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Ciamillo SA, Pownder SL, Potter HG, Stefanovski D, Nixon AJ, Ortved KF. Correlation of Arthroscopic Grading and Optical Coherence Tomography as Markers of Early Repair and Predictors of Later Healing Evident on MRI and Histomorphometric Assessment of Cartilage Defects Implanted with Chondrocytes Overexpressing IGF-I. Cartilage 2023; 14:210-219. [PMID: 36864720 PMCID: PMC10416204 DOI: 10.1177/19476035231154508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 12/20/2022] [Accepted: 12/22/2022] [Indexed: 03/04/2023] Open
Abstract
OBJECTIVE Injury of articular cartilage is common, and due to the poor intrinsic capabilities of chondrocytes, it can precipitate joint degradation and osteoarthritis (OA). Implantation of autologous chondrocytes into cartilaginous defects has been used to bolster repair. Accurate assessment of the quality of repair tissue remains challenging. This study aimed to investigate the utility of noninvasive imaging modalities, including arthroscopic grading and optical coherence tomography (OCT) for assessment of early cartilage repair (8 weeks), and MRI to determine long-term healing (8 months). DESIGN Large (15 mm diameter), full-thickness chondral defects were created on both lateral trochlear ridges of the femur in 24 horses. Defects were implanted with autologous chondrocytes transduced with rAAV5-IGF-I, autologous chondrocytes transduced with rAAV5-GFP, naïve autologous chondrocytes, or autologous fibrin. Healing was evaluated at 8 weeks post-implantation using arthroscopy and OCT, and at 8 months post-implantation using MRI, gross pathology, and histopathology. RESULTS OCT and arthroscopic scoring of short-term repair tissue were significantly correlated. Arthroscopy was also correlated with later gross pathology and histopathology of repair tissue at 8 months post-implantation, while OCT was not correlated. MRI was not correlated with any other assessment variable. CONCLUSIONS This study indicated that arthroscopic inspection and manual probing to develop an early repair score may be a better predictor of long-term cartilage repair quality following autologous chondrocyte implantation. Furthermore, qualitative MRI may not provide additional discriminatory information when assessing mature repair tissue, at least in this equine model of cartilage repair.
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Affiliation(s)
- Sarah A. Ciamillo
- New Bolton Center, Department of Clinical Studies, University of Pennsylvania, Kennett Square, PA, USA
| | | | | | - Darko Stefanovski
- New Bolton Center, Department of Clinical Studies, University of Pennsylvania, Kennett Square, PA, USA
| | - Alan J. Nixon
- Department of Clinical Sciences, Cornell University, Ithaca, NY, USA
| | - Kyla F. Ortved
- New Bolton Center, Department of Clinical Studies, University of Pennsylvania, Kennett Square, PA, USA
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2
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Martin S, Rashidifard C, Norris D, Goncalves A, Vercollone C, Brezinski M. Minimally Invasive Polarization Sensitive Optical Coherence Tomography (PS-OCT) for assessing Pre-OA, a pilot study on technical feasibility. OSTEOARTHRITIS AND CARTILAGE OPEN 2022; 4. [DOI: 10.1016/j.ocarto.2022.100313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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3
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Goth W, Potter S, Allen ACB, Zoldan J, Sacks MS, Tunnell JW. Non-Destructive Reflectance Mapping of Collagen Fiber Alignment in Heart Valve Leaflets. Ann Biomed Eng 2019; 47:1250-1264. [PMID: 30783832 PMCID: PMC6456388 DOI: 10.1007/s10439-019-02233-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 02/15/2019] [Indexed: 12/11/2022]
Abstract
Collagen fibers are the primary structural elements that define many soft-tissue structure and mechanical function relationships, so that quantification of collagen organization is essential to many disciplines. Current tissue-level collagen fiber imaging techniques remain limited in their ability to quantify fiber organization at macroscopic spatial scales and multiple time points, especially in a non-contacting manner, requiring no modifications to the tissue, and in near real-time. Our group has previously developed polarized spatial frequency domain imaging (pSFDI), a reflectance imaging technique that rapidly and non-destructively quantifies planar collagen fiber orientation in superficial layers of soft tissues over large fields-of-view. In this current work, we extend the light scattering models and image processing techniques to extract a critical measure of the degree of collagen fiber alignment, the normalized orientation index (NOI), directly from pSFDI data. Electrospun fiber samples with architectures similar to many collagenous soft tissues and known NOI were used for validation. An inverse model was then used to extract NOI from pSFDI measurements of aortic heart valve leaflets and clearly demonstrated changes in degree of fiber alignment between opposing sides of the sample. These results show that our model was capable of extracting absolute measures of degree of fiber alignment in superficial layers of heart valve leaflets with only general a priori knowledge of fiber properties, providing a novel approach to rapid, non-destructive study of microstructure in heart valve leaflets using a reflectance geometry.
