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Rubinoff I, Kuranov RV, Fang R, Ghassabi Z, Wang Y, Beckmann L, Miller DA, Wollstein G, Ishikawa H, Schuman JS, Zhang HF. Adaptive spectroscopic visible-light optical coherence tomography for clinical retinal oximetry. Commun Med (Lond) 2023; 3:57. [PMID: 37095177 PMCID: PMC10126115 DOI: 10.1038/s43856-023-00288-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 04/13/2023] [Indexed: 04/26/2023] Open
Abstract
BACKGROUND Retinal oxygen saturation (sO2) provides essential information about the eye's response to pathological changes that can result in vision loss. Visible-light optical coherence tomography (vis-OCT) is a noninvasive tool that has the potential to measure retinal sO2 in a clinical setting. However, its reliability is currently limited by unwanted signals referred to as spectral contaminants (SCs), and a comprehensive strategy to isolate true oxygen-dependent signals from SCs in vis-OCT is lacking. METHODS We develop an adaptive spectroscopic vis-OCT (ADS-vis-OCT) technique that can adaptively remove SCs and accurately measure sO2 under the unique conditions of each vessel. We also validate the accuracy of ADS-vis-OCT using ex vivo blood phantoms and assess its repeatability in the retina of healthy volunteers. RESULTS In ex vivo blood phantoms, ADS-vis-OCT agrees with a blood gas machine with only a 1% bias in samples with sO2 ranging from 0% to 100%. In the human retina, the root mean squared error between sO2 values in major arteries measured by ADS-vis-OCT and a pulse oximeter is 2.1% across 18 research participants. Additionally, the standard deviations of repeated ADS-vis-OCT measurements of sO2 values in smaller arteries and veins are 2.5% and 2.3%, respectively. Non-adaptive methods do not achieve comparable repeatabilities from healthy volunteers. CONCLUSIONS ADS-vis-OCT effectively removes SCs from human images, yielding accurate and repeatable sO2 measurements in retinal arteries and veins with varying diameters. This work could have important implications for the clinical use of vis-OCT to manage eye diseases.
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Affiliation(s)
- Ian Rubinoff
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Roman V Kuranov
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
- Opticent Inc., Evanston, IL, 60201, USA
| | - Raymond Fang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Zeinab Ghassabi
- Department of Ophthalmology, New York University, New York, NY, 10017, USA
| | - Yuanbo Wang
- Currently with Department of Ophthalmology, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Lisa Beckmann
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - David A Miller
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Gadi Wollstein
- Department of Ophthalmology, New York University, New York, NY, 10017, USA
| | - Hiroshi Ishikawa
- Department of Ophthalmology, New York University, New York, NY, 10017, USA
- Currently with Department of Ophthalmology, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Joel S Schuman
- Department of Ophthalmology, New York University, New York, NY, 10017, USA
| | - Hao F Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA.
