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Bisignano KK, Smith JD, Harrison WW. Variations in Retinal Oxygen Saturation in a Diverse Healthy Population. CLINICAL OPTOMETRY 2024; 16:147-155. [PMID: 39045010 PMCID: PMC11265219 DOI: 10.2147/opto.s468076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Accepted: 06/05/2024] [Indexed: 07/25/2024]
Abstract
Purpose Local retinal oxygen saturation is a research technique, which has the potential as a biomarker for diabetes. However, normative data has not been established. This study examined differences in oxygen saturation around the macula and characterizes the relationship between age, race, refractive error (RE), sex, blood pressure (BP), prediabetic status and oxygen saturation. Methods Fifty-nine subjects aged 22-69 (38.8 ± 14.7 years) were included who were racially diverse and with equal gender distribution. None had eye disease. Oxygen saturation was taken with the Zilia Ocular in 4 locations around the macula 3.1 degrees from the fovea and they were also averaged. BP, RE, and HbA1c were noted. Regression analyses for oximetry and other factors were completed as were t-tests with multiple comparison corrections. Results There were significant variations in oximetry measures by race, with higher pigmentation levels associated with lower oximetry values (p < 0.01). There was no relationship between oximetry and sex (p = 0.34), RE (p = 0.67), BP (systolic p = 0.61, diastolic p = 0.71) nor prediabetic status (p = 0.87). Oximetry was associated with age when controlling for race (P < 0.002). Nasal-temporal variations showed nasal oximetry to higher than temporal measures (P < 0.01). Conclusion This study revealed race/pigmentation is an important influence on oximetry measures. Retinal location also caused variations, likely due to proximity to larger vessels nasally. No differences in sex, RE nor BP were observed to alter local oxygen saturation. However, age was correlated when considered with race. This study will inform our future work in different disease states and is an important first step in evaluating this technology.
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Affiliation(s)
- Kelly K Bisignano
- Department of Clinical Sciences College of Optometry, University of Houston, Houston, TX, USA
| | - Jennyffer D Smith
- Department of Clinical Sciences College of Optometry, University of Houston, Houston, TX, USA
| | - Wendy W Harrison
- Department of Clinical Sciences College of Optometry, University of Houston, Houston, TX, USA
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2
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Wu J. Hyperspectral imaging for non-invasive blood oxygen saturation assessment. Photodiagnosis Photodyn Ther 2024; 45:104003. [PMID: 38336148 DOI: 10.1016/j.pdpdt.2024.104003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/27/2024] [Accepted: 02/05/2024] [Indexed: 02/12/2024]
Abstract
Hyperspectral Imaging (HSI) seamlessly integrates imaging and spectroscopy, capturing both spatial and spectral data concurrently. With widespread applications in medical diagnostics, HSI serves as a noninvasive tool for gaining insights into tissue characteristics. The distinctive spectral profiles of biological tissues set HSI apart from traditional microscopy in enabling in vivo tissue analysis. Despite its potential, existing HSI techniques face challenges such as alignment issues, low light throughput, and tissue heating due to intense illumination. This study introduces an innovative HSI system featuring active sequential bandpass illumination seamlessly integrated into conventional optical instruments. The primary focus is on analyzing oxyhemoglobin and deoxyhemoglobin saturation in animal tissue samples using multivariate linear regression. This approach holds promise for enhancing noninvasive medical diagnostics. A key feature of the system, active bandpass illumination, effectively prevents tissue overheating, thereby bolstering its suitability for medical applications.
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Affiliation(s)
- Jiangbo Wu
- School of Information Science and Technology, Fudan University, Shanghai 200433, China.
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3
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Akitegetse C, Poirier J, Sauvageau D. Sensitivity of visible range multi-wavelength algorithms for retinal tissue oximetry to acquisition parameters. BIOMEDICAL OPTICS EXPRESS 2023; 14:4296-4309. [PMID: 37799705 PMCID: PMC10549742 DOI: 10.1364/boe.495721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/16/2023] [Accepted: 07/18/2023] [Indexed: 10/07/2023]
Abstract
This study examined the sensitivity of broadband spectroscopy algorithms for retinal tissue oximetry to spectral acquisition parameters. Monte Carlo simulations were conducted on a 4-layer retinal model to assess the impact of various parameters. The optimal spectral range for accurate measurements was determined to be 530 nm to 585 nm. Decreased spectral resolution below 4 nm significantly reduced accuracy. Using an acquisition area larger than the blood vessel resulted in an underestimation of oxygen saturation, especially for high values. A threshold was observed where increased light intensity had no significant impact on measurement variability. The study highlights the importance of informed parameter selection for accurately assessing retinal microcapillary oxygenation and studying local hemodynamics.
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Affiliation(s)
| | | | - Dominic Sauvageau
- Zilia inc., Québec, QC, G1K 3G5, Canada
- Chemical and Materials Engineering, University of Alberta, Edmonton, AB, T6G 1H9, Canada
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4
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Fang R, Rubinoff I, Zhang HF. Multiple forward scattering reduces the measured scattering coefficient of whole blood in visible-light optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2022; 13:4510-4527. [PMID: 36187273 PMCID: PMC9484418 DOI: 10.1364/boe.459607] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 07/18/2022] [Accepted: 07/19/2022] [Indexed: 05/10/2023]
Abstract
The optical properties of blood encode oxygen-dependent information. Noninvasive optical detection of these properties is increasingly desirable to extract biomarkers for tissue health. Recently, visible-light optical coherence tomography (vis-OCT) demonstrated retinal oxygen saturation (sO2) measurements by inversely measuring the oxygen-dependent absorption and scattering coefficients of whole blood. However, vis-OCT may be sensitive to optical scattering properties of whole blood, different from those reported in the literature. Incorrect assumptions of such properties can add additional uncertainties or biases to vis-OCT's sO2 model. This work investigates whole blood's scattering coefficient measured by vis-OCT. Using Monte Carlo simulation of a retinal vessel, we determined that vis-OCT almost exclusively detects multiple-scattered photons in whole blood. Meanwhile, photons mostly forward scatter in whole blood within the visible spectral range, allowing photons to maintain ballistic paths and penetrate deeply, leading to a reduction in the measured scattering coefficient. We defined a scattering scaling factor (SSF) to account for such a reduction and found that SSF varied with measurement conditions, such as numerical aperture, depth resolution, and depth selection. We further experimentally validated SSF in ex vivo blood phantoms with pre-set sO2 levels and in the human retina, both of which agreed well with our simulation.
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Affiliation(s)
- Raymond Fang
- Department of Biomedical Engineering, Northwestern University, Evanston IL 60208, USA
- These authors contributed equally to this work
| | - Ian Rubinoff
- Department of Biomedical Engineering, Northwestern University, Evanston IL 60208, USA
- These authors contributed equally to this work
| | - Hao F. Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston IL 60208, USA
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5
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Taylor-Williams M, Spicer G, Bale G, Bohndiek SE. Noninvasive hemoglobin sensing and imaging: optical tools for disease diagnosis. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:JBO-220074VR. [PMID: 35922891 PMCID: PMC9346606 DOI: 10.1117/1.jbo.27.8.080901] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/27/2022] [Indexed: 05/08/2023]
Abstract
SIGNIFICANCE Measurement and imaging of hemoglobin oxygenation are used extensively in the detection and diagnosis of disease; however, the applied instruments vary widely in their depth of imaging, spatiotemporal resolution, sensitivity, accuracy, complexity, physical size, and cost. The wide variation in available instrumentation can make it challenging for end users to select the appropriate tools for their application and to understand the relative limitations of different methods. AIM We aim to provide a systematic overview of the field of hemoglobin imaging and sensing. APPROACH We reviewed the sensing and imaging methods used to analyze hemoglobin oxygenation, including pulse oximetry, spectral reflectance imaging, diffuse optical imaging, spectroscopic optical coherence tomography, photoacoustic imaging, and diffuse correlation spectroscopy. RESULTS We compared and contrasted the ability of different methods to determine hemoglobin biomarkers such as oxygenation while considering factors that influence their practical application. CONCLUSIONS We highlight key limitations in the current state-of-the-art and make suggestions for routes to advance the clinical use and interpretation of hemoglobin oxygenation information.
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Affiliation(s)
- Michaela Taylor-Williams
- University of Cambridge, Department of Physics, Cavendish Laboratory, Cambridge, United Kingdom, United Kingdom
- University of Cambridge, Cancer Research UK Cambridge Institute, Cambridge, United Kingdom, United Kingdom
| | - Graham Spicer
- University of Cambridge, Department of Physics, Cavendish Laboratory, Cambridge, United Kingdom, United Kingdom
- University of Cambridge, Cancer Research UK Cambridge Institute, Cambridge, United Kingdom, United Kingdom
| | - Gemma Bale
- University of Cambridge, Department of Physics, Cavendish Laboratory, Cambridge, United Kingdom, United Kingdom
- University of Cambridge, Electrical Division, Department of Engineering, Cambridge, United Kingdom, United Kingdom
| | - Sarah E Bohndiek
- University of Cambridge, Department of Physics, Cavendish Laboratory, Cambridge, United Kingdom, United Kingdom
- University of Cambridge, Cancer Research UK Cambridge Institute, Cambridge, United Kingdom, United Kingdom
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6
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Alexopoulos P, Madu C, Wollstein G, Schuman JS. The Development and Clinical Application of Innovative Optical Ophthalmic Imaging Techniques. Front Med (Lausanne) 2022; 9:891369. [PMID: 35847772 PMCID: PMC9279625 DOI: 10.3389/fmed.2022.891369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/23/2022] [Indexed: 11/22/2022] Open
Abstract
The field of ophthalmic imaging has grown substantially over the last years. Massive improvements in image processing and computer hardware have allowed the emergence of multiple imaging techniques of the eye that can transform patient care. The purpose of this review is to describe the most recent advances in eye imaging and explain how new technologies and imaging methods can be utilized in a clinical setting. The introduction of optical coherence tomography (OCT) was a revolution in eye imaging and has since become the standard of care for a plethora of conditions. Its most recent iterations, OCT angiography, and visible light OCT, as well as imaging modalities, such as fluorescent lifetime imaging ophthalmoscopy, would allow a more thorough evaluation of patients and provide additional information on disease processes. Toward that goal, the application of adaptive optics (AO) and full-field scanning to a variety of eye imaging techniques has further allowed the histologic study of single cells in the retina and anterior segment. Toward the goal of remote eye care and more accessible eye imaging, methods such as handheld OCT devices and imaging through smartphones, have emerged. Finally, incorporating artificial intelligence (AI) in eye images has the potential to become a new milestone for eye imaging while also contributing in social aspects of eye care.
