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Galiano E, Liu J, Ren B, Xu P. Mechanical and Architectural Changes in Animal Bone Following Fast Neutron Irradiation. HEALTH PHYSICS 2024; 127:298-305. [PMID: 38506670 DOI: 10.1097/hp.0000000000001811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
ABSTRACT Damage to healthy bone following exposure to ionizing radiation has been well documented for at least seven decades. Among the reported effects are a transient increase in stiffness and a reduction in breaking strength. These changes have been linked to a decrease in osteoblast proliferation and differentiation, inducing cell cycle arrest, reducing collagen production, and increasing sensitivity to apoptotic agents. In this work, we analyzed some mechanical and structural changes in compact costal bovine bone (Hereford breed, n = 9) subjected to escalating doses of fast neutrons from a 7 Li(p,n) 7 Be reaction. The mean neutron energy was 233 keV with calculated absorbed doses ranging from 0 to 4.05 ± 10% Gy. Samples were subjected to Young's Modulus (YM) and breaking strength testing with a Universal Testing Machine (UTM). We found an increase in Young's Modulus and a decrease in breaking strength as functions of increasing dose equivalent. Optical coherence tomography (OCT) revealed trabecular displacement into compact bone in an irradiated sample (D = 4.05 ± 10% Gy), with breaching of the endosteal wall. OCT further revealed a "crack-like" structure across the irradiated sample, potentially consistent with damage from a proton track resulting from an elastic (n,p) reaction. No previous report has been found on mechanical changes in large mammalian bones following fast neutron doses, nor of the OCT imaging of such samples.
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Affiliation(s)
- Eduardo Galiano
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4L8, Canada
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2
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Barroso Á, Ketelhut S, Nettels-Hackert G, Heiduschka P, del Amor R, Naranjo V, Kemper B, Schnekenburger J. Durable 3D murine ex vivo retina glaucoma models for optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2023; 14:4421-4438. [PMID: 37791268 PMCID: PMC10545187 DOI: 10.1364/boe.494271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 07/07/2023] [Accepted: 07/08/2023] [Indexed: 10/05/2023]
Abstract
Durable and standardized phantoms with optical properties similar to native healthy and disease-like biological tissues are essential tools for the development, performance testing, calibration and comparison of label-free high-resolution optical coherence tomography (HR-OCT) systems. Available phantoms are based on artificial materials and reflect thus only partially ocular properties. To address this limitation, we have performed investigations on the establishment of durable tissue phantoms from ex vivo mouse retina for enhanced reproduction of in vivo structure and complexity. In a proof-of-concept study, we explored the establishment of durable 3D models from dissected mouse eyes that reproduce the properties of normal retina structures and tissue with glaucoma-like layer thickness alterations. We explored different sectioning and preparation procedures for embedding normal and N-methyl-D-aspartate (NMDA)-treated mouse retina in transparent gel matrices and epoxy resins, to generate durable three-dimensional tissue models. Sample quality and reproducibility were quantified by thickness determination of the generated layered structures utilizing computer-assisted segmentation of OCT B-scans that were acquired with a commercial HR-OCT system at a central wavelength of 905 nm and analyzed with custom build software. Our results show that the generated 3D models feature thin biological layers close to current OCT resolution limits and glaucoma-like tissue alterations that are suitable for reliable HR-OCT performance characterization. The comparison of data from resin-embedded tissue with native murine retina in gels demonstrates that by utilization of appropriate preparation protocols, highly stable samples with layered structures equivalent to native tissues can be fabricated. The experimental data demonstrate our concept as a promising approach toward the fabrication of durable biological 3D models suitable for high-resolution OCT system performance characterization supporting the development of optimized instruments for ophthalmology applications.