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Ghassabi Z, Kuranov RV, Schuman JS, Zambrano R, Wu M, Liu M, Tayebi B, Wang Y, Rubinoff I, Liu X, Wollstein G, Zhang HF, Ishikawa H. In Vivo Sublayer Analysis of Human Retinal Inner Plexiform Layer Obtained by Visible-Light Optical Coherence Tomography. Invest Ophthalmol Vis Sci 2022; 63:18. [PMID: 35024761 PMCID: PMC8762683 DOI: 10.1167/iovs.63.1.18] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Purpose Growing evidence suggests that dendrite retraction or degeneration in a subpopulation of the retinal ganglion cells (RGCs) may precede detectable soma abnormalities and RGC death in glaucoma. Visualization of the lamellar structure of the inner plexiform layer (IPL) could advance clinical management and fundamental understanding of glaucoma. We investigated whether visible-light optical coherence tomography (vis-OCT) could detect the difference in the IPL sublayer thicknesses between small cohorts of healthy and glaucomatous subjects. Method We imaged nine healthy and five glaucomatous subjects with vis-OCT. Four of the healthy subjects were scanned three times each in two separate visits, and five healthy and five glaucoma subjects were scanned three times during a single visit. IPL sublayers were manually segmented using averaged A-line profiles. Results The mean ages of glaucoma and healthy subjects are 59.6 ± 13.4 and 45.4 ± 14.4 years (P = 0.02.) The visual field mean deviations (MDs) are −26.4 to −7.7 dB in glaucoma patients and −1.6 to 1.1 dB in healthy subjects (P = 0.002). Median coefficients of variation (CVs) of intrasession repeatability for the entire IPL and three sublayers are 3.1%, 5.6%, 6.9%, and 5.6% in healthy subjects and 1.8%, 6.0%, 7.7%, and 6.2% in glaucoma patients, respectively. The mean IPL thicknesses are 36.2 ± 1.5 µm in glaucomatous and 40.1 ± 1.7 µm in healthy eyes (P = 0.003). Conclusions IPL sublayer analysis revealed that the middle sublayer could be responsible for the majority of IPL thinning in glaucoma. Vis-OCT quantified IPL sublayers with good repeatability in both glaucoma and healthy subjects.
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Affiliation(s)
- Zeinab Ghassabi
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States
| | - Roman V Kuranov
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States.,Opticent Inc., Evanston, Illinois, United States
| | - Joel S Schuman
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States.,Department of Biomedical Engineering, New York University Tandon School of Engineering, Brooklyn, New York, United States.,Neuroscience Institute, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States.,Department of Electrical and Computer Engineering, New York University Tandon School of Engineering, Brooklyn, New York, United States.,Center for Neural Science, NYU College of Arts and Sciences, New York, New York, United States.,Department of Physiology and Neuroscience, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States
| | - Ronald Zambrano
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States
| | - Mengfei Wu
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States
| | - Mengling Liu
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States
| | - Behnam Tayebi
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States.,Neuroscience Institute, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States
| | - Yuanbo Wang
- Opticent Inc., Evanston, Illinois, United States
| | - Ian Rubinoff
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States
| | - Xiaorong Liu
- Department of Biology, University of Virginia, Charlottesville, Virginia, United States
| | - Gadi Wollstein
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States.,Department of Biomedical Engineering, New York University Tandon School of Engineering, Brooklyn, New York, United States
| | - Hao F Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States
| | - Hiroshi Ishikawa
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, New York, United States.,Department of Biomedical Engineering, New York University Tandon School of Engineering, Brooklyn, New York, United States.,Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
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Rubinoff I, Kuranov RV, Zhang HF. Intrinsic spectrally-dependent background in spectroscopic visible-light optical coherence tomography. Biomed Opt Express 2021; 12:110-124. [PMID: 33520380 PMCID: PMC7818955 DOI: 10.1364/boe.410011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/15/2020] [Accepted: 11/16/2020] [Indexed: 05/10/2023]
Abstract
Visible-light optical coherence tomography (vis-OCT) has enabled new spectroscopic applications, such as retinal oximetry, as a result of increased optical absorption and scattering contacts in biological tissue and improved axial resolution. Besides extracting tissue properties from back-scattered light, spectroscopic analyses must consider spectral alterations induced by image reconstruction itself. We investigated an intrinsic spectral bias in the background noise floor, which is hereby referred to as the spectrally-dependent background (SDBG). We developed an analytical model to predict the SDBG-induced bias and validated this model using numerically simulated and experimentally acquired data. We found that SDBG systemically altered the measured spectra of blood in human retinal vessels in vis-OCT, as compared to literature data. We provided solutions to quantify and compensate for SDBG in retinal oximetry. This work is particularly significant for clinical applications of vis-OCT.
