reconstruction of depth-dependent stiffness within crosslinked corneas in an ex vivo human cornea sample. Experimental OCT images are analyzed to define the penetration depth of CXL into the cornea. In a representative ex vivo human cornea sample, crosslinking depth varied from $\sim 100\mu m$ in the periphery to $\sim 150\mu m$ in the cornea center and exhibited a sharp in-depth transition between crosslinked and untreated areas. This information was used in an analytical two-layer guided wave propagation model to quantify the stiffness of the treated layer. We also discuss how the elastic moduli of partially CXL-treated cornea layers reflect the effective engineering stiffness of the entire cornea to properly quantify corneal deformation.
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Affiliation(s)
- Gabriel Regnault
- Department of Bioengineering, University of Washington, Seattle, USA
| | - Mitchell A. Kirby
- Department of Bioengineering, University of Washington, Seattle, USA
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, USA
- Department of Ophthalmology, University of Washington, Seattle, USA
| | - Tueng T. Shen
- Department of Ophthalmology, University of Washington, Seattle, USA
- School of Medicine, University of Washington, Seattle, USA
| | - Matthew O’Donnell
- Department of Bioengineering, University of Washington, Seattle, USA
| | - Ivan Pelivanov
- Department of Bioengineering, University of Washington, Seattle, USA
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Ma G, Cai J, Zhong R, He W, Ye H, Duvvuri C, Song C, Feng J, An L, Qin J, Huang Y, Xu J, Twa MD, Lan G. Corneal Surface Wave Propagation Associated with Intraocular Pressures: OCT Elastography Assessment in a Simplified Eye Model. Bioengineering (Basel) 2023; 10:754. [PMID: 37508781 PMCID: PMC10376591 DOI: 10.3390/bioengineering10070754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 06/18/2023] [Accepted: 06/21/2023] [Indexed: 07/30/2023] Open
Abstract
Assessing corneal biomechanics in vivo has long been a challenge in the field of ophthalmology. Despite recent advances in optical coherence tomography (OCT)-based elastography (OCE) methods, controversy remains regarding the effect of intraocular pressure (IOP) on mechanical wave propagation speed in the cornea. This could be attributed to the complexity of corneal biomechanics and the difficulties associated with conducting in vivo corneal shear-wave OCE measurements. We constructed a simplified artificial eye model with a silicone cornea and controllable IOPs and performed surface wave OCE measurements in radial directions (54-324°) of the silicone cornea at different IOP levels (10-40 mmHg). The results demonstrated increases in wave propagation speeds (mean ± STD) from 6.55 ± 0.09 m/s (10 mmHg) to 9.82 ± 0.19 m/s (40 mmHg), leading to an estimate of Young's modulus, which increased from 145.23 ± 4.43 kPa to 326.44 ± 13.30 kPa. Our implementation of an artificial eye model highlighted that the impact of IOP on Young's modulus (ΔE = 165.59 kPa, IOP: 10-40 mmHg) was more significant than the effect of stretching of the silicone cornea (ΔE = 15.79 kPa, relative elongation: 0.98-6.49%). Our study sheds light on the potential advantages of using an artificial eye model to represent the response of the human cornea during OCE measurement and provides valuable insights into the impact of IOP on wave-based OCE measurement for future in vivo corneal biomechanics studies.
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Affiliation(s)
- Guoqin Ma
- School of Mechatronic Engineering and Automation, Foshan University, Foshan 528000, China
| | - Jing Cai
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China
| | - Rijian Zhong
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China
| | - Weichao He
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China
| | - Haoxi Ye
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China
| | | | - Chengjin Song
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China
| | - Jinping Feng
- Institute of Engineering and Technology, Hubei University of Science and Technology, Xianning 437100, China
| | - Lin An
- Weiren Meditech Co., Ltd., Foshan 528000, China
| | - Jia Qin
- Weiren Meditech Co., Ltd., Foshan 528000, China
| | - Yanping Huang
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China
- Weiren Meditech Co., Ltd., Foshan 528000, China
| | - Jingjiang Xu
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China
- Weiren Meditech Co., Ltd., Foshan 528000, China
| | - Michael D. Twa
- College of Optometry, University of Houston, Houston, TX 77204, USA
| | - Gongpu Lan
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan 528000, China
- Weiren Meditech Co., Ltd., Foshan 528000, China
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Lan G, Twa MD, Song C, Feng J, Huang Y, Xu J, Qin J, An L, Wei X. In vivo corneal elastography: A topical review of challenges and opportunities. Comput Struct Biotechnol J 2023; 21:2664-2687. [PMID: 37181662 PMCID: PMC10173410 DOI: 10.1016/j.csbj.2023.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 04/07/2023] [Accepted: 04/12/2023] [Indexed: 05/16/2023] Open
Abstract
Clinical measurement of corneal biomechanics can aid in the early diagnosis, progression tracking, and treatment evaluation of ocular diseases. Over the past two decades, interdisciplinary collaborations between investigators in optical engineering, analytical biomechanical modeling, and clinical research has expanded our knowledge of corneal biomechanics. These advances have led to innovations in testing methods (ex vivo, and recently, in vivo) across multiple spatial and strain scales. However, in vivo measurement of corneal biomechanics remains a long-standing challenge and is currently an active area of research. Here, we review the existing and emerging approaches for in vivo corneal biomechanics evaluation, which include corneal applanation methods, such as ocular response analyzer (ORA) and corneal visualization Scheimpflug technology (Corvis ST), Brillouin microscopy, and elastography methods, and the emerging field of optical coherence elastography (OCE). We describe the fundamental concepts, analytical methods, and current clinical status for each of these methods. Finally, we discuss open questions for the current state of in vivo biomechanics assessment techniques and requirements for wider use that will further broaden our understanding of corneal biomechanics for the detection and management of ocular diseases, and improve the safety and efficacy of future clinical practice.
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Affiliation(s)
- Gongpu Lan
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, Guangdong 528000, China
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Michael D. Twa
- College of Optometry, University of Houston, Houston, TX 77204, United States
| | - Chengjin Song
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, Guangdong 528000, China
| | - JinPing Feng
- Institute of Engineering and Technology, Hubei University of Science and Technology, Xianning, Hubei 437100, China
| | - Yanping Huang
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, Guangdong 528000, China
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Jingjiang Xu
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, School of Physics and Optoelectronic Engineering, Foshan University, Foshan, Guangdong 528000, China
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Jia Qin
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Lin An
- Weiren Meditech Co., Ltd., Foshan, Guangdong 528000, China
| | - Xunbin Wei
- Biomedical Engineering Department, Peking University, Beijing 100081, China
- International Cancer Institute, Peking University, Beijing 100191, China
- Institute of Medical Technology, Peking University Health Science Center, Beijing 100191, China
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Kirby MA, Regnault G, Pelivanov I, O'Donnell M, Wang RK, Shen TT. Noncontact Acoustic Micro-Tapping Optical Coherence Elastography for Quantification of Corneal Anisotropic Elasticity: In Vivo Rabbit Study. Transl Vis Sci Technol 2023; 12:15. [PMID: 36930138 PMCID: PMC10036949 DOI: 10.1167/tvst.12.3.15] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 01/29/2023] [Indexed: 03/18/2023] Open
Abstract
Purpose The purpose of this study was to demonstrate accurate measurement of corneal elastic moduli in vivo with noncontact and noninvasive optical coherence elastography. Methods Elastic properties (in-plane Young's modulus, E, and both in-plane, μ, and out-of-plane, G, shear moduli) of rabbit cornea were quantified in vivo using noncontact dynamic acoustic micro-tapping optical coherence elastography (AµT-OCE). The intraocular pressure (IOP)-dependence of measured mechanical properties was explored in extracted whole globes following in vivo measurement. A nearly incompressible transverse isotropic (NITI) model was used to reconstruct moduli from AµT-OCE data. Independently, cornea elastic moduli were also measured ex vivo with traditional, destructive mechanical tests (tensile extensometry and shear rheometry). Results Our study demonstrates strong anisotropy of corneal elasticity in rabbits. The in-plane Young's modulus, computed as E = 3μ, was in the range of 20 MPa to 44 MPa, whereas the out-of-plane shear modulus was in the range of 34 kPa to 261 kPa. Both pressure-dependent ex vivo OCE and destructive mechanical tests performed on the same samples within an hour of euthanasia strongly support the results of AµT-OCE measurements. Conclusions Noncontact AµT-OCE can noninvasively quantify cornea anisotropic elastic properties in vivo. Translational Relevance As optical coherence tomography (OCT) is broadly accepted in ophthalmology, these results suggest the potential for rapid translation of AµT-OCE into clinical practice. In addition, AµT-OCE can likely improve diagnostic criteria of ectatic corneal diseases, leading to early diagnosis, reduced complications, customized surgical treatment, and personalized biomechanical models of the eye.
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Affiliation(s)
- Mitchell A. Kirby
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Gabriel Regnault
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Ivan Pelivanov
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Matthew O'Donnell
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Department of Ophthalmology, University of Washington, Seattle, WA, USA
| | - Tueng T. Shen
- School of Medicine, University of Washington, Seattle, WA, USA
- Department of Ophthalmology, University of Washington, Seattle, WA, USA
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Kirby MA, Regnault G, Pelivanov I, O’Donnell M, Wang RK, Shen TT. Non-contact acoustic micro-tapping optical coherence elastography for quantification of corneal anisotropic elasticity: in vivo rabbit study. ARXIV 2023:arXiv:2301.10652v1. [PMID: 36748003 PMCID: PMC9900963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
PURPOSE To demonstrate accurate measurement of corneal elastic moduli in vivo with non-contact and non-invasive optical coherence elastography. METHODS Elastic properties (in-plane Young's modulus E and both in-plane, u, and out-of-plane, G, shear moduli) of rabbit cornea were quantified in vivo using non-contact dynamic Acoustic micro-Tapping Optical Coherence Elastography (AuT-OCE). The IOP-dependence of measured mechanical properties was explored in extracted whole globes following in vivo measurement. A nearly-incompressible transverse isotropic (NITI) model was used to reconstruct moduli from AuT-OCE data. Independently, cornea elastic moduli were also measured ex vivo with traditional, destructive mechanical tests (tensile extensometry and shear rheometry). RESULTS Our study demonstrates strong anisotropy of corneal elasticity in rabbits. The in-plane Young's modulus, computer as E=3u, was in the range of 20-44 MPa, whereas the out-of-plane shear modulus was in the range of 34-261 kPa. Both pressure-dependent ex vivo OCE and destructive mechanical tests performed on the same samples within an hour of euthanasia strongly support the results of AuT-OCE measurements. CONCLUSIONS Non-contact AuT-OCE can non-invasively quantify cornea anisotropic elastic properties in vivo. TRANSLATIONAL RELEVANCE As OCT is broadly accepted in Ophthalmology, these results suggest the potential for rapid translation of AuT-OCE into clinical practice. In addition, AuT-OCE can likely improve diagnostic criteria of ectatic corneal diseases, leading to early diagnosis, reduced complications, customized surgical treatment, and personalized biomechanical models of the eye.
