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Kim GS, Moon HH, Lee HS, Jeong JS. Compound Acoustic Radiation Force Impulse Imaging of Bovine Eye by Using Phase-Inverted Ultrasound Transducer. SENSORS (BASEL, SWITZERLAND) 2024; 24:2700. [PMID: 38732804 PMCID: PMC11085659 DOI: 10.3390/s24092700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 04/19/2024] [Accepted: 04/22/2024] [Indexed: 05/13/2024]
Abstract
In general, it is difficult to visualize internal ocular structure and detect a lesion such as a cataract or glaucoma using the current ultrasound brightness-mode (B-mode) imaging. This is because the internal structure of the eye is rich in moisture, resulting in a lack of contrast between tissues in the B-mode image, and the penetration depth is low due to the attenuation of the ultrasound wave. In this study, the entire internal ocular structure of a bovine eye was visualized in an ex vivo environment using the compound acoustic radiation force impulse (CARFI) imaging scheme based on the phase-inverted ultrasound transducer (PIUT). In the proposed method, the aperture of the PIUT is divided into four sections, and the PIUT is driven by the out-of-phase input signal capable of generating split-focusing at the same time. Subsequently, the compound imaging technique was employed to increase signal-to-noise ratio (SNR) and to reduce displacement error. The experimental results demonstrated that the proposed technique could provide an acoustic radiation force impulse (ARFI) image of the bovine eye with a broader depth-of-field (DOF) and about 80% increased SNR compared to the conventional ARFI image obtained using the in-phase input signal. Therefore, the proposed technique can be one of the useful techniques capable of providing the image of the entire ocular structure to diagnose various eye diseases.
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Affiliation(s)
| | | | | | - Jong Seob Jeong
- Department of Biomedical Engineering, Dongguk University, Seoul 04620, Republic of Korea; (G.S.K.); (H.H.M.); (H.S.L.)
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2
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Zhang F, Li R, Li Y, Zhu Z, Zhou Q, Chen Z. Quantitative Optical Coherence Elastography of the Optic Nerve Head In Vivo. IEEE Trans Biomed Eng 2024; 71:732-737. [PMID: 37721876 PMCID: PMC11224776 DOI: 10.1109/tbme.2023.3316606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/20/2023]
Abstract
OBJECTIVE Optical coherence elastography (OCE) was used to demonstrate the relationship between the elasticity of the optic nerve head (ONH) and different intraocular pressure (IOP) levels in an in-vivo rabbit model for the first time. METHOD Both ex-vivo and in-vivo rabbit ONH were imaged using OCE system. A mechanical shaker initiated the propagation of elastic waves, and the elasticity of the ONH was determined by tracking the wave propagation speed. The elasticity of the ONH under varying IOP levels was reconstructed based on the wave speed. Notably, the ONH exhibited increased stiffness with elevated IOP. RESULTS In the in-vivo rabbit models, the Young's modulus of ONH increased from 14 kPa to 81 kPa with the IOP increased from 15 mmHg to 35 mmHg. This revealed a positive correlation between the Young's modulus of the ONH and intraocular pressure. CONCLUSION The OCE system proved effective in measuring the mechanical properties of ONH at different IOP levels, with validation in an in-vivo rabbit model. SIGNIFICANCE Considering ONH plays a critical role in vision and eye diseases, the capability to image and quantify in vivo ONH biomechanical properties has great potential to advance vision science research and improve the clinical management of glaucoma patients.
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3
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Zhu Y, Shi J, Alvarez-arenas TEG, Li C, Wang H, Cai H, Zhang D, He X, Wu X. Supershear Rayleigh wave imaging for quantitative assessment of biomechanical properties of brain using air-coupled optical coherence elastography. APL Bioeng 2023; 7:046107. [PMID: 37915751 PMCID: PMC10618026 DOI: 10.1063/5.0160213] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 10/12/2023] [Indexed: 11/03/2023] Open
Abstract
Recently, supershear Rayleigh waves (SRWs) have been proposed to characterize the biomechanical properties of soft tissues. The SRWs propagate along the surface of the medium, unlike surface Rayleigh waves, SRWs propagate faster than bulk shear waves. However, their behavior and application in biological tissues is still elusive. In brain tissue elastography, shear waves combined with magnetic resonance elastography or ultrasound elastography are generally used to quantify the shear modulus, but high spatial resolution elasticity assessment in 10 μm scale is still improving. Here, we develop an air-coupled ultrasonic transducer for noncontact excitation of SRWs and Rayleigh waves in brain tissue, use optical coherent elastography (OCE) to detect, and reconstruct the SRW propagation process; in combing with a derived theoretical model of SRWs on a free boundary surface, we quantify the shear modulus of brain tissue with high spatial resolution. We first complete validation experiments using a homogeneous isotropic agar phantom, and the experimental results clearly show the SRW is 1.9649 times faster than the bulk shear waves. Furthermore, the propagation velocity of SRWs in both the frontal and parietal lobe regions of the brain is all 1.87 times faster than the bulk shear wave velocity. Finally, we evaluated the anisotropy in different brain regions, and the medulla oblongata region had the highest anisotropy index. Our study shows that the OCE system using the SRW model is a new potential approach for high-resolution assessment of the biomechanical properties of brain tissue.
