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Rathbone E, Fu D. Quantitative Optical Imaging of Oxygen in Brain Vasculature. J Phys Chem B 2024; 128:6975-6989. [PMID: 38991095 DOI: 10.1021/acs.jpcb.4c01277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2024]
Abstract
The intimate relationship between neuronal activity and cerebral oxygenation underpins fundamental brain functions like cognition, sensation, and motor control. Optical imaging offers a noninvasive approach to assess brain oxygenation and often serves as an indirect proxy for neuronal activity. However, deciphering neurovascular coupling─the intricate interplay between neuronal activity, blood flow, and oxygen delivery─necessitates independent, high spatial resolution, and high temporal resolution measurements of both microvasculature oxygenation and neuronal activation. This Perspective examines the established optical techniques employed for brain oxygen imaging, specifically functional near-infrared spectroscopy, photoacoustic imaging, optical coherence tomography, and two-photon phosphorescent lifetime microscopy, highlighting their fundamental principles, strengths, and limitations. Several other emerging optical techniques are also introduced. Finally, we discuss key technological challenges and future directions for quantitative optical oxygen imaging, paving the way for a deeper understanding of oxygen metabolism in the brain.
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Affiliation(s)
- Emily Rathbone
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Dan Fu
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
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2
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Lapointe N, Akitegetse C, Poirier J, Picard M, Sauvageau P, Sauvageau D. Targeted spectroscopy in the eye fundus. JOURNAL OF BIOMEDICAL OPTICS 2023; 28:126004. [PMID: 38111476 PMCID: PMC10725981 DOI: 10.1117/1.jbo.28.12.126004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 11/18/2023] [Accepted: 11/21/2023] [Indexed: 12/20/2023]
Abstract
Significance The assessment of biomarkers in the eye is rapidly gaining traction for the screening, diagnosis, and monitoring of ocular and neurological diseases. Targeted ocular spectroscopy is a technology that enables concurrent imaging of the eye fundus and analysis of high-quality spectra from a targeted region within the imaged area. This provides structural, compositional, and functional information of specific regions of the eye fundus from a non-invasive approach to ocular biomarker detection. Aim The aim of our study was to demonstrate the multimodal functionality and validation of targeted ocular spectroscopy. This was done in vitro, using a reference target and a model eye, and in vivo. Approach Images and spectra from different regions of a reference target and a model eye were acquired and analyzed to validate the system. Targeted ocular fluorescence spectroscopy was also demonstrated with the same model. Subsequently, in vivo imaging and diffuse reflectance spectra were acquired to assess blood oxygen saturation in the optic nerve head and the parafovea of healthy subjects. Results Tests conducted with the reference target showed accurate spectral analysis within specific areas of the imaging space. In the model eye, distinct spectral signatures were observed for the optic disc, blood vessels, the retina, and the macula, consistent with the variations in tissue composition and functions between these regions. An ocular oximetry algorithm was applied to in vivo spectra from the optic nerve head and parafovea of healthy patients, showing significant differences in blood oxygen saturation. Finally, targeted fluorescence spectral analysis was performed in vitro. Conclusions Diffuse reflectance and fluorescence spectroscopy in specific regions of the eye fundus open the door to a whole new range of monitoring and diagnostic capabilities, from assessment of oxygenation in glaucoma and diabetic retinopathy to photo-oxidation and photodegradation in age-related macular degeneration.
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Affiliation(s)
| | | | | | | | | | - Dominic Sauvageau
- Zilia Inc., Quebec City, Québec, Canada
- University of Alberta, Department of Chemical and Materials Engineering, Edmonton, Alberta, Canada
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3
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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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4
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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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5
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Abstract
Early detection and monitoring are critical to the diagnosis and management of glaucoma, a progressive optic neuropathy that causes irreversible blindness. Optical coherence tomography (OCT) has become a commonly utilized imaging modality that aids in the detection and monitoring of structural glaucomatous damage. Since its inception in 1991, OCT has progressed through multiple iterations, from time-domain OCT, to spectral-domain OCT, to swept-source OCT, all of which have progressively improved the resolution and speed of scans. Even newer technological advancements and OCT applications, such as adaptive optics, visible-light OCT, and OCT-angiography, have enriched the use of OCT in the evaluation of glaucoma. This article reviews current commercial and state-of-the-art OCT technologies and analytic techniques in the context of their utility for glaucoma diagnosis and management, as well as promising future directions.