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Affiliation(s)
- Will Goth
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Sam Potter
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, USA
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Alicia C B Allen
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Janet Zoldan
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Michael S Sacks
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, USA
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - James W Tunnell
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA.
- James T. Willerson Center for Cardiovascular Modeling and Simulation, Institute for Computational Engineering and Sciences, Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA.
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4
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Shen S, Wang H, Qu Y, Huang K, Liu G, Chen Z, Ma C, Shao P, Hong J, Lemaillet P, Dong E, Xu RX. Simulating orientation and polarization characteristics of dense fibrous tissue by electrostatic spinning of polymeric fibers. BIOMEDICAL OPTICS EXPRESS 2019; 10:571-583. [PMID: 30800500 PMCID: PMC6377871 DOI: 10.1364/boe.10.000571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 12/15/2018] [Accepted: 12/17/2018] [Indexed: 06/09/2023]
Abstract
Phantoms simulating polarization characteristics of soft tissue play an important role in the development, calibration, and validation of diagnostic polarized imaging devices and of therapeutic strategy, in both laboratory and clinical settings. We propose to fabricate optical phantoms that simulate polarization characteristics of dense fibrous tissues by bonding electrospun polylactic acid (PLA) fibers between polydimethylsiloxane (PDMS) substrate with a groove. Increasing the rotational speed of an electrospinning collector helps improve the orientation of the electrospun fibers. The phantoms simulate the polarization characteristics of dense fibrous tissue of collagenous fibroma and healthy skin with high fidelity. Our experiments demonstrate the technical potential of using such phantoms for validation and calibration of polarimetric medical devices.
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Affiliation(s)
- Shuwei Shen
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
| | - Haili Wang
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
| | - Yingjie Qu
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
| | - Kuiming Huang
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
| | - Guangli Liu
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
| | - Zexin Chen
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
| | - Canzhen Ma
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
| | - Pengfei Shao
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
| | - Jin Hong
- Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
| | - Paul Lemaillet
- National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
| | - Erbao Dong
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
| | - Ronald X. Xu
- Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA
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5
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Polarization Sensitive Optical Coherence Tomography: A Review of Technology and Applications. APPLIED SCIENCES-BASEL 2017. [DOI: 10.3390/app7050474] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Goth W, Yang B, Lesicko J, Allen A, Sacks MS, Tunnell JW. POLARIZED SPATIAL FREQUENCY DOMAIN IMAGING OF HEART VALVE FIBER STRUCTURE. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2016; 9710. [PMID: 28775394 DOI: 10.1117/12.2212812] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Our group previously introduced Polarized Spatial Frequency Domain Imaging (PSFDI), a wide-field, reflectance imaging technique which we used to empirically map fiber direction in porcine pulmonary heart valve leaflets (PHVL) without optical clearing or physical sectioning of the sample. Presented is an extended analysis of our PSFDI results using an inverse Mueller matrix model of polarized light scattering that allows additional maps of fiber orientation distribution, along with instrumentation permitting increased imaging speed for dynamic PHVL fiber measurements. We imaged electrospun fiber phantoms with PSFDI, and then compared these measurements to SEM data collected for the same phantoms. PHVL was then imaged and compared to results of the same leaflets optically cleared and imaged with small angle light scattering (SALS). The static PHVL images showed distinct regional variance of fiber orientation distribution, matching our SALS results. We used our improved imaging speed to observe bovine tendon subjected to dynamic loading using a biaxial stretching device. Our dynamic imaging experiment showed trackable changes in the fiber microstructure of biological tissue under loading. Our new PSFDI analysis model and instrumentation allows characterization of fiber structure within heart valve tissues (as validated with SALS measurements), along with imaging of dynamic fiber remodeling. The experimental data will be used as inputs to our constitutive models of PHVL tissue to fully characterize these tissues' elastic behavior, and has immediate application in determining the mechanisms of structural and functional failure in PHVLs used as bio-prosthetic implants.