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Affiliation(s)
| | - Jiulin Shi
- School of Testing and Opto-electric Engineering, Nanchang Hangkong University, Nanchang 330063, China
| | - Tomas E. Gomez Alvarez-arenas
- Ultrasonic and Sensors Technologies Department, Information and Physical Technologies Institute, Spanish National Research Council, Serrano 144, 28006 Madrid, Spain
| | - Chenxi Li
- School of Testing and Opto-electric Engineering, Nanchang Hangkong University, Nanchang 330063, China
| | - Haohao Wang
- School of Testing and Opto-electric Engineering, Nanchang Hangkong University, Nanchang 330063, China
| | - Hongling Cai
- School of Physics, Nanjing University, Nanjing 210093, China
| | - Dong Zhang
- School of Physics, Nanjing University, Nanjing 210093, China
| | - Xingdao He
- School of Testing and Opto-electric Engineering, Nanchang Hangkong University, Nanchang 330063, China
| | - Xiaoshan Wu
- School of Physics, Nanjing University, Nanjing 210093, China
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4
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Gong C, Li R, Lu G, Ji J, Zeng Y, Chen J, Chang C, Zhang J, Xia L, Nair DSR, Thomas BB, Song BJ, Humayun MS, Zhou Q. Non-Invasive Hybrid Ultrasound Stimulation of Visual Cortex In Vivo. Bioengineering (Basel) 2023; 10:bioengineering10050577. [PMID: 37237647 DOI: 10.3390/bioengineering10050577] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/06/2023] [Accepted: 05/08/2023] [Indexed: 05/28/2023] Open
Abstract
The optic nerve is the second cranial nerve (CN II) that connects and transmits visual information between the retina and the brain. Severe damage to the optic nerve often leads to distorted vision, vision loss, and even blindness. Such damage can be caused by various types of degenerative diseases, such as glaucoma and traumatic optic neuropathy, and result in an impaired visual pathway. To date, researchers have not found a viable therapeutic method to restore the impaired visual pathway; however, in this paper, a newly synthesized model is proposed to bypass the damaged portion of the visual pathway and set up a direct connection between a stimulated visual input and the visual cortex (VC) using Low-frequency Ring-transducer Ultrasound Stimulation (LRUS). In this study, by utilizing and integrating various advanced ultrasonic and neurological technologies, the following advantages are achieved by the proposed LRUS model: 1. This is a non-invasive procedure that uses enhanced sound field intensity to overcome the loss of ultrasound signal due to the blockage of the skull. 2. The simulated visual signal generated by LRUS in the visual-cortex-elicited neuronal response in the visual cortex is comparable to light stimulation of the retina. The result was confirmed by a combination of real-time electrophysiology and fiber photometry. 3. VC showed a faster response rate under LRUS than light stimulation through the retina. These results suggest a potential non-invasive therapeutic method for restoring vision in optic-nerve-impaired patients using ultrasound stimulation (US).