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Affiliation(s)
- Mitchell A. Kirby
- Department of Bioengineering, University of Washington, Seattle, Washington 98105, USA
| | - Gabriel Regnault
- Department of Bioengineering, University of Washington, Seattle, Washington 98105, USA
| | - Ivan Pelivanov
- Department of Bioengineering, University of Washington, Seattle, Washington 98105, USA
| | - Matthew O’Donnell
- Department of Bioengineering, University of Washington, Seattle, Washington 98105, USA
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, Washington 98105, USA
- Department of Ophthalmology, University of Washington, Seattle, Washington 98104, USA
| | - Tueng T. Shen
- School of Medicine, University of Washington, Seattle, Washington 98195, USA
- Department of Ophthalmology, University of Washington, Seattle, Washington 98104, USA
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Leartprapun N, Adie SG. Recent advances in optical elastography and emerging opportunities in the basic sciences and translational medicine [Invited]. BIOMEDICAL OPTICS EXPRESS 2023; 14:208-248. [PMID: 36698669 PMCID: PMC9842001 DOI: 10.1364/boe.468932] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 11/29/2022] [Accepted: 11/29/2022] [Indexed: 05/28/2023]
Abstract
Optical elastography offers a rich body of imaging capabilities that can serve as a bridge between organ-level medical elastography and single-molecule biophysics. We review the methodologies and recent developments in optical coherence elastography, Brillouin microscopy, optical microrheology, and photoacoustic elastography. With an outlook toward maximizing the basic science and translational clinical impact of optical elastography technologies, we discuss potential ways that these techniques can integrate not only with each other, but also with supporting technologies and capabilities in other biomedical fields. By embracing cross-modality and cross-disciplinary interactions with these parallel fields, optical elastography can greatly increase its potential to drive new discoveries in the biomedical sciences as well as the development of novel biomechanics-based clinical diagnostics and therapeutics.
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Affiliation(s)
- Nichaluk Leartprapun
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York 14853, USA
- Present affiliation: Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Steven G. Adie
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York 14853, USA
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11
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Regnault G, Kirby MA, Kuriakose M, Shen T, Wang RK, O’Donnell M, Pelivanov I. Spatial resolution in optical coherence elastography of bounded media. BIOMEDICAL OPTICS EXPRESS 2022; 13:4851-4869. [PMID: 36187272 PMCID: PMC9484430 DOI: 10.1364/boe.469019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 07/30/2022] [Accepted: 08/03/2022] [Indexed: 05/11/2023]
Abstract
Dynamic optical coherence elastography (OCE) tracks mechanical wave propagation in the subsurface region of tissue to image its shear modulus. For bulk shear waves, the lateral resolution of the reconstructed modulus map (i.e., elastographic resolution) can approach that of optical coherence tomography (OCT), typically a few tens of microns. Here we perform comprehensive numerical simulations and acoustic micro-tapping OCE experiments to show that for the typical situation of guided wave propagation in bounded media, such as cornea, the elastographic resolution cannot reach the OCT resolution and is mainly defined by the thickness of the bounded tissue layer. We considered the excitation of both broadband and quasi-harmonic guided waves in a bounded, isotropic medium. Leveraging the properties of broadband pulses, a robust method for modulus reconstruction with minimum artifacts at interfaces is demonstrated. In contrast, tissue bounding creates large instabilities in the phase of harmonic waves, leading to serious artifacts in modulus reconstructions.
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Affiliation(s)
- Gabriel Regnault
- University of Washington, Department of Bioengineering, Seattle, Washington, 3720 15th Ave NE, Seattle, WA 98105, USA
| | - Mitchell A. Kirby
- University of Washington, Department of Bioengineering, Seattle, Washington, 3720 15th Ave NE, Seattle, WA 98105, USA
| | - Maju Kuriakose
- University of Washington, Department of Bioengineering, Seattle, Washington, 3720 15th Ave NE, Seattle, WA 98105, USA
| | - Tueng Shen
- University of Washington, Department of Bioengineering, Seattle, Washington, 3720 15th Ave NE, Seattle, WA 98105, USA
- University of Washington, Department of Ophthalmology, Seattle, Washington, 1959 NE Pacific St, Seattle, WA 98195, USA
| | - Ruikang K. Wang
- University of Washington, Department of Bioengineering, Seattle, Washington, 3720 15th Ave NE, Seattle, WA 98105, USA
- University of Washington, Department of Ophthalmology, Seattle, Washington, 1959 NE Pacific St, Seattle, WA 98195, USA
| | - Matthew O’Donnell
- University of Washington, Department of Bioengineering, Seattle, Washington, 3720 15th Ave NE, Seattle, WA 98105, USA
| | - Ivan Pelivanov
- University of Washington, Department of Bioengineering, Seattle, Washington, 3720 15th Ave NE, Seattle, WA 98105, USA
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12
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Chen G, Xia J. Non-Contact Shear Wave Generation and Detection Using High Frequency Air-Coupled Focused Transducer and Fiber Optic Based Sagnac Interferometer for Mechanical Characterization. SENSORS 2022; 22:s22155824. [PMID: 35957381 PMCID: PMC9370967 DOI: 10.3390/s22155824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 07/31/2022] [Accepted: 08/02/2022] [Indexed: 11/16/2022]
Abstract
In shear wave-based material mechanical characterization, the transmit/receiver transducer is generally in contact with the material through a coupling medium. In many applications, especially in biological tissue-related characterization, the application of the coupling medium and the contact method are not ideal, sometimes even unacceptable, due to contamination or stress response concerns. To avoid contact, we developed a 1 MHz air-coupled focused PZT transducer as a moderate pressure generator that could induce a shear wave in soft material and a fiber optic-based Sagnac system for the detection of the propagating shear wave. A calibration indicated that the fabricated air-coupled focused PZT transducer could generate pressure above 1 KPa within its focal range. This pressure is three to five times as much as the pressure generated by a 1 MHz air-coupled transducer currently available on the market. The integrated system was demonstrated through shear wave generation by the fabricated air-coupled PZT transducer and shear wave detection by the fiber optic Sagnac system in a nylon membrane. The results demonstrated the capability of the integrated system in non-contact material mechanical characterization, such as in material modulus measurement.
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13
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Chen X, Peng Y, Li C, Zhao C. Simulation of sound propagation and calculation of its velocity in spherical and superellipsoidal particle systems. POWDER TECHNOL 2022. [DOI: 10.1016/j.powtec.2022.117657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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14
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Li W, Feng J, Wang Y, Shi Q, Ma G, Aglyamov S, Larin KV, Lan G, Twa M. Micron-scale hysteresis measurement using dynamic optical coherence elastography. BIOMEDICAL OPTICS EXPRESS 2022; 13:3021-3041. [PMID: 35774312 PMCID: PMC9203113 DOI: 10.1364/boe.457617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/11/2022] [Accepted: 04/14/2022] [Indexed: 05/28/2023]
Abstract
We present a novel optical coherence elastography (OCE) method to characterize mechanical hysteresis of soft tissues based on transient (milliseconds), low-pressure (<20 Pa) non-contact microliter air-pulse stimulation and micrometer-scale sample displacements. The energy dissipation rate (sample hysteresis) was quantified for soft-tissue phantoms (0.8% to 2.0% agar) and beef shank samples under different loading forces and displacement amplitudes. Sample hysteresis was defined as the loss ratio (hysteresis loop area divided by the total loading energy). The loss ratio was primarily driven by the sample unloading response which decreased as loading energy increased. Samples were distinguishable based on their loss ratio responses as a function loading energy or displacement amplitude. Finite element analysis and mechanical testing methods were used to validate these observations. We further performed the OCE measurements on a beef shank tissue sample to distinguish the muscle and connective tissue components based on the displacement and hysteresis features. This novel, noninvasive OCE approach has the potential to differentiate soft tissues by quantifying their viscoelasticity using micron-scale transient tissue displacement dynamics. Focal tissue hysteresis measurements could provide additional clinically useful metrics for guiding disease diagnosis and tissue treatment responses.
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Affiliation(s)
- Wenjie Li
- Foshan University, School of Mechatronic Engineering and Automation, Foshan, Guangdong, 528000, China
- Contributed equally
| | - Jinping Feng
- Hubei University of Science and Technology, Institute of Engineering and Technology, Xianning, Hubei, 437100, China
- Contributed equally
| | - Yicheng Wang
- Foshan University, School of Mechatronic Engineering and Automation, Foshan, Guangdong, 528000, China
| | - Qun Shi
- Foshan University, School of Mechatronic Engineering and Automation, Foshan, Guangdong, 528000, China
| | - Guoqin Ma
- Foshan University, School of Mechatronic Engineering and Automation, Foshan, Guangdong, 528000, China
| | - Salavat Aglyamov
- University of Houston, Mechanical Engineering, Houston, TX 77204, USA
| | - Kirill V Larin
- University of Houston, Biomedical Engineering, Houston, TX 77204, USA
| | - Gongpu Lan
- Foshan University, School of Physics and Optoelectronic Engineering, Guangdong-Hong Kong-Macao Joint Laboratory for Intelligent Micro-Nano Optoelectronic Technology, Foshan, Guangdong 528000, China
- Innovation and Entrepreneurship Team of Guangdong Pearl River Talents Program, Weiren Meditech Co., Ltd., Foshan, Guangdong, 528000, China
| | - Michael Twa
- University of Houston, College of Optometry, Houston, TX 77204, USA
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15
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Lan G, Shi Q, Wang Y, Ma G, Cai J, Feng J, Huang Y, Gu B, An L, Xu J, Qin J, Twa MD. Spatial Assessment of Heterogeneous Tissue Natural Frequency Using Micro-Force Optical Coherence Elastography. Front Bioeng Biotechnol 2022; 10:851094. [PMID: 35360399 PMCID: PMC8962667 DOI: 10.3389/fbioe.2022.851094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 02/28/2022] [Indexed: 11/20/2022] Open
Abstract
Analysis of corneal tissue natural frequency was recently proposed as a biomarker for corneal biomechanics and has been performed using high-resolution optical coherence tomography (OCT)-based elastography (OCE). However, it remains unknown whether natural frequency analysis can resolve local variations in tissue structure. We measured heterogeneous samples to evaluate the correspondence between natural frequency distributions and regional structural variations. Sub-micrometer sample oscillations were induced point-wise by microliter air pulses (60–85 Pa, 3 ms) and detected correspondingly at each point using a 1,300 nm spectral domain common path OCT system with 0.44 nm phase detection sensitivity. The resulting oscillation frequency features were analyzed via fast Fourier transform and natural frequency was characterized using a single degree of freedom (SDOF) model. Oscillation features at each measurement point showed a complex frequency response with multiple frequency components that corresponded with global structural features; while the variation of frequency magnitude at each location reflected the local sample features. Silicone blocks (255.1 ± 11.0 Hz and 249.0 ± 4.6 Hz) embedded in an agar base (355.6 ± 0.8 Hz and 361.3 ± 5.5 Hz) were clearly distinguishable by natural frequency. In a beef shank sample, central fat and connective tissues had lower natural frequencies (91.7 ± 58.2 Hz) than muscle tissue (left side: 252.6 ± 52.3 Hz; right side: 161.5 ± 35.8 Hz). As a first step, we have shown the possibility of natural frequency OCE methods to characterize global and local features of heterogeneous samples. This method can provide additional information on corneal properties, complementary to current clinical biomechanical assessments, and could become a useful tool for clinical detection of ocular disease and evaluation of medical or surgical treatment outcomes.