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Affiliation(s)
- Álvaro Barroso
- Biomedical Technology Center of the Medical Faculty, University of Muenster, Mendelstr. 17, D-48149 Muenster, Germany
| | - Steffi Ketelhut
- Biomedical Technology Center of the Medical Faculty, University of Muenster, Mendelstr. 17, D-48149 Muenster, Germany
| | - Gerburg Nettels-Hackert
- Department of Ophthalmology of the Medical Faculty, University of Muenster, Domagkstr. 15, D-48149 Muenster, Germany
| | - Peter Heiduschka
- Department of Ophthalmology of the Medical Faculty, University of Muenster, Domagkstr. 15, D-48149 Muenster, Germany
| | - Rocío del Amor
- Instituto Universitario de Investigación en Tecnología Centrada en el Ser Humano, Universitat Politècnica de València, Valencia, Spain
| | - Valery Naranjo
- Instituto Universitario de Investigación en Tecnología Centrada en el Ser Humano, Universitat Politècnica de València, Valencia, Spain
| | - Björn Kemper
- Biomedical Technology Center of the Medical Faculty, University of Muenster, Mendelstr. 17, D-48149 Muenster, Germany
| | - Jürgen Schnekenburger
- Biomedical Technology Center of the Medical Faculty, University of Muenster, Mendelstr. 17, D-48149 Muenster, Germany
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Merkle CW, Augustin M, Harper DJ, Glösmann M, Baumann B. Degeneration of Melanin-Containing Structures Observed Longitudinally in the Eyes of SOD1-/- Mice Using Intensity, Polarization, and Spectroscopic OCT. Transl Vis Sci Technol 2022; 11:28. [PMID: 36259678 PMCID: PMC9587514 DOI: 10.1167/tvst.11.10.28] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Purpose Melanin plays an important function in maintaining eye health, however there are few metrics that can be used to study retinal melanin content in vivo. Methods The slope of the spectral coefficient of variation (SSCoV) is a novel biomarker that measures chromophore concentration by analyzing the local divergence of spectral intensities using optical coherence tomography (OCT). This metric was validated in a phantom and applied in a longitudinal study of superoxide dismutase 1 knockout (SOD1−/−) mice, a model for wet and dry age-related macular degeneration. We also examined a new feature of interest in standard OCT image data, the ratio of maximum intensity in the retinal pigment epithelium to that of the choroid (RC ratio). These new biomarkers were supported by polarization-sensitive OCT and histological analysis. Results SSCoV correlated well with depolarization metrics both in phantom and in vivo with both metrics decreasing more rapidly in SOD1−/− mice with age (P < 0.05). This finding is correlated with reduced melanin pigmentation in the choroid over time. The RC ratio clearly differentiated the SOD1−/− and control groups (P < 0.0005) irrespective of time and may indicate lower retinal pigment epithelium melanin in the SOD1−/− mice. Histological analysis showed decreased melanin content and potential differences in melanin granule shape in SOD1−/− mice. Conclusions SSCoV and RC ratio biomarkers provided insights into the changes of retinal melanin in the SOD1−/− model longitudinally and noninvasively. Translational Relevance These biomarkers were designed with the potential for rapid adoption by existing clinical OCT systems without requiring new hardware.
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Affiliation(s)
- Conrad W Merkle
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria
| | - Marco Augustin
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria
| | - Danielle J Harper
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria
| | - Martin Glösmann
- Core Facility for Research and Technology, University of Veterinary Medicine Vienna, Austria
| | - Bernhard Baumann
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria
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4
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Kho AM, Srinivasan VJ. Proactive spectrometer matching for excess noise suppression in balanced visible light optical coherence tomography (OCT). OPTICS EXPRESS 2021; 29. [PMCID: PMC8970694 DOI: 10.1364/oe.439919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Supercontinuum sources for visible light spectral domain OCT (SDOCT) are noisy and often expensive. Balanced detection can reduce excess noise, but is rarely used in SDOCT. Here, we show that balanced detection can achieve effective excess noise cancellation across all depths if two linear array spectrometers are spectrally well-matched. We propose excess noise correlation matrices as tools to achieve such precise spectral matching. Using optomechanical adjustments, while monitoring noise correlations, we proactively match wavelength sampling of two different spectrometers to just a few picometers in wavelength, or 0.001% of the overall spectral range. We show that proactively-matched spectrometers can achieve an excess noise suppression of more than two orders-of-magnitude in balanced visible light OCT, outperforming simple retrospective software calibration of mismatched spectrometers. High noise suppression enables visible light OCT of the mouse retina at 70 kHz with 125 microwatts incident power, with an inexpensive, 30 MHz repetition rate supercontinuum source. Averaged images resolve the retinal pigment epithelium in a highly pigmented mouse strain.
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Affiliation(s)
- Aaron M. Kho
- Department of Biomedical Engineering, University of California Davis, Davis, California 95616, USA
| | - Vivek J. Srinivasan
- Department of Biomedical Engineering, University of California Davis, Davis, California 95616, USA
- Department of Ophthalmology and Vision Science, University of California Davis, Davis School of Medicine, Sacramento, California 96817, USA
- Department of Ophthalmology, NYU Langone Health, New York, New York 10017, USA
- Department of Radiology, NYU Langone Health, New York, New York 10016, USA
- Tech4Health Institute, NYU Langone Health, New York, New York 10010, USA
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Lichtenegger A, Salas M, Sing A, Duelk M, Licandro R, Gesperger J, Baumann B, Drexler W, Leitgeb RA. Reconstruction of visible light optical coherence tomography images retrieved from discontinuous spectral data using a conditional generative adversarial network. BIOMEDICAL OPTICS EXPRESS 2021; 12:6780-6795. [PMID: 34858680 PMCID: PMC8606123 DOI: 10.1364/boe.435124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 08/16/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023]
Abstract
Achieving high resolution in optical coherence tomography typically requires the continuous extension of the spectral bandwidth of the light source. This work demonstrates an alternative approach: combining two discrete spectral windows located in the visible spectrum with a trained conditional generative adversarial network (cGAN) to reconstruct a high-resolution image equivalent to that generated using a continuous spectral band. The cGAN was trained using OCT image pairs acquired with the continuous and discontinuous visible range spectra to learn the relation between low- and high-resolution data. The reconstruction performance was tested using 6000 B-scans of a layered phantom, micro-beads and ex-vivo mouse ear tissue. The resultant cGAN-generated images demonstrate an image quality and axial resolution which approaches that of the high-resolution system.