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Affiliation(s)
- Chen Gong
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
- USC Roski Eye Institute, Keck School of Medicine of University of Southern California, Los Angeles, CA 90033, USA
| | - Runze Li
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
- USC Roski Eye Institute, Keck School of Medicine of University of Southern California, Los Angeles, CA 90033, USA
| | - Gengxi Lu
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
- USC Roski Eye Institute, Keck School of Medicine of University of Southern California, Los Angeles, CA 90033, USA
| | - Jie Ji
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Yushun Zeng
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Jiawen Chen
- Department of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Chifeng Chang
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
- USC Roski Eye Institute, Keck School of Medicine of University of Southern California, Los Angeles, CA 90033, USA
| | - Junhang Zhang
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
- USC Roski Eye Institute, Keck School of Medicine of University of Southern California, Los Angeles, CA 90033, USA
| | - Lily Xia
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Deepthi S Rajendran Nair
- USC Roski Eye Institute, Keck School of Medicine of University of Southern California, Los Angeles, CA 90033, USA
| | - Biju B Thomas
- USC Roski Eye Institute, Keck School of Medicine of University of Southern California, Los Angeles, CA 90033, USA
| | - Brian J Song
- USC Roski Eye Institute, Keck School of Medicine of University of Southern California, Los Angeles, CA 90033, USA
| | - Mark S Humayun
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
- USC Roski Eye Institute, Keck School of Medicine of University of Southern California, Los Angeles, CA 90033, USA
| | - Qifa Zhou
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
- USC Roski Eye Institute, Keck School of Medicine of University of Southern California, Los Angeles, CA 90033, USA
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Batista A, Serranho P, Santos MJ, Correia C, Domingues JP, Loureiro C, Cardoso J, Barbeiro S, Morgado M, Bernardes R. Phase-Resolved Optical Coherence Elastography: An Insight into Tissue Displacement Estimation. SENSORS (BASEL, SWITZERLAND) 2023; 23:3974. [PMID: 37112314 PMCID: PMC10142248 DOI: 10.3390/s23083974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/03/2023] [Accepted: 04/12/2023] [Indexed: 06/19/2023]
Abstract
Robust methods to compute tissue displacements in optical coherence elastography (OCE) data are paramount, as they play a significant role in the accuracy of tissue elastic properties estimation. In this study, the accuracy of different phase estimators was evaluated on simulated OCE data, where the displacements can be accurately set, and on real data. Displacement (∆d) estimates were computed from (i) the original interferogram data (Δφori) and two phase-invariant mathematical manipulations of the interferogram: (ii) its first-order derivative (Δφd) and (iii) its integral (Δφint). We observed a dependence of the phase difference estimation accuracy on the initial depth location of the scatterer and the magnitude of the tissue displacement. However, by combining the three phase-difference estimates (Δdav), the error in phase difference estimation could be minimized. By using Δdav, the median root-mean-square error associated with displacement prediction in simulated OCE data was reduced by 85% and 70% in data with and without noise, respectively, in relation to the traditional estimate. Furthermore, a modest improvement in the minimum detectable displacement in real OCE data was also observed, particularly in data with low signal-to-noise ratios. The feasibility of using Δdav to estimate agarose phantoms' Young's modulus is illustrated.
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Affiliation(s)
- Ana Batista
- Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), Institute for Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, 3000-548 Coimbra, Portugal
- Department of Physics, Faculty of Science and Technology, University of Coimbra, 3004-531 Coimbra, Portugal
| | - Pedro Serranho
- Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), Institute for Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, 3000-548 Coimbra, Portugal
- Department of Science and Technology, Mathematics Section, Aberta University, 1250-100 Lisbon, Portugal
| | - Mário J. Santos
- Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Coimbra, 3004-531 Coimbra, Portugal
| | - Carlos Correia
- Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), Institute for Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, 3000-548 Coimbra, Portugal
| | - José P. Domingues
- Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), Institute for Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, 3000-548 Coimbra, Portugal
- Department of Physics, Faculty of Science and Technology, University of Coimbra, 3004-531 Coimbra, Portugal
| | - Custódio Loureiro
- Department of Physics, Faculty of Science and Technology, University of Coimbra, 3004-531 Coimbra, Portugal
| | - João Cardoso
- Department of Physics, Faculty of Science and Technology, University of Coimbra, 3004-531 Coimbra, Portugal
| | - Sílvia Barbeiro
- Department of Mathematics, CMUC, University of Coimbra, 3004-531 Coimbra, Portugal
| | - Miguel Morgado
- Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), Institute for Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, 3000-548 Coimbra, Portugal
- Department of Physics, Faculty of Science and Technology, University of Coimbra, 3004-531 Coimbra, Portugal
| | - Rui Bernardes
- Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), Institute for Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, 3000-548 Coimbra, Portugal
- Faculty of Medicine (FMUC), Clinical Academic Center of Coimbra (CACC), University of Coimbra, 3000-143 Coimbra, Portugal
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6