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Affiliation(s)
- Will Goth
- The University of Texas at Austin, 107 W. Dean Keeton St. Austin, TX, USA
| | - Bin Yang
- The University of Texas at Austin
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7
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Vercollone C, Liu B, Brezinski ME. Fossilized Teeth as a New Robust and Reproducible Standard for Polarization-Sensitive Optical Coherence Tomography. ISRN OPTICS 2013; 2013:391972. [PMID: 33686357 PMCID: PMC7937190 DOI: 10.1155/2013/391972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A clinical need exists for a cheap and efficient standard for polarization sensitive optical coherence tomography (PS-OCT). We utilize prehistoric fossilized teeth from the Megalodon shark and European horse as an unconventional, yet robust standard. Given their easy accessibility and the microstructural consistency conferred by the process of fossilization, they provide a means of calibration to reduce error from sources such as catheter bending and temperature changes. We tested the maximum difference in birefringence values in each tooth and found the fossilized teeth to be fast and repeatable. The results were compared to measurements from bovine meniscus, tendon, and destroyed tendon, which were verified with histology.
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Affiliation(s)
- Christopher Vercollone
- Center for Optical Coherence Tomography and Optical Physics, Department of Orthopedic Surgery, Brigham and Women’s Hospital, 75 Francis Street, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Bin Liu
- Center for Optical Coherence Tomography and Optical Physics, Department of Orthopedic Surgery, Brigham and Women’s Hospital, 75 Francis Street, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Mark E. Brezinski
- Center for Optical Coherence Tomography and Optical Physics, Department of Orthopedic Surgery, Brigham and Women’s Hospital, 75 Francis Street, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
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8
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Ribeiro JF, dos Anjos EHM, Mello MLS, de Campos Vidal B. Skin collagen fiber molecular order: a pattern of distributional fiber orientation as assessed by optical anisotropy and image analysis. PLoS One 2013; 8:e54724. [PMID: 23349957 PMCID: PMC3548803 DOI: 10.1371/journal.pone.0054724] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 12/17/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Birefringence can reveal much of the morphology, molecular order, heterogeneity of fiber orientation, and nonlinear optical properties of biopolymers such as collagen. However, the detailed characterization of skin collagen fibers using optical anisotropy methods remains elusive. A clear understanding of collagen fiber organization in skin tissues may be important in the interpretation of their structural-functional relationships under normal and pathological conditions. In this study, fiber orientation in collagen bundles (CBs) and their supramolecular organization were examined in rat skin using polarization microscopy and image analysis. METHODOLOGY/PRINCIPAL FINDINGS Image variations with rotation of the microscope stage and selection of the in-depth focus plane were investigated in unstained sections of varying thicknesses from rat skin fragments. Total birefringence (image analysis) and form and intrinsic birefringence (Sénarmont's method) were estimated. Based on the birefringent images, CBs were found to contain intercrossing points with a twisted helical distribution of collagen fibers (chiral elements) and frequently presented circular structures. Collagen fibers were observed to extend from the surface level to deeper planes, creating a 3D-network of oriented intertwined CBs. At least three levels of birefringent brilliance intensity were revealed by image analysis, indicating a heterogeneous spatial organization of the CBs. Slight differences in optical retardations were found for CBs immersed in some of the fluids used in a comparison of 170- and 240-day old rats. CONCLUSION/SIGNIFICANCE Polarization microscopy studies provide detailed high-quality structural information on rat skin CBs. A 3D-network structure based on image analysis and birefringence compensation for collagen fibers is suggested for CBs. Form and intrinsic birefringence evaluation can reveal differences in the rat skin associated with age at the levels of collagen fiber crystallinity and macromolecular organization. These findings may inspire future studies of the feedback mechanisms by which spatial, bioelectrical and biomechanical information is transmitted from CBs to skin cells.