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Affiliation(s)
- Alexi Geevarghese
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA;
| | - Gadi Wollstein
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA;
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, New York 11201, USA
- Center for Neural Science, NYU College of Arts and Sciences, New York, NY 10003, USA
| | - Hiroshi Ishikawa
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA;
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, New York 11201, USA
| | - Joel S Schuman
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA;
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, New York 11201, USA
- Center for Neural Science, NYU College of Arts and Sciences, New York, NY 10003, USA
- Department of Physiology and Neuroscience, NYU Langone Health, NYU Grossman School of Medicine, New York, NY 10016, USA
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6
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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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7
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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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8
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Wei X, Hormel TT, Jia Y. Phase-stabilized complex-decorrelation angiography. BIOMEDICAL OPTICS EXPRESS 2021; 12:2419-2431. [PMID: 33996238 PMCID: PMC8086438 DOI: 10.1364/boe.420503] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 03/20/2021] [Accepted: 03/23/2021] [Indexed: 06/12/2023]
Abstract
In this study, we developed a novel phase-stabilized complex-decorrelation (PSCD) optical coherence tomography (OCT) angiography (OCTA) method that can generate high quality OCTA images. This method has been validated using three different types of OCT systems and compared with conventional complex- and amplitude-based OCTA algorithms. Our results suggest that in combination with a pre-processing phase stabilization method, the PSCD method is insensitive to bulk motion phase shifts, less dependent on OCT reflectance than conventional complex methods and demonstrates extended dynamic range of flow signal, in contrast to other two methods.
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Affiliation(s)
- Xiang Wei
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
- Department of Biomedical Engineer, Oregon Health and Science University, Portland, Oregon 97239, USA
| | - Tristan T. Hormel
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
| | - Yali Jia
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
- Department of Biomedical Engineer, Oregon Health and Science University, Portland, Oregon 97239, USA
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9
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Nicholas MP, Mysore N. Corneal neovascularization. Exp Eye Res 2020; 202:108363. [PMID: 33221371 DOI: 10.1016/j.exer.2020.108363] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 11/09/2020] [Accepted: 11/11/2020] [Indexed: 12/12/2022]
Abstract
The optical clarity of the cornea is essential for maintaining good visual acuity. Corneal neovascularization, which is a major cause of vision loss worldwide, leads to corneal opacification and often contributes to a cycle of chronic inflammation. While numerous factors prevent angiogenesis within the cornea, infection, inflammation, hypoxia, trauma, corneal degeneration, and corneal transplantation can all disrupt these homeostatic safeguards to promote neovascularization. Here, we summarize its etiopathogenesis and discuss the molecular biology of angiogenesis within the cornea. We then review the clinical assessment and diagnostic evaluation of corneal neovascularization. Finally, we describe current and emerging therapies.
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Affiliation(s)
- Matthew P Nicholas
- Flaum Eye Institute, University of Rochester Medical Center, 210 Crittenden Blvd., Rochester, NY, USA
| | - Naveen Mysore
- Flaum Eye Institute, University of Rochester Medical Center, 210 Crittenden Blvd., Rochester, NY, USA.