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Affiliation(s)
- Ian Rubinoff
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Roman V. Kuranov
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
- Opticent Health, Evanston, IL 60201, USA
| | - Hao F. Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
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Miller DA, Grannonico M, Liu M, Kuranov RV, Netland PA, Liu X, Zhang HF. Visible-Light Optical Coherence Tomography Fibergraphy for Quantitative Imaging of Retinal Ganglion Cell Axon Bundles. Transl Vis Sci Technol 2020; 9:11. [PMID: 33110707 PMCID: PMC7552935 DOI: 10.1167/tvst.9.11.11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 09/18/2020] [Indexed: 01/15/2023] Open
Abstract
Purpose To develop a practical technique for visualizing and quantifying retinal ganglion cell (RGC) axon bundles in vivo. Methods We applied visible-light optical coherence tomography (vis-OCT) to image the RGC axon bundles, referred to as vis-OCT fibergraphy, of healthy wild-type C57BL/6 mice. After vis-OCT imaging, retinas were flat-mounted, immunostained with anti-beta-III tubulin (Tuj1) antibody for RGC axons, and imaged with confocal microscopy. We quantitatively compared the RGC axon bundle networks imaged by in vivo vis-OCT and ex vivo confocal microscopy using semi-log Sholl analysis. Results Side-by-side comparison of ex vivo confocal microscopy and in vivo vis-OCT confirmed that vis-OCT fibergraphy captures true RGC axon bundle networks. The semi-log Sholl regression coefficients extracted from vis-OCT fibergrams (3.7 ± 0.8 mm–1) and confocal microscopy (3.6 ± 0.3 mm–1) images also showed good agreement with each other (n = 6). Conclusions We demonstrated the feasibility of using vis-OCT fibergraphy to visualize RGC axon bundles. Further applying Sholl analysis has the potential to identify biomarkers for non-invasively assessing RGC health. Translational Relevance Our novel technique for visualizing and quantifying RGC axon bundles in vivo provides a potential measurement tool for diagnosing and tracking the progression of optic neuropathies.
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Affiliation(s)
- David A Miller
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - Marta Grannonico
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Mingna Liu
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Roman V Kuranov
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA.,Opticent Health, Evanston, IL, USA
| | - Peter A Netland
- Department of Ophthalmology, University of Virginia, Charlottesville, VA, USA
| | - Xiaorong Liu
- Department of Biology, University of Virginia, Charlottesville, VA, USA.,Department of Psychology, University of Virginia, Charlottesville, VA, USA
| | - Hao F Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA.,Department of Ophthalmology, Northwestern University, Evanston, IL, USA
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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 DOI: 10.21037/qims.2019.05.01] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [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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Sapozhnikova VV, Prough D, Kuranov RV, Cicenaite I, Esenaliev RO. Influence of Osmolytes on In Vivo Glucose Monitoring Using Optical Coherence Tomography. Exp Biol Med (Maywood) 2016; 231:1323-32. [PMID: 16946401 DOI: 10.1177/153537020623100806] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Diabetes mellitus and its complications are the third leading cause of death in the world, exceeded only by cardiovascular disease and cancer. Tighter monitoring and control of blood glucose could minimize complications associated with diabetes. Recently, optical coherence tomography (OCT) for noninvasive glucose monitoring was proposed and tested in vivo. The aim of this work was to investigate the influence of changes in blood glucose concentration ([glu]) and sodium concentration ([Na+]) on the OCT signal. We also investigated the influence of other important analytes on the sensitivity of glucose monitoring with OCT. The experiments were carried out in anesthetized female pigs. The OCT images were acquired continuously from skin, while [glu] and [Na+] were experimentally varied within their physiological ranges. Correlations of the OCT signal slope with [glu] and [Na+] were studied at different tissue depths. The tissue area probed with OCT was marked and cut for histological examination. The correlation of blood [glu] and [Na+] with the OCT signal slope was observed in separate tissue layers. On average, equimolar changes in [glu] produced 2.26 ± 1.15 greater alterations of the OCT signal slope than changes in [Na+]. Variation of concentrations of other analytes did not Influence the OCT signal slope. The influence of [Na+] on relative changes in the OCT signal slope was generally less than [glu]-induced changes. OCT is a promising method for noninvasive glucose monitoring because of its ability to track the influence of changing [glu] on individual tissue layers.