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Affiliation(s)
- Antonia Lichtenegger
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria
- Christian Doppler Laboratory for Innovative Optical Imaging and Its Translation to Medicine, Medical University of Vienna, Austria
- These authors contributed equally
| | - Matthias Salas
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria
- Christian Doppler Laboratory for Innovative Optical Imaging and Its Translation to Medicine, Medical University of Vienna, Austria
- These authors contributed equally
| | - Alexander Sing
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria
| | | | - Roxane Licandro
- Department of and Biomedical Imaging and Image-guided Therapy, Computational Imaging Research, Medical University of Vienna, Austria
- Institute of Visual Computing and Human-Centered Technology, Computer Vision Lab, TU Wien, Austria
| | - Johanna Gesperger
- Division of Neuropathology and Neurochemistry, Department of Neurology, Medical University of Vienna, Austria
| | - Bernhard Baumann
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria
| | - Wolfgang Drexler
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria
| | - Rainer A. Leitgeb
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria
- Christian Doppler Laboratory for Innovative Optical Imaging and Its Translation to Medicine, Medical University of Vienna, Austria
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6
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Rao D S S, Jensen M, Grüner-Nielsen L, Olsen JT, Heiduschka P, Kemper B, Schnekenburger J, Glud M, Mogensen M, Israelsen NM, Bang O. Shot-noise limited, supercontinuum-based optical coherence tomography. LIGHT, SCIENCE & APPLICATIONS 2021; 10:133. [PMID: 34183643 PMCID: PMC8239030 DOI: 10.1038/s41377-021-00574-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 05/26/2021] [Accepted: 06/07/2021] [Indexed: 05/19/2023]
Abstract
We present the first demonstration of shot-noise limited supercontinuum-based spectral domain optical coherence tomography (SD-OCT) with an axial resolution of 5.9 μm at a center wavelength of 1370 nm. Current supercontinuum-based SD-OCT systems cannot be operated in the shot-noise limited detection regime because of severe pulse-to-pulse relative intensity noise of the supercontinuum source. To overcome this disadvantage, we have developed a low-noise supercontinuum source based on an all-normal dispersion (ANDi) fiber, pumped by a femtosecond laser. The noise performance of our 90 MHz ANDi fiber-based supercontinuum source is compared to that of two commercial sources operating at 80 and 320 MHz repetition rate. We show that the low-noise of the ANDi fiber-based supercontinuum source improves the OCT images significantly in terms of both higher contrast, better sensitivity, and improved penetration. From SD-OCT imaging of skin, retina, and multilayer stacks we conclude that supercontinuum-based SD-OCT can enter the domain of shot-noise limited detection.
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Affiliation(s)
- Shreesha Rao D S
- DTU Fotonik, Dept. of Photonics Engineering, Technical University of Denmark, Ørsteds Plads, 2800, Kongens Lyngby, Denmark
| | - Mikkel Jensen
- DTU Fotonik, Dept. of Photonics Engineering, Technical University of Denmark, Ørsteds Plads, 2800, Kongens Lyngby, Denmark
| | - Lars Grüner-Nielsen
- DTU Fotonik, Dept. of Photonics Engineering, Technical University of Denmark, Ørsteds Plads, 2800, Kongens Lyngby, Denmark
| | | | - Peter Heiduschka
- Department of Ophthalmology, University of Münster Medical Centre, Domagkstr. 15, D-48149, Münster, Germany
| | - Björn Kemper
- Biomedical Technology Center of the Medical Faculty, University of Münster, Mendelstr. 17, D-48149, Münster, Germany
| | - Jürgen Schnekenburger
- Biomedical Technology Center of the Medical Faculty, University of Münster, Mendelstr. 17, D-48149, Münster, Germany
| | - Martin Glud
- Department of Dermatology, Bisbebjerg Hospital, University of Copenhagen, Bispebjerg Bakke 23, 2400, Copenhagen NV, Denmark
| | - Mette Mogensen
- Department of Dermatology, Bisbebjerg Hospital, University of Copenhagen, Bispebjerg Bakke 23, 2400, Copenhagen NV, Denmark
| | - Niels Møller Israelsen
- DTU Fotonik, Dept. of Photonics Engineering, Technical University of Denmark, Ørsteds Plads, 2800, Kongens Lyngby, Denmark
| | - Ole Bang
- DTU Fotonik, Dept. of Photonics Engineering, Technical University of Denmark, Ørsteds Plads, 2800, Kongens Lyngby, Denmark.
- NKT Photonics A/S, Blokken 84, 3460, Birkerød, Denmark.