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Li R, Qian X, Gong C, Zhang J, Liu Y, Xu B, Humayun MS, Zhou Q. Simultaneous Assessment of the Whole Eye Biomechanics Using Ultrasonic Elastography. IEEE Trans Biomed Eng 2023; 70:1310-1317. [PMID: 36260593 PMCID: PMC10365545 DOI: 10.1109/tbme.2022.3215498] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Current elastography techniques in the field of ophthalmology usually target one specific tissue, such as the cornea or the sclera. However, the eye is an inter-related organ, and some ocular diseases can alter the biomechanical properties of multiple anatomical structures. Hence, there is a need to develop an imaging tool that can non-invasively, quantitatively, and accurately characterize dynamic changes among these biomechanical properties. METHODS A high resolution ultrasound elastography system was developed to achieve this goal. The efficacy and accuracy of the system was first validated on tissue-mimicking phantoms while mechanical testing measurements served as the gold standard. Next, an in vivo elevated intraocular pressure (IOP) model was established in rabbits to further test our system. In particular, elastography measurements were obtained at 5 IOP levels, ranging from 10 mmHg to 30 mmHg in 5 mmHg increments. Spatial-temporal maps of the multiple ocular tissues (cornea, lens, iris, optic nerve head, and peripapillary sclera) were obtained. RESULTS The spatial-temporal maps were acquired simultaneously for the ocular tissues at the 5 different IOP levels. The statistical analysis of the elastic wave speed was presented for ocular tissues. Finally, the mapping for the elastic wave speed of each ocular component was acquired at each IOP level. CONCLUSION Our elastography system can concurrently assess the biomechanical properties of multiple ocular structures and detect changes in biomechanical properties associated with changes in IOP. SIGNIFICANCE This system provides a novel tool to measure and quantify the biomechanical properties of the whole eye.
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7
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Rayes A, Zhang J, Lu G, Qian X, Schroff ST, Ryu R, Jiang X, Zhou Q. Estimating Thrombus Elasticity by Shear Wave Elastography to Evaluate Ultrasound Thrombolysis for Thrombus With Different Stiffness. IEEE Trans Biomed Eng 2023; 70:135-143. [PMID: 35759590 PMCID: PMC10370280 DOI: 10.1109/tbme.2022.3186586] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE There is uncertainty about deep vein thrombosis standard treatment as thrombus stiffness alters each case. Here, we investigated thrombus' stiffness of different compositions and ages using shear wave elastography (SWE). We then studied the effectiveness of ultrasound-thrombolysis on different thrombus compositions. METHODS Shear waves generated through mechanical shaker and traveled along thrombus of different hematocrit (HCT) levels, whereas 18-MHz ultrasound array used to detect wave propagation. Thrombus' stiffness was identified by the shear wave speed (SWS). In thrombolysis, a 3.2 MHz focused transducer was applied to different thrombus compositions using different powers. The thrombolysis rate was defined as the percentage of weight loss. RESULTS The estimated average SWS of 20%, 40%, and 60% HCT thrombus were 0.75 m/s, 0.44 m/s, and 0.32 m/s, respectively. For Thrombolysis, the percentage weight loss at 8 MPa Negative pressure for the same HCT groups were 23.1%, 35.29%, and 39.66% respectively. CONCLUSION SWS is inversely related to HCT level and positively related to thrombus age. High HCT thrombus had higher weight loss compared to low HCT. However, the difference between 20% and 40% HCT was more significant than between 40% and 60% HCT in both studies. Our results suggest that thrombus with higher SWS require more power to achieve the same thrombolysis rate as thrombus with lower SWS. SIGNIFICANCE Characterizing thrombus elastic property undergoing thrombolysis enables evaluation of ultrasound efficacy for fractionating thrombus and reveals the appropriate ultrasound parameters selection to achieve a certain thrombolysis rate in the case of a specific thrombus stiffness.
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Affiliation(s)
- Adnan Rayes
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
- Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Junhang Zhang
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
- Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Gengxi Lu
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
- Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Xuejun Qian
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
- Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Stuart T. Schroff
- Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
| | - Robert Ryu
- Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
| | - Xiaoning Jiang
- department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA
| | - Qifa Zhou
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
- Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
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8
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Zhang J, Murgoitio-Esandi J, Qian X, Li R, Gong C, Nankali A, Hao L, Xu BY, Kirk Shung K, Oberai A, Zhou Q. High-Frequency Ultrasound Elastography to Assess the Nonlinear Elastic Properties of the Cornea and Ciliary Body. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2022; 69:2621-2629. [PMID: 35820015 PMCID: PMC9547080 DOI: 10.1109/tuffc.2022.3190400] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Mechanical properties of the anterior anatomical structures of the eye, such as the cornea and ciliary body, play a key role in the ocular function and homeostasis. However, measuring the biomechanical properties of the anterior ocular structures, especially deeper structures, such as the ciliary body, remains a challenge due to the lack of high-resolution imaging tools. Herein, we implement a mechanical shaker-based high-frequency ultrasound elastography technique that can track the induced elastic wave propagation to assess the linear and nonlinear elastic properties of anterior ocular structures. The findings of this study advance our understanding of the role of anterior ocular structures in the pathogenesis of different ocular disorders, such as glaucoma.