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Affiliation(s)
- Gongpu Lan
- School of Physics and Optoelectronic Engineering, Foshan University, Foshan, China
- Innovation and Entrepreneurship Teams of Guangdong Pearl River Talents Program, Weiren Meditech Co., Ltd., Foshan, China
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, Foshan University, Foshan, China
- *Correspondence: Gongpu Lan, ; Michael D. Twa,
| | - Qun Shi
- School of Mechatronic Engineering and Automation, Foshan University, Foshan, China
| | - Yicheng Wang
- School of Mechatronic Engineering and Automation, Foshan University, Foshan, China
| | - Guoqin Ma
- School of Mechatronic Engineering and Automation, Foshan University, Foshan, China
| | - Jing Cai
- School of Physics and Optoelectronic Engineering, Foshan University, Foshan, China
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, Foshan University, Foshan, China
| | - Jinping Feng
- Institute of Engineering and Technology, Hubei University of Science and Technology, Xianning, China
| | - Yanping Huang
- School of Physics and Optoelectronic Engineering, Foshan University, Foshan, China
- Innovation and Entrepreneurship Teams of Guangdong Pearl River Talents Program, Weiren Meditech Co., Ltd., Foshan, China
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, Foshan University, Foshan, China
| | - Boyu Gu
- School of Computer and Information Engineering, Tianjin Chengjian University, Tianjin, China
| | - Lin An
- Innovation and Entrepreneurship Teams of Guangdong Pearl River Talents Program, Weiren Meditech Co., Ltd., Foshan, China
| | - Jingjiang Xu
- School of Physics and Optoelectronic Engineering, Foshan University, Foshan, China
- Innovation and Entrepreneurship Teams of Guangdong Pearl River Talents Program, Weiren Meditech Co., Ltd., Foshan, China
- Guangdong-Hong Kong-Macao Intelligent Micro-Nano Optoelectronic Technology Joint Laboratory, Foshan University, Foshan, China
| | - Jia Qin
- Innovation and Entrepreneurship Teams of Guangdong Pearl River Talents Program, Weiren Meditech Co., Ltd., Foshan, China
| | - Michael D. Twa
- College of Optometry, University of Houston, Houston, TX, United States
- *Correspondence: Gongpu Lan, ; Michael D. Twa,
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Urbańska MA, Kolenderska SM, Rodrigues SA, Thakur SS, Vanholsbeeck F. Broadband-excitation-based mechanical spectroscopy of highly viscous tissue-mimicking phantoms. OPTICS EXPRESS 2022; 30:603-618. [PMID: 35201234 DOI: 10.1364/oe.445259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 12/01/2021] [Indexed: 06/14/2023]
Abstract
Standard rheometers assess mechanical properties of viscoelastic samples up to 100 Hz, which often hinders the assessment of the local-scale dynamics. We demonstrate that high-frequency analysis can be achieved by inducing broadband waves and monitoring their media-dependent propagation using optical coherence tomography. Here, we present a new broadband wave analysis based on two-dimensional Fourier transformation. We validated this method by comparing the mechanical parameters to monochromatic excitation and a standard oscillatory test data. Our method allows for high-frequency mechanical spectroscopy, which could be used to investigate the local-scale dynamics of different biological tissues and the influence of diseases on their microstructure.
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Zvietcovich F, Larin KV. Wave-based optical coherence elastography: The 10-year perspective. PROGRESS IN BIOMEDICAL ENGINEERING (BRISTOL, ENGLAND) 2022; 4:012007. [PMID: 35187403 PMCID: PMC8856668 DOI: 10.1088/2516-1091/ac4512] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
After 10 years of progress and innovation, optical coherence elastography (OCE) based on the propagation of mechanical waves has become one of the major and the most studied OCE branches, producing a fundamental impact in the quantitative and nondestructive biomechanical characterization of tissues. Preceding previous progress made in ultrasound and magnetic resonance elastography; wave-based OCE has pushed to the limit the advance of three major pillars: (1) implementation of novel wave excitation methods in tissues, (2) understanding new types of mechanical waves in complex boundary conditions by proposing advance analytical and numerical models, and (3) the development of novel estimators capable of retrieving quantitative 2D/3D biomechanical information of tissues. This remarkable progress promoted a major advance in answering basic science questions and the improvement of medical disease diagnosis and treatment monitoring in several types of tissues leading, ultimately, to the first attempts of clinical trials and translational research aiming to have wave-based OCE working in clinical environments. This paper summarizes the fundamental up-to-date principles and categories of wave-based OCE, revises the timeline and the state-of-the-art techniques and applications lying in those categories, and concludes with a discussion on the current challenges and future directions, including clinical translation research.
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Affiliation(s)
- Fernando Zvietcovich
- University of Houston, Biomedical Engineering, Houston, TX, United States, 77204
| | - Kirill V. Larin
- University of Houston, Biomedical Engineering, Houston, TX, United States, 77204,
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18
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Customized eye modeling for optical quality assessment in myopic femto-LASIK surgery. Sci Rep 2021; 11:16049. [PMID: 34362982 PMCID: PMC8346559 DOI: 10.1038/s41598-021-95730-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 07/27/2021] [Indexed: 02/07/2023] Open
Abstract
Refractive surgery is recognized as an effective method for myopia treatment, but it can induce night vision disturbances such as glare. We present an eye modeling method for the optical quality assessment in response to the structural changes in the eyes by femto-LASIK surgery. Customized eye models were built from the measurements of 134 right eyes pre- and post-operatively. Optical performance was evaluated using spot diagrams, point spread functions (PSFs), modulation transfer functions (MTFs), and chromatic aberrations at various fields (0°-30°), different pupil diameters (2-6 mm), and initial myopias (- 1.25 to - 10.5 D). Pupil size and initial myopia are the two major factors that affect visual performance of post-operative eyes. The results of spot diagrams, PSFs, and MTFs indicated that post-operative visual performance deteriorated as the visual field and pupil size increased, and it was significantly influenced by initial myopia. Post-operative chromatic aberrations were also affected by initial myopia. As pupil size increased, the post-operative longitudinal chromatic aberrations tended to decrease slightly, while the transverse chromatic aberrations remained similar. The use of eye modeling for refractive surgery assessment could possibly provide a more personalized surgical approach, could improve the prediction accuracy of refractive surgery outcomes, and promote the invention and development of better surgical methods.
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Rippy JR, Singh M, Aglyamov SR, Larin KV. Ultrasound Shear Wave Elastography and Transient Optical Coherence Elastography: Side-by-Side Comparison of Repeatability and Accuracy. IEEE OPEN JOURNAL OF ENGINEERING IN MEDICINE AND BIOLOGY 2021; 2:179-186. [PMID: 34179823 PMCID: PMC8224461 DOI: 10.1109/ojemb.2021.3075569] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Objective: We compare the repeatability and accuracy of ultrasound shear wave elastography (USE) and transient optical coherence elastography (OCE). Methods: Elastic wave speed in gelatin phantoms and chicken breast was measured with USE and OCE and compared with uniaxial mechanical compression testing. Intra- and Inter-repeatability were analyzed using Bland-Altman plots and intraclass correlation coefficients (ICC). Results: OCE and USE differed from uniaxial testing by a mean absolute percent error of 8.92% and 16.9%, respectively, across eight phantoms of varying stiffness. Upper and lower limits of agreement for intrasample repeatability for USE and OCE were ±0.075 m/s and −0.14 m/s and 0.13 m/s, respectively. OCE and USE both had ICCs of 0.9991. In chicken breast, ICC for USE was 0.9385 and for OCE was 0.9924. Conclusion: OCE and USE can detect small speed changes and give comparable measurements. These measurements correspond well with uniaxial testing.
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20
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Lan G, Aglyamov S, Larin KV, Twa MD. In vivo human corneal natural frequency quantification using dynamic optical coherence elastography: Repeatability and reproducibility. J Biomech 2021; 121:110427. [PMID: 33873114 DOI: 10.1016/j.jbiomech.2021.110427] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 03/20/2021] [Accepted: 03/29/2021] [Indexed: 12/14/2022]
Abstract
Reliable and quantitative assessment of corneal biomechanics is important for the detection and treatment of corneal disease. The present study evaluates the repeatability and reproducibility of a novel optical coherence tomography (OCT)-based elastography (OCE) method for in vivo quantification of corneal natural frequency in 20 normal human eyes. Sub-micron corneal oscillations were induced by repeated low-force (13 Pa) microliter air pulses at the corneal apex and were observed by common-path phase-sensitive OCT imaging adjacent to a measurement region of 1-6.25 mm2. Corneal natural frequencies were quantified using a single degree of freedom model based on the corneal oscillations. Corneal natural frequencies ranged from 234 to 277 Hz (coefficient of variation: 3.2%; n = 286 for a 2.5 × 2.5 mm2 area; time: 28.6 s). The same natural frequencies can be acquired using a smaller sampling size (n = 9 for 1 mm2) and a shorter time (0.9 s). Spatial distribution and local changes in natural frequencies can be distinguished using denser sampling (e.g., 26 × 41 points for 2.5 × 5 mm2). This novel optical method demonstrates highly repeatable and reliable in vivo measurements of human corneal natural frequencies. While further studies are required to fully characterize anatomical and structural dependencies, this method may be complementary to the current OCE methods used to estimate Young's modulus from strain- or shear-wave-based measurements for the quantitative determination of corneal biomechanics.
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Affiliation(s)
- Gongpu Lan
- Foshan University, School of Physics and Optoelectronic Engineering, Foshan, Guangdong 528000, China
| | - Salavat Aglyamov
- University of Houston, Mechanical Engineering, Houston, TX 77204, United States
| | - Kirill V Larin
- University of Houston, Biomedical Engineering, Houston, TX 77204, United States
| | - Michael D Twa
- University of Houston, College of Optometry, Houston, TX 77204, United States.
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21
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Zhou K, Feng K, Li C, Huang Z. A Weighted Average Phase Velocity Inversion Model for Depth-Resolved Elasticity Evaluation in Human Skin In-Vivo. IEEE Trans Biomed Eng 2020; 68:1969-1977. [PMID: 33326373 DOI: 10.1109/tbme.2020.3045133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE In current surface acoustic wave (SAW) elastography field, wavelength-depth inversion model is a straightforward and widely used inversion model for depth-resolved elasticity profile reconstruction. However, the elasticity directly evaluated from the wavelength-depth relationship is biased. Thus, a new inversion model, termed weighted average phase velocity (WAPV) inversion model, is proposed to provide depth-resolved Young's modulus estimate with better accuracy. METHODS The forward model for SAW phase velocity dispersion curve generation was derived from the numerical simulations of SAWs in layered materials, and inversion was implemented by matching the measured phase velocity dispersion curve to the one generated from the forward model using the least squares fitting. Three two-layer agar phantoms with different top-layer thicknesses and one three-layer agar phantom were tested to validate the proposed inversion model. Then the model was demonstrated on human skin at various sites (palm, forearm and back of hand) in-vivo. RESULTS In multi-layered agar phantoms, depth-resolved elasticity estimates provided by the model have a maximal total inversion error of 15.2% per sample after inversion error compensation. In in-vivo human skin, the quantified bulk Young's moduli (palm: 212 ± 78 kPa; forearm: 32 ± 11 kPa and back of hand: 29 ± 8 kPa) are comparable to the reference values in the literature. CONCLUSION The WAPV inversion model can provide accurate depth-resolved Young's modulus estimates in layered biological soft tissues. SIGNIFICANCE The proposed model can predict depth-resolved elasticity in layered biological soft tissues with a reasonable accuracy which traditional wavelength-depth inversion model cannot provide.