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7
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Yang D, Hu M, Zhang M, Liang Y. High-resolution polarization-sensitive optical coherence tomography for zebrafish muscle imaging. BIOMEDICAL OPTICS EXPRESS 2020; 11:5618-5632. [PMID: 33149975 PMCID: PMC7587288 DOI: 10.1364/boe.402267] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/18/2020] [Accepted: 09/07/2020] [Indexed: 05/20/2023]
Abstract
Zebrafish are an important animal model, whose structure and function information can be used to study development, pathologic changes and genetic mutations. However, limited by the penetration depth, the available optical methods are difficult to image the whole-body zebrafish in juvenile and adult stages. Based on a home-made high-resolution polarization-sensitive optical coherence tomography (PS-OCT) system, we finished in vivo volumetric imaging for zebrafish, and various muscles can be clearly discerned by scanning from dorsal, ventral, and lateral directions. Besides structure information, polarization properties extracted from PS-OCT images provide abundant function information to distinguish different muscles. Furthermore, we found local retardation and local optic axis of zebrafish muscle are related to their composition and fiber orientation. We think high-resolution PS-OCT will be a promising tool in studying myopathy models of zebrafish.
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8
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Zhang T, Kho AM, Srinivasan VJ. Water wavenumber calibration for visible light optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:JBO-200166LR. [PMID: 32935500 PMCID: PMC7490762 DOI: 10.1117/1.jbo.25.9.090501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 08/28/2020] [Indexed: 06/11/2023]
Abstract
SIGNIFICANCE Visible light optical coherence tomography (OCT) is emerging for spectroscopic and ultrahigh resolution imaging, but challenges remain. Depth-dependent dispersion limits retinal image quality and current correction approaches are cumbersome. Inconsistent group refractive indices during image reconstruction also limit reproducibility. AIM To introduce and evaluate water wavenumber calibration (WWC), which corrects depth-dependent dispersion and provides an accurate depth axis in water. APPROACH Enabled by a visible light OCT spectrometer configuration with a 3- to 4-dB sensitivity roll-off over 1 mm in air across a 90-nm bandwidth, we determine the spectral phase of a 1-mm water cell, an affine function of water wavenumber. Via WWC, we reconstruct visible light OCT human retinal images with 1.3-μm depth resolution in water. RESULTS Images clearly reveal Bruch's membrane, inner plexiform layer lamination, and a thin nerve fiber layer in the temporal parafovea. WWC halves the processing time, while achieving the same image definition as an assumption-free gold standard approach, suggesting that water wavenumber is a suitable proxy for tissue wavenumber. WWC also provides a depth axis in water without explicitly assuming a group refractive index. CONCLUSIONS WWC is a simple method that helps to realize the full potential of visible light OCT.
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Affiliation(s)
- Tingwei Zhang
- University of California Davis, Department of Biomedical Engineering, Davis, California, United States
| | - Aaron M. Kho
- University of California Davis, Department of Biomedical Engineering, Davis, California, United States
| | - Vivek J. Srinivasan
- University of California Davis, Department of Biomedical Engineering, Davis, California, United States
- University of California Davis, School of Medicine, Department of Ophthalmology and Vision Science, Sacramento, California, United States
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Haindl R, Duelk M, Gloor S, Dahdah J, Ojeda J, Sturtzel C, Deng S, Joyce Deloria A, Li Q, Liu M, Distel M, Drexler W, Leitgeb R. Ultra-high-resolution SD-OCM imaging with a compact polarization-aligned 840 nm broadband combined-SLED source. BIOMEDICAL OPTICS EXPRESS 2020; 11:3395-3406. [PMID: 32637262 PMCID: PMC7316001 DOI: 10.1364/boe.394229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 05/12/2020] [Accepted: 05/16/2020] [Indexed: 05/15/2023]
Abstract
We analyze the influence of intrinsic polarization alignment on image quality and axial resolution employing a broadband 840 nm light source with an optical bandwidth of 160 nm and an output power of 12 mW tailored for spectral-domain optical coherence microscopy (SD-OCM) applications. Three superluminescent diodes (SLEDs) are integrated into a 14-pin butterfly module using a free-space micro-optical bench architecture, maintaining a constant polarization state across the full spectral output. We demonstrate superior imaging performance in comparison to traditionally coupled-SLED broadband light sources in a teleost model organism in-vivo.