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10
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Retinal capillary oximetry with visible light optical coherence tomography. Proc Natl Acad Sci U S A 2020; 117:11658-11666. [PMID: 32398376 DOI: 10.1073/pnas.1918546117] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Assessing oxygen saturation (sO2) remains challenging but is nonetheless necessary for understanding retinal metabolism. We and others previously achieved oximetry on major retinal vessels and measured the total retinal oxygen metabolic rate in rats using visible-light optical coherence tomography. Here we extend oximetry measurements to capillaries and investigate all three retinal vascular plexuses by amplifying and extracting the spectroscopic signal from each capillary segment under the guidance of optical coherence tomography (OCT) angiography. Using this approach, we measured capillary sO2 in the retinal circulation in rats, demonstrated reproducibility of the results, validated the measurements in superficial capillaries with known perfusion pathways, and determined sO2 responses to hypoxia and hyperoxia in the different retinal capillary beds. OCT capillary oximetry has the potential to provide new insights into the retinal circulation in the normal eye as well as in retinal vascular diseases.
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11
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Zhou KC, Qian R, Farsiu S, Izatt JA. Spectroscopic optical coherence refraction tomography. OPTICS LETTERS 2020; 45:2091-2094. [PMID: 32236076 DOI: 10.1364/ol.389703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 03/05/2020] [Indexed: 05/24/2023]
Abstract
In optical coherence tomography (OCT), the axial resolution is often superior to the lateral resolution, which is sacrificed for long imaging depths. To address this anisotropy, we previously developed optical coherence refraction tomography (OCRT), which uses images from multiple angles to computationally reconstruct an image with isotropic resolution, given by the OCT axial resolution. On the other hand, spectroscopic OCT (SOCT), an extension of OCT, trades axial resolution for spectral resolution and hence often has superior lateral resolution. Here, we present spectroscopic OCRT (SOCRT), which uses SOCT images from multiple angles to reconstruct a spectroscopic image with isotropic spatial resolution limited by the OCT lateral resolution. We experimentally show that SOCRT can estimate bead size based on Mie theory at simultaneously high spectral and isotropic spatial resolution. We also applied SOCRT to a biological sample, achieving axial resolution enhancement limited by the lateral resolution.
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12
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Harper DJ, Konegger T, Augustin M, Schützenberger K, Eugui P, Lichtenegger A, Merkle CW, Hitzenberger CK, Glösmann M, Baumann B. Hyperspectral optical coherence tomography for in vivo visualization of melanin in the retinal pigment epithelium. JOURNAL OF BIOPHOTONICS 2019; 12:e201900153. [PMID: 31334610 PMCID: PMC7065636 DOI: 10.1002/jbio.201900153] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 06/19/2019] [Accepted: 07/18/2019] [Indexed: 05/09/2023]
Abstract
Previous studies for melanin visualization in the retinal pigment epithelium (RPE) have exploited either its absorption properties (using photoacoustic tomography or photothermal optical coherence tomography [OCT]) or its depolarization properties (using polarization sensitive OCT). However, these methods are only suitable when the melanin concentration is sufficiently high. In this work, we present the concept of hyperspectral OCT for melanin visualization in the RPE when the concentration is low. Based on white light OCT, a hyperspectral stack of 27 wavelengths (440-700 nm) was created in post-processing for each depth-resolved image. Owing to the size and shape of the melanin granules in the RPE, the variations in backscattering coefficient as a function of wavelength could be identified-a result which is to be expected from Mie theory. This effect was successfully identified both in eumelanin-containing phantoms and in vivo in the low-concentration Brown Norway rat RPE.