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Affiliation(s)
- Palaiologos Alexopoulos
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
| | - Chisom Madu
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
| | - Gadi Wollstein
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY, United States
- Center for Neural Science, College of Arts & Science, New York University, New York, NY, United States
| | - Joel S. Schuman
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY, United States
- Center for Neural Science, College of Arts & Science, New York University, New York, NY, United States
- Department of Electrical and Computer Engineering, NYU Tandon School of Engineering, Brooklyn, NY, United States
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7
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Lejoyeux R, Benillouche J, Ong J, Errera MH, Rossi EA, Singh SR, Dansingani KK, da Silva S, Sinha D, Sahel JA, Freund KB, Sadda SR, Lutty GA, Chhablani J. Choriocapillaris: Fundamentals and advancements. Prog Retin Eye Res 2021; 87:100997. [PMID: 34293477 DOI: 10.1016/j.preteyeres.2021.100997] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 07/02/2021] [Accepted: 07/13/2021] [Indexed: 12/19/2022]
Abstract
The choriocapillaris is the innermost structure of the choroid that directly nourishes the retinal pigment epithelium and photoreceptors. This article provides an overview of its hemovasculogenesis development to achieve its final architecture as a lobular vasculature, and also summarizes the current histological and molecular knowledge about choriocapillaris and its dysfunction. After describing the existing state-of-the-art tools to image the choriocapillaris, we report the findings in the choriocapillaris encountered in the most frequent retinochoroidal diseases including vascular diseases, inflammatory diseases, myopia, pachychoroid disease spectrum disorders, and glaucoma. The final section focuses on the development of imaging technology to optimize visualization of the choriocapillaris as well as current treatments of retinochoroidal disorders that specifically target the choriocapillaris. We conclude the article with pertinent unanswered questions and future directions in research for the choriocapillaris.
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Affiliation(s)
| | | | - Joshua Ong
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Marie-Hélène Errera
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Ethan A Rossi
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA 15213, USA
| | - Sumit R Singh
- Jacobs Retina Center, Shiley Eye Institute, University of California San Diego, San Diego, CA, USA
| | - Kunal K Dansingani
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Susana da Silva
- Department of Ophthalmology and Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Debasish Sinha
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Cell Biology and Center for Biologic Imaging, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - José-Alain Sahel
- Rothschild Foundation, 75019, Paris, France; Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France; CHNO des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, France
| | - K Bailey Freund
- LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear, and Throat Hospital, New York, NY, USA; Vitreous Retina Macula Consultants of New York, New York, NY, USA; Department of Ophthalmology, New York University of Medicine, New York, NY, USA; Edward S. Harkness Eye Institute, Columbia University Medical Center, New York, NY, USA
| | - SriniVas R Sadda
- Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, CA, 90033, USA; Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Gerard A Lutty
- Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, MD, 21287, USA
| | - Jay Chhablani
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
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8
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Abstract
Similar to other organs, the retina relies on tightly regulated perfusion and oxygenation. Previous studies have demonstrated that retinal blood flow is affected in a variety of eye and systemic diseases, including diabetic retinopathy, age-related macular degeneration, and glaucoma. Although measurement of peripheral oxygen saturation has become a standard clinical measurement through the development of pulse oximetry, developing a noninvasive technique to measure retinal oxygen saturation has proven challenging, and retinal oximetry technology currently remains inadequate for reliable clinical use. Here, we review current strategies and approaches, as well as several newer technologies in development, and discuss the future of retinal oximetry.
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Affiliation(s)
- Anupam K Garg
- Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA, USA.,School of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Darren Knight
- Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA, USA
| | - Leonardo Lando
- Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA, USA
| | - Daniel L Chao
- Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA, USA.,School of Medicine, University of California San Diego, La Jolla, CA, USA.,Janssen Research and Development, Raritan, NJ, USA
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9
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Hosseinaee Z, Nima Abbasi, Pellegrino N, Khalili L, Mukhangaliyeva L, Haji Reza P. Functional and structural ophthalmic imaging using noncontact multimodal photoacoustic remote sensing microscopy and optical coherence tomography. Sci Rep 2021; 11:11466. [PMID: 34075105 PMCID: PMC8169886 DOI: 10.1038/s41598-021-90776-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 05/17/2021] [Indexed: 11/09/2022] Open
Abstract
Early diagnosis of ocular diseases improves the understanding of pathophysiology and aids in accurate monitoring and effective treatment. Advanced, multimodal ocular imaging platforms play a crucial role in visualization of ocular components and provide clinicians with a valuable tool for evaluating various eye diseases. Here, for the first time we present a non-contact, multiwavelength photoacoustic remote sensing (PARS) microscopy and swept-source optical coherence tomography (SS-OCT) for in-vivo functional and structural imaging of the eye. The system provides complementary imaging contrasts of optical absorption and optical scattering, and is used for simultaneous, non-contact, in-vivo imaging of murine eye. Results of vasculature and structural imaging as well as melanin content in the retinal pigment epithelium layer are presented. Multiwavelength PARS microscopy using Stimulated Raman scattering is applied to enable in-vivo, non-contact oxygen saturation estimation in the ocular tissue. The reported work may be a major step towards clinical translation of ophthalmic technologies and has the potential to advance the diagnosis and treatment of ocular diseases.
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Affiliation(s)
- Zohreh Hosseinaee
- PhotoMedicine Labs, Department of System Design Engineering, University of Waterloo, 200 University Ave W, Waterloo, ON, N2L 3G1, Canada
| | - Nima Abbasi
- PhotoMedicine Labs, Department of System Design Engineering, University of Waterloo, 200 University Ave W, Waterloo, ON, N2L 3G1, Canada
| | - Nicholas Pellegrino
- PhotoMedicine Labs, Department of System Design Engineering, University of Waterloo, 200 University Ave W, Waterloo, ON, N2L 3G1, Canada
| | - Layla Khalili
- PhotoMedicine Labs, Department of System Design Engineering, University of Waterloo, 200 University Ave W, Waterloo, ON, N2L 3G1, Canada
| | - Lyazzat Mukhangaliyeva
- PhotoMedicine Labs, Department of System Design Engineering, University of Waterloo, 200 University Ave W, Waterloo, ON, N2L 3G1, Canada
| | - Parsin Haji Reza
- PhotoMedicine Labs, Department of System Design Engineering, University of Waterloo, 200 University Ave W, Waterloo, ON, N2L 3G1, Canada.
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10
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Optical density based quantification of total haemoglobin concentrations with spectroscopic optical coherence tomography. Sci Rep 2021; 11:8680. [PMID: 33883617 PMCID: PMC8060256 DOI: 10.1038/s41598-021-88063-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 04/05/2021] [Indexed: 11/21/2022] Open
Abstract
Spectroscopic optical coherence tomography (sOCT) has emerged as a new possibility for non-invasive quantification of total haemoglobin concentrations [tHb]. Recently, we demonstrated that [tHb] measured in ex-vivo human whole-blood with a conventional sOCT system achieves a precision of 9.10 g/dL with a bias of 1.50 g/dL. This precision improved by acquiring data with a combination of focus tracking and zero-delay acquisition (FZA) that compensated for experimental limitations, increasing to 3.80 g/dL with a bias of 1.50 g/dL. Nevertheless, sOCT precision should improve at least to \documentclass[12pt]{minimal}
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\begin{document}$$\sim 2$$\end{document}∼2 g/dL to be clinically relevant. Therefore, sOCT-based [tHb] determinations require the development of new analysis methods that reduce the variability of [tHb] estimations. In this work, we aim to increase sOCT precision by retrieving the [tHb] content from a numerical optimisation of the optical density (OD), while considering the blood absorption flattening effect. The OD-based approach simplifies previous two-step Lambert–Beer fitting approaches to a single step, thereby reducing errors during the fitting procedure. We validated our model with ex-vivo [tHb] measurements on flowing whole-blood samples in the clinical range (7–23 g/dL). Our results show that, with the new model, conventional sOCT can determine [tHb] with a precision of 3.09 g/dL and a bias of 0.86 g/dL compared to a commercial blood analyser. We present further precision improvement by combining the OD methodology with FZA, leading to a precision of 2.08 g/dL with a bias of 0.46 g/dL.