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22
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Pitre JJ, Kirby MA, Li DS, Shen TT, Wang RK, O'Donnell M, Pelivanov I. Nearly-incompressible transverse isotropy (NITI) of cornea elasticity: model and experiments with acoustic micro-tapping OCE. Sci Rep 2020; 10:12983. [PMID: 32737363 PMCID: PMC7395720 DOI: 10.1038/s41598-020-69909-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 07/21/2020] [Indexed: 12/28/2022] Open
Abstract
The cornea provides the largest refractive power for the human visual system. Its stiffness, along with intraocular pressure (IOP), are linked to several pathologies, including keratoconus and glaucoma. Although mechanical tests can quantify corneal elasticity ex vivo, they cannot be used clinically. Dynamic optical coherence elastography (OCE), which launches and tracks shear waves to estimate stiffness, provides an attractive non-contact probe of corneal elasticity. To date, however, OCE studies report corneal moduli around tens of kPa, orders-of-magnitude less than those (few MPa) obtained by tensile/inflation testing. This large discrepancy impedes OCE's clinical adoption. Based on corneal microstructure, we introduce and fully characterize a nearly-incompressible transversely isotropic (NITI) model depicting corneal biomechanics. We show that the cornea must be described by at least two shear moduli, contrary to current single-modulus models, decoupling tensile and shear responses. We measure both as a function of IOP in ex vivo porcine cornea, obtaining values consistent with both tensile and shear tests. At pressures above 30 mmHg, the model begins to fail, consistent with non-linear changes in cornea at high IOP.
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Affiliation(s)
- John J Pitre
- Department of Bioengineering, University of Washington, Seattle, WA, USA.
| | - Mitchell A Kirby
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - David S Li
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Department of Chemical Engineering, University of Washington, Seattle, WA, USA
| | - Tueng T Shen
- Department of Ophthalmology, University of Washington, Seattle, WA, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Department of Ophthalmology, University of Washington, Seattle, WA, USA
| | - Matthew O'Donnell
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Ivan Pelivanov
- Department of Bioengineering, University of Washington, Seattle, WA, USA
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Lan G, Larin KV, Aglyamov S, Twa MD. Characterization of natural frequencies from nanoscale tissue oscillations using dynamic optical coherence elastography. BIOMEDICAL OPTICS EXPRESS 2020; 11:3301-3318. [PMID: 32637256 PMCID: PMC7316029 DOI: 10.1364/boe.391324] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/01/2020] [Accepted: 05/12/2020] [Indexed: 05/09/2023]
Abstract
We demonstrate the use of OCT-based elastography for soft-tissue characterization using natural frequency oscillations. Sub-micrometer to sub-nanometer oscillations were induced in tissue phantoms and human cornea in vivo by perpendicular air-pulse stimulation and observed by common-path OCT imaging (sensitivity: 0.24 nm). Natural frequency and damping ratio were acquired in temporal and frequency domains using a single degree of freedom method. The dominant natural frequency was constant for different stimulation pressures (4-32 Pa) and measured distances (0.3-5.3 mm), and decreased as the sample thickness increased. The dominant natural frequencies of 0.75-2% agar phantoms were 127-774 Hz (mean coefficient of variation [CV]: 0.9%), and correlated with the square root of Young's moduli (16.5-117.8 kPa, mean CV: 5.8%). These preliminary studies show repeatable in vivo corneal natural frequency measurements (259 Hz, CV: 1.9%). This novel OCE approach can distinguish tissues and materials with different mechanical properties using the small-amplitude tissue oscillation features, and is suitable for characterizing delicate tissues in vivo such as the eye.
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Affiliation(s)
- Gongpu Lan
- Foshan University, School of Physics and Optoelectronic Engineering, Foshan, Guangdong, 528000, China
- University of Alabama at Birmingham, School of Optometry, Birmingham, AL 35290, USA
- University of Houston, College of Optometry, Houston, TX 77204, USA
| | - Kirill V. Larin
- University of Houston, Biomedical Engineering, Houston, TX 77204, USA
| | - Salavat Aglyamov
- University of Houston, Mechanical Engineering, Houston, TX 77204, USA
| | - Michael D. Twa
- University of Alabama at Birmingham, School of Optometry, Birmingham, AL 35290, USA
- University of Houston, College of Optometry, Houston, TX 77204, USA
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24
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Lan G, Gu B, Larin KV, Twa MD. Clinical Corneal Optical Coherence Elastography Measurement Precision: Effect of Heartbeat and Respiration. Transl Vis Sci Technol 2020; 9:3. [PMID: 32821475 PMCID: PMC7401940 DOI: 10.1167/tvst.9.5.3] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 11/30/2019] [Indexed: 01/29/2023] Open
Abstract
Purpose Normal physiological movements (e.g., respiration and heartbeat) induce eye motions during clinical measurements of human corneal biomechanical properties using optical coherence elastography (OCE). We quantified the effects of respiratory and cardiac-induced eye motions on clinical corneal OCE measurement precision and repeatability. Methods Corneal OCE was performed using low-force, micro-air-pulse tissue stimulation and high-resolution phase-sensitive optical coherence tomography (OCT) imaging. Axial surface displacements of the corneal apex were measured (M-mode) at a 70-kHz sampling rate and three different stimulation pressures (20-60 Pa). Simultaneously, the axial corneal position was tracked with structural OCT imaging, while the heartrate and respiration were monitored over a 90 second period. Results Respiratory- and cardiac-induced eye motions have distinctly lower frequency (0.1-1 Hz) and much greater amplitude (up to ± 50 µm movements) than air-pulse-induced corneal tissue deformations (∼250 Hz, <1 µm). The corneal displacements induced during OCE measurements in vivo were -0.41 ± 0.06 µm (n = 22 measurements, coefficient of variation [CV]: 14.6%) and -0.44 ± 0.07 µm (n = 50 measurements, CV: 15.9%), respectively, from two human subjects at 40 Pa stimulation pressure. Observed variation in corneal tissue displacements were not associated with tissue stimulation magnitude, or the amplitude of physiologically induced axial eye motion. Conclusions The microsecond timescale and submicron tissue displacements observed during corneal OCE measurements are separable from normal involuntary physiological movements, such as the oculocardiac pulse and respiratory movements. Translational Relevance This work advances innovations in biomedical imaging and engineering for clinical diagnostic applications for soft-tissue biomechanical testing.
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Affiliation(s)
- Gongpu Lan
- Department of Photoelectric Technology, Foshan University, Foshan, Guangdong, China.,School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Boyu Gu
- Department of Ophthalmology, Doheny Eye Institute, University of California -Los Angeles, Los Angeles, CA, USA
| | - Kirill V Larin
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Michael D Twa
- School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA.,College of Optometry, University of Houston, Houston, TX, USA
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25
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Jin Z, Zhou Y, Shen M, Wang Y, Lu F, Zhu D. Assessment of corneal viscoelasticity using elastic wave optical coherence elastography. JOURNAL OF BIOPHOTONICS 2020; 13:e201960074. [PMID: 31626371 DOI: 10.1002/jbio.201960074] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/21/2019] [Accepted: 10/16/2019] [Indexed: 06/10/2023]
Abstract
The corneal viscoelasticity have great clinical significance, such as the early diagnosis of keratoconus. In this work, an analysis method which utilized the elastic wave velocity, frequency and energy attenuation to assess the corneal viscoelasticity is presented. Using phase-resolved optical coherence tomography, the spatial-temporal displacement map is derived. The phase velocity dispersion curve and center frequency are obtained by transforming the displacement map into the wavenumber-frequency domain through the 2D fast Fourier transform (FFT). The shear modulus is calculated through Rayleigh wave equation using the phase velocity in the high frequency. The normalized energy distribution is plotted by transforming the displacement map into the spatial-frequency domain through the 1D FFT. The energy attenuation coefficient is derived by exponential fitting to calculate the viscous modulus. Different concentrations of tissue-mimicking phantoms and porcine corneas are imaged to validate this method, which demonstrates that the method has the capability to assess the corneal viscoelasticity.
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Affiliation(s)
- Zi Jin
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
| | - Yuheng Zhou
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
| | - Meixiao Shen
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
| | - Yuanyuan Wang
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
| | - Fan Lu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
| | - Dexi Zhu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
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Miyazawa A, Makita S, Li E, Yamazaki K, Kobayashi M, Sakai S, Yasuno Y. Polarization-sensitive optical coherence elastography. BIOMEDICAL OPTICS EXPRESS 2019; 10:5162-5181. [PMID: 31646039 PMCID: PMC6788587 DOI: 10.1364/boe.10.005162] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 09/09/2019] [Accepted: 09/11/2019] [Indexed: 05/05/2023]
Abstract
Polarization-sensitive optical coherence elastography (PS-OCE) is developed for improved tissue discrimination. It integrates Jones matrix-based PS-optical coherence tomography (PS-OCT) with compression OCE. The method simultaneously measures the OCT intensity, attenuation coefficient, birefringence, and microstructural deformation (MSD) induced by tissue compression. Ex vivo porcine aorta and esophagus tissues were investigated by PS-OCE and histological imaging. The tissue properties measured by PS-OCE are shown as cross-sectional images and a three-dimensional (3-D) depth-trajectory plot. In this trajectory plot, the average attenuation coefficient, birefringence, and MSD were computed at each depth, and the trajectory in the depth direction was plotted in a 3-D feature space of these three properties. The tissue boundaries in a histological image corresponded with the depth-trajectory inflection points. Histogram analysis and t-distributed stochastic neighbour embedding (t-SNE) visualization of the three tissue properties indicated that the PS-OCE measurements provide sufficient information to discriminate porcine esophagus tissues.
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Affiliation(s)
- Arata Miyazawa
- Computational Optics Group, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki, 305-8573, Japan
| | - Shuichi Makita
- Computational Optics Group, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki, 305-8573, Japan
| | - En Li
- Computational Optics Group, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki, 305-8573, Japan
| | - Kohei Yamazaki
- Biological Science Research, Kao Corporation, 5-3-28, Kotobukicho, Odawara, Kanagawa, 250-0002, Japan
| | - Masaki Kobayashi
- Biological Science Research, Kao Corporation, 5-3-28, Kotobukicho, Odawara, Kanagawa, 250-0002, Japan
| | - Shingo Sakai
- Skin Care Product Research, Kao Corporation, 5-3-28, Kotobukicho, Odawara, Kanagawa, 250-0002, Japan
| | - Yoshiaki Yasuno
- Computational Optics Group, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki, 305-8573, Japan
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Zhou Y, Wang Y, Shen M, Jin Z, Chen Y, Zhou Y, Qu J, Zhu D. In vivo evaluation of corneal biomechanical properties by optical coherence elastography at different cross-linking irradiances. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-7. [PMID: 31605471 PMCID: PMC7000888 DOI: 10.1117/1.jbo.24.10.105001] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 09/06/2019] [Indexed: 05/18/2023]
Abstract
Corneal collagen cross-linking (CXL) strengthens the biomechanical properties of damaged corneas. Quantifying the changes of stiffness due to different CXL protocols is difficult, especially in vivo. A noninvasive elastic wave-based optical coherence elastography system was developed to construct in vivo corneal elasticity maps by excitation of air puff. Biomechanical differences were compared for rabbit corneas given three different CXL protocols while keeping the total energy delivered constant. The Young’s modulus was weaker in corneas treated with higher irradiance levels over shorter durations, and a slight increase of Young’s modulus was present in all groups one week after the recovery process. Due to the noninvasive nature and minimal force to generate corneal elastic waves, this technique has the potential for early detection and treatment of corneal diseases in clinic.