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Affiliation(s)
- Juliana Fulan Ribeiro
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (Unicamp), Campinas, São Paulo, Brazil
| | - Eli Heber Martins dos Anjos
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (Unicamp), Campinas, São Paulo, Brazil
| | - Maria Luiza S. Mello
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (Unicamp), Campinas, São Paulo, Brazil
| | - Benedicto de Campos Vidal
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (Unicamp), Campinas, São Paulo, Brazil
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9
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Rashidifard C, Vercollone C, Martin S, Liu B, Brezinski ME. The application of optical coherence tomography in musculoskeletal disease. ARTHRITIS 2013; 2013:563268. [PMID: 23424683 PMCID: PMC3568691 DOI: 10.1155/2013/563268] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 12/15/2012] [Indexed: 12/31/2022]
Abstract
Many musculoskeletal disorders (MDs) are associated with irreversible bone and cartilage damage; this is particularly true for osteoarthritis (OA). Therefore, a clinical need exists for modalities which can detect OA and other MDs at early stages. Optical coherence tomography (OCT) is an infrared-based imaging, currently FDA approved in cardiology and ophthalmology, which has a resolution greater than 10 microns and acquisition rate of 120 frames/second. It has shown feasibility for imaging early OA, identifying changes prior to cartilage thinning both in vitro and in vivo in patients and in OA animal models. In addition, OCT has shown an ability to identify early rheumatoid arthritis (RA) and guide tendon repair, but has the potential for an even greater impact. Clinical trials in OA are currently underway, as well as in several other MDs.
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Affiliation(s)
- Christopher Rashidifard
- Center for Optical Coherence Tomography and Optical Physics, Department of Orthopedic Surgery, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
- Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
| | - Christopher Vercollone
- Center for Optical Coherence Tomography and Optical Physics, Department of Orthopedic Surgery, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
- Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
| | - Scott Martin
- Center for Optical Coherence Tomography and Optical Physics, Department of Orthopedic Surgery, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
- Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
| | - Bin Liu
- Center for Optical Coherence Tomography and Optical Physics, Department of Orthopedic Surgery, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
- Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
| | - Mark E. Brezinski
- Center for Optical Coherence Tomography and Optical Physics, Department of Orthopedic Surgery, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA
- Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
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10
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Towards improved collagen assessment: polarization-sensitive optical coherence tomography with tailored reference arm polarization. Int J Biomed Imaging 2012; 2012:892680. [PMID: 22481911 PMCID: PMC3312257 DOI: 10.1155/2012/892680] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 11/10/2011] [Accepted: 11/10/2011] [Indexed: 11/26/2022] Open
Abstract
Single channel PS-OCT has advantages for assessing birefringent tissue components in various clinical scenarios, with implications for assessing pathology, ranging from osteoarthritis to myocardial infarction. While the technique has been successfully used both in vitro and in vivo, there have been limited attempts to optimize single channel PS-OCT with respect to performance, particularly paddle rotation. In this study, we developed and tested a new approach for the real-time assessment of birefringence through tailoring of reference arm polarization. Different polarization rotation patterns, as depicted on a Poincare sphere, were assessed with polarization filters and retarders. When further tested in tissue, PS-OCT assessments of bovine cartilage and tendon demonstrated that contrast was sensitive to the pattern selected, indicating that rotation pattern influenced birefringence assessment and providing insights into optimal patterns. We also discuss the difference between diagnostic accuracy and precision with respect to both the construction and application of PS-OCT embodiments.