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11
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Ringel MJ, Tang EM, Tao YK. Advances in multimodal imaging in ophthalmology. Ther Adv Ophthalmol 2021; 13:25158414211002400. [PMID: 35187398 PMCID: PMC8855415 DOI: 10.1177/25158414211002400] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 02/23/2021] [Indexed: 12/12/2022] Open
Abstract
Multimodality ophthalmic imaging systems aim to enhance the contrast, resolution, and functionality of existing technologies to improve disease diagnostics and therapeutic guidance. These systems include advanced acquisition and post-processing methods using optical coherence tomography (OCT), combined scanning laser ophthalmoscopy and OCT systems, adaptive optics, surgical guidance, and photoacoustic technologies. Here, we provide an overview of these ophthalmic imaging systems and their clinical and basic science applications.
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Affiliation(s)
- Morgan J. Ringel
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Eric M. Tang
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Yuankai K. Tao
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
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12
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Karapapak M, Güven D, Demir M, Tiryaki Demir S, Uslu Dogan C. Optical coherence tomography angiography of central serous chorioretinopathy patients' response to breath-holding manoeuvre. Acta Ophthalmol 2020; 98:787-794. [PMID: 32996704 DOI: 10.1111/aos.14625] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 06/28/2020] [Accepted: 08/28/2020] [Indexed: 12/16/2022]
Abstract
PURPOSE To demonstrate through the use of optical coherence tomography angiography (OCTA) that normal vasoreactivity cannot be monitored in central serous chorioretinopathy (CSR) patients in the presence of vasoactive stimuli owing to hypoxia caused by the breath-holding manoeuvre (BHM). METHODS This cross-sectional study included a total of 210 eyes, including 70 CSR patients (70 symptomatic eyes, 70 asymptomatic eyes) and 70 control group. Images of the macula (3 × 3 mm) and the optic disc (4.5 × 4.5 mm) were obtained at the baseline and after BHM using OCTA. The change in vascular parameters in the OCTA after BHM was evaluated in CSR patients and the control group. RESULTS In the symptomatic eyes of CSR patients, the mean whole image vessel density (VD) in the superficial capillary plexus decreased from 48.0 ± 3.5% under baseline conditions to 46.0 ± 4.5% after BHM (p < 0.01), and the mean whole VD in the deep capillary plexus decreased from 47.9 ± 8.0% under baseline conditions to 46.9 ± 6.7% after BHM (p < 0.01). The OCTA after BHM revealed a decrease in the mean whole image VD of the optic disc in both symptomatic (50.4 ± 2.1% to 49.6 ± 2.0%, p < 0.05) and asymptomatic (50.9 ± 1.8% to 50.4 ± 1.9%, p < 0.05) eyes of CSR patients. No difference for any mean VD of the control group was seen between the baseline and after BHM. Outer retinal flow areas increased significantly after BHM compared with the baseline in both eyes of CSR patients. CONCLUSION These results suggest that CSR pathogenesis is related to an imbalance in local vascular regulation and the sympathetic activity of the autonomic nervous system. This technique constitutes a new way of studying retinal vascular changes and may be applied to CSR patients.
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Affiliation(s)
- Murat Karapapak
- Department of Ophthalmology Basaksehir Cam and Sakura City Hospital Istanbul Turkey
| | - Dilek Güven
- Department of Ophthalmology Sisli Hamidiye Etfal Training and Research Hospital University of Health Sciences Istanbul Turkey
| | - Mehmet Demir
- Department of Ophthalmology Sisli Hamidiye Etfal Training and Research Hospital University of Health Sciences Istanbul Turkey
| | - Semra Tiryaki Demir
- Department of Ophthalmology Sisli Hamidiye Etfal Training and Research Hospital University of Health Sciences Istanbul Turkey
| | - Ceylan Uslu Dogan
- Department of Ophthalmology Sisli Hamidiye Etfal Training and Research Hospital University of Health Sciences Istanbul Turkey
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13
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Schwarzhans F, Desissaire S, Steiner S, Pircher M, Hitzenberger CK, Resch H, Vass C, Fischer G. Generating large field of view en-face projection images from intra-acquisition motion compensated volumetric optical coherence tomography data. BIOMEDICAL OPTICS EXPRESS 2020; 11:6881-6904. [PMID: 33408968 PMCID: PMC7747913 DOI: 10.1364/boe.404738] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/16/2020] [Accepted: 10/21/2020] [Indexed: 05/21/2023]
Abstract
A technique to generate large field of view projection maps of arbitrary optical coherence tomography (OCT) data is described. The technique is divided into two stages - an image acquisition stage that features a simple to use fast and robust retinal tracker to get motion free retinal OCT volume scans - and a stitching stage where OCT data from different retinal locations is first registered against a reference image using a custom pyramid-based approach and finally stitched together into one seamless large field of view (FOV) image. The method is applied to data recorded with a polarization sensitive OCT instrument in healthy subjects and glaucoma patients. The tracking and stitching accuracies are quantified, and finally, large FOV images of retinal nerve fiber layer retardation that contain the arcuate nerve fiber bundles from the optic nerve head to the raphe are demonstrated.
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Affiliation(s)
- Florian Schwarzhans
- Center for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna, Vienna, 1090, Austria
| | - Sylvia Desissaire
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, 1090, Austria
| | - Stefan Steiner
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, 1090, Austria
| | - Michael Pircher
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, 1090, Austria
| | - Christoph K. Hitzenberger
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, 1090, Austria
| | - Hemma Resch
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, 1090, Austria
| | - Clemens Vass
- Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, 1090, Austria
| | - Georg Fischer
- Center for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna, Vienna, 1090, Austria
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14
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Liu R, Cheng S, Tian L, Yi J. Deep spectral learning for label-free optical imaging oximetry with uncertainty quantification. LIGHT, SCIENCE & APPLICATIONS 2019; 8:102. [PMID: 31754429 PMCID: PMC6864044 DOI: 10.1038/s41377-019-0216-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 10/17/2019] [Accepted: 11/01/2019] [Indexed: 05/06/2023]
Abstract
Measurement of blood oxygen saturation (sO2) by optical imaging oximetry provides invaluable insight into local tissue functions and metabolism. Despite different embodiments and modalities, all label-free optical-imaging oximetry techniques utilize the same principle of sO2-dependent spectral contrast from haemoglobin. Traditional approaches for quantifying sO2 often rely on analytical models that are fitted by the spectral measurements. These approaches in practice suffer from uncertainties due to biological variability, tissue geometry, light scattering, systemic spectral bias, and variations in the experimental conditions. Here, we propose a new data-driven approach, termed deep spectral learning (DSL), to achieve oximetry that is highly robust to experimental variations and, more importantly, able to provide uncertainty quantification for each sO2 prediction. To demonstrate the robustness and generalizability of DSL, we analyse data from two visible light optical coherence tomography (vis-OCT) setups across two separate in vivo experiments on rat retinas. Predictions made by DSL are highly adaptive to experimental variabilities as well as the depth-dependent backscattering spectra. Two neural-network-based models are tested and compared with the traditional least-squares fitting (LSF) method. The DSL-predicted sO2 shows significantly lower mean-square errors than those of the LSF. For the first time, we have demonstrated en face maps of retinal oximetry along with a pixel-wise confidence assessment. Our DSL overcomes several limitations of traditional approaches and provides a more flexible, robust, and reliable deep learning approach for in vivo non-invasive label-free optical oximetry.
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Affiliation(s)
- Rongrong Liu
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208 USA
| | - Shiyi Cheng
- Department of Electrical and Computer Engineering, Boston University, Boston, MA 02215 USA
| | - Lei Tian
- Department of Electrical and Computer Engineering, Boston University, Boston, MA 02215 USA
| | - Ji Yi
- Department of Electrical and Computer Engineering, Boston University, Boston, MA 02215 USA
- Department of Biomedical Engineering, Boston University, Boston, MA 02215 USA
- Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, MA 02118 USA
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15
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Quantification of total haemoglobin concentrations in human whole blood by spectroscopic visible-light optical coherence tomography. Sci Rep 2019; 9:15115. [PMID: 31641197 PMCID: PMC6806004 DOI: 10.1038/s41598-019-51721-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 10/02/2019] [Indexed: 11/08/2022] Open
Abstract
The non-invasive quantification of total haemoglobin concentrations [tHb] is highly desired for the assessment of haematologic disorders in vulnerable patient groups, but invasive blood sampling is still the gold standard in current clinical practice. This work demonstrates the potential of visible-light spectroscopic optical coherence tomography (sOCT) for quantifying the [tHb] in human whole blood. To accurately quantify the [tHb] from the substantial optical attenuation by blood in the visible wavelength range, we used a combination of zero-delay acquisition and focus tracking that ensures optimal system sensitivity at any depth inside the sample. Subsequently, we developed an analysis model to adequately correct for the high scattering contribution by red blood cells to the sOCT signal. We validate our method and compare it to conventional sOCT (without focus tracking and zero-delay acquisition) through ex-vivo measurements on flowing human whole blood, with [tHb] values in the clinical range of 7-23 g/dL. For our method with optimized sensitivity, the measured and expected values correlate well (Pearson correlation coefficient = 0.89, p < 0.01), with a precision of 3.8 g/dL. This is a considerable improvement compared to conventional sOCT (Pearson correlation coefficient = 0.59, p = 0.16; precision of 9.1 g/dL).