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9
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Leitgeb R, Placzek F, Rank E, Krainz L, Haindl R, Li Q, Liu M, Andreana M, Unterhuber A, Schmoll T, Drexler W. Enhanced medical diagnosis for dOCTors: a perspective of optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210150-PER. [PMID: 34672145 PMCID: PMC8528212 DOI: 10.1117/1.jbo.26.10.100601] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 09/23/2021] [Indexed: 05/17/2023]
Abstract
SIGNIFICANCE After three decades, more than 75,000 publications, tens of companies being involved in its commercialization, and a global market perspective of about USD 1.5 billion in 2023, optical coherence tomography (OCT) has become one of the fastest successfully translated imaging techniques with substantial clinical and economic impacts and acceptance. AIM Our perspective focuses on disruptive forward-looking innovations and key technologies to further boost OCT performance and therefore enable significantly enhanced medical diagnosis. APPROACH A comprehensive review of state-of-the-art accomplishments in OCT has been performed. RESULTS The most disruptive future OCT innovations include imaging resolution and speed (single-beam raster scanning versus parallelization) improvement, new implementations for dual modality or even multimodality systems, and using endogenous or exogenous contrast in these hybrid OCT systems targeting molecular and metabolic imaging. Aside from OCT angiography, no other functional or contrast enhancing OCT extension has accomplished comparable clinical and commercial impacts. Some more recently developed extensions, e.g., optical coherence elastography, dynamic contrast OCT, optoretinography, and artificial intelligence enhanced OCT are also considered with high potential for the future. In addition, OCT miniaturization for portable, compact, handheld, and/or cost-effective capsule-based OCT applications, home-OCT, and self-OCT systems based on micro-optic assemblies or photonic integrated circuits will revolutionize new applications and availability in the near future. Finally, clinical translation of OCT including medical device regulatory challenges will continue to be absolutely essential. CONCLUSIONS With its exquisite non-invasive, micrometer resolution depth sectioning capability, OCT has especially revolutionized ophthalmic diagnosis and hence is the fastest adopted imaging technology in the history of ophthalmology. Nonetheless, OCT has not been completely exploited and has substantial growth potential-in academics as well as in industry. This applies not only to the ophthalmic application field, but also especially to the original motivation of OCT to enable optical biopsy, i.e., the in situ imaging of tissue microstructure with a resolution approaching that of histology but without the need for tissue excision.
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Affiliation(s)
- Rainer Leitgeb
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- Medical University of Vienna, Christian Doppler Laboratory OPTRAMED, Vienna, Austria
| | - Fabian Placzek
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Elisabet Rank
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Lisa Krainz
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Richard Haindl
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Qian Li
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Mengyang Liu
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Marco Andreana
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Angelika Unterhuber
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Tilman Schmoll
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- Carl Zeiss Meditec, Inc., Dublin, California, United States
| | - Wolfgang Drexler
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- Address all correspondence to Wolfgang Drexler,
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10
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Qian X, Li R, Lu G, Jiang L, Kang H, Kirk Shung K, Humayun MS, Zhou Q. Ultrasonic elastography to assess biomechanical properties of the optic nerve head and peripapillary sclera of the eye. ULTRASONICS 2021; 110:106263. [PMID: 33065466 PMCID: PMC7736296 DOI: 10.1016/j.ultras.2020.106263] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 08/13/2020] [Accepted: 09/22/2020] [Indexed: 05/30/2023]
Abstract
PURPOSE To quantitatively investigate both optic nerve head (ONH) and peripapillary sclera (PPS) biomechanical properties of porcine eyes through an ultrasonic elastography imaging system in response to both increasing and decreasing intraocular pressure (IOP). METHODS The Young's modulus of the ONH and PPS were assessed using our high resolution ultrasonic imaging system which utilized a mechanical shaker to induce shear waves and an off-axis aligned 40 MHz needle transducer to track micron-level displacement along the direction of wave propagation. In this study, imaging on a total of 8 ex vivo porcine eyes preloaded with IOPs from 6 mmHg to 30 mmHg was performed. To have a better understanding of the effect of varying IOP on biomechanics, both increasing and decreasing IOPs were investigated. RESULTS The increase of the Young's modulus of ONH (92.4 ± 13.9 kPa at 6 mmHg to 224.7 ± 71.1 kPa at 30 mmHg) and PPS (176.8 ± 14.3 kPa at 6 mmHg to 573.5 ± 64.4 kPa at 30 mmHg) following IOP elevation could be observed in the reconstructed Young's modulus of the shear wave elasticity (SWE) imaging while the B-mode structural images remained almost unchanged. In addition, for the same IOP level, both ONH and PPS have a tendency to be stiffer with decreasing IOP as compared to increasing IOP. CONCLUSIONS Our results demonstrate the feasibility of using our ultrasonic elastography system to investigate the stiffness mapping of posterior eye with high resolution in both increasing and decreasing IOPs, making this technique potentially useful for glaucoma.