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Affiliation(s)
- Danielle J. Harper
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Thomas Konegger
- Institute of Chemical Technologies and Analytics, TU WienViennaAustria
| | - Marco Augustin
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Kornelia Schützenberger
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Pablo Eugui
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Antonia Lichtenegger
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Conrad W. Merkle
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | | | - Martin Glösmann
- Core Facility for Research and TechnologyUniversity of Veterinary MedicineViennaAustria
| | - Bernhard Baumann
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
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13
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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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14
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Wang TA, Chan MC, Lee HC, Lee CY, Tsai MT. Ultrahigh-resolution optical coherence tomography/angiography with an economic and compact supercontinuum laser. BIOMEDICAL OPTICS EXPRESS 2019; 10:5687-5702. [PMID: 31799040 PMCID: PMC6865110 DOI: 10.1364/boe.10.005687] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 10/06/2019] [Accepted: 10/07/2019] [Indexed: 05/19/2023]
Abstract
In this study, a Q-switch pumped supercontinuum laser (QS-SCL) is used as a light source for in vivo imaging via ultrahigh-resolution optical coherence tomography and angiography (UHR-OCT/OCTA). For this purpose, an OCT system based on a spectral-domain detection scheme is constructed, and a spectrometer with a spectral range of 635 - 875 nm is designed. The effective full-width at half maximum of spectrum covers 150 nm, and the corresponding axial and transverse resolutions are 2 and 10 µm in air, respectively. The relative intensity noise of the QS-SCL and mode-locked SCL is quantitatively compared. Furthermore, a special processing algorithm is developed to eliminate the intrinsic noise of QS-SCL. This work demonstrates that QS-SCLs can effectively reduce the cost and size of UHR-OCT/OCTA instruments, making clinical applications feasible.
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Affiliation(s)
- Tai-Ang Wang
- Institute of Photonic System, College of Photonics, National Chiao-Tung University, Tainan City 71150, Taiwan
- The authors contributed equally to this work
| | - Ming-Che Chan
- Institute of Photonic System, College of Photonics, National Chiao-Tung University, Tainan City 71150, Taiwan
- The authors contributed equally to this work
| | - Hsiang-Chieh Lee
- Graduate Institute of Photonics and Optoelectronics, National Taiwan University, 10617, Taiwan
- Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan
| | - Cheng-Yu Lee
- Department of Electrical Engineering, Chang Gung University, Taoyuan 33302, Taiwan
| | - Meng-Tsan Tsai
- Department of Electrical Engineering, Chang Gung University, Taoyuan 33302, Taiwan
- Department of Neurosurgery, Chang Gung Memorial Hospital, Linkou, Taoyuan 33305, Taiwan
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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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Beckmann L, Zhang X, Nadkarni NA, Cai Z, Batra A, Sullivan DP, Muller WA, Sun C, Kuranov R, Zhang HF. Longitudinal deep-brain imaging in mouse using visible-light optical coherence tomography through chronic microprism cranial window. BIOMEDICAL OPTICS EXPRESS 2019; 10:5235-5250. [PMID: 31646044 PMCID: PMC6788609 DOI: 10.1364/boe.10.005235] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 09/10/2019] [Accepted: 09/10/2019] [Indexed: 05/02/2023]
Abstract
We longitudinally imaged both the superficial and deep cortical microvascular networks in brains of healthy mice and in a mouse model of stroke in vivo using visible-light optical coherence tomography (vis-OCT). We surgically implanted a microprism in mouse brains sealed by a chronic cranial window. The microprism enabled vis-OCT to image the entire depth of the mouse cortex. Following microprism implantation, we imaged the mice for 28 days and found that that it took around 15 days for both the superficial and deep cortical microvessels to recover from the implantation surgery. After the brains recovered, we introduced ischemic strokes by transient middle cerebral artery occlusion (tMCAO). We monitored the strokes for up to 60 days and observed different microvascular responses to tMCAO at different cortical depths in both the acute and chronic phases of the stroke. This work demonstrates that the combined microprism and cranial window is well-suited for longitudinal investigation of cortical microvascular disorders using vis-OCT.