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16
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Pi S, Hormel TT, Wei X, Cepurna W, Camino A, Guo Y, Huang D, Morrison J, Jia Y. Monitoring retinal responses to acute intraocular pressure elevation in rats with visible light optical coherence tomography. NEUROPHOTONICS 2019; 6:041104. [PMID: 31312671 PMCID: PMC6624745 DOI: 10.1117/1.nph.6.4.041104] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 06/21/2019] [Indexed: 05/08/2023]
Abstract
Elevated intraocular pressure (IOP) is an important risk factor for glaucoma. However, the role of IOP in glaucoma progression, as well as retinal physiology in general, remains incompletely understood. We demonstrate the use of visible light optical coherence tomography to measure retinal responses to acute IOP elevation in Brown Norway rats. We monitored retinal responses in reflectivity, angiography, blood flow, oxygen saturation ( sO 2 ), and oxygen metabolism over a range of IOP from 10 to 100 mmHg. As IOP was elevated, nerve fiber layer reflectivity was found to decrease. Vascular perfusion in the three retinal capillary plexuses remained steady until IOP exceeded 70 mmHg and arterial flow was noted to reverse periodically at high IOPs. However, a significant drop in total retinal blood flow was observed first at 40 mmHg. As IOP increased, the venous sO 2 demonstrated a gradual decrease despite steady arterial sO 2 , which is consistent with increased arterial-venous oxygen extraction across the retinal capillary beds. Calculated total retinal oxygen metabolism was steady, reflecting balanced responses of blood flow and oxygen extraction, until IOP exceeded 40 mmHg, and fell to 0 at 70 and 80 mmHg. Above this, measurements were unattainable. All measurements reverted to baseline when the IOP was returned to 10 mmHg, indicating good recovery following acute pressure challenge. These results demonstrate the ability of this system to monitor retinal oxygen metabolism noninvasively and how it can help us understand retinal responses to elevated IOP.
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Affiliation(s)
- Shaohua Pi
- Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
| | - Tristan T. Hormel
- Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
| | - Xiang Wei
- Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
| | - William Cepurna
- Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
| | - Acner Camino
- Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
| | - Yukun Guo
- Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
| | - David Huang
- Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
| | - John Morrison
- Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
| | - Yali Jia
- Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
- Address all correspondence to Yali Jia, E-mail:
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17
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Liu R, Song W, Backman V, Yi J. Quantitative quality-control metrics for in vivo oximetry in small vessels by visible light optical coherence tomography angiography. BIOMEDICAL OPTICS EXPRESS 2019; 10:465-486. [PMID: 30800493 PMCID: PMC6377897 DOI: 10.1364/boe.10.000465] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 12/14/2018] [Accepted: 12/14/2018] [Indexed: 05/23/2023]
Abstract
Biological functions rely on local microvasculature to deliver oxygen and nutrients and carry away metabolic waste. Alterations to local oxygenation levels are manifested in diseases including cancer, diabetes mellitus, etc. The ability to quantify oxygen saturation (sO2) within microvasculature in vivo to assess local tissue oxygenation and metabolic function is highly sought after. Visible light optical coherence tomography (vis-OCT) angiography has shown promise in reaching this goal. However, achieving reliable measurements in small vessels can be challenging due to the reduced contrast and requires data averaging to improve the spectral data quality. Therefore, a method for quality-control of the vis-OCT data from small vessels becomes essential to reject unreliable readings. In this work, we present a quantitative metrics to evaluate the spectral data for a reliable measurement of sO2, including angiography signal to noise ratio (SNR), spectral anomaly detection and discard, and theory-experiment correlation analysis. The thresholds for each quantity can be flexibly adjusted according to different applications and system performance. We used these metrics to measure sO2 of C57BL/6J mouse lower extremity microvasculature and validated it by introducing hyperoxia for expected sO2 changes. After validation, we applied this protocol on C57BL/6J mouse ear microvasculature to conduct in vivo small blood vessel OCT oximetry. This work seeks to standardize the data processing method for in vivo oximetry in small vessels by vis-OCT.
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Affiliation(s)
- Rongrong Liu
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Weiye Song
- Department of Medicine, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Ji Yi
- Department of Medicine, Boston University School of Medicine, Boston, MA, 02118, USA
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18
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Winkelmann JA, Eid A, Spicer G, Almassalha LM, Nguyen TQ, Backman V. Spectral contrast optical coherence tomography angiography enables single-scan vessel imaging. LIGHT, SCIENCE & APPLICATIONS 2019; 8:7. [PMID: 30651982 PMCID: PMC6333625 DOI: 10.1038/s41377-018-0117-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 12/14/2018] [Accepted: 12/15/2018] [Indexed: 05/06/2023]
Abstract
Optical coherence tomography angiography relies on motion for contrast and requires at least two data acquisitions per pointwise scanning location. We present a method termed spectral contrast optical coherence tomography angiography using visible light that relies on the spectral signatures of blood for angiography from a single scan using endogenous contrast. We demonstrate the molecular sensitivity of this method, which enables lymphatic vessel, blood, and tissue discrimination.
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Affiliation(s)
- James A. Winkelmann
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208 USA
| | - Aya Eid
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208 USA
| | - Graham Spicer
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208 USA
| | - Luay M. Almassalha
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208 USA
| | - The-Quyen Nguyen
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208 USA
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208 USA
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19
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Pi S, Camino A, Wei X, Simonett J, Cepurna W, Huang D, Morrison JC, Jia Y. Rodent retinal circulation organization and oxygen metabolism revealed by visible-light optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2018; 9:5851-5862. [PMID: 30460167 PMCID: PMC6238898 DOI: 10.1364/boe.9.005851] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 10/22/2018] [Accepted: 10/24/2018] [Indexed: 05/06/2023]
Abstract
Visible light optical coherence tomography (vis-OCT) is an emerging label-free and high-resolution 3-dimensional imaging technique that can provide retinal oximetry, angiography, and flowmetry in one modality. In this paper, we studied the organization of the arterial and venous retinal circulation in rats using vis-OCT. Arterioles were found predominantly in the superficial vascular plexus whereas veins tended to drain capillaries from the deep capillary plexus. After that, we determined the oxygen metabolic rate supported by retinal microcirculation by combining retinal vessel oxygen saturation and blood flow measurements. The ability to visualize and monitor retinal circulation organization and oxygen metabolism by vis-OCT may provide new opportunities for understanding the pathology of ocular diseases.
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Affiliation(s)
- Shaohua Pi
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
| | - Acner Camino
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
| | - Xiang Wei
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
| | - Joseph Simonett
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
| | - William Cepurna
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
| | - David Huang
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
| | - John C. Morrison
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
| | - Yali Jia
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
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20
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Song W, Zhou L, Kot KL, Fan H, Han J, Yi J. Measurement of flow-mediated dilation of mouse femoral artery in vivo by optical coherence tomography. JOURNAL OF BIOPHOTONICS 2018; 11:e201800053. [PMID: 29855165 PMCID: PMC6226329 DOI: 10.1002/jbio.201800053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 05/30/2018] [Indexed: 05/03/2023]
Abstract
Flow-mediated vasodilation (FMD) is used for assessment of vascular endothelial function in humans as a predictor of cardiovascular events. It has been challenging to carry it on preclinical murine models due to the diminutive size of the femoral artery. Here, we present a new approach to accurately measure the blood velocity and femoral artery diameters of mice by acquiring Doppler optical coherence tomography and optical coherence tomography angiography continuously within 1 single experimental scanning protocol. Using the 3-dimensional imaging and new velocity algorithm, the measurement precision of diameter, blood flow, velocity and wall shear stress are improved to 0.91%, 11.0%, 10.7% and 14.0%, respectively. FMD of healthy mouse femoral artery measured by this method was 11.96% ± 0.98%, which was blunted to 5.69% ± 0.4% by intravenous administration of endothelial nitric oxide synthase inhibitor (L-NG -Nitroarginine methyl ester), in agreement with that reported in the literature.
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Affiliation(s)
- Weiye Song
- Department of Medicine, Boston Universty School of Medicine, Boston, MA, 02118, USA
| | - Libo Zhou
- Vascular Biology Section, Evans Department of Medicine, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, 02118, USA
- State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun, Jilin, 130012, China
| | - Kevin Liu Kot
- Vascular Biology Section, Evans Department of Medicine, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Huijie Fan
- Vascular Biology Section, Evans Department of Medicine, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Jingyan Han
- Vascular Biology Section, Evans Department of Medicine, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Ji Yi
- Department of Medicine, Boston Universty School of Medicine, Boston, MA, 02118, USA
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21
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Ju MJ, Huang C, Wahl DJ, Jian Y, Sarunic MV. Visible light sensorless adaptive optics for retinal structure and fluorescence imaging. OPTICS LETTERS 2018; 43:5162-5165. [PMID: 30320845 DOI: 10.1364/ol.43.005162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Optical coherence tomography (OCT) has emerged as a powerful imaging instrument and technology in biomedicine. OCT imaging is predominantly performed using wavelengths in the near infrared; however, visible light (VIS) has been recently employed in OCT systems with encouraging results for high-resolution retinal imaging. Using a broadband supercontinuum VIS source, we present a sensorless adaptive optics (SAO) multimodal imaging system driven by VIS-OCT for volumetric retinal structural imaging, followed by the acquisition of fluorescence emission. The coherence-gated, depth-resolved VIS-OCT images used for image-guided SAO aberration correction enable high-resolution structural and fluorescence imaging.
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22
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Soetikno BT, Beckmann L, Zhang X, Fawzi AA, Zhang HF. Visible-light optical coherence tomography oximetry based on circumpapillary scan and graph-search segmentation. BIOMEDICAL OPTICS EXPRESS 2018; 9:3640-3652. [PMID: 30338145 PMCID: PMC6191632 DOI: 10.1364/boe.9.003640] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 06/25/2018] [Accepted: 06/25/2018] [Indexed: 05/18/2023]
Abstract
Visible-light optical coherence tomography (vis-OCT) enables retinal oximetry by measuring the oxygen saturation of hemoglobin (sO2) from within individual retinal blood vessels. The sO2 calculation requires reliable estimation of the true spectrum of backscattered light from the posterior vessel wall. Unfortunately, subject motion and image noise make averaging from multiple A-lines at the same depth position challenging, and lead to inaccurate sO2 estimation. In this study, we developed an algorithm to reliably extract the backscattered light's spectrum. We used circumpapillary scanning to sample the vessels repeatedly at the same location. A combination of cross-correlation and graph-search based segmentation extracted the posterior wall locations. Using measurements from 100 B-scans as a gold standard, we demonstrated that our method achieved highly accurate measures of sO2 with minimal bias. In addition, we also investigated how the number of repeated measurements affects the accuracy of sO2 measurement. Our method sets the stage for large-scale studies of retinal oxygenation in animals and humans.