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11
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Chen X, Nadiarynkh O, Plotnikov S, Campagnola PJ. Second harmonic generation microscopy for quantitative analysis of collagen fibrillar structure. Nat Protoc 2012; 7:654-69. [PMID: 22402635 DOI: 10.1038/nprot.2012.009] [Citation(s) in RCA: 574] [Impact Index Per Article: 47.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Second-harmonic generation (SHG) microscopy has emerged as a powerful modality for imaging fibrillar collagen in a diverse range of tissues. Because of its underlying physical origin, it is highly sensitive to the collagen fibril/fiber structure, and, importantly, to changes that occur in diseases such as cancer, fibrosis and connective tissue disorders. We discuss how SHG can be used to obtain more structural information on the assembly of collagen in tissues than is possible by other microscopy techniques. We first provide an overview of the state of the art and the physical background of SHG microscopy, and then describe the optical modifications that need to be made to a laser-scanning microscope to enable the measurements. Crucial aspects for biomedical applications are the capabilities and limitations of the different experimental configurations. We estimate that the setup and calibration of the SHG instrument from its component parts will require 2-4 weeks, depending on the level of the user's experience.
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Affiliation(s)
- Xiyi Chen
- Department of Biomedica l Engineering, University of Wisconsin-Madison, Madison, Wisconsin, USA
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12
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Marschall S, Sander B, Mogensen M, Jørgensen TM, Andersen PE. Optical coherence tomography-current technology and applications in clinical and biomedical research. Anal Bioanal Chem 2011; 400:2699-720. [PMID: 21547430 DOI: 10.1007/s00216-011-5008-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 03/25/2011] [Accepted: 04/08/2011] [Indexed: 12/21/2022]
Abstract
Optical coherence tomography (OCT) is a noninvasive imaging technique that provides real-time two- and three-dimensional images of scattering samples with micrometer resolution. By mapping the local reflectivity, OCT visualizes the morphology of the sample. In addition, functional properties such as birefringence, motion, or the distributions of certain substances can be detected with high spatial resolution. Its main field of application is biomedical imaging and diagnostics. In ophthalmology, OCT is accepted as a clinical standard for diagnosing and monitoring the treatment of a number of retinal diseases, and OCT is becoming an important instrument for clinical cardiology. New applications are emerging in various medical fields, such as early-stage cancer detection, surgical guidance, and the early diagnosis of musculoskeletal diseases. OCT has also proven its value as a tool for developmental biology. The number of companies involved in manufacturing OCT systems has increased substantially during the last few years (especially due to its success in opthalmology), and this technology can be expected to continue to spread into various fields of application.
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Affiliation(s)
- Sebastian Marschall
- DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, Roskilde, Denmark
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Lippok N, Nielsen P, Vanholsbeeck F. Improving the efficiency of optical coherence tomography by using the non-ideal behaviour of a polarising beam splitter. OPTICS EXPRESS 2011; 19:7161-7175. [PMID: 21503030 DOI: 10.1364/oe.19.007161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We present a new way of improving the efficiency of optical coherence tomography by using the polarisation crosstalk of a polarising beam splitter to direct most of the available source optical power to the sample. The use of a quarter wave plate in both the reference and the sample arms allows most of the sample power to be directed to the detector while adjusting the reference arm to ensure noise optimised operation. As a result, the sensitivity of such a system can be improved by 6 dB, or alternatively the acquisition time can be improved by a factor of 4 for shot noise limited performance,compared to a traditional OCT configuration using a 50/50 beam splitter.