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Affiliation(s)
- Lisa Beckmann
- Department of Biomedical Engineering, Northwestern University, Evanston IL 60208, USA
- These authors contributed equally to this work
| | - Xian Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston IL 60208, USA
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, HuaZhong University of Science and Technology, Wuhan, Hubei, China
- These authors contributed equally to this work
| | - Neil A. Nadkarni
- Department of Neurology, Northwestern University, Chicago IL 60611, USA
| | - Zhen Cai
- Department of Biomedical Engineering, Northwestern University, Evanston IL 60208, USA
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, HuaZhong University of Science and Technology, Wuhan, Hubei, China
| | - Ayush Batra
- Department of Neurology, Northwestern University, Chicago IL 60611, USA
| | - David P. Sullivan
- Department of Pathology, Northwestern University, Chicago IL 60611, USA
| | - William A. Muller
- Department of Pathology, Northwestern University, Chicago IL 60611, USA
| | - Cheng Sun
- Department of Mechanical Engineering, Northwestern University, Evanston IL 60208, USA
| | - Roman Kuranov
- Department of Biomedical Engineering, Northwestern University, Evanston IL 60208, USA
- Opticent Health, Evanston IL, Evanston IL 60201, USA
| | - Hao F. Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston IL 60208, USA
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18
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Zhang T, Kho AM, Srinivasan VJ. Improving visible light OCT of the human retina with rapid spectral shaping and axial tracking. BIOMEDICAL OPTICS EXPRESS 2019; 10:2918-2931. [PMID: 31259062 PMCID: PMC6583340 DOI: 10.1364/boe.10.002918] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/30/2019] [Accepted: 04/30/2019] [Indexed: 05/23/2023]
Abstract
Visible light optical coherence tomography (OCT) theoretically provides finer axial resolution than near-infrared OCT for a given wavelength bandwidth. To realize this potential in the human retina in vivo, the unique technical challenges of visible light OCT must be addressed. We introduce three advances to further the performance of visible light OCT in the human retina. First, we incorporate a grating light valve spatial light modulator (GLV-SLM) spectral shaping stage to modify the source spectrum. This enables comfortable subject alignment with a red light spectrum, and image acquisition with a broad "white light" spectrum, shaped to minimize sidelobes. Second, we develop a novel, Fourier transform-free, software axial motion tracking algorithm with fast, magnetically actuated stage to maintain near-optimal axial resolution and sensitivity in the presence of eye motion. Third, we implement spatially dependent numerical dispersion compensation for the first time in the human eye in vivo. In vivo human retinal OCT images clearly show that the inner plexiform layer consists of 3 hyper-reflective bands and 2 hypo-reflective bands, corresponding with the standard anatomical division of the IPL. Wavelength-dependent images of the outer retina suggest that, beyond merely improving the axial resolution, shorter wavelength visible light may also provide unique advantages for visualizing Bruch's membrane.
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Affiliation(s)
- Tingwei Zhang
- Biomedical Engineering Department, University of California Davis, Davis, California, 95616, USA
| | - Aaron M. Kho
- Biomedical Engineering Department, University of California Davis, Davis, California, 95616, USA
| | - Vivek J. Srinivasan
- Biomedical Engineering Department, University of California Davis, Davis, California, 95616, USA
- Department of Ophthalmology and Vision Science, University of California Davis School of Medicine, Sacramento, California, 95817, USA
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19
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Son T, Alam M, Kim TH, Liu C, Toslak D, Yao X. Near infrared oximetry-guided artery-vein classification in optical coherence tomography angiography. Exp Biol Med (Maywood) 2019; 244:813-818. [PMID: 31088115 DOI: 10.1177/1535370219850791] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Differential artery–vein analysis is valuable for early detection of diabetic retinopathy and other eye diseases. As a new optical coherence tomography imaging modality, optical coherence tomography angiography provides capillary level resolution for accurate examination of retinal vasculatures. However, differential artery–vein analysis in optical coherence tomography angiography particularly for macular region in which blood vessels are small is challenging. In coordination with an automatic vessel tracking algorithm, we report here the feasibility of using near infrared optical coherence tomography oximetry to guide artery–vein classification in optical coherence tomography angiography of macular region. Impact statement It is known that arteries and veins can be affected by retinal diseases differently. Therefore, quantitative artery–vein analysis holds the promise for better disease detection and treatment evaluation. However, clinical optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) instruments lack the function of differential artery–vein analysis. Here, we report the feasibility of near infrared OCT oximetry-guided artery–vein classification in OCTA. Because the OCT and OCTA are naturally captured from the same instrument simultaneously, the presented method is feasible for practical deployment of differential artery–vein analysis in OCTA.