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Affiliation(s)
- Xuejun Qian
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA; USC Roski Eye Institute, University of Southern California, Los Angeles, CA 90033, USA
| | - Runze Li
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA; USC Roski Eye Institute, University of Southern California, Los Angeles, CA 90033, USA
| | - Gengxi Lu
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA; USC Roski Eye Institute, University of Southern California, Los Angeles, CA 90033, USA
| | - Laiming Jiang
- USC Roski Eye Institute, University of Southern California, Los Angeles, CA 90033, USA
| | - Haochen Kang
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - K Kirk Shung
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Mark S Humayun
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA; USC Roski Eye Institute, University of Southern California, Los Angeles, CA 90033, USA
| | - Qifa Zhou
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA; USC Roski Eye Institute, University of Southern California, Los Angeles, CA 90033, USA.
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11
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Jiao S. Biomedical optical imaging technology and applications: From basic research toward clinical diagnosis. Exp Biol Med (Maywood) 2020; 245:269-272. [PMID: 32141780 DOI: 10.1177/1535370220909543] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Affiliation(s)
- Shuliang Jiao
- Department of Biomedical Engineering, Florida International University, Miami, FL 33174, USA
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Li R, Du Z, Qian X, Li Y, Martinez-Camarillo JC, Jiang L, Humayun MS, Chen Z, Zhou Q. High resolution optical coherence elastography of retina under prosthetic electrode. Quant Imaging Med Surg 2020; 11:918-927. [PMID: 33654665 DOI: 10.21037/qims-20-1137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Quantitatively investigating the biomechanics of retina with a retinal prosthetic electrode, we explored the effects of the prosthetic electrode on the retina, and further supplemented data for a potential clinical trial. Methods Biomechanical properties were assessed with a high resolution optical coherence tomography (OCT) based elastography (OCE) system. A shaker was used to initiate elastic waves and an OCT system was used to track axial displacement along with wave propagation. Rabbits received surgery to implant the retinal prosthetic electrode, and elastic wave speed was measured before and after implantation; anatomical B-mode images were also acquired. Results Spatial-temporal maps of each layer in retina with and without prosthetic electrodes were acquired. Elastic wave speed of nerve fiber to inner plexiform layer, inner nuclear to outer nuclear layer, retinal pigmented epithelium layer and choroid to sclera layer without prosthetic electrode were found to be 3.66±0.36, 5.33±0.07, 6.85±0.37, and 9.69±0.24 m/s, respectively. With prosthetic electrode, the elastic wave speed was found to be 4.09±0.26, 5.14±0.11, 6.88±0.70, and 9.99±0.73 m/s, respectively in each layer. Conclusions Our results show that the elastic wave speed in each layer of retina is slightly faster with the retinal electrode, and further demonstrate that the retinal prosthetic electrode does not affect biomechanical properties significantly. In the future, we expect OCE technology to be used by clinicians where it could become part of routine testing and evaluation of the biomechanical properties of the retina in response to long term use of prosthetic electrodes in patients.
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Affiliation(s)
- Runze Li
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA.,USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Zhaodong Du
- USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Xuejun Qian
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA.,USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Yan Li
- Beckman Laser Institute, University of California, Irvine, CA, USA.,Department of Biomedical Engineering, University of California, Irvine, CA, USA
| | | | - Laiming Jiang
- USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Mark S Humayun
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA.,USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Zhongping Chen
- Beckman Laser Institute, University of California, Irvine, CA, USA.,Department of Biomedical Engineering, University of California, Irvine, CA, USA
| | - Qifa Zhou
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA.,USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
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