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Affiliation(s)
- Brian T. Soetikno
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
- Department of Ophthalmology, Northwestern University, Chicago, IL, USA
- Medical Scientist Training Program, Northwestern University, Chicago, IL, USA
| | - Lisa Beckmann
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Xian Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Amani A. Fawzi
- Department of Ophthalmology, Northwestern University, Chicago, IL, USA
| | - Hao F. Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
- Department of Ophthalmology, Northwestern University, Chicago, IL, USA
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23
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Liu R, Winkelmann JA, Spicer G, Zhu Y, Eid A, Ameer GA, Backman V, Yi J. Single capillary oximetry and tissue ultrastructural sensing by dual-band dual-scan inverse spectroscopic optical coherence tomography. LIGHT, SCIENCE & APPLICATIONS 2018; 7:57. [PMID: 30839641 PMCID: PMC6113297 DOI: 10.1038/s41377-018-0057-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 08/03/2018] [Accepted: 08/03/2018] [Indexed: 05/03/2023]
Abstract
Measuring capillary oxygenation and the surrounding ultrastructure can allow one to monitor a microvascular niche and better understand crucial biological mechanisms. However, capillary oximetry and pericapillary ultrastructure are challenging to measure in vivo. Here we demonstrate a novel optical imaging system, dual-band dual-scan inverse spectroscopic optical coherence tomography (D2-ISOCT), that, for the first time, can simultaneously obtain the following metrics in vivo using endogenous contrast: (1) capillary-level oxygen saturation and arteriolar-level blood flow rates, oxygen delivery rates, and oxygen metabolic rates; (2) spatial characteristics of tissue structures at length scales down to 30 nm; and (3) morphological images up to 2 mm in depth. To illustrate the capabilities of D2-ISOCT, we monitored alterations to capillaries and the surrounding pericapillary tissue (tissue between the capillaries) in the healing response of a mouse ear wound model. The obtained microvascular and ultrastructural metrics corroborated well with each other, showing the promise of D2-ISOCT for becoming a powerful new non-invasive imaging tool.
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Affiliation(s)
- Rongrong Liu
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208 USA
| | - James A. Winkelmann
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208 USA
| | - Graham Spicer
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208 USA
| | - Yunxiao Zhu
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208 USA
| | - Aya Eid
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208 USA
| | - Guillermo A. Ameer
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208 USA
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208 USA
| | - Ji Yi
- Department of Medicine, Boston University School of Medicine, Boston, MA 02118 USA
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24
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Zhang L, Song W, Shao D, Zhang S, Desai M, Ness S, Roy S, Yi J. Volumetric fluorescence retinal imaging in vivo over a 30-degree field of view by oblique scanning laser ophthalmoscopy (oSLO). BIOMEDICAL OPTICS EXPRESS 2018; 9:25-40. [PMID: 29359085 PMCID: PMC5772579 DOI: 10.1364/boe.9.000025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 11/24/2017] [Accepted: 11/25/2017] [Indexed: 05/03/2023]
Abstract
While fluorescent contrast is widely used in ophthalmology, three-dimensional (3D) fluorescence retinal imaging over a large field of view (FOV) has been challenging. In this paper, we describe a novel oblique scanning laser ophthalmoscopy (oSLO) technique that provides 3D volumetric fluorescence retinal imaging with only one raster scan. The technique utilizes scanned oblique illumination and angled detection to obtain fluorescent cross-sectional images, analogous to optical coherence tomography (OCT) line scans (or B-scans). By breaking the coaxial optical alignment used in conventional retinal imaging modalities, depth resolution is drastically improved. To demonstrate the capability of oSLO, we have performed in vivo volumetric fluorescein angiography (FA) of the rat retina with ~25μm depth resolution and over a 30° FOV. Using depth segmentation, oSLO can obtain high contrast images of the microvasculature down to single capillaries in 3D. The multi-modal nature of oSLO also allows for seamless combination with simultaneous OCT angiography.
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Affiliation(s)
- Lei Zhang
- Department of Medicine, Boston University School of Medicine, Boston MA, 02118, USA
- These authors contributed equally to this work
| | - Weiye Song
- Department of Medicine, Boston University School of Medicine, Boston MA, 02118, USA
- These authors contributed equally to this work
| | - Di Shao
- Department of Medicine, Boston University School of Medicine, Boston MA, 02118, USA
| | - Sui Zhang
- Danna-Farber Cancer Institute, Boston MA, 02215, USA
| | - Manishi Desai
- Department of Ophthalmology, Boston University School of Medicine, Boston MA, 02118, USA
| | - Steven Ness
- Department of Ophthalmology, Boston University School of Medicine, Boston MA, 02118, USA
| | - Sayon Roy
- Department of Medicine, Boston University School of Medicine, Boston MA, 02118, USA
- Department of Ophthalmology, Boston University School of Medicine, Boston MA, 02118, USA
| | - Ji Yi
- Department of Medicine, Boston University School of Medicine, Boston MA, 02118, USA
- Center of Regenerative Medicine, Boston University, Boston, MA, 02118, USA
- Boston University Photonics Center, Boston MA, 02215, USA
- These authors contributed equally to this work
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25
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Shu X, Beckmann L, Zhang HF. Visible-light optical coherence tomography: a review. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:1-14. [PMID: 29218923 PMCID: PMC5745673 DOI: 10.1117/1.jbo.22.12.121707] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 11/13/2017] [Indexed: 05/03/2023]
Abstract
Visible-light optical coherence tomography (vis-OCT) is an emerging imaging modality, providing new capabilities in both anatomical and functional imaging of biological tissue. It relies on visible light illumination, whereas most commercial and investigational OCTs use near-infrared light. As a result, vis-OCT requires different considerations in engineering design and implementation but brings unique potential benefits to both fundamental research and clinical care of several diseases. Here, we intend to provide a summary of the development of vis-OCT and its demonstrated applications. We also provide perspectives on future technology improvement and applications.
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Affiliation(s)
- Xiao Shu
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
| | - Lisa Beckmann
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
| | - Hao F. Zhang
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
- Northwestern University, Department of Ophthalmology, Chicago, Illinois, United States
- Address all correspondence to: Hao F. Zhang, E-mail:
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26
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Pi S, Camino A, Zhang M, Cepurna W, Liu G, Huang D, Morrison J, Jia Y. Angiographic and structural imaging using high axial resolution fiber-based visible-light OCT. BIOMEDICAL OPTICS EXPRESS 2017; 8:4595-4608. [PMID: 29082087 PMCID: PMC5654802 DOI: 10.1364/boe.8.004595] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/14/2017] [Accepted: 09/17/2017] [Indexed: 05/20/2023]
Abstract
Optical coherence tomography using visible-light sources can increase the axial resolution without the need for broader spectral bandwidth. Here, a high-resolution, fiber-based, visible-light optical coherence tomography system is built and used to image normal retina in rats and blood vessels in chicken embryo. In the rat retina, accurate segmentation of retinal layer boundaries and quantification of layer thicknesses are accomplished. Furthermore, three distinct capillary plexuses in the retina and the choriocapillaris are identified and the characteristic pattern of the nerve fiber layer thickness in rats is revealed. In the chicken embryo model, the microvascular network and a venous bifurcation are examined and the ability to identify and segment large vessel walls is demonstrated.
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Affiliation(s)
- Shaohua Pi
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
- These authors contributed equally to this work
| | - Acner Camino
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
- These authors contributed equally to this work
| | - Miao Zhang
- Optovue Inc. 2800 Bayview Dr., Fremont, CA 94538, USA
| | - William Cepurna
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
| | - Gangjun Liu
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
| | - David Huang
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
| | - John Morrison
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
| | - Yali Jia
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
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27
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Nesper PL, Soetikno BT, Zhang HF, Fawzi AA. OCT angiography and visible-light OCT in diabetic retinopathy. Vision Res 2017; 139:191-203. [PMID: 28601429 PMCID: PMC5723235 DOI: 10.1016/j.visres.2017.05.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Revised: 05/23/2017] [Accepted: 05/24/2017] [Indexed: 12/31/2022]
Abstract
In recent years, advances in optical coherence tomography (OCT) techniques have increased our understanding of diabetic retinopathy, an important microvascular complication of diabetes. OCT angiography is a non-invasive method that visualizes the retinal vasculature by detecting motion contrast from flowing blood. Visible-light OCT shows promise as a novel technique for quantifying retinal hypoxia by measuring the retinal oxygen delivery and metabolic rates. In this article, we discuss recent insights provided by these techniques into the vascular pathophysiology of diabetic retinopathy. The next milestones for these modalities are large multicenter studies to establish consensus on the most reliable and consistent outcome parameters to study diabetic retinopathy.
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Affiliation(s)
- Peter L Nesper
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, 645 N. Michigan Avenue, Suite 440, Chicago, IL 60611, USA.
| | - Brian T Soetikno
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, 645 N. Michigan Avenue, Suite 440, Chicago, IL 60611, USA; Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA; Medical Scientist Training Program, Feinberg School of Medicine, Northwestern University, 303 East Chicago Avenue, Chicago, IL 60611, USA.
| | - Hao F Zhang
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, 645 N. Michigan Avenue, Suite 440, Chicago, IL 60611, USA; Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA.
| | - Amani A Fawzi
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, 645 N. Michigan Avenue, Suite 440, Chicago, IL 60611, USA.