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Affiliation(s)
- Richard Haindl
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Marcus Duelk
- EXALOS AG, Wagistrasse 21, 8952 Schlieren, Switzerland
| | - Stefan Gloor
- EXALOS AG, Wagistrasse 21, 8952 Schlieren, Switzerland
| | - Jean Dahdah
- EXALOS AG, Wagistrasse 21, 8952 Schlieren, Switzerland
| | - Jose Ojeda
- EXALOS AG, Wagistrasse 21, 8952 Schlieren, Switzerland
| | - Caterina Sturtzel
- Innovative Cancer Models, Children’s Cancer Research Institute, Vienna, Austria
| | - Shiyu Deng
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Abigail Joyce Deloria
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Qian Li
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Mengyang Liu
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Martin Distel
- Innovative Cancer Models, Children’s Cancer Research Institute, Vienna, Austria
| | - Wolfgang Drexler
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Rainer Leitgeb
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- Christian Doppler Laboratory OPTRAMED, Medical University of Vienna, Vienna, Austria
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10
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Augustin M, Harper DJ, Merkle CW, Glösmann M, Hitzenberger CK, Baumann B. Optical Coherence Tomography Findings in the Retinas of SOD1 Knockout Mice. Transl Vis Sci Technol 2020; 9:15. [PMID: 32818102 PMCID: PMC7396182 DOI: 10.1167/tvst.9.4.15] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 12/16/2019] [Indexed: 01/22/2023] Open
Abstract
Purpose The retinal phenotype of popular mouse models mimicking ophthalmic diseases, such as the superoxide dismutase 1 (SOD1) knockout (KO) mouse model, has mainly been assessed by ex vivo histology and in vivo fundus photography. We used multifunctional optical coherence tomography (OCT) to characterize the retinas of SOD1 KO mice in vivo. Methods The custom-made ophthalmoscope featured a combination of conventional OCT, polarization-sensitive OCT, and OCT angiography. Seven SOD1 KO mice and nine age-matched controls were imaged between 6 and 17 months of age. A postprocessing framework was used to analyze total and outer retinal thickness changes. Drusenlike lesions were segmented, and their sizes and the number of lesions were assessed quantitatively. Their appearance in the conventional reflectivity images, as well as in the corresponding polarization-sensitive images, was characterized qualitatively. Results Drusenlike lesions increased in size and number with age for SOD1 KO mice. Exploiting the multiple contrast channels, the appearance of the lesions was found to resemble pseudodrusen observed in eyes of patients suffering from dry age-related macular degeneration. The total and outer retinal thicknesses were lower on average after 11 months and 7 months in SOD1 KO mice compared with age-matched controls. Neovascularizations were found in one out of seven KO animals. Conclusions OCT imaging proved beneficial for a detailed in vivo characterization of the pathological changes in SOD1 KO mice. Translational Relevance Phenotyping of animal models using modern imaging concepts can be conducted with more precision and might also ease the translation of conclusions between clinical and preclinical research.
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Affiliation(s)
- Marco Augustin
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Danielle J Harper
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Conrad W Merkle
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Martin Glösmann
- VetCore Facility for Research, Imaging Unit, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Christoph K Hitzenberger
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Bernhard Baumann
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
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11
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Harper DJ, Augustin M, Lichtenegger A, Gesperger J, Himmel T, Muck M, Merkle CW, Eugui P, Kummer S, Woehrer A, Glösmann M, Baumann B. Retinal analysis of a mouse model of Alzheimer's disease with multicontrast optical coherence tomography. NEUROPHOTONICS 2020; 7:015006. [PMID: 32042855 PMCID: PMC6999077 DOI: 10.1117/1.nph.7.1.015006] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 01/07/2020] [Indexed: 05/18/2023]
Abstract
Significance. Recent Alzheimer's disease (AD) patient studies have focused on retinal analysis, as the retina is the only part of the central nervous system that can be imaged noninvasively by optical methods. However, as this is a relatively new approach, the occurrence and role of retinal pathological features are still debated. Aim. The retina of an APP/PS1 mouse model was investigated using multicontrast optical coherence tomography (OCT) in order to provide a documentation of what was observed in both transgenic and wild-type mice. Approach. Both eyes of 24 APP/PS1 transgenic mice (age: 45 to 104 weeks) and 15 age-matched wild-type littermates were imaged by the custom-built OCT system. At the end of the experiment, retinas and brains were harvested from a subset of the mice (14 transgenic, 7 age-matched control) in order to compare the in vivo results to histological analysis and to quantify the cortical amyloid beta plaque load. Results. The system provided a combination of standard reflectivity data, polarization-sensitive data, and OCT angiograms. Qualitative and quantitative information from the resultant OCT images was extracted on retinal layer thickness and structure, presence of hyper-reflective foci, phase retardation abnormalities, and retinal vasculature. Conclusions. Although multicontrast OCT revealed abnormal structural properties and phase retardation signals in the retina of this APP/PS1 mouse model, the observations were very similar in transgenic and control mice.