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Affiliation(s)
- Yuheng Zhou
- Wenzhou Medical University, School of Ophthalmology and Optometry, Wenzhou, China
| | - Yuanyuan Wang
- Wenzhou Medical University, School of Ophthalmology and Optometry, Wenzhou, China
| | - Meixiao Shen
- Wenzhou Medical University, School of Ophthalmology and Optometry, Wenzhou, China
| | - Zi Jin
- Wenzhou Medical University, School of Ophthalmology and Optometry, Wenzhou, China
| | - Yihong Chen
- Wenzhou Medical University, School of Ophthalmology and Optometry, Wenzhou, China
| | - Yue Zhou
- Wenzhou Medical University, School of Ophthalmology and Optometry, Wenzhou, China
| | - Jia Qu
- Wenzhou Medical University, School of Ophthalmology and Optometry, Wenzhou, China
| | - Dexi Zhu
- Wenzhou Medical University, School of Ophthalmology and Optometry, Wenzhou, China
- Address all correspondence to Dexi Zhu, E-mail:
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28
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Kirby MA, Zhou K, Pitre JJ, Gao L, Li D, Pelivanov I, Song S, Li C, Huang Z, Shen T, Wang R, O’Donnell M. Spatial resolution in dynamic optical coherence elastography. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-16. [PMID: 31535538 PMCID: PMC6749618 DOI: 10.1117/1.jbo.24.9.096006] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Accepted: 08/26/2019] [Indexed: 05/03/2023]
Abstract
Dynamic optical coherence elastography (OCE) tracks elastic wave propagation speed within tissue, enabling quantitative three-dimensional imaging of the elastic modulus. We show that propagating mechanical waves are mode converted at interfaces, creating a finite region on the order of an acoustic wavelength where there is not a simple one-to-one correspondence between wave speed and elastic modulus. Depending on the details of a boundary’s geometry and elasticity contrast, highly complex propagating fields produced near the boundary can substantially affect both the spatial resolution and contrast of the elasticity image. We demonstrate boundary effects on Rayleigh waves incident on a vertical boundary between media of different shear moduli. Lateral resolution is defined by the width of the transition zone between two media and is the limit at which a physical inclusion can be detected with full contrast. We experimentally demonstrate results using a spectral-domain OCT system on tissue-mimicking phantoms, which are replicated using numerical simulations. It is shown that the spatial resolution in dynamic OCE is determined by the temporal and spatial characteristics (i.e., bandwidth and spatial pulse width) of the propagating mechanical wave. Thus, mechanical resolution in dynamic OCE inherently differs from the optical resolution of the OCT imaging system.
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Affiliation(s)
- Mitchell A. Kirby
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Kanheng Zhou
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
- University of Dundee, School of Science and Engineering, Dundee, United Kingdom
| | - John J. Pitre
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Liang Gao
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - David Li
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
- University of Washington, Department of Chemical Engineering, Seattle, Washington, United States
| | - Ivan Pelivanov
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
- Address all correspondence to Ivan Pelivanov, E-mail:
| | - Shaozhen Song
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Chunhui Li
- University of Dundee, School of Science and Engineering, Dundee, United Kingdom
| | - Zhihong Huang
- University of Dundee, School of Science and Engineering, Dundee, United Kingdom
| | - Tueng Shen
- University of Washington, Department of Ophthalmology, Seattle, Washington, United States
| | - Ruikang Wang
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
- University of Washington, Department of Ophthalmology, Seattle, Washington, United States
| | - Matthew O’Donnell
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
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29
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Pitre JJ, Kirby MA, Gao L, Li DS, Shen T, Wang RK, O'Donnell M, Pelivanov I. Super-shear evanescent waves for non-contact elastography of soft tissues. APPLIED PHYSICS LETTERS 2019; 115:083701. [PMID: 32127722 PMCID: PMC7043857 DOI: 10.1063/1.5111952] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 08/01/2019] [Indexed: 05/12/2023]
Abstract
We describe surface wave propagation in soft elastic media at speeds exceeding the bulk shear wave speed. By linking these waves to the elastodynamic Green's function, we derive a simple relationship to quantify the elasticity of a soft medium from the speed of this supershear evanescent wave (SEW). We experimentally probe SEW propagation in tissue-mimicking phantoms, human cornea ex vivo, and skin in vivo using a high-speed optical coherence elastography system. Measurements confirm the predicted relationship between SEW and bulk shear wave speeds, agreeing well with both theoretical and numerical models. These results suggest that SEW measurements may be a robust method to quantify elasticity in soft media, particularly in complex, bounded materials where dispersive Rayleigh-Lamb modes complicate measurements.
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Affiliation(s)
- John J Pitre
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
| | - Mitchell A Kirby
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
| | - Liang Gao
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
| | | | - Tueng Shen
- Department of Ophthalmology, University of Washington, Seattle, Washington 98104, USA
| | | | - Matthew O'Donnell
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
| | - Ivan Pelivanov
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
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30
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Liou HC, Sabba F, Packman AI, Rosenthal A, Wells G, Balogun O. Towards mechanical characterization of granular biofilms by optical coherence elastography measurements of circumferential elastic waves. SOFT MATTER 2019; 15:5562-5573. [PMID: 31282532 DOI: 10.1039/c9sm00739c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Microbial granular biofilms are spherical, multi-layered aggregates composed of communities of bacterial cells encased in a complex matrix of hydrated extracellular polymeric substances (EPS). While granular aggregates are increasingly used for applications in industrial and municipal wastewater treatment, their underlying mechanical properties are poorly understood. The challenges of viscoelastic characterization for these structures are due to their spherical geometry, spatially heterogeneous properties, and their delicate nature. In this study, we report a model-based approach for nondestructive characterization of viscoelastic properties (shear modulus and shear viscosity) of alginate spheres with different concentrations, which was motivated by our measurements in granular biofilms. The characterization technique relies on experimental measurements of circumferential elastic wave speeds as a function of frequency in the samples using the Optical Coherence Elastography (OCE) technique. A theoretical model was developed to estimate the viscoelastic properties of the samples from OCE data through inverse analysis. This work represents the first attempt to explore elastic waves for mechanical characterization of granular biofilms. The combination of the OCE technique and the theoretical model presented in this paper provides a framework that can facilitate quantitative viscoelastic characterization of samples with curved geometries and the study of the relationships between morphology and mechanical properties in granular biofilms.
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Affiliation(s)
- Hong-Cin Liou
- Mechanical Engineering Department, Northwestern University, Evanston, IL 60208, USA.
| | - Fabrizio Sabba
- Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208, USA
| | - Aaron I Packman
- Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208, USA
| | - Alex Rosenthal
- Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208, USA
| | - George Wells
- Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208, USA
| | - Oluwaseyi Balogun
- Mechanical Engineering Department, Northwestern University, Evanston, IL 60208, USA. and Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208, USA
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31
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Pelivanov I, Gao L, Pitre J, Kirby MA, Song S, Li D, Shen TT, Wang RK, O’Donnell M. Does group velocity always reflect elastic modulus in shear wave elastography? JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-11. [PMID: 31342691 PMCID: PMC6650747 DOI: 10.1117/1.jbo.24.7.076003] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 07/08/2019] [Indexed: 05/04/2023]
Abstract
Dynamic elastography is an attractive method to evaluate tissue biomechanical properties. Recently, it was extended from US- and MR-based modalities to optical ones, such as optical coherence tomography for three-dimensional (3-D) imaging of propagating mechanical waves in subsurface regions of soft tissues, such as the eye. The measured group velocity is often used to convert wave speed maps into 3-D images of the elastic modulus distribution based on the assumption of bulk shear waves. However, the specific geometry of OCE measurements in bounded materials such as the cornea and skin calls into question elasticity reconstruction assuming a simple relationship between group velocity and shear modulus. We show that in layered media the bulk shear wave assumption results in highly underestimated shear modulus reconstructions and significant structural artifacts in modulus images. We urge the OCE community to be careful in using the group velocity to evaluate tissue elasticity and to focus on developing robust reconstruction methods to accurately reconstruct images of the shear elastic modulus in bounded media.
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Affiliation(s)
- Ivan Pelivanov
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
- Address all correspondence to Ivan Pelivanov, E-mail:
| | - Liang Gao
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - John Pitre
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Mitchell A. Kirby
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Shaozhen Song
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - David Li
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
- University of Washington, Department of Chemical Engineering, Seattle, Washington, United States
| | - Tueng T. Shen
- University of Washington, Department of Ophthalmology, Seattle, Washington, United States
| | - Ruikang K. Wang
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Matthew O’Donnell
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
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32
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Hepburn MS, Wijesinghe P, Chin L, Kennedy BF. Analysis of spatial resolution in phase-sensitive compression optical coherence elastography. BIOMEDICAL OPTICS EXPRESS 2019; 10:1496-1513. [PMID: 30891363 PMCID: PMC6420276 DOI: 10.1364/boe.10.001496] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/12/2019] [Accepted: 02/12/2019] [Indexed: 05/03/2023]
Abstract
Optical coherence elastography (OCE) is emerging as a method to image the mechanical properties of tissue on the microscale. However, the spatial resolution, a main advantage of OCE, has not been investigated and is not trivial to evaluate. To address this, we present a framework to analyze resolution in phase-sensitive compression OCE that incorporates the three main determinants of resolution: mechanical deformation of the sample, detection of this deformation using optical coherence tomography (OCT), and signal processing to estimate local axial strain. We demonstrate for the first time, through close correspondence between experiment and simulation of structured phantoms, that resolution in compression OCE is both spatially varying and sample dependent, which we link to the discrepancies between the model of elasticity and the mechanical deformation of the sample. We demonstrate that resolution is dependent on factors such as feature size and mechanical contrast. We believe that the analysis of image formation provided by our framework can expedite the development of compression OCE.