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Shu X, Liu W, Duan L, Zhang HF. Spectroscopic Doppler analysis for visible-light optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:1-8. [PMID: 29043714 PMCID: PMC5644441 DOI: 10.1117/1.jbo.22.12.121702] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 08/18/2017] [Indexed: 05/20/2023]
Abstract
Retinal oxygen metabolic rate can be effectively measured by visible-light optical coherence tomography (vis-OCT), which simultaneously quantifies oxygen saturation and blood flow rate in retinal vessels through spectroscopic analysis and Doppler measurement, respectively. Doppler OCT relates phase variation between sequential A-lines to the axial flow velocity of the scattering medium. The detectable phase shift is between -π and π due to its periodicity, which limits the maximum measurable unambiguous velocity without phase unwrapping. Using shorter wavelengths, vis-OCT is more vulnerable to phase ambiguity since flow induced phase variation is linearly related to the center wavenumber of the probing light. We eliminated the need for phase unwrapping using spectroscopic Doppler analysis. We split the whole vis-OCT spectrum into a series of narrow subbands and reconstructed vis-OCT images to extract corresponding Doppler phase shifts in all the subbands. Then, we quantified flow velocity by analyzing subband-dependent phase shift using linear regression. In the phantom experiment, we showed that spectroscopic Doppler analysis extended the measurable absolute phase shift range without conducting phase unwrapping. We also tested this method to quantify retinal blood flow in rodents in vivo.
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Affiliation(s)
- Xiao Shu
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
| | - Wenzhong Liu
- Opticent Health, Evanston, Illinois, United States
| | - Lian Duan
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
| | - Hao F. Zhang
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
- Northwestern University, Department of Ophthalmology, Chicago, Illinois, United States
- Address all correspondence to: Hao F. Zhang, E-mail:
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Liu W, Wang S, Soetikno B, Yi J, Zhang K, Chen S, Linsenmeier RA, Sorenson CM, Sheibani N, Zhang HF. Increased Retinal Oxygen Metabolism Precedes Microvascular Alterations in Type 1 Diabetic Mice. Invest Ophthalmol Vis Sci 2017; 58:981-989. [PMID: 28535269 PMCID: PMC5308771 DOI: 10.1167/iovs.16-20600] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Purpose To investigate inner retinal oxygen metabolic rate (IRMRO2) during early stages of type 1 diabetes in a transgenic mouse model. Methods In current study, we involved seven diabetic mice (Akita/+, TSP1−/−) and seven control mice (TSP1−/−), and applied visible-light optical coherence tomography (vis-OCT) to image functional parameters including retinal blood flow rate, oxygen saturation (sO2) and the IRMRO2 value longitudinally from 5 weeks of age to 13 weeks of age. After imaging at 13 weeks of age, we analyzed the imaging results, and examined histology of mouse retina. Results Between diabetic mice and the control group, we observed significant differences in venous sO2 from 9 weeks of age (P = 0.006), and significant increment in IRMRO2 from 11 weeks of age (P = 0.001) in diabetic mice compared with control group. We did not find significant differences in retinal blood flow rate as well as arterial sO2 during imaging between diabetic and control mice. Histologic examination of diabetic and control mice at 13 weeks of age also revealed no anatomical retinal alternations. Conclusions In diabetic retinopathy, complications in retinal oxygen metabolism may occur before changes of retinal anatomical structure.
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Affiliation(s)
- Wenzhong Liu
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States
| | - Shoujian Wang
- Departments of Ophthalmology and Visual Science, University of Wisconsin, Madison, Wisconsin, United States
| | - Brian Soetikno
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States
| | - Ji Yi
- Department of Medicine, Boston University, Boston, Massachusetts, United States
| | - Kevin Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States
| | - Siyu Chen
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States
| | - Robert A Linsenmeier
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States 4Department of Ophthalmology, Northwestern University, Chicago, Illinois, United States 5Department of Neurobiology, Northwestern University, Evanston, Illinois, United States
| | - Christine M Sorenson
- Department of Pediatrics, University Wisconsin, Madison, Wisconsin, United States
| | - Nader Sheibani
- Departments of Ophthalmology and Visual Science, University of Wisconsin, Madison, Wisconsin, United States
| | - Hao F Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States 4Department of Ophthalmology, Northwestern University, Chicago, Illinois, United States
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Seo S, Chen L, Liu W, Zhao D, Schultz KM, Sasman A, Liu T, Zhang HF, Gage PJ, Kume T. Foxc1 and Foxc2 in the Neural Crest Are Required for Ocular Anterior Segment Development. Invest Ophthalmol Vis Sci 2017; 58:1368-1377. [PMID: 28253399 PMCID: PMC5361455 DOI: 10.1167/iovs.16-21217] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Purpose The large Forkhead (Fox) transcription factor family has essential roles in development, and mutations cause a wide range of ocular and nonocular disease. One member, Foxc2 is expressed in neural crest (NC)-derived periocular mesenchymal cells of the developing murine eye; however, its precise role in the development, establishment, and maintenance of the ocular surface has yet to be investigated. Methods To specifically delete Foxc2 from NC-derived cells, conditional knockout mice for Foxc2 (NC-Foxc2−/−) were generated by crossing Foxc2F mice with Wnt1-Cre mice. Similarly, we also generated compound NC-specific mutations of Foxc2 and a closely related gene, Foxc1 (NC-Foxc1−/−;NC-Foxc2−/−) in mice. Results Neural crest-Foxc2−/− mice show abnormal thickness in the peripheral-to-central corneal stroma and limbus and displaced pupils with irregular iris. The neural crest-specific mutation in Foxc2 also leads to ectopic neovascularization in the cornea, as well as impaired ocular epithelial cell identity and corneal conjunctivalization. Compound, NC-specific Foxc1; Foxc2 homozygous mutant mice have more severe defects in structures of the ocular surface, such as the cornea and eyelids, accompanied by significant declines in the expression of another key developmental factor, Pitx2, and its downstream effector Dkk2, which antagonizes canonical Wnt signaling. Conclusions The neural crest-Foxc2 mutation is associated with corneal conjunctivalization, ectopic corneal neovascularization, and disrupted ocular epithelial cell identity. Furthermore, Foxc2 and Foxc1 cooperatively function in NC-derived mesenchymal cells to ensure proper morphogenesis of the ocular surface via the regulation of Wnt signaling. Together, Foxc2 is required in the NC lineage for mesenchymal-epithelial interactions in corneal and ocular surface development.
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Affiliation(s)
- Seungwoon Seo
- Feinberg Cardiovascular Research Institute, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States 2Department of Life Science, Research Center for Cellular Homeostasis, Ewha Womans University, Seoul, Korea
| | - Lisheng Chen
- Department of Ophthalmology and Visual Science, University of Michigan, Ann Arbor, Michigan, United States
| | - Wenzhong Liu
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States
| | - Demin Zhao
- Feinberg Cardiovascular Research Institute, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Kathryn M Schultz
- Feinberg Cardiovascular Research Institute, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Amy Sasman
- Feinberg Cardiovascular Research Institute, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Ting Liu
- Feinberg Cardiovascular Research Institute, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Hao F Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States
| | - Philip J Gage
- Department of Ophthalmology and Visual Science, University of Michigan, Ann Arbor, Michigan, United States
| | - Tsutomu Kume
- Feinberg Cardiovascular Research Institute, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
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Shah RS, Soetikno BT, Yi J, Liu W, Skondra D, Zhang HF, Fawzi AA. Visible-Light Optical Coherence Tomography Angiography for Monitoring Laser-Induced Choroidal Neovascularization in Mice. Invest Ophthalmol Vis Sci 2017; 57:OCT86-95. [PMID: 27409510 PMCID: PMC4968775 DOI: 10.1167/iovs.15-18891] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose This study sought to determine the earliest time-point at which evidence of choroidal neovascularization (CNV) could be detected with visible-light optical coherence tomography angiography (vis-OCTA) in a mouse model of laser-induced CNV. Methods Visible light-OCTA was used to study laser-induced CNV at different time-points after laser injury to monitor CNV development and measure CNV lesion size. Measurements obtained from vis-OCTA angiograms were compared with histopathologic measurements from isolectin-stained choroidal flatmounts. Results Choroidal neovascularization area measurements between the vis-OCTA system and isolectin-stained choroidal flatmounts were significantly different in area for days 2 to 4 postlaser injury, and were not significantly different in area for days 5, 7, and 14. Choroidal neovascularization area measurements taken from the stained flatmounts were larger than their vis-OCTA counterparts for all time-points. Both modalities showed a similar trend of CNV size increasing from the day of laser injury until a peak of day 7 postlaser injury and subsequently decreasing by day 14. Conclusions The earliest vis-OCTA can detect the presence of aberrant vessels in a mouse laser-induced CNV model is 5 days after laser injury. Visible light-OCTA was able to visualize the maximum of the CNV network 7 days postlaser injury, in accordance with choroidal flatmount immunostaining. Visible light-OCTA is a reliable tool in both detecting the presence of CNV development, as well as accurately determining the size of the lesion in a mouse laser-induced CNV model.