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Affiliation(s)
- Danielle J. Harper
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- Address all correspondence to Danielle J. Harper, E-mail:
| | - Marco Augustin
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Antonia Lichtenegger
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Johanna Gesperger
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- General Hospital and Medical University of Vienna, Institute of Neurology, Vienna, Austria
| | - Tanja Himmel
- University of Veterinary Medicine, Institute of Pathology, Vienna, Austria
| | - Martina Muck
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Conrad W. Merkle
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Pablo Eugui
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Stefan Kummer
- University of Veterinary Medicine, Core Facility for Research and Technology, Vienna, Austria
| | - Adelheid Woehrer
- General Hospital and Medical University of Vienna, Institute of Neurology, Vienna, Austria
| | - Martin Glösmann
- University of Veterinary Medicine, Core Facility for Research and Technology, Vienna, Austria
| | - Bernhard Baumann
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
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12
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Harper DJ, Konegger T, Augustin M, Schützenberger K, Eugui P, Lichtenegger A, Merkle CW, Hitzenberger CK, Glösmann M, Baumann B. Hyperspectral optical coherence tomography for in vivo visualization of melanin in the retinal pigment epithelium. JOURNAL OF BIOPHOTONICS 2019; 12:e201900153. [PMID: 31334610 PMCID: PMC7065636 DOI: 10.1002/jbio.201900153] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 06/19/2019] [Accepted: 07/18/2019] [Indexed: 05/09/2023]
Abstract
Previous studies for melanin visualization in the retinal pigment epithelium (RPE) have exploited either its absorption properties (using photoacoustic tomography or photothermal optical coherence tomography [OCT]) or its depolarization properties (using polarization sensitive OCT). However, these methods are only suitable when the melanin concentration is sufficiently high. In this work, we present the concept of hyperspectral OCT for melanin visualization in the RPE when the concentration is low. Based on white light OCT, a hyperspectral stack of 27 wavelengths (440-700 nm) was created in post-processing for each depth-resolved image. Owing to the size and shape of the melanin granules in the RPE, the variations in backscattering coefficient as a function of wavelength could be identified-a result which is to be expected from Mie theory. This effect was successfully identified both in eumelanin-containing phantoms and in vivo in the low-concentration Brown Norway rat RPE.
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Affiliation(s)
- Danielle J. Harper
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Thomas Konegger
- Institute of Chemical Technologies and Analytics, TU WienViennaAustria
| | - Marco Augustin
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Kornelia Schützenberger
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Pablo Eugui
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Antonia Lichtenegger
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Conrad W. Merkle
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | | | - Martin Glösmann
- Core Facility for Research and TechnologyUniversity of Veterinary MedicineViennaAustria
| | - Bernhard Baumann
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
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13
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Della Volpe-Waizel M, Traber GL, Maloca P, Zinkernagel M, Schmidt-Erfurth U, Rubin G, Roska B, Otto T, Weleber RG, Scholl HPN. New Technologies for Outcome Measures in Retinal Disease: Review from the European Vision Institute Special Interest Focus Group. Ophthalmic Res 2019; 63:77-87. [PMID: 31352462 DOI: 10.1159/000501887] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 07/03/2019] [Indexed: 01/03/2023]
Abstract
Novel diagnostic tools to measure retinal function and structure are rapidly being developed and introduced into clinical use. Opportunities exist to use these informative and robust measures as endpoints for clinical trials to determine efficacy and to monitor safety of therapeutic interventions. In order to inform researchers and clinician-scientists about these new diagnostic tools, a workshop was organized by the European Vision Institute. Invited speakers highlighted the recent advances in state-of-the-art technologies for outcome measures in the field of retina. This review highlights the workshop's presentations in the context of published literature.
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Affiliation(s)
- Maria Della Volpe-Waizel
- Department of Ophthalmology, University of Basel, Basel, Switzerland.,Institute of Molecular and Clinical Ophthalmology (IOB), Basel, Switzerland
| | - Ghislaine L Traber
- Department of Ophthalmology, University of Basel, Basel, Switzerland.,Institute of Molecular and Clinical Ophthalmology (IOB), Basel, Switzerland
| | - Peter Maloca
- Institute of Molecular and Clinical Ophthalmology (IOB), Basel, Switzerland
| | - Martin Zinkernagel
- Department of Ophthalmology and Department of Clinical Research, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | | | - Gary Rubin
- UCL University College London, Institute of Ophthalmology, London, United Kingdom
| | - Botond Roska
- Institute of Molecular and Clinical Ophthalmology (IOB), Basel, Switzerland
| | - Tilman Otto
- Heidelberg Engineering GmbH, Heidelberg, Germany
| | - Richard G Weleber
- Casey Eye Institute, Departments of Ophthalmology and Molecular and Medical Genetics, University of Oregon Health and Science University, Portland, Oregon, USA
| | - Hendrik P N Scholl
- Department of Ophthalmology, University of Basel, Basel, Switzerland, .,Institute of Molecular and Clinical Ophthalmology (IOB), Basel, Switzerland,
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14
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Zhang T, Kho AM, Srinivasan VJ. Improving visible light OCT of the human retina with rapid spectral shaping and axial tracking. BIOMEDICAL OPTICS EXPRESS 2019; 10:2918-2931. [PMID: 31259062 PMCID: PMC6583340 DOI: 10.1364/boe.10.002918] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/30/2019] [Accepted: 04/30/2019] [Indexed: 05/23/2023]
Abstract
Visible light optical coherence tomography (OCT) theoretically provides finer axial resolution than near-infrared OCT for a given wavelength bandwidth. To realize this potential in the human retina in vivo, the unique technical challenges of visible light OCT must be addressed. We introduce three advances to further the performance of visible light OCT in the human retina. First, we incorporate a grating light valve spatial light modulator (GLV-SLM) spectral shaping stage to modify the source spectrum. This enables comfortable subject alignment with a red light spectrum, and image acquisition with a broad "white light" spectrum, shaped to minimize sidelobes. Second, we develop a novel, Fourier transform-free, software axial motion tracking algorithm with fast, magnetically actuated stage to maintain near-optimal axial resolution and sensitivity in the presence of eye motion. Third, we implement spatially dependent numerical dispersion compensation for the first time in the human eye in vivo. In vivo human retinal OCT images clearly show that the inner plexiform layer consists of 3 hyper-reflective bands and 2 hypo-reflective bands, corresponding with the standard anatomical division of the IPL. Wavelength-dependent images of the outer retina suggest that, beyond merely improving the axial resolution, shorter wavelength visible light may also provide unique advantages for visualizing Bruch's membrane.