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Affiliation(s)
- Veronika V Sapozhnikova
- Laboratory for Optical Sensing and Monitoring, Center for Biomedical Engineering, University of Texas Medical Branch, 301 University Blvd., Rt. 0456, Galveston, TX 77555-0456, USA
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Yin B, Kuranov RV, McElroy AB, Kazmi S, Dunn AK, Duong TQ, Milner TE. Dual-wavelength photothermal optical coherence tomography for imaging microvasculature blood oxygen saturation. J Biomed Opt 2013; 18:56005. [PMID: 23640076 PMCID: PMC3642243 DOI: 10.1117/1.jbo.18.5.056005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A swept-source dual-wavelength photothermal (DWP) optical coherence tomography (OCT) system is demonstrated for quantitative imaging of microvasculature oxygen saturation. DWP-OCT is capable of recording three-dimensional images of tissue and depth-resolved phase variation in response to photothermal excitation. A 1,064-nm OCT probe and 770-nm and 800-nm photothermal excitation beams are combined in a single-mode optical fiber to measure microvasculature hemoglobin oxygen saturation (SO(2)) levels in phantom blood vessels with a range of blood flow speeds (0 to 17 mm/s). A 50-μm-diameter blood vessel phantom is imaged, and SO(2) levels are measured using DWP-OCT and compared with values provided by a commercial oximeter at various blood oxygen concentrations. The influences of blood flow speed and mechanisms of SNR phase degradation on the accuracy of SO(2) measurement are identified and investigated.
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Affiliation(s)
- Biwei Yin
- University of Texas at Austin, Departments of Electrical and Computer Engineering, 1 University Station C0803, Austin, Texas 78712
| | - Roman V. Kuranov
- University of Texas Health Science Center at San Antonio, Department of Ophthalmology, 7703 Floyd Curl Drive, San Antonio, Texas 78229
- Address all correspondence to: Roman V. Kuranov, University of Texas Health Science Center at San Antonio, Department of Ophthalmology, 7703 Floyd Curl Drive, San Antonio, Texas 78229. Tel: 210-567-8402; Fax: 210-567-8413; E-mail:
| | - Austin B. McElroy
- University of Texas at Austin, Department of Biomedical Engineering, 1 University Station C0800, Austin, Texas 78712
| | - Shams Kazmi
- University of Texas at Austin, Department of Biomedical Engineering, 1 University Station C0800, Austin, Texas 78712
| | - Andrew K. Dunn
- University of Texas at Austin, Department of Biomedical Engineering, 1 University Station C0800, Austin, Texas 78712
| | - Timothy Q. Duong
- University of Texas Health Science Center at San Antonio, Department of Ophthalmology, 7703 Floyd Curl Drive, San Antonio, Texas 78229
| | - Thomas E. Milner
- University of Texas at Austin, Department of Biomedical Engineering, 1 University Station C0800, Austin, Texas 78712
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Kuranov RV, Kazmi S, McElroy AB, Kiel JW, Dunn AK, Milner TE, Duong TQ. In vivo depth-resolved oxygen saturation by Dual-Wavelength Photothermal (DWP) OCT. Opt Express 2011; 19:23831-44. [PMID: 22109408 PMCID: PMC3482904 DOI: 10.1364/oe.19.023831] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Microvasculature hemoglobin oxygen saturation (SaO2) is important in the progression of various pathologies. Non-invasive depth-resolved measurement of SaO2 levels in tissue microvasculature has the potential to provide early biomarkers and a better understanding of the pathophysiological processes allowing improved diagnostics and prediction of disease progression. We report proof-of-concept in vivo depth-resolved measurement of SaO(2) levels in selected 30 µm diameter arterioles in the murine brain using Dual-Wavelength Photothermal (DWP) Optical Coherence Tomography (OCT) with 800 nm and 770 nm photothermal excitation wavelengths. Depth location of back-reflected light from a target arteriole was confirmed using Doppler and speckle contrast OCT images. SaO(2) measured in a murine arteriole with DWP-OCT is linearly correlated (R(2)=0.98) with systemic SaO(2) values recorded by a pulse-oximeter. DWP-OCT are steadily lower (10.1%) than systemic SaO(2) values except during pure oxygen breathing. DWP-OCT is insensitive to OCT intensity variations and is a candidate approach for in vivo depth-resolved quantitative imaging of microvascular SaO(2) levels.