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Affiliation(s)
- Norman Lippok
- Auckland Bioengineering Institute, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
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Huang YP, Saarakkala S, Toyras J, Wang LK, Jurvelin JS, Zheng YP. Effects of optical beam angle on quantitative optical coherence tomography (OCT) in normal and surface degenerated bovine articular cartilage. Phys Med Biol 2010; 56:491-509. [PMID: 21191151 DOI: 10.1088/0031-9155/56/2/013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Quantitative measurement of articular cartilage using optical coherence tomography (OCT) is a potential approach for diagnosing the early degeneration of cartilage and assessing the quality of its repair. However, a non-perpendicular angle of the incident optical beam with respect to the tissue surface may cause uncertainty to the quantitative analysis, and therefore, significantly affect the reliability of measurement. This non-perpendicularity was systematically investigated in the current study using bovine articular cartilage with and without mechanical degradation. Ten fresh osteochondral disks were quantitatively measured before and after artificially induced surface degradation by mechanical grinding. The following quantitative OCT parameters were determined with a precise control of the surface inclination up to an angle of 10° using a step of 2°: optical reflection coefficient (ORC), variation of surface reflection (VSR) along the surface profile, optical roughness index (ORI) and optical backscattering (OBS). It was found that non-perpendicularity caused systematic changes to all of the parameters. ORC was the most sensitive and OBS the most insensitive to the inclination angle. At the optimal perpendicular angle, all parameters could detect significant changes after surface degradation (p < 0.01), except OBS (p > 0.05). Nonsignificant change of OBS after surface degradation was expected since OBS reflected properties of the internal cartilage tissue and was not affected by the superficial mechanical degradation. As a conclusion, quantitative OCT parameters are diagnostically potential for characterizing the cartilage degeneration. However, efforts through a better controlled operation or corrections based on computational compensation mechanism should be made to minimize the effects of non-perpendicularity of the incident optical beam when clinical use of quantitative OCT is considered for assessing the articular cartilage.
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Affiliation(s)
- Yan-Ping Huang
- Department of Health Technology and Informatics, Hong Kong Polytechnic University, Hong Kong, People's Republic of China.
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15
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Fleming CP, Quan KJ, Wang H, Amit G, Rollins AM. In vitro characterization of cardiac radiofrequency ablation lesions using optical coherence tomography. OPTICS EXPRESS 2010; 18:3079-92. [PMID: 20174138 DOI: 10.1364/oe.18.003079] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Currently, cardiac radiofrequency ablation (RFA) is guided by indirect signals. We demonstrate optical coherence tomography (OCT) characterization of RFA lesions within swine ventricular wedges. Untreated tissue exhibited a consistent birefringence artifact within OCT images due to the organized myocardium, which was not present in treated tissue. Birefringence artifacts were detected by filtering with a Laplacian of Gaussian (LoG) to quantify gradient strength. The gradient strength distinguished RFA lesions from untreated sites (p=5.93 x 10(-15)) with a sensitivity and specificity of 94.5% and 86.7% respectively. This study demonstrates the potential of OCT for monitoring cardiac RFA, confirming lesion formation and providing feedback to avoid complications.
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Affiliation(s)
- Christine P Fleming
- Case Western Reserve University. Biomedical Engineering Department. Cleveland, OH 44106, USA
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Wilson BC, Vitkin IA, Matthews DL. The potential of biophotonic techniques in stem cell tracking and monitoring of tissue regeneration applied to cardiac stem cell therapy. JOURNAL OF BIOPHOTONICS 2009; 2:669-681. [PMID: 19787683 DOI: 10.1002/jbio.200910079] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The use of injected stem cells, leading to regeneration of ischemic heart tissue, for example, following coronary artery occlusion, has emerged as a major new option for managing 'heart attack' patients. While some clinical trials have been encouraging, there have also been failures and there is little understanding of the multiplicity of factors that lead to the outcome. In this overview paper, the opportunities and challenges in applying biophotonic techniques to regenerative medicine, exemplified by the challenge of stem cell therapy of ischemic heart disease, are considered. The focus is on optical imaging to track stem cell distribution and fate, and optical spectroscopies and/or imaging to monitor the structural remodeling of the tissue and the resulting functional changes. The scientific, technological, and logistics issues involved in moving some of these techniques from pre-clinical research mode ultimately into the clinic are also highlighted.
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Affiliation(s)
- Brian C Wilson
- Division of Biophysics and Bioimaging, University Health Network, 610 University Ave., Toronto, ON M5G 2M9, Canada.