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Affiliation(s)
- Tingwei Zhang
- Biomedical Engineering Department, University of California Davis, Davis, California, 95616, USA
| | - Aaron M. Kho
- Biomedical Engineering Department, University of California Davis, Davis, California, 95616, USA
| | - Vivek J. Srinivasan
- Biomedical Engineering Department, University of California Davis, Davis, California, 95616, USA
- Department of Ophthalmology and Vision Science, University of California Davis School of Medicine, Sacramento, California, 95817, USA
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15
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Lichtenegger A, Gesperger J, Kiesel B, Muck M, Eugui P, Harper DJ, Salas M, Augustin M, Merkle CW, Hitzenberger CK, Widhalm G, Woehrer A, Baumann B. Revealing brain pathologies with multimodal visible light optical coherence microscopy and fluorescence imaging. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-11. [PMID: 31240898 PMCID: PMC6977170 DOI: 10.1117/1.jbo.24.6.066010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 06/07/2019] [Indexed: 05/28/2023]
Abstract
We present a multimodal visible light optical coherence microscopy (OCM) and fluorescence imaging (FI) setup. Specification and phantom measurements were performed to characterize the system. Two applications in neuroimaging were investigated. First, curcumin-stained brain slices of a mouse model of Alzheimer's disease were examined. Amyloid-beta plaques were identified based on the fluorescence of curcumin, and coregistered morphological images of the brain tissue were provided by the OCM channel. Second, human brain tumor biopsies retrieved intraoperatively were imaged prior to conventional neuropathologic work-up. OCM revealed the three-dimensional structure of the brain parenchyma, and FI added the tumor tissue-specific contrast. Attenuation coefficients computed from the OCM data and the florescence intensity values were analyzed and showed a statistically significant difference for 5-aminolevulinic acid (5-ALA)-positive and -negative brain tissues. OCM findings correlated well with malignant hot spots within brain tumor biopsies upon histopathology. The combination of OCM and FI seems to be a promising optical imaging modality providing complementary contrast for applications in the field of neuroimaging.
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Affiliation(s)
- Antonia Lichtenegger
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Johanna Gesperger
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- General Hospital and Medical University of Vienna, Institute of Neurology, Vienna, Austria
| | - Barbara Kiesel
- General Hospital and Medical University of Vienna, Univ. Klinik Neurochirurgie, Vienna, Austria
| | - Martina Muck
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
- General Hospital and Medical University of Vienna, Institute of Neurology, Vienna, Austria
| | - Pablo Eugui
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Danielle J. Harper
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Matthias Salas
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Marco Augustin
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Conrad W. Merkle
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Christoph K. Hitzenberger
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
| | - Georg Widhalm
- General Hospital and Medical University of Vienna, Univ. Klinik Neurochirurgie, Vienna, Austria
| | - Adelheid Woehrer
- General Hospital and Medical University of Vienna, Institute of Neurology, Vienna, Austria
| | - Bernhard Baumann
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna, Austria
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16
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Engelsholm RD, Bang O. Supercontinuum noise reduction by fiber undertapering. OPTICS EXPRESS 2019; 27:10320-10331. [PMID: 31045176 DOI: 10.1364/oe.27.010320] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We demonstrate that the Relative Intensity Noise (RIN) of a supercontinuum source can be significantly reduced using the new concept of undertapering, where the fiber is tapered to a diameter that is smaller than the diameter that gives the shortest blue edge, which is typically regarded as the optimum. We show that undertapering allows to control the second zero dispersion wavelength and use it as a soliton barrier to stop the redshifting solitons at a pre-defined wavelength, and thereby strongly reduce the RIN. We demonstrate how undertapering can reduce the spectrally averaged RIN in the optical coherence tomography bands, 500-800nm and 1150-1450nm, by more than a factor two.