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Affiliation(s)
- Roman V Kuranov
- Department of Ophthalmology, The University of Texas Health Science Center, San Antonio, Texas 78229, USA.
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Zhang Y, Nateras OSE, Peng Q, Kuranov RV, Harrison JM, Milner TE, Duong TQ. Lamina-specific anatomic magnetic resonance imaging of the human retina. Invest Ophthalmol Vis Sci 2011; 52:7232-7. [PMID: 21828153 DOI: 10.1167/iovs.11-7623] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Magnetic resonance imaging (MRI) of the human retina faces two major challenges: eye movement and hardware limitation that could preclude human retinal MRI with adequate spatiotemporal resolution. This study investigated eye-fixation stability and high-resolution anatomic MRI of the human retina on a 3-Tesla (T) MRI scanner. Comparison was made with optical coherence tomography (OCT) on the same subjects. METHODS Eye-fixation stability of protocols used in MRI was evaluated on four normal volunteers using an eye tracker. High-resolution MRI (100 × 200 × 2000 μm) protocol was developed on a 3-T scanner. Subjects were instructed to maintain stable eye fixation on a target with cued blinks every 8 seconds during MRI. OCT imaging of the retina was performed. Retinal layer thicknesses measured with MRI and OCT were analyzed for matching regions of the same eyes close to the optic nerve head. RESULTS The temporal SDs of the horizontal and vertical displacements were 78 ± 51 and 130 ± 51 μm (±SD, n = 4), respectively. MRI detected three layers within the human retina, consistent with MRI findings in rodent, feline, and baboon retinas. The hyperintense layer 1 closest to the vitreous likely consisted of nerve fiber, ganglion cell, and inner nuclear layer; the hypointense layer 2, the outer nuclear layer and the inner and outer segments; and the hyperintense layer 3, the choroid. The MRI retina/choroid thickness was 711 ± 37 μm, 19% (P < 0.05) thicker than OCT thickness (579 ± 34 μm). CONCLUSIONS This study reports high-resolution MRI of lamina-specific structures in the human retina. These initial results are encouraging. Further improvement in spatiotemporal resolution is warranted.
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Affiliation(s)
- Yi Zhang
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, Texas 78229, USA
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Wang T, Mallidi S, Qiu J, Ma LL, Paranjape AS, Sun J, Kuranov RV, Johnston KP, Milner TE. Comparison of pulsed photothermal radiometry, optical coherence tomography and ultrasound for melanoma thickness measurement in PDMS tissue phantoms. J Biophotonics 2011; 4:335-344. [PMID: 20954204 DOI: 10.1002/jbio.201000078] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 09/10/2010] [Accepted: 09/30/2010] [Indexed: 05/30/2023]
Abstract
Melanoma accounts for 75% of all skin cancer deaths. Pulsed photothermal radiometry (PPTR), optical coherence tomography (OCT) and ultrasound (US) are non-invasive imaging techniques that may be used to measure melanoma thickness, thus, determining surgical margins. We constructed a series of PDMS tissue phantoms simulating melanomas of different thicknesses. PPTR, OCT and US measurements were recorded from PDMS tissue phantoms and results were compared in terms of axial imaging range, axial resolution and imaging time. A Monte Carlo simulation and three-dimensional heat transfer model was constructed to simulate PPTR measurement. Experimental results show that PPTR and US can provide a wide axial imaging range (75 μm-1.7 mm and 120-910 μm respectively) but poor axial resolution (75 and 120 μm respectively) in PDMS tissue phantoms, while OCT has the most superficial axial imaging range (14-450 μm) but highest axial resolution (14 μm). The Monte Carlo simulation and three-dimensional heat transfer model give good agreement with PPTR measurement. PPTR and US are suited to measure thicker melanoma lesions (>400 μm), while OCT is better to measure thin melanoma lesions (<400 μm).