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Affiliation(s)
- Matt S. Hepburn
- BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia, 6009, Australia
- Department of Electrical, Electronic & Computer Engineering, School of Engineering, The University of Western Australia, 35, Stirling Highway, Perth, Western Australia, 6009, Australia
| | - Philip Wijesinghe
- BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia, 6009, Australia
- Department of Electrical, Electronic & Computer Engineering, School of Engineering, The University of Western Australia, 35, Stirling Highway, Perth, Western Australia, 6009, Australia
- Current address: SUPA, School of Physics and Astronomy, University of St. Andrews, KY16 9SS, UK
| | - Lixin Chin
- BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia, 6009, Australia
- Department of Electrical, Electronic & Computer Engineering, School of Engineering, The University of Western Australia, 35, Stirling Highway, Perth, Western Australia, 6009, Australia
| | - Brendan F. Kennedy
- BRITElab, Harry Perkins Institute of Medical Research, QEII Medical Centre, Nedlands, Western Australia, 6009, Australia and Centre for Medical Research, The University of Western Australia, Crawley, Western Australia, 6009, Australia
- Department of Electrical, Electronic & Computer Engineering, School of Engineering, The University of Western Australia, 35, Stirling Highway, Perth, Western Australia, 6009, Australia
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33
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Lan G, Twa MD. Theory and design of Schwarzschild scan objective for Optical Coherence Tomography. OPTICS EXPRESS 2019; 27:5048-5064. [PMID: 30876110 PMCID: PMC6410919 DOI: 10.1364/oe.27.005048] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Optical coherence elastography (OCE) is one form of multi-channel imaging that combines high-resolution optical coherence tomography (OCT) imaging with mechanical tissue stimulation. This combination of structural and functional imaging can require additional space to integrate imaging capabilities with additional functional elements (e.g., optical, mechanical, or acoustic modulators) either at or near the imaging axis. We address this challenge by designing a novel scan lens based on a modified Schwarzchild objective lens, comprised of a pair of concentric mirrors with potential space to incorporate additional functional elements and minimal compromise to the available scan field. This scan objective design allows perpendicular tissue-excitation and response recording. The optimized scan lens design results in a working distance that is extended to ~140 mm (nearly 2x the focal length), an expanded central space suitable for additional functional elements (>15 mm in diameter) and diffraction-limited lateral resolution (19.33 μm) across a full annular scan field ~ ± 7.5 mm to ± 12.7 mm.
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Affiliation(s)
- Gongpu Lan
- Foshan University, Department of Photoelectric Technology, Foshan, Guangdong 528000, China
- University of Alabama at Birmingham, School of Optometry, Birmingham, Alabama 35294, USA
| | - Michael D. Twa
- University of Alabama at Birmingham, School of Optometry, Birmingham, Alabama 35294, USA
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34
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Liou HC, Sabba F, Packman AI, Wells G, Balogun O. Nondestructive characterization of soft materials and biofilms by measurement of guided elastic wave propagation using optical coherence elastography. SOFT MATTER 2019; 15:575-586. [PMID: 30601536 DOI: 10.1039/c8sm01902a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Biofilms are soft multicomponent biological materials composed of microbial communities attached to surfaces. Despite the crucial relevance of biofilms to diverse industrial, medical, and environmental applications, the mechanical properties of biofilms are understudied. Moreover, most of the available techniques for the characterization of biofilm mechanical properties are destructive. Here, we detail a model-based approach developed to characterize the viscoelastic properties of soft materials and bacterial biofilms based on experimental data obtained using the nondestructive dynamic optical coherence elastography (OCE) technique. The model predicted the frequency- and geometry-dependent propagation velocities of elastic waves in a soft viscoelastic plate supported by a rigid substratum. Our numerical calculations suggest that the dispersion curves of guided waves recorded in thin soft plates by the dynamic OCE technique are dominated by guided waves, whose phase velocities depend on the viscoelastic properties and plate thickness. The numerical model was validated against experimental measurements in agarose phantom samples with different thicknesses and concentrations. The model was then used to interpret guided wave dispersion curves obtained by the OCE technique in bacterial biofilms developed in a rotating annular reactor, which allowed the quantitative characterization of biofilm shear modulus and viscosity. This study is the first to employ measurements of elastic wave propagation to characterize biofilms, and it provides a novel framework combining a theoretical model and an experimental approach for studying the relationship between the biofilm internal physical structure and mechanical properties.
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Affiliation(s)
- Hong-Cin Liou
- Mechanical Engineering Department, Northwestern University, Evanston, IL 60208, USA
| | - Fabrizio Sabba
- Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208, USA.
| | - Aaron I Packman
- Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208, USA.
| | - George Wells
- Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208, USA.
| | - Oluwaseyi Balogun
- Mechanical Engineering Department, Northwestern University, Evanston, IL 60208, USA and Civil and Environmental Engineering Department, Northwestern University, Evanston, IL 60208, USA.
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Zhu J, He X, Chen Z. Acoustic radiation force optical coherence elastography for elasticity assessment of soft tissues. APPLIED SPECTROSCOPY REVIEWS 2019; 54:457-481. [PMID: 31749516 PMCID: PMC6867804 DOI: 10.1080/05704928.2018.1467436] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Biomechanical properties of soft tissues are important indicators of tissue functions which can be used for clinical diagnosis and disease monitoring. Elastography, incorporating the principles of elasticity measurements into imaging modalities, provides quantitative assessment of elastic properties of biological tissues. Benefiting from high-resolution, noninvasive and three-dimensional optical coherence tomography (OCT), optical coherence elastography (OCE) is an emerging optical imaging modality to characterize and map biomechanical properties of soft tissues. Recently, acoustic radiation force (ARF) OCE has been developed for elasticity measurements of ocular tissues, detection of vascular lesions and monitoring of blood coagulation based on remote and noninvasive ARF excitation to both internal and superficial tissues. Here, we describe the advantages of the ARF-OCE technique, the measurement methods in ARF-OCE, the applications in biomedical detection, current challenges and advances. ARF-OCE technology has the potential to become a powerful tool for in vivo elasticity assessment of biological samples in a non-contact, non-invasive and high-resolution nature.
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Affiliation(s)
- Jiang Zhu
- Beckman Laser Institute, University of California, Irvine, Irvine, California 92612, USA
| | - Xingdao He
- Key Laboratory of Nondestructive Test (Ministry of Education), Nanchang Hangkong University, Nanchang 330063, China
| | - Zhongping Chen
- Beckman Laser Institute, University of California, Irvine, Irvine, California 92612, USA
- Key Laboratory of Nondestructive Test (Ministry of Education), Nanchang Hangkong University, Nanchang 330063, China
- Department of Biomedical Engineering, University of California, Irvine, Irvine, California 92697, USA
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36
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Song S, Xu J, Wang R. Flexible wide-field optical micro-angiography based on Fourier-domain multiplexed dual-beam swept source optical coherence tomography. JOURNAL OF BIOPHOTONICS 2018; 11:10.1002/jbio.201700203. [PMID: 28941235 PMCID: PMC5839934 DOI: 10.1002/jbio.201700203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/13/2017] [Accepted: 09/14/2017] [Indexed: 05/19/2023]
Abstract
Wide-field optical coherence tomography angiography (OCTA) is gaining interest in clinical imaging applications. In this pursuit, it is challenging to maintain the imaging resolution and sensitivity throughout the wide field of view (FoV). Here, we propose a novel method/system of dual-beam arrangement and Fourier-domain multiplexing to achieve wide-field OCTA when imaging the uneven surface samples. The proposed system provides 2 separate FoVs, with flexibility that the imaging area, focus of the imaging beam and imaging depth range can be individually adjusted for each FoV, leading to either (1) increased system imaging FoV or (2) capability of targeting 2 regions of interests that locate at depths with large difference between each other. We demonstrate this novel method by employing 100 kHz laser source in a swept source OCTA to achieve an effective 200 kHz sweeping rate, covering a 22 × 22 mm FoV. The results are verified by a SS-OCTA system employing a 200 kHz laser source, together with the experimental demonstrations when imaging whole brain vasculature in rodent models and skin blood perfusion in human fingers, show-casing the capability of proposed system to image live large samples with complex surface topography.
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Affiliation(s)
- Shaozhen Song
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
| | - Jingjiang Xu
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
| | - Ruikang Wang
- Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA
- Department of Ophthalmology, University of Washington, Seattle, Washington 98195, USA
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37
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Seo JB, Yoon SH, Lee JY, Kim JK, Yoo JS. What Is the Most Effective Eccentric Stretching Position in Lateral Elbow Tendinopathy? Clin Orthop Surg 2018; 10:47-54. [PMID: 29564047 PMCID: PMC5851854 DOI: 10.4055/cios.2018.10.1.47] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 10/08/2017] [Indexed: 01/06/2023] Open
Abstract
Background A variety of treatment options suggest that the optimal treatment strategy for lateral elbow tendinopathy (LET) is not known, and further research is needed to discover the most effective treatment for LET. The purpose of the present study was to verify the most effective position of eccentric stretching for the extensor carpi radialis brevis (ECRB) in vivo using ultrasonic shear wave elastography. Methods A total of 20 healthy males participated in this study. Resting position was defined as 90° elbow flexion and neutral position of the forearm and wrist. Elongation of the ECRB was measured for four stretching maneuvers (forearm supination/pronation and wrist extension/flexion) at two elbow angles (90° flexion and full extension). The shear elastic modulus, used as the index of muscle elongation, was computed using ultrasonic shear wave elastography for the eight aforementioned stretching maneuverangle combinations. Results The shear elastic modulus was the highest in elbow extension, forearm pronation, and wrist flexion. The shear elastic moduli of wrist flexion with any forearm and elbow position were significantly higher than the resting position. There was no significant difference associated with elbow and forearm positions except for elbow extension, forearm pronation, and wrist flexion positions. Conclusions This study determined that elbow extension, forearm pronation, and wrist flexion was the most effective eccentric stretching for the ECRB in vivo.
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Affiliation(s)
- Joong-Bae Seo
- Department of Orthopedic Surgery, Dankook University College of Medicine, Cheonan, Korea
| | - Sung-Hyun Yoon
- Department of Orthopedic Surgery, Dankook University College of Medicine, Cheonan, Korea
| | - Joon-Yeul Lee
- Department of Orthopedic Surgery, Dankook University College of Medicine, Cheonan, Korea
| | - Jun-Kyom Kim
- Department of Orthopedic Surgery, Dankook University College of Medicine, Cheonan, Korea
| | - Jae-Sung Yoo
- Department of Orthopedic Surgery, Dankook University College of Medicine, Cheonan, Korea
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38
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Zhou K, Le N, Huang Z, Li C. High-intensity-focused ultrasound and phase-sensitive optical coherence tomography for high resolution surface acoustic wave elastography. JOURNAL OF BIOPHOTONICS 2018; 11. [PMID: 28700131 DOI: 10.1002/jbio.201700051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 06/27/2017] [Accepted: 06/29/2017] [Indexed: 05/04/2023]
Abstract
Elastography has the ability of quantitatively evaluating the mechanical properties of soft tissue; thus it is helpful for diagnosis and treatment monitoring of many diseases, for example, skin diseases. Surface acoustic waves (SAWs) have been proven to be a non-invasive, non-destructive method for accurate characterization of tissue elastic properties. Current SAW elastography using high-energy laser pulse or mechanical shaker still have some problems. In order to improve SAW elastography in medical application, a new technique was proposed in this paper, which combines high-intensity-focused ultrasound as a SAWs impulse inducer and phase-sensitive optical coherence tomography as a SAWs detector. A 2% agar-agar phantom and ex-vivo porcine skin were tested. The data were processed by a new algorithm based on the Fourier analysis. The results show that the proposed method has the capability of quantifying the elastic properties of soft tissue-mimicking materials. The lateral resolution of the elastogram has been significantly improved and the different layers in heterogeneous material could also been distinguished. Our improved technique of SAW elastography has a large potential to be widely applied in clinical use for skin disease diagnosis and treatment monitoring.