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17
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Kho A, Srinivasan VJ. Compensating spatially dependent dispersion in visible light OCT. OPTICS LETTERS 2019; 44:775-778. [PMID: 30767984 PMCID: PMC6503663 DOI: 10.1364/ol.44.000775] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 01/06/2019] [Indexed: 05/02/2023]
Abstract
Visible light optical coherence tomography (OCT) has recently emerged in retinal imaging, with claims of micrometer-scale axial resolution and multi-color (sub-band) imaging. Here, we show that the large dispersion of optical glass and aqueous media, together with broad optical bandwidths often used in visible light OCT, compromises both of these claims. To rectify this, we introduce the notion of spatially dependent (i.e., depth and transverse position-dependent) dispersion. We use a novel sub-band, sub-image correlation algorithm to estimate spatially dependent dispersion in our 109 nm bandwidth visible light OCT mouse retinal imaging system centered at 587 nm. After carefully compensating spatially dependent dispersion, we achieve delineation of fine outer retinal bands in mouse strains of varying pigmentation. Spatially dependent dispersion correction is critical for broader bandwidths and shorter visible wavelengths.
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Affiliation(s)
- Aaron Kho
- Department of Biomedical Engineering, University of California, Davis, California 95616, USA
| | - Vivek J. Srinivasan
- Department of Biomedical Engineering, University of California, Davis, California 95616, USA
- Department of Ophthalmology and Vision Science, University of California Davis School of Medicine, Sacramento, California 96817, USA
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18
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Lapierre-Landry M, Carroll J, Skala MC. Imaging retinal melanin: a review of current technologies. J Biol Eng 2018; 12:29. [PMID: 30534199 PMCID: PMC6280494 DOI: 10.1186/s13036-018-0124-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 11/22/2018] [Indexed: 11/10/2022] Open
Abstract
The retinal pigment epithelium (RPE) is essential to the health of the retina and the proper functioning of the photoreceptors. The RPE is rich in melanosomes, which contain the pigment melanin. Changes in RPE pigmentation are seen with normal aging and in diseases such as albinism and age-related macular degeneration. However, most techniques used to this day to detect and quantify ocular melanin are performed ex vivo and are destructive to the tissue. There is a need for in vivo imaging of melanin both at the clinical and pre-clinical level to study how pigmentation changes can inform disease progression. In this manuscript, we review in vivo imaging techniques such as fundus photography, fundus reflectometry, near-infrared autofluorescence imaging, photoacoustic imaging, and functional optical coherence tomography that specifically detect melanin in the retina. These methods use different contrast mechanisms to detect melanin and provide images with different resolutions and field-of-views, making them complementary to each other.
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Affiliation(s)
- Maryse Lapierre-Landry
- 1Morgridge Institute for Research, Madison, WI USA.,2Department of Biomedical Engineering, Vanderbilt University, Nashville, TN USA.,6Department of Pediatrics, Case Western Reserve University, Cleveland, OH USA
| | - Joseph Carroll
- 3Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, WI USA.,4Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI USA
| | - Melissa C Skala
- 1Morgridge Institute for Research, Madison, WI USA.,5Department of Biomedical Engineering, University of Wisconsin Madison, Madison, WI USA
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19
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Song W, Zhou L, Zhang S, Ness S, Desai M, Yi J. Fiber-based visible and near infrared optical coherence tomography (vnOCT) enables quantitative elastic light scattering spectroscopy in human retina. BIOMEDICAL OPTICS EXPRESS 2018; 9:3464-3480. [PMID: 29984110 PMCID: PMC6033571 DOI: 10.1364/boe.9.003464] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 06/09/2018] [Accepted: 06/21/2018] [Indexed: 05/18/2023]
Abstract
Elastic light scattering spectroscopy (ELSS) has been proven a powerful method in measuring tissue structures with exquisite nanoscale sensitivity. However, ELSS contrast in the living human retina has been relatively underexplored, primarily due to the lack of imaging tools with a large spectral bandwidth. Here, we report a simple all fiber-based setup to implement dual-channel visible and near infrared (NIR) optical coherence tomography (vnOCT) for human retinal imaging, bridging over a 300nm spectral gap. Remarkably, the fiber components in our vnOCT system support single-mode propagation for both visible and NIR light, both of which maintain excellent interference efficiencies with fringe visibility of 97% and 90%, respectively. The longitudinal chromatic aberration from the eye is corrected by a custom-designed achromatizing lens. The elegant fiber-based design enables simultaneous imaging for both channels and allows comprehensive ELSS analysis on several important anatomical layers, including nerve fiber layer, outer segment of the photoreceptors and retinal pigment epithelium. This vnOCT platform and method of ELSS analysis open new opportunities in understanding structure-function relationship in the human retina and in exploring new biomarkers for retinal diseases.
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Affiliation(s)
- Weiye Song
- Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, MA 02118, USA
| | - Libo Zhou
- College of Electronic Science and Engineering, Jilin University, Changchun, Jilin, 130012, China
| | - Sui Zhang
- Danna-Farber Cancer Institute, Boston, MA 02215, USA
| | - Steven Ness
- Department of Ophthalmology, Boston Medical Center, Boston University School of Medicine, Boston, MA 02118, USA
| | - Manishi Desai
- Department of Ophthalmology, Boston Medical Center, Boston University School of Medicine, Boston, MA 02118, USA
| | - Ji Yi
- Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, MA 02118, USA
- Department of Biomedical Engineering, Boston University, Boston, MA 02118, USA
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