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Affiliation(s)
- Tianyi Wang
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas 78712, USA.
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11
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Kuranov RV, Qiu J, McElroy AB, Estrada A, Salvaggio A, Kiel J, Dunn AK, Duong TQ, Milner TE. Depth-resolved blood oxygen saturation measurement by dual-wavelength photothermal (DWP) optical coherence tomography. Biomed Opt Express 2011; 2:491-504. [PMID: 21412455 PMCID: PMC3047355 DOI: 10.1364/boe.2.000491] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 01/24/2011] [Accepted: 01/29/2011] [Indexed: 05/03/2023]
Abstract
Non-invasive depth-resolved measurement of hemoglobin oxygen saturation (SaO(2)) levels in discrete blood vessels may have implications for diagnosis and treatment of various pathologies. We introduce a novel Dual-Wavelength Photothermal (DWP) Optical Coherence Tomography (OCT) for non-invasive depth-resolved measurement of SaO(2) levels in a blood vessel phantom. DWP OCT SaO(2) is linearly correlated with blood-gas SaO(2) measurements. We demonstrate 6.3% precision in SaO(2) levels measured a phantom blood vessel using DWP-OCT with 800 and 765 nm excitation wavelengths. Sources of uncertainty in SaO(2) levels measured with DWP-OCT are identified and characterized.
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Affiliation(s)
- Roman V. Kuranov
- Department of Ophthalmology, The University of Texas Health Science Center, San Antonio, Texas 78229, USA
- Dept. of Biomedical Engineering, The University of Texas at Austin, Texas 78712, USA
| | - Jinze Qiu
- Dept. of Biomedical Engineering, The University of Texas at Austin, Texas 78712, USA
| | - Austin B. McElroy
- Dept. of Biomedical Engineering, The University of Texas at Austin, Texas 78712, USA
| | - Arnold Estrada
- Dept. of Biomedical Engineering, The University of Texas at Austin, Texas 78712, USA
| | - Anthony Salvaggio
- Dept. of Biomedical Engineering, The University of Texas at Austin, Texas 78712, USA
| | - Jeffrey Kiel
- Department of Ophthalmology, The University of Texas Health Science Center, San Antonio, Texas 78229, USA
| | - Andrew K. Dunn
- Dept. of Biomedical Engineering, The University of Texas at Austin, Texas 78712, USA
| | - Timothy Q. Duong
- Department of Ophthalmology, The University of Texas Health Science Center, San Antonio, Texas 78229, USA
- South Texas Veterans Health Care System, San Antonio, Texas 78229, USA
| | - Thomas E. Milner
- Dept. of Biomedical Engineering, The University of Texas at Austin, Texas 78712, USA
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Sapozhnikova VV, Kuranov RV, Cicenaite I, Esenaliev RO, Prough DS. Effect on blood glucose monitoring of skin pressure exerted by an optical coherence tomography probe. J Biomed Opt 2008; 13:021112. [PMID: 18465961 DOI: 10.1117/1.2909671] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We proposed to use optical coherence tomography (OCT) for continuous noninvasive blood glucose monitoring, and recently we significantly improved the sensitivity of this technique. The accuracy of OCT glucose monitoring is limited by several factors, including variation of tissue pressure exerted by the OCT probe. We studied the influence of high (>10 kPa) and low (<1 kPa) pressure levels on OCT blood glucose monitoring. We showed that controlling external pressure to <1 kPa substantially improved the accuracy and reproducibility of OCT-based glucose monitoring.