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Affiliation(s)
- Kanheng Zhou
- School of Science and Engineering, University of Dundee, Dundee, UK
| | - Nhan Le
- School of Science and Engineering, University of Dundee, Dundee, UK
| | - Zhihong Huang
- School of Science and Engineering, University of Dundee, Dundee, UK
| | - Chunhui Li
- School of Science and Engineering, University of Dundee, Dundee, UK
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39
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Kirby MA, Pelivanov I, Song S, Ambrozinski Ł, Yoon SJ, Gao L, Li D, Shen TT, Wang RK, O’Donnell M. Optical coherence elastography in ophthalmology. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:1-28. [PMID: 29275544 PMCID: PMC5745712 DOI: 10.1117/1.jbo.22.12.121720] [Citation(s) in RCA: 120] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 12/14/2017] [Indexed: 05/03/2023]
Abstract
Optical coherence elastography (OCE) can provide clinically valuable information based on local measurements of tissue stiffness. Improved light sources and scanning methods in optical coherence tomography (OCT) have led to rapid growth in systems for high-resolution, quantitative elastography using imaged displacements and strains within soft tissue to infer local mechanical properties. We describe in some detail the physical processes underlying tissue mechanical response based on static and dynamic displacement methods. Namely, the assumptions commonly used to interpret displacement and strain measurements in terms of tissue elasticity for static OCE and propagating wave modes in dynamic OCE are discussed with the ultimate focus on OCT system design for ophthalmic applications. Practical OCT motion-tracking methods used to map tissue elasticity are also presented to fully describe technical developments in OCE, particularly noting those focused on the anterior segment of the eye. Clinical issues and future directions are discussed in the hope that OCE techniques will rapidly move forward to translational studies and clinical applications.
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Affiliation(s)
- Mitchell A. Kirby
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Ivan Pelivanov
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Shaozhen Song
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Łukasz Ambrozinski
- Akademia Górniczo-Hutnicza University of Science and Technology, Krakow, Poland
| | - Soon Joon Yoon
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Liang Gao
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - David Li
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
- University of Washington, Department of Chemical Engineering, Seattle, Washington, United States
| | - Tueng T. Shen
- University of Washington, Department of Ophthalmology, Seattle, Washington, United States
| | - Ruikang K. Wang
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
- University of Washington, Department of Ophthalmology, Seattle, Washington, United States
| | - Matthew O’Donnell
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
- Address all correspondence to: Matthew O’Donnell, E-mail:
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40
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Lan G, Singh M, Larin KV, Twa MD. Common-path phase-sensitive optical coherence tomography provides enhanced phase stability and detection sensitivity for dynamic elastography. BIOMEDICAL OPTICS EXPRESS 2017; 8:5253-5266. [PMID: 29188118 PMCID: PMC5695968 DOI: 10.1364/boe.8.005253] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 10/16/2017] [Accepted: 10/23/2017] [Indexed: 05/08/2023]
Abstract
Phase-sensitive optical coherence elastography (PhS-OCE) is an emerging optical technique to quantify soft-tissue biomechanical properties. We implemented a common-path OCT design to enhance displacement sensitivity and optical phase stability for dynamic elastography imaging. The background phase stability was greater in common-path PhS-OCE (0.24 ± 0.07nm) than conventional PhS-OCE (1.60 ± 0.11μm). The coefficient of variation for surface displacement measurements using conventional PhS-OCE averaged 11% versus 2% for common-path PhS-OCE. Young's modulus estimates showed good precision (95% CIs) for tissue phantoms: 24.96 ± 2.18kPa (1% agar), 49.69 ± 4.87kPa (1.5% agar), and 116.08 ± 12.14kPa (2% agar), respectively. Common-path PhS-OCE effectively reduced the amplitude of background dynamic optical phase instability to a sub-nanometer level, which provided a larger dynamic detection range and higher detection sensitivity for surface displacement measurements than conventional PhS-OCE.
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Affiliation(s)
- Gongpu Lan
- School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Manmohan Singh
- Biomedical Engineering, University of Houston, Houston, TX, USA
| | - Kirill V. Larin
- Biomedical Engineering, University of Houston, Houston, TX, USA
- Interdisciplinary Laboratory of Biophotonics, Tomsk State University, Tomsk, Russia
| | - Michael D. Twa
- School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA
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41
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Song S, Xu J, Men S, Shen TT, Wang RK. Robust numerical phase stabilization for long-range swept-source optical coherence tomography. JOURNAL OF BIOPHOTONICS 2017; 10:1398-1410. [PMID: 28485132 PMCID: PMC5831409 DOI: 10.1002/jbio.201700034] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 03/28/2017] [Accepted: 04/03/2017] [Indexed: 05/03/2023]
Abstract
A novel phase stabilization technique is demonstrated with significant improvement in the phase stability of a micro-electromechanical (MEMS) vertical cavity surface-emitting laser (VCSEL) based swept-source optical coherence tomography (SS-OCT) system. Without any requirements of hardware modifications, the new fully numerical phase stabilization technique features high tolerance to acquisition jitter, and significantly reduced budget in computational effort. We demonstrate that when measured with biological tissue, this technique enables a phase sensitivity of 89 mrad in highly scattering tissue, with image ranging distance of up to 12.5 mm at A-line scan rate of 100.3 kHz. We further compare the performances delivered by the phase-stabilization approach with conventional numerical approach for accuracy and computational efficiency. Imaging result of complex signal-based optical coherence tomography angiography (OCTA) and Doppler OCTA indicate that the proposed phase stabilization technique is robust, and efficient in improving the image contrast-to-noise ratio and extending OCTA depth range. The proposed technique can be universally applied to improve phase-stability in generic SS-OCT with different scale of scan rates without a need for special treatment.
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Affiliation(s)
- Shaozhen Song
- University of Washington, Department of Bioengineering, Seattle, WA 98195, USA
| | - Jingjiang Xu
- University of Washington, Department of Bioengineering, Seattle, WA 98195, USA
| | - Shaojie Men
- University of Washington, Department of Bioengineering, Seattle, WA 98195, USA
| | - Tueng T Shen
- University of Washington, Department of Bioengineering, Seattle, WA 98195, USA
- University of Washington, Department of Ophthalmology, Seattle, WA 98195, USA
| | - Ruikang K Wang
- University of Washington, Department of Bioengineering, Seattle, WA 98195, USA
- University of Washington, Department of Ophthalmology, Seattle, WA 98195, USA
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42
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Zhu J, Miao Y, Qi L, Qu Y, He Y, Yang Q, Chen Z. Longitudinal shear wave imaging for elasticity mapping using optical coherence elastography. APPLIED PHYSICS LETTERS 2017; 110:201101. [PMID: 28611483 PMCID: PMC5432373 DOI: 10.1063/1.4983292] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 03/28/2017] [Indexed: 05/18/2023]
Abstract
Shear wave measurements for the determination of tissue elastic properties have been used in clinical diagnosis and soft tissue assessment. A shear wave propagates as a transverse wave where vibration is perpendicular to the wave propagation direction. Previous transverse shear wave measurements could detect the shear modulus in the lateral region of the force; however, they could not provide the elastic information in the axial region of the force. In this study, we report the imaging and quantification of longitudinal shear wave propagation using optical coherence tomography to measure the elastic properties along the force direction. The experimental validation and finite element simulations show that the longitudinal shear wave propagates along the vibration direction as a plane wave in the near field of a planar source. The wave velocity measurement can quantify the shear moduli in a homogeneous phantom and a side-by-side phantom. Combining the transverse shear wave and longitudinal shear wave measurements, this system has great potential to detect the directionally dependent elastic properties in tissues without a change in the force direction.
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Affiliation(s)
- Jiang Zhu
- Beckman Laser Institute, University of California, Irvine, Irvine, California 92612, USA
| | | | - Li Qi
- Beckman Laser Institute, University of California, Irvine, Irvine, California 92612, USA
| | | | | | - Qiang Yang
- Beckman Laser Institute, University of California, Irvine, Irvine, California 92612, USA
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43
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Full-Field Optical Coherence Tomography as a Diagnosis Tool: Recent Progress with Multimodal Imaging. APPLIED SCIENCES-BASEL 2017. [DOI: 10.3390/app7030236] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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44
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Liu CH, Schill A, Raghunathan R, Wu C, Singh M, Han Z, Nair A, Larin KV. Ultra-fast line-field low coherence holographic elastography using spatial phase shifting. BIOMEDICAL OPTICS EXPRESS 2017; 8:993-1004. [PMID: 28270998 PMCID: PMC5330560 DOI: 10.1364/boe.8.000993] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 01/16/2017] [Accepted: 01/16/2017] [Indexed: 05/02/2023]
Abstract
Optical coherence elastography (OCE) is an emerging technique for quantifying tissue biomechanical properties. Generally, OCE relies on point-by-point scanning. However, long acquisition times make point-by-point scanning unfeasible for clinical use. Here we demonstrate a noncontact single shot line-field low coherence holography system utilizing an automatic Hilbert transform analysis based on a spatial phase shifting technique. Spatio-temporal maps of elastic wave propagation were acquired with only one air-pulse excitation and used to quantify wave velocity and sample mechanical properties at a line rate of 200 kHz. Results obtained on phantoms were correlated with data from mechanical testing. Finally, the stiffness of porcine cornea at different intraocular pressures was also quantified in situ.
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Affiliation(s)
- Chih-Hao Liu
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, Texas 77204, USA
| | - Alexander Schill
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, Texas 77204, USA
| | - Raksha Raghunathan
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, Texas 77204, USA
| | - Chen Wu
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, Texas 77204, USA
| | - Manmohan Singh
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, Texas 77204, USA
| | - Zhaolong Han
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, Texas 77204, USA
| | - Achuth Nair
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, Texas 77204, USA
| | - Kirill V. Larin
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, Texas 77204, USA
- Interdisciplinary Laboratory of Biophotonics, Tomsk State University, Tomsk, Russia
- Molecular Physiology and Biophysics, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77584, USA
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45
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Larin KV, Sampson DD. Optical coherence elastography - OCT at work in tissue biomechanics [Invited]. BIOMEDICAL OPTICS EXPRESS 2017; 8:1172-1202. [PMID: 28271011 PMCID: PMC5330567 DOI: 10.1364/boe.8.001172] [Citation(s) in RCA: 223] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 01/18/2017] [Accepted: 01/19/2017] [Indexed: 05/18/2023]
Abstract
Optical coherence elastography (OCE), as the use of OCT to perform elastography has come to be known, began in 1998, around ten years after the rest of the field of elastography - the use of imaging to deduce mechanical properties of tissues. After a slow start, the maturation of OCT technology in the early to mid 2000s has underpinned a recent acceleration in the field. With more than 20 papers published in 2015, and more than 25 in 2016, OCE is growing fast, but still small compared to the companion fields of cell mechanics research methods, and medical elastography. In this review, we describe the early developments in OCE, and the factors that led to the current acceleration. Much of our attention is on the key recent advances, with a strong emphasis on future prospects, which are exceptionally bright.