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Affiliation(s)
- Ronil S Shah
- Department of Ophthalmology Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Brian T Soetikno
- Department of Ophthalmology Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States 2Functional Optical Imaging Laboratory, Department of Biomedical Engineering, Northwestern University, Chicago, Illinois, United States 3Med
| | - Ji Yi
- Functional Optical Imaging Laboratory, Department of Biomedical Engineering, Northwestern University, Chicago, Illinois, United States
| | - Wenzhong Liu
- Functional Optical Imaging Laboratory, Department of Biomedical Engineering, Northwestern University, Chicago, Illinois, United States
| | - Dimitra Skondra
- Department of Ophthalmology Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Hao F Zhang
- Department of Ophthalmology Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States 2Functional Optical Imaging Laboratory, Department of Biomedical Engineering, Northwestern University, Chicago, Illinois, United States
| | - Amani A Fawzi
- Department of Ophthalmology Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
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Yi J, Puyang Z, Feng L, Duan L, Liang P, Backman V, Liu X, Zhang HF. Optical Detection of Early Damage in Retinal Ganglion Cells in a Mouse Model of Partial Optic Nerve Crush Injury. Invest Ophthalmol Vis Sci 2017; 57:5665-5671. [PMID: 27784071 PMCID: PMC5089219 DOI: 10.1167/iovs.16-19955] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Elastic light backscattering spectroscopy (ELBS) has exquisite sensitivity to the ultrastructural properties of tissue and thus has been applied to detect various diseases associated with ultrastructural alterations in their early stages. This study aims to test whether ELBS can detect early damage in retinal ganglion cells (RGCs). Methods We used a mouse model of partial optic nerve crush (pONC) to induce rapid RGC death. We confirmed RGC loss by axon counting and characterized the changes in retinal morphology by optical coherence tomography (OCT) and in retinal function by full-field electroretinogram (ERG), respectively. To quantify the ultrastructural properties, elastic backscattering spectroscopic analysis was implemented in the wavelength-dependent images recorded by reflectance confocal microscopy. Results At 3 days post-pONC injury, no significant change was found in the thickness of the RGC layer or in the mean amplitude of the oscillatory potentials measured by OCT and ERG, respectively; however, we did observe a significantly decreased number of axons compared with the controls. At 3 days post-pONC, we used ELBS to calculate the ultrastructural marker (D), the shape factor quantifying the shape of the local mass density correlation functions. It was significantly reduced in the crushed eyes compared with the controls, indicating the ultrastructural fragmentation in the crushed eyes. Conclusions Elastic light backscattering spectroscopy detected ultrastructural neuronal damage in RGCs following the pONC injury when OCT and ERG tests appeared normal. Our study suggests a potential clinical method for detecting early neuronal damage prior to anatomical alterations in the nerve fiber and ganglion cell layers.
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Affiliation(s)
- Ji Yi
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States
| | - Zhen Puyang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China 3Department of Ophthalmology, Northwestern University, Chicago, Illinois, United States
| | - Liang Feng
- Department of Ophthalmology, Northwestern University, Chicago, Illinois, United States
| | - Lian Duan
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States
| | - Peiji Liang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States
| | - Xiaorong Liu
- Department of Ophthalmology, Northwestern University, Chicago, Illinois, United States 4Department of Neurobiology, Northwestern University, Evanston, Illinois, United States
| | - Hao F Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States 3Department of Ophthalmology, Northwestern University, Chicago, Illinois, United States
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Affiliation(s)
- Lewis. E. MacKenzie
- School of Biomedical Sciences, University of Leeds, Garstang Building Leeds, Leeds, UK
| | - Andy. R. Harvey
- School of Physics and Astronomy, Kelvin Building University of Glasgow University Avenue, Glasgow, UK
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Liu R, Spicer G, Chen S, Zhang HF, Yi J, Backman V. Theoretical model for optical oximetry at the capillary level: exploring hemoglobin oxygen saturation through backscattering of single red blood cells. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:25002. [PMID: 28157244 PMCID: PMC5290596 DOI: 10.1117/1.jbo.22.2.025002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 01/09/2017] [Indexed: 05/20/2023]
Abstract
Oxygen saturation ( sO 2 ) of red blood cells (RBCs) in capillaries can indirectly assess local tissue oxygenation and metabolic function. For example, the altered retinal oxygenation in diabetic retinopathy and local hypoxia during tumor development in cancer are reflected by abnormal sO 2 of local capillary networks. However, it is far from clear whether accurate label-free optical oximetry (i.e., measuring hemoglobin sO 2 ) is feasible from dispersed RBCs at the single capillary level. The sO 2 -dependent hemoglobin absorption contrast present in optical scattering signal is complicated by geometry-dependent scattering from RBCs. We present a numerical study of backscattering spectra from single RBCs based on the first-order Born approximation, considering practical factors: RBC orientations, size variation, and deformations. We show that the oscillatory spectral behavior of RBC geometries is smoothed by variations in cell size and orientation, resulting in clear sO 2 -dependent spectral contrast. In addition, this spectral contrast persists with different mean cellular hemoglobin content and different deformations of RBCs. This study shows for the first time the feasibility of, and provides a theoretical model for, label-free optical oximetry at the single capillary level using backscattering-based imaging modalities, challenging the popular view that such measurements are impossible at the single capillary level.
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Affiliation(s)
- Rongrong Liu
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
| | - Graham Spicer
- Northwestern University, Department of Chemical and Biological Engineering, Evanston, Illinois, United States
| | - Siyu Chen
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
| | - Hao F. Zhang
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
- Northwestern University, Department of Ophthalmology, Chicago, Illinois, United States
| | - Ji Yi
- Boston University, Department of Medicine, Boston, Massachusetts, United States
- Address all correspondence to: Vadim Backman, E-mail: ; Ji Yi, E-mail:
| | - Vadim Backman
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
- Address all correspondence to: Vadim Backman, E-mail: ; Ji Yi, E-mail:
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Linsenmeier RA, Zhang HF. Retinal oxygen: from animals to humans. Prog Retin Eye Res 2017; 58:115-151. [PMID: 28109737 DOI: 10.1016/j.preteyeres.2017.01.003] [Citation(s) in RCA: 148] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 01/13/2017] [Accepted: 01/17/2017] [Indexed: 10/20/2022]
Abstract
This article discusses retinal oxygenation and retinal metabolism by focusing on measurements made with two of the principal methods used to study O2 in the retina: measurements of PO2 with oxygen-sensitive microelectrodes in vivo in animals with a retinal circulation similar to that of humans, and oximetry, which can be used non-invasively in both animals and humans to measure O2 concentration in retinal vessels. Microelectrodes uniquely have high spatial resolution, allowing the mapping of PO2 in detail, and when combined with mathematical models of diffusion and consumption, they provide information about retinal metabolism. Mathematical models, grounded in experiments, can also be used to simulate situations that are not amenable to experimental study. New methods of oximetry, particularly photoacoustic ophthalmoscopy and visible light optical coherence tomography, provide depth-resolved methods that can separate signals from blood vessels and surrounding tissues, and can be combined with blood flow measures to determine metabolic rate. We discuss the effects on retinal oxygenation of illumination, hypoxia and hyperoxia, and describe retinal oxygenation in diabetes, retinal detachment, arterial occlusion, and macular degeneration. We explain how the metabolic measurements obtained from microelectrodes and imaging are different, and how they need to be brought together in the future. Finally, we argue for revisiting the clinical use of hyperoxia in ophthalmology, particularly in retinal arterial occlusions and retinal detachment, based on animal research and diffusion theory.
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Affiliation(s)
- Robert A Linsenmeier
- Biomedical Engineering Department, Northwestern University, 2145 Sheridan Road, Evanston 60208-3107, IL, USA; Neurobiology Department, Northwestern University, 2205 Tech Drive, Evanston 60208-3520, IL, USA; Ophthalmology Department, Northwestern University, 645 N. Michigan Ave, Suite 440, Chicago 60611, IL, USA.
| | - Hao F Zhang
- Biomedical Engineering Department, Northwestern University, 2145 Sheridan Road, Evanston 60208-3107, IL, USA; Ophthalmology Department, Northwestern University, 645 N. Michigan Ave, Suite 440, Chicago 60611, IL, USA.
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Augustin M, Fialová S, Himmel T, Glösmann M, Lengheimer T, Harper DJ, Plasenzotti R, Pircher M, Hitzenberger CK, Baumann B. Multi-Functional OCT Enables Longitudinal Study of Retinal Changes in a VLDLR Knockout Mouse Model. PLoS One 2016; 11:e0164419. [PMID: 27711217 PMCID: PMC5053493 DOI: 10.1371/journal.pone.0164419] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 09/23/2016] [Indexed: 12/24/2022] Open
Abstract
We present a multi-functional optical coherence tomography (OCT) imaging approach to study retinal changes in the very-low-density-lipoprotein-receptor (VLDLR) knockout mouse model with a threefold contrast. In the retinas of VLDLR knockout mice spontaneous retinal-chorodoidal neovascularizations form, having an appearance similar to choroidal and retinal neovascularizations (CNV and RNV) in neovascular age-related macular degeneration (AMD) or retinal angiomatous proliferation (RAP). For this longitudinal study, the mice were imaged every 4 to 6 weeks starting with an age of 4 weeks and following up to the age of 11 months. Significant retinal changes were identified by the multi-functional imaging approach offering a threefold contrast: reflectivity, polarization sensitivity (PS) and motion contrast based OCT angiography (OCTA). By use of this intrinsic contrast, the long-term development of neovascularizations was studied and associated processes, such as the migration of melanin pigments or retinal-choroidal anastomosis, were assessed in vivo. Furthermore, the in vivo imaging results were validated with histological sections at the endpoint of the experiment. Multi-functional OCT proves as a powerful tool for longitudinal retinal studies in preclinical research of ophthalmic diseases. Intrinsic contrast offered by the functional extensions of OCT might help to describe regulative processes in genetic animal models and potentially deepen the understanding of the pathogenesis of retinal diseases such as wet AMD.