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Affiliation(s)
- Veronika V Sapozhnikova
- The University of Texas Medical Branch, Center for Biomedical Engineering, Laboratory for Optical Sensing and Monitoring, Galveston, Texas 77555-0456, USA
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Kuranov RV, Sapozhnikova VV, Prough DS, Cicenaite I, Esenaliev RO. Prediction capability of optical coherence tomography for blood glucose concentration monitoring. J Diabetes Sci Technol 2007; 1:470-7. [PMID: 19885109 PMCID: PMC2769644 DOI: 10.1177/193229680700100404] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Optical coherence tomography (OCT) has been shown to be a promising optical approach to noninvasive monitoring of blood glucose concentration because of its capability of probing optical properties at different depths in tissue with high resolution. This article investigates the capability of OCT to predict changes in blood glucose concentration. METHODS We varied blood glucose concentration in the physiological range in three sets of experiments. In the first set, we investigated large variations of blood glucose concentration ( approximately 400 mg/dl) and used 2100 OCT A scans for signal averaging. In the second set, we varied blood glucose concentration by approximately 200 mg/dl and used 8400 A scans for signal averaging. In the third set, we improved OCT blood glucose monitoring by increasing and controlling skin temperature under the OCT probe. In this set of experiments we increased the glucose concentration by approximately 300 mg/dl and used 4200 A scans for averaging. RESULTS The predicted glucose concentrations in the first two sets were lower than actual glucose concentration by 10-20% (the mean shift), while the heating and temperature control in the third set of experiments reduced the mean shift down to 1.5%. Therefore, the mean shift was reduced substantially by tissue heating and temperature control. However, it did not depend on the number of A scans to be averaged. In contrast, the uncertainty in OCT prediction of glucose concentration (the standard deviation) did not depend on heating and temperature control, but was reduced substantially from 56 to 24 mg/dl by increasing the number of A scans from 2100 to 8400, respectively. CONCLUSION These results suggest that the accuracy of OCT-based glucose monitoring is approaching that of standard invasive and minimally invasive techniques.
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Kuranov RV, Sapozhnikova VV, Prough DS, Cicenaite I, Esenaliev RO. In vivo study of glucose-induced changes in skin properties assessed with optical coherence tomography. Phys Med Biol 2006; 51:3885-900. [PMID: 16885613 DOI: 10.1088/0031-9155/51/16/001] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Recently, our in vivo studies demonstrated a strong correlation between blood glucose concentration and the slope of the optical coherence tomography (OCT) signal when the probing beam was scanned over a straight line. To improve the sensitivity of OCT for blood glucose monitoring, two-dimensional (2D) lateral scanning of the OCT probing beam was proposed. Depth-dependent changes in pig skin properties with variation of blood glucose concentration were revealed due to significant suppression of speckle noise and motion artefacts in 2D scanning mode. The correlation coefficient of the OCT signal slope with blood glucose concentration varied periodically in the range from -0.9 to +0.9 depending on depth. The period of variation of the correlation coefficient was 100-150 microm that corresponded to the distance between neighbour collagen bundles. We also observed a decrease of skin thickness by 10 +/- 7.5 microm with an increase of blood glucose concentration by 277 +/- 56 mg dl(-1). Mechanisms of glucose-induced changes in skin properties owing to tissue layer shift caused by dehydration associated with the glucose osmotic effect were considered.