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Affiliation(s)
- Taeyoon Son
- 1 Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Minhaj Alam
- 1 Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Tae-Hoon Kim
- 1 Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Changgeng Liu
- 1 Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Devrim Toslak
- 1 Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA.,2 Department of Ophthalmology, Antalya Training and Research Hospital, Antalya 07100, Turkey
| | - Xincheng Yao
- 1 Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA.,3 Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
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20
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Shu X, Beckmann L, Wang Y, Rubinoff I, Lucy K, Ishikawa H, Wollstein G, Fawzi AA, Schuman JS, Kuranov RV, Zhang HF. Designing visible-light optical coherence tomography towards clinics. Quant Imaging Med Surg 2019; 9:769-781. [PMID: 31281773 PMCID: PMC6571199 DOI: 10.21037/qims.2019.05.01] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 05/04/2019] [Indexed: 12/31/2022]
Abstract
BACKGROUND The capabilities of visible-light optical coherence tomography (vis-OCT) in noninvasive anatomical and functional retinal imaging have been demonstrated by multiple groups in both rodents and healthy human subjects. Translating laboratory prototypes to an integrated clinical-environment-friendly system is required to explore the full potential of vis-OCT in disease management. METHODS We developed and optimized a portable vis-OCT system for human retinal imaging in clinical settings. We acquired raster- and circular-scan images from both healthy and diseased human eyes. RESULTS The new vis-OCT provided high-quality retinal images of both subjects without any known eye diseases and patients with various retinal diseases, including retinal occlusive disease and diabetic retinopathy (DR) over a broad range of ages. CONCLUSIONS A newly designed vis-OCT system is sufficiently optimized to be suited for routine patients' examinations in clinics. Vis-OCT has the potential to add new anatomical and functional imaging capabilities to ophthalmic clinical care.
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Affiliation(s)
- Xiao Shu
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Lisa Beckmann
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | | | - Ian Rubinoff
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Katie Lucy
- NYU Langone Eye Center, NYU School of Medicine, New York, NY, USA
| | - Hiroshi Ishikawa
- NYU Langone Eye Center, NYU School of Medicine, New York, NY, USA
| | - Gadi Wollstein
- NYU Langone Eye Center, NYU School of Medicine, New York, NY, USA
| | - Amani A. Fawzi
- Department of Ophthalmology, Northwestern University, Chicago, IL, USA
| | - Joel S. Schuman
- NYU Langone Eye Center, NYU School of Medicine, New York, NY, USA
| | - Roman V. Kuranov
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
- Opticent Health, Evanston, 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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21
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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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22
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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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23
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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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24
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Veenstra C, Petersen W, Vellekoop IM, Steenbergen W, Bosschaart N. Spatially confined quantification of bilirubin concentrations by spectroscopic visible-light optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2018; 9:3581-3589. [PMID: 30338141 PMCID: PMC6191639 DOI: 10.1364/boe.9.003581] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 05/09/2018] [Accepted: 06/06/2018] [Indexed: 05/18/2023]
Abstract
Spatially confined measurements of bilirubin in tissue can be of great value for noninvasive bilirubin estimations during neonatal jaundice, as well as our understanding of the physiology behind bilirubin extravasation. This work shows the potential of spectroscopic visible-light optical coherence tomography (sOCT) for this purpose. At the bilirubin absorption peak around 460 nm, sOCT suffers from a strong signal decay with depth, which we overcome by optimizing our system sensitivity through a combination of zero-delay acquisition and focus tracking. In a phantom study, we demonstrate the quantification of bilirubin concentrations between 0 and 650 µM with only a 10% difference to the expected value, thereby covering the entire clinical pathophysiological range.
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