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Affiliation(s)
- Kirill V Larin
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Blvd., Houston, Texas 77204-5060, USA; Department of Molecular Physiology and Biophysics, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas 77030, USA;
| | - David D Sampson
- Optical + Biomedical Engineering Laboratory, School of Electrical, Electronic & Computer Engineering, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia; Centre for Microscopy, Characterisation & Analysis, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia;
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46
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Elyas E, Grimwood A, Erler JT, Robinson SP, Cox TR, Woods D, Clowes P, De Luca R, Marinozzi F, Fromageau J, Bamber JC. Multi-Channel Optical Coherence Elastography Using Relative and Absolute Shear-Wave Time of Flight. PLoS One 2017; 12:e0169664. [PMID: 28107368 PMCID: PMC5249105 DOI: 10.1371/journal.pone.0169664] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 12/20/2016] [Indexed: 11/18/2022] Open
Abstract
Elastography, the imaging of elastic properties of soft tissues, is well developed for macroscopic clinical imaging of soft tissues and can provide useful information about various pathological processes which is complementary to that provided by the original modality. Scaling down of this technique should ply the field of cellular biology with valuable information with regard to elastic properties of cells and their environment. This paper evaluates the potential to develop such a tool by modifying a commercial optical coherence tomography (OCT) device to measure the speed of shear waves propagating in a three-dimensional (3D) medium. A needle, embedded in the gel, was excited to vibrate along its long axis and the displacement as a function of time and distance from the needle associated with the resulting shear waves was detected using four M-mode images acquired simultaneously using a commercial four-channel swept-source OCT system. Shear-wave time of arrival (TOA) was detected by tracking the axial OCT-speckle motion using cross-correlation methods. Shear-wave speed was then calculated from inter-channel differences of TOA for a single burst (the relative TOA method) and compared with the shear-wave speed determined from positional differences of TOA for a single channel over multiple bursts (the absolute TOA method). For homogeneous gels the relative method provided shear-wave speed with acceptable precision and accuracy when judged against the expected linear dependence of shear modulus on gelatine concentration (R2 = 0.95) and ultimate resolution capabilities limited by 184μm inter-channel distance. This overall approach shows promise for its eventual provision as a research tool in cancer cell biology. Further work is required to optimize parameters such as vibration frequency, burst length and amplitude, and to assess the lateral and axial resolutions of this type of device as well as to create 3D elastograms.
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Affiliation(s)
- Eli Elyas
- CRUK Imaging Centre, Division of Radiotherapy and Imaging, Institute of Cancer Research, Sutton, Surrey, United Kingdom
- Joint Department of Physics, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom
| | - Alex Grimwood
- Department of Medical Physics, Royal Surrey County Hospital, Guildford, Surrey, United Kingdom
| | - Janine T. Erler
- Biotech Research & Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Simon P. Robinson
- CRUK Imaging Centre, Division of Radiotherapy and Imaging, Institute of Cancer Research, Sutton, Surrey, United Kingdom
| | - Thomas R. Cox
- Biotech Research & Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Daniel Woods
- Michelson Diagnostics, 1 Grays Farm Production Village, Orpington, Kent, United Kingdom
| | - Peter Clowes
- Joint Department of Physics, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom
| | - Ramona De Luca
- CRUK Imaging Centre, Division of Radiotherapy and Imaging, Institute of Cancer Research, Sutton, Surrey, United Kingdom
- Joint Department of Physics, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom
- Department of Mechanical and Aerospace Engineering, Sapienza University of Rome, Rome, Italy
| | - Franco Marinozzi
- Department of Mechanical and Aerospace Engineering, Sapienza University of Rome, Rome, Italy
| | - Jérémie Fromageau
- CRUK Imaging Centre, Division of Radiotherapy and Imaging, Institute of Cancer Research, Sutton, Surrey, United Kingdom
- Joint Department of Physics, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom
| | - Jeffrey C. Bamber
- CRUK Imaging Centre, Division of Radiotherapy and Imaging, Institute of Cancer Research, Sutton, Surrey, United Kingdom
- Joint Department of Physics, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom
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47
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Ambroziński Ł, Song S, Yoon SJ, Pelivanov I, Li D, Gao L, Shen TT, Wang RK, O'Donnell M. Acoustic micro-tapping for non-contact 4D imaging of tissue elasticity. Sci Rep 2016; 6:38967. [PMID: 28008920 PMCID: PMC5180181 DOI: 10.1038/srep38967] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 11/15/2016] [Indexed: 01/22/2023] Open
Abstract
Elastography plays a key role in characterizing soft media such as biological tissue. Although this technology has found widespread use in both clinical diagnostics and basic science research, nearly all methods require direct physical contact with the object of interest and can even be invasive. For a number of applications, such as diagnostic measurements on the anterior segment of the eye, physical contact is not desired and may even be prohibited. Here we present a fundamentally new approach to dynamic elastography using non-contact mechanical stimulation of soft media with precise spatial and temporal shaping. We call it acoustic micro-tapping (AμT) because it employs focused, air-coupled ultrasound to induce significant mechanical displacement at the boundary of a soft material using reflection-based radiation force. Combining it with high-speed, four-dimensional (three space dimensions plus time) phase-sensitive optical coherence tomography creates a non-contact tool for high-resolution and quantitative dynamic elastography of soft tissue at near real-time imaging rates. The overall approach is demonstrated in ex-vivo porcine cornea.
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Affiliation(s)
- Łukasz Ambroziński
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA.,AGH University of Science and Technology, Krakow, Poland
| | - Shaozhen Song
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Soon Joon Yoon
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Ivan Pelivanov
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA.,Faculty of Physics, Moscow State University, Moscow, 119991, Russia
| | - David Li
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA.,Department of Chemical Engineering, University of Washington, Seattle, WA 98195, USA
| | - Liang Gao
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Tueng T Shen
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA.,Department of Ophthalmology, University of Washington, Seattle, WA 98104, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA.,Department of Ophthalmology, University of Washington, Seattle, WA 98104, USA
| | - Matthew O'Donnell
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
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48
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Nguyen TM, Zorgani A, Lescanne M, Boccara C, Fink M, Catheline S. Diffuse shear wave imaging: toward passive elastography using low-frame rate spectral-domain optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:126013. [PMID: 27999863 DOI: 10.1117/1.jbo.21.12.126013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 12/01/2016] [Indexed: 05/18/2023]
Abstract
Optical coherence tomography (OCT) can map the stiffness of biological tissue by imaging mechanical perturbations (shear waves) propagating in the tissue. Most shear wave elastography (SWE) techniques rely on active shear sources to generate controlled displacements that are tracked at ultrafast imaging rates. Here, we propose a noise-correlation approach to retrieve stiffness information from the imaging of diffuse displacement fields using low-frame rate spectral-domain OCT. We demonstrated the method on tissue-mimicking phantoms and validated the results by comparison with classic ultrafast SWE. Then we investigated the in vivo feasibility on the eye of an anesthetized rat by applying noise correlation to naturally occurring displacements. The results suggest a great potential for passive elastography based on the detection of natural pulsatile motions using conventional spectral-domain OCT systems. This would facilitate the transfer of OCT-elastography to clinical practice, in particular, in ophthalmology or dermatology.
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Affiliation(s)
- Thu-Mai Nguyen
- Institut Langevin Ondes et Images, ESPCI Paris, Université Paris-Sciences-Lettres, CNRS UMR 7587, Inserm U979-1 rue Jussieu, 75005 Paris, France
| | - Ali Zorgani
- Laboratory of Therapeutic Applications of Ultrasound, Inserm U1032-151 cours Albert Thomas, 69003 Lyon, France
| | - Maxime Lescanne
- Laboratory of Therapeutic Applications of Ultrasound, Inserm U1032-151 cours Albert Thomas, 69003 Lyon, France
| | - Claude Boccara
- Institut Langevin Ondes et Images, ESPCI Paris, Université Paris-Sciences-Lettres, CNRS UMR 7587, Inserm U979-1 rue Jussieu, 75005 Paris, France
| | - Mathias Fink
- Institut Langevin Ondes et Images, ESPCI Paris, Université Paris-Sciences-Lettres, CNRS UMR 7587, Inserm U979-1 rue Jussieu, 75005 Paris, France
| | - Stefan Catheline
- Laboratory of Therapeutic Applications of Ultrasound, Inserm U1032-151 cours Albert Thomas, 69003 Lyon, France
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49
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Hsieh BY, Song S, Nguyen TM, Yoon SJ, Shen TT, Wang RK, O’Donnell M. Moving-source elastic wave reconstruction for high-resolution optical coherence elastography. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:116006. [PMID: 27822580 PMCID: PMC5995137 DOI: 10.1117/1.jbo.21.11.116006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/18/2016] [Indexed: 05/03/2023]
Abstract
Optical coherence tomography (OCT)-based elasticity imaging can map soft tissue elasticity based on speckle-tracking of elastic wave propagation using highly sensitive phase measurements of OCT signals. Using a fixed elastic wave source and moving detection, current imaging sequences have difficulty in reconstructing tissue elasticity within speckle-free regions, for example, within the crystalline lens of the eye. We present a moving acoustic radiation force imaging sequence to reconstruct elastic properties within a speckle-free region by tracking elastic wave propagation from multiple laterally moving sources across the field of view. We demonstrate the proposed strategy using heterogeneous and partial speckle-free tissue-mimicking phantoms. Harder inclusions within the speckle-free region can be detected, and the contrast-to-noise ratio slightly enhanced compared to current OCE imaging sequences. The results suggest that a moving source approach may be appropriate for OCE studies within the large speckle-free regions of the crystalline lens.
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Affiliation(s)
- Bao-Yu Hsieh
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, P. O. Box 355013, Seattle, Washington 98105, United States
- China Medical University, Department of Biomedical Imaging and Radiological Science, 91 Hsueh-Shih Road, Taichung 40402, Taiwan
- Address all correspondence to: Bao-Yu Hsieh, E-mail:
| | - Shaozhen Song
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, P. O. Box 355013, Seattle, Washington 98105, United States
| | - Thu-Mai Nguyen
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, P. O. Box 355013, Seattle, Washington 98105, United States
| | - Soon Joon Yoon
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, P. O. Box 355013, Seattle, Washington 98105, United States
| | - Tueng T. Shen
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, P. O. Box 355013, Seattle, Washington 98105, United States
- University of Washington, Department of Ophthalmology, 325 9th Avenue, Seattle, Washington 98104, United States
| | - Ruikang K. Wang
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, P. O. Box 355013, Seattle, Washington 98105, United States
- University of Washington, Department of Ophthalmology, 325 9th Avenue, Seattle, Washington 98104, United States
| | - Matthew O’Donnell
- University of Washington, Department of Bioengineering, 3720 15th Avenue NE, P. O. Box 355013, Seattle, Washington 98105, United States
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50
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3D mapping of elastic modulus using shear wave optical micro-elastography. Sci Rep 2016; 6:35499. [PMID: 27762276 PMCID: PMC5071855 DOI: 10.1038/srep35499] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 09/30/2016] [Indexed: 12/31/2022] Open
Abstract
Elastography provides a powerful tool for histopathological identification and clinical diagnosis based on information from tissue stiffness. Benefiting from high resolution, three-dimensional (3D), and noninvasive optical coherence tomography (OCT), optical micro-elastography has the ability to determine elastic properties with a resolution of ~10 μm in a 3D specimen. The shear wave velocity measurement can be used to quantify the elastic modulus. However, in current methods, shear waves are measured near the surface with an interference of surface waves. In this study, we developed acoustic radiation force (ARF) orthogonal excitation optical coherence elastography (ARFOE-OCE) to visualize shear waves in 3D. This method uses acoustic force perpendicular to the OCT beam to excite shear waves in internal specimens and uses Doppler variance method to visualize shear wave propagation in 3D. The measured propagation of shear waves agrees well with the simulation results obtained from finite element analysis (FEA). Orthogonal acoustic excitation allows this method to measure the shear modulus in a deeper specimen which extends the elasticity measurement range beyond the OCT imaging depth. The results show that the ARFOE-OCE system has the ability to noninvasively determine the 3D elastic map.
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