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Affiliation(s)
- Roman V Kuranov
- Laboratory for Optical Sensing and Monitoring, Center for Biomedical Engineering, University of Texas Medical Branch, Galveston, TX, USA
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Sapozhnikova VV, Kamensky VA, Kuranov RV, Kutis I, Snopova LB, Myakov AV. In vivo visualization of Tradescantia leaf tissue and monitoring the physiological and morphological states under different water supply conditions using optical coherence tomography. Planta 2004; 219:601-609. [PMID: 15133665 DOI: 10.1007/s00425-004-1276-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2003] [Accepted: 03/15/2004] [Indexed: 05/24/2023]
Abstract
The optical coherence tomography (OCT) capabilities of plants were evaluated using leaves of Tradescantia pallida (Rose) D. Hunt. The internal structure of the leaf tissues was visualized in vivo and the physiological and morphological states of the tissues under different water supply conditions were monitored using OCT. The OCT technique provides non-invasive two-dimensional images directly on intact plants. The acquisition time of a two-dimensional image with a size of 200x200 pixels and a spatial resolution of 15 microm is 1-3 s. It was shown that OCT is a useful tool for monitoring the physiological and morphological states of plant tissues supplied with varying amounts of water and under the influence of different chemical factors.
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Affiliation(s)
- Veronika V Sapozhnikova
- Institute of Applied Physics of the Russian Academy of Science, 46 Ulyanov Street, 603950, Nizhny Novgorod.
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Bagayev SN, Gelikonov VM, Gelikonov GV, Kargapoltsev ES, Kuranov RV, Razhev AM, Turchin IV, Zhupikov AA. Optical coherence tomography for in situ monitoring of laser corneal ablation. J Biomed Opt 2002; 7:633-642. [PMID: 12421132 DOI: 10.1117/1.1501891] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2001] [Revised: 11/19/2001] [Accepted: 04/12/2002] [Indexed: 05/24/2023]
Abstract
OBJECTIVE To improve the precision of refractive surgery, a new approach for determination of the removed corneal thickness profile in situ with laser ablation by optical coherence tomography (OCT) is developed. STUDY DESIGN/MATERIALS AND METHODS The traditional method for precision (less than 10 microm) measurements of intraocular distances is based on the use of the reflected component of probing radiation. This component is characterized by a small range of operating angles between a probing beam and a normal to the surface under study. To enhance this range of operating angles we suggest using a light component backscattered from a biological object. This will enable precision measurements over the entire surface of the cornea without any changes in the orientation between a probing beam and the eye, a necessary condition for in situ monitoring of laser refraction correction in the eye. We suggest a specially developed algorithm of OCT signal processing to measure the corneal thickness by the backscattered light component for a single longitudinal scan (A scan). The corneal thickness profile is obtained by a series of such A scans acquired by successively scanning a probing beam along the corneal surface. The thickness profile of removed layer is determined by changes in the corneal thickness profile in the process of ablation. When the cornea is ablated by a beam with a fixed transverse profile, we propose using integral characteristics of the ablated layer profile, for example, the maximum ablation depth, as criteria of changes in refractive power of the eye. The measurement precision by these characteristics is considerably higher than by a single A scan. Since the cornea is a poorly scattering medium, the Fourier filtering is employed to increase reliability and precision of the method. Model experiments on monitoring the ablation process in a lavsan film and ex vivo human cornea are described. Preliminary experiments on in vivo measurements of human corneal thickness are performed. RESULTS In model experiments the precision of measurement of laser ablation depth by one A scan was 5-20 microm, depending on the signal-to-noise ratio (SNR), whereas the precision of measurement of laser ablation depth as the integral characteristic of the ablated layer profile was 0.3-5 microm. The experimental results showed that at small SNR Fourier filtering might considerably increase reliability and precision of measurements. When SNR is high, the measurement precision does not change. The precision of measurements of the corneal thickness in preliminary in vivo experiments was higher than in ex vivo experiments. This factor is very promising for application of the method suggested herein in refractive surgery.
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Affiliation(s)
- Sergey N Bagayev
- SD Russian Academy of Sciences, Institute of Laser Physics, Lavrentiev st. 13, Novosibirsk, Russia
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