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Affiliation(s)
- Marco Augustin
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
- * E-mail:
| | - Stanislava Fialová
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Tanja Himmel
- Core Facility for Research and Technology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Martin Glösmann
- Core Facility for Research and Technology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Theresia Lengheimer
- Division of Biomedical Research, Medical University of Vienna, Vienna, Austria
| | - Danielle J. Harper
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Roberto Plasenzotti
- Division of Biomedical Research, Medical University of Vienna, Vienna, Austria
| | - Michael Pircher
- Center for Medical Physics and Biomedical Engineering, Medical University of 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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Liu W, Zhang HF. Photoacoustic imaging of the eye: A mini review. PHOTOACOUSTICS 2016; 4:112-123. [PMID: 27761410 PMCID: PMC5063360 DOI: 10.1016/j.pacs.2016.05.001] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 04/15/2016] [Accepted: 05/17/2016] [Indexed: 05/04/2023]
Abstract
The eye relies on the synergistic cooperation of many different ocular components, including the cornea, crystalline lens, photoreceptors, and retinal neurons, to precisely sense visual information. Complications with a single ocular component can degrade vision and sometimes cause blindness. Immediate treatment and long-term monitoring are paramount to alleviate symptoms, restore vision, and cure ocular diseases. However, successful treatment requires understanding ocular pathological mechanisms, precisely detecting and monitoring the diseases. The investigation and diagnosis of ocular diseases require advanced medical tools. In this mini review, we discuss non-invasive photoacoustic (PA) imaging as a potential research tool and medical screening device. In the research setting, PA imaging can provide valuable information on the disease progression. In the clinical setting, PA imaging can potentially aid in disease detection and treatment monitoring.
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Affiliation(s)
- Wenzhong Liu
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208,USA
| | - Hao F. Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208,USA
- Department of Ophthalmology, Northwestern University, Chicago, IL 60611, USA
- Corresponding author at: Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA.
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De Pretto LR, Yoshimura TM, Ribeiro MS, Zanardi de Freitas A. Optical coherence tomography for blood glucose monitoring in vitro through spatial and temporal approaches. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:86007. [PMID: 27533444 DOI: 10.1117/1.jbo.21.8.086007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 07/25/2016] [Indexed: 05/18/2023]
Abstract
As diabetes causes millions of deaths worldwide every year, new methods for blood glucose monitoring are in demand. Noninvasive approaches may increase patient adherence to treatment while reducing costs, and optical coherence tomography (OCT) may be a feasible alternative to current invasive diagnostics. This study presents two methods for blood sugar monitoring with OCT in vitro. The first, based on spatial statistics, exploits changes in the light total attenuation coefficient caused by different concentrations of glucose in the sample using a 930-nm commercial OCT system. The second, based on temporal analysis, calculates differences in the decorrelation time of the speckle pattern in the OCT signal due to blood viscosity variations with the addition of glucose with data acquired by a custom built Swept Source 1325-nm OCT system. Samples consisted of heparinized mouse blood, phosphate buffer saline, and glucose. Additionally, further samples were prepared by diluting mouse blood with isotonic saline solution to verify the effect of higher multiple scattering components on the ability of the methods to differentiate glucose levels. Our results suggest a direct relationship between glucose concentration and both decorrelation rate and attenuation coefficient, with our systems being able to detect changes of 65 mg/dL in glucose concentration.
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Affiliation(s)
- Lucas Ramos De Pretto
- Nuclear and Energy Research Institute, Av. Professor Lineu Prestes, 2242, São Paulo, SP, 05508-000, BrazilbUniversity of São Paulo, Postgraduate Program in Nuclear Technology, Av. Professor Lineu Prestes, 2242, São Paulo, SP, 05508-000, Brazil
| | - Tania Mateus Yoshimura
- Nuclear and Energy Research Institute, Av. Professor Lineu Prestes, 2242, São Paulo, SP, 05508-000, BrazilbUniversity of São Paulo, Postgraduate Program in Nuclear Technology, Av. Professor Lineu Prestes, 2242, São Paulo, SP, 05508-000, Brazil
| | - Martha Simões Ribeiro
- Nuclear and Energy Research Institute, Av. Professor Lineu Prestes, 2242, São Paulo, SP, 05508-000, Brazil
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Chen S, Shu X, Yi J, Fawzi A, Zhang HF. Dual-band optical coherence tomography using a single supercontinuum laser source. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:66013. [PMID: 27304421 PMCID: PMC4908275 DOI: 10.1117/1.jbo.21.6.066013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 05/20/2016] [Indexed: 05/03/2023]
Abstract
We developed a simultaneous visible-light (Vis) and near-infrared (NIR) dual-band optical coherence tomography (OCT) system using a single supercontinuum laser source. The goal was to benchmark our newly developed Vis-OCT against the well-developed NIR-OCT. The Vis-OCT subsystem operated at 91 nm full-width-at-half-maximum (FWHM) bandwidth centered at 566 nm; the NIR-OCT subsystem operated at 93 nm FWHM bandwidth centered at 841 nm. The axial resolutions were 1.8 and 4.4 μm in air for the Vis- and NIR-OCT subsystems, respectively. We compared the respective performances, including anatomical imaging, angiography, absolute retinal blood flow measurements, and spectroscopic analysis for retinal blood oxygen saturation (sO2), between the two subsystems in rodents in vivo. While demonstrating minor discrepancies related to operation wavelengths, both subsystems showed comparable performances in the first three tests. However, we were only able to retrieve sO2 using the Vis-OCT subsystem.
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Affiliation(s)
- Siyu Chen
- Northwestern University, Department of Biomedical Engineering, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Xiao Shu
- Northwestern University, Department of Biomedical Engineering, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Ji Yi
- Northwestern University, Department of Biomedical Engineering, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Boston University, Department of Medicine, 650 Albany Street, Boston, Massachusetts 02118, United States
| | - Amani Fawzi
- Northwestern University, Department of Ophthalmology, 300 East Superior Street, Chicago, Illinois 60611, United States
| | - Hao F. Zhang
- Northwestern University, Department of Biomedical Engineering, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Northwestern University, Department of Ophthalmology, 300 East Superior Street, Chicago, Illinois 60611, United States
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Inner retinal oxygen metabolism in the 50/10 oxygen-induced retinopathy model. Sci Rep 2015; 5:16752. [PMID: 26576731 PMCID: PMC4649746 DOI: 10.1038/srep16752] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 10/20/2015] [Indexed: 02/06/2023] Open
Abstract
Retinopathy of prematurity (ROP) represents a major cause of childhood vision loss worldwide. The 50/10 oxygen-induced retinopathy (OIR) model mimics the findings of ROP, including peripheral vascular attenuation and neovascularization. The oxygen metabolism of the inner retina has not been previously explored in this model. Using visible-light optical coherence tomography (vis-OCT), we measured the oxygen saturation of hemoglobin and blood flow within inner retinal vessels, enabling us to compute the inner retinal oxygen delivery (irDO2) and metabolic rate of oxygen (irMRO2). We compared these measurements between age-matched room-air controls and rats with 50/10 OIR on postnatal day 18. To account for a 61% decrease in the irDO2 in the OIR group, we found an overall statistically significant decrease in retinal vascular density affecting the superficial and deep retinal vascular capillary networks in rats with OIR compared to controls. Furthermore, matching the reduced irDO2, we found a 59% decrease in irMRO2, which we correlated with a statistically significant reduction in retinal thickness in the OIR group, suggesting that the decreased irMRO2 was due to decreased neuronal oxygen utilization. By exploring these biological and metabolic changes in great detail, our study provides an improved understanding of the pathophysiology of OIR model.
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Yi J, Chen S, Shu X, Fawzi AA, Zhang HF. Human retinal imaging using visible-light optical coherence tomography guided by scanning laser ophthalmoscopy. BIOMEDICAL OPTICS EXPRESS 2015; 6:3701-13. [PMID: 26504622 PMCID: PMC4605031 DOI: 10.1364/boe.6.003701] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 08/21/2015] [Accepted: 08/23/2015] [Indexed: 05/18/2023]
Abstract
We achieved human retinal imaging using visible-light optical coherence tomography (vis-OCT) guided by an integrated scanning laser ophthalmoscopy (SLO). We adapted a spectral domain OCT configuration and used a supercontinuum laser as the illumating source. The center wavelength was 564 nm and the bandwidth was 115 nm, which provided a 0.97 µm axial resolution measured in air. We characterized the sensitivity to be 86 dB with 226 µW incidence power on the pupil. We also integrated an SLO that shared the same optical path of the vis-OCT sample arm for alignment purposes. We demonstrated the retinal imaging from both systems centered at the fovea and optic nerve head with 20° × 20° and 10° × 10° field of view. We observed similar anatomical structures in vis-OCT and NIR-OCT. The contrast appeared different from vis-OCT to NIR-OCT, including slightly weaker signal from intra-retinal layers, and increased visibility and contrast of anatomical layers in the outer retina.
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Affiliation(s)
- Ji Yi
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, IL, 60208 USA
- These authors contributed equally to this work
| | - Siyu Chen
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, IL, 60208 USA
- These authors contributed equally to this work
| | - Xiao Shu
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, IL, 60208 USA
- These authors contributed equally to this work
| | - Amani A. Fawzi
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, 645 N Michigan Ave, Chicago, IL 60611 USA
| | - Hao F. Zhang
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Rd., Evanston, IL, 60208 USA
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, 645 N Michigan Ave, Chicago, IL 60611 USA
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