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Zheng K, Liu B, Huang C, Brezinski ME. Experimental confirmation of potential swept source optical coherence tomography performance limitations. APPLIED OPTICS 2008; 47:6151-8. [PMID: 19023378 PMCID: PMC2640108 DOI: 10.1364/ao.47.006151] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Optical coherence tomography (OCT) has demonstrated considerable potential for a wide range of medical applications. Initial work was done in the time domain OCT (TD-OCT) approach, but recent interest has been generated with spectral domain OCT (SD-OCT) approaches. While SD-OCT offers higher data acquisition rates and no movable parts, we recently pointed out theoretical inferior aspects to its performance relative to TD-OCT. In this paper we focus on specific limitations of swept source OCT (SS-OCT), as this is the more versatile of the two SD-OCT embodiments. We present experimental evidence of reduced imaging penetration, increased low frequency noise, higher multiple scattering (which can be worsened still via aliasing), increased need to control the distance from the sample, and saturation of central bandwidth frequencies. We conclude that for scenarios where the dynamic range is relatively low (e.g., retina), the distance from the sample is relatively constant, or high acquisition rates are needed, SS-OCT has a role. However, when penetration remains important in the setting of a relatively high dynamic range, acquisition rates above video rate are not needed, or the distance to the tissue is not constant, TD-OCT may be the superior approach.
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Affiliation(s)
- Kathy Zheng
- Center for Optical Coherence Tomography and Optical Physics, Department of Orthopedic Surgery, Brigham and Women's Hospital, 75 Francis Street, Boston, Massachusetts 02115, USA
| | - Bin Liu
- Center for Optical Coherence Tomography and Optical Physics, Department of Orthopedic Surgery, Brigham and Women's Hospital, 75 Francis Street, Boston, Massachusetts 02115, USA
- Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Chuanyong Huang
- Center for Optical Coherence Tomography and Optical Physics, Department of Orthopedic Surgery, Brigham and Women's Hospital, 75 Francis Street, Boston, Massachusetts 02115, USA
- Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Mark E. Brezinski
- Center for Optical Coherence Tomography and Optical Physics, Department of Orthopedic Surgery, Brigham and Women's Hospital, 75 Francis Street, Boston, Massachusetts 02115, USA
- Harvard Medical School, Boston, Massachusetts 02115, USA
- Corresponding author:
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Brezinski ME. Applications of optical coherence tomography to cardiac and musculoskeletal diseases: bench to bedside? JOURNAL OF BIOMEDICAL OPTICS 2007; 12:051705. [PMID: 17994878 DOI: 10.1117/1.2795689] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Selected historical aspects of the transition of optical coherence tomography (OCT) research from the bench to bedside are focused on. The primary function of the National Institutes of Health (NIH) is to improve the diagnosis and treatment of human pathologies. Therefore, research funded by the NIH should have a direct envisioned pathway for transitioning bench work to the bedside. Ultimately, to be successful, this work must be accepted by physicians and by the general science community. This typically requires robustly validated hypothesis-driven research. Work that is not appropriately compared to the current gold standard or does not address a specific pathology is unlikely to achieve widespread acceptance. I outline OCT research in the musculoskeletal and cardiovascular systems, examining the rapid transition from bench to bedside and look at initial validated hypothesis-driven research data that suggested clinical utility, which drove technology development toward specific clinical scenarios. I also consider the time of initial funding compared to when it was applied in patients with clinical pathologies. Finally, ongoing bench work being performed in parallel with clinical studies is examined. The specific applications examined here are identifying unstable coronary plaque and the early detection of osteoarthritis, the former was brought to the bedside primarily through a commercial route while the latter through NIH-funded research.
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Affiliation(s)
- Mark E Brezinski
- Brigham and Women's Hospital, Department of Orthopedic Surgery, 75 Francis Street and Harvard Medical School, Boston, Massachusetts 02115, USA.
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Wells WA, Barker PE, MacAulay C, Novelli M, Levenson RM, Crawford JM. Validation of novel optical imaging technologies: the pathologists' view. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:051801. [PMID: 17994879 DOI: 10.1117/1.2795569] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Noninvasive optical imaging technology has the potential to improve the accuracy of disease detection and predict treatment response. Pathology provides the critical link between the biological basis of an image or spectral signature and clinical outcomes obtained through optical imaging. The validation of optical images and spectra requires both morphologic diagnosis from histopathology and parametric analysis of tissue features above and beyond the declared pathologic "diagnosis." Enhancement of optical imaging modalities with exogenously applied biomarkers also requires validation of the biological basis for molecular contrast. For an optical diagnostic or prognostic technology to be useful, it must be clinically important, independently informative, and of demonstrated beneficial value to patient care. Its usage must be standardized with regard to methods, interpretation, reproducibility, and reporting, in which the pathologist plays a key role. By providing insight into disease pathobiology, interpretive or quantitative analysis of tissue material, and expertise in molecular diagnosis, the pathologist should be an integral part of any team that is validating novel optical imaging modalities. This review will consider (1) the selection of validation biomarkers; (2) standardization in tissue processing, diagnosis, reporting, and quantitative analysis; (3) the role of the pathologist in study design; and (4) reference standards, controls, and interobserver variability.
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Affiliation(s)
- Wendy A Wells
- Dartmouth Medical School, Department of Pathology, 1 Rope Ferry Road, Hanover, New Hampshire 03755, USA
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Langevin HM, Rizzo DM, Fox JR, Badger GJ, Wu J, Konofagou EE, Stevens-Tuttle D, Bouffard NA, Krag MH. Dynamic morphometric characterization of local connective tissue network structure in humans using ultrasound. BMC SYSTEMS BIOLOGY 2007; 1:25. [PMID: 17550618 PMCID: PMC1913929 DOI: 10.1186/1752-0509-1-25] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Accepted: 06/05/2007] [Indexed: 11/21/2022]
Abstract
Background In humans, connective tissue forms a complex, interconnected network throughout the body that may have mechanosensory, regulatory and signaling functions. Understanding these potentially important phenomena requires non-invasive measurements of collagen network structure that can be performed in live animals or humans. The goal of this study was to show that ultrasound can be used to quantify dynamic changes in local connective tissue structure in vivo. We first performed combined ultrasound and histology examinations of the same tissue in two subjects undergoing surgery: in one subject, we examined the relationship of ultrasound to histological images in three dimensions; in the other, we examined the effect of a localized tissue perturbation using a previously developed robotic acupuncture needling technique. In ten additional non-surgical subjects, we quantified changes in tissue spatial organization over time during needle rotation vs. no rotation using ultrasound and semi-variogram analyses. Results 3-D renditions of ultrasound images showed longitudinal echogenic sheets that matched with collagenous sheets seen in histological preparations. Rank correlations between serial 2-D ultrasound and corresponding histology images resulted in high positive correlations for semi-variogram ranges computed parallel (r = 0.79, p < 0.001) and perpendicular (r = 0.63, p < 0.001) to the surface of the skin, indicating concordance in spatial structure between the two data sets. Needle rotation caused tissue displacement in the area surrounding the needle that was mapped spatially with ultrasound elastography and corresponded to collagen bundles winding around the needle on histological sections. In semi-variograms computed for each ultrasound frame, there was a greater change in the area under the semi-variogram curve across successive frames during needle rotation compared with no rotation. The direction of this change was heterogeneous across subjects. The frame-to-frame variability was 10-fold (p < 0.001) greater with rotation than with no rotation indicating changes in tissue structure during rotation. Conclusion The combination of ultrasound and semi-variogram analyses allows quantitative assessment of dynamic changes in the structure of human connective tissue in vivo.
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Affiliation(s)
- Helene M Langevin
- Department of Neurology, University of Vermont, Burlington, VT, USA
- Department of Orthopaedics & Rehabilitation, University of Vermont, Burlington, VT, USA
| | - Donna M Rizzo
- Department of Civil & Environmental Engineering, University of Vermont, Burlington, VT, USA
| | - James R Fox
- Department of Neurology, University of Vermont, Burlington, VT, USA
| | - Gary J Badger
- Department of Medical Biostatistics, University of Vermont, Burlington, VT, USA
| | - Junru Wu
- Department of Physics, University of Vermont, Burlington, VT, USA
| | - Elisa E Konofagou
- Department of Biomedical Engineering, Columbia University, New York, NY, USA
| | | | | | - Martin H Krag
- Department of Orthopaedics & Rehabilitation, University of Vermont, Burlington, VT, USA
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