1
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Xu Z, Wang Y, Chen X, Lin K, Liu L. Dual beam optical coherence tomography angiography for decoupling axial velocity gradient. Sci Rep 2024; 14:19464. [PMID: 39174584 PMCID: PMC11341915 DOI: 10.1038/s41598-024-68924-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Accepted: 07/30/2024] [Indexed: 08/24/2024] Open
Abstract
Axial velocity gradient (AVG) in the optical coherence tomography angiography (OCTA) signal affects measurement accuracy when the flow is not perpendicular to the scanning beam. We developed a dual beam OCTA method to decouple the contribution of AVG from the decorrelation signal. Decoupling is first verified by phantom experiments which reduces measurement uncertainty from 1.5 to 0.7% (standard deviation). We also tested the method in human skin in vivo and the results indicate that the contribution of AVG to decorrelation signal is reduced.
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Affiliation(s)
- Zhengyang Xu
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, Singapore
| | - Yukun Wang
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, Singapore
- Changchun Institute of Optics, Fine Mechanics and Physics, Changchun, China
| | - Xi Chen
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, Singapore
| | - Kan Lin
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, Singapore
| | - Linbo Liu
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, Singapore.
- China-Singapore International Joint Research Institute (CSIJRI), Guangzhou, China.
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2
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Gruionu G, Baish J, McMahon S, Blauvelt D, Gruionu LG, Lenco MO, Vakoc BJ, Padera TP, Munn LL. Experimental and theoretical model of microvascular network remodeling and blood flow redistribution following minimally invasive microvessel laser ablation. Sci Rep 2024; 14:8767. [PMID: 38627467 PMCID: PMC11021487 DOI: 10.1038/s41598-024-59296-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 04/09/2024] [Indexed: 04/19/2024] Open
Abstract
Overly dense microvascular networks are treated by selective reduction of vascular elements. Inappropriate manipulation of microvessels could result in loss of host tissue function or a worsening of the clinical problem. Here, experimental, and computational models were developed to induce blood flow changes via selective artery and vein laser ablation and study the compensatory collateral flow redistribution and vessel diameter remodeling. The microvasculature was imaged non-invasively by bright-field and multi-photon laser microscopy, and optical coherence tomography pre-ablation and up to 30 days post-ablation. A theoretical model of network remodeling was developed to compute blood flow and intravascular pressure and identify vessels most susceptible to changes in flow direction. The skin microvascular remodeling patterns were consistent among the five specimens studied. Significant remodeling occurred at various time points, beginning as early as days 1-3 and continuing beyond day 20. The remodeling patterns included collateral development, venous and arterial reopening, and both outward and inward remodeling, with variations in the time frames for each mouse. In a representative specimen, immediately post-ablation, the average artery and vein diameters increased by 14% and 23%, respectively. At day 20 post-ablation, the maximum increases in arterial and venous diameters were 2.5× and 3.3×, respectively. By day 30, the average artery diameter remained 11% increased whereas the vein diameters returned to near pre-ablation values. Some arteries regenerated across the ablation sites via endothelial cell migration, while veins either reconnected or rerouted flow around the ablation site, likely depending on local pressure driving forces. In the intact network, the theoretical model predicts that the vessels that act as collaterals after flow disruption are those most sensitive to distant changes in pressure. The model results correlate with the post-ablation microvascular remodeling patterns.
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Affiliation(s)
- Gabriel Gruionu
- Department of Medicine, Krannert Cardiovascular Research Center, Indiana University School of Medicine, Indianapolis, 46202, USA.
- Department of Radiation Oncology, Edwin L. Steele Laboratory for Tumor Biology, Massachusetts General Hospital and Harvard Medical School, Boston, 02114, USA.
- Department of Mechanical Engineering, University of Craiova, 200585, Craiova, Romania.
| | - James Baish
- Department of Biomedical Engineering, Bucknell University, Lewisburg, 17837, USA
| | - Sean McMahon
- Department of Physics, Virginia Tech, Blacksburg, 24060, USA
| | - David Blauvelt
- Department of Anesthesia, Critical Care, and Pain Medicine, Boston Children's Hospital, Boston, 02115, USA
| | - Lucian G Gruionu
- Department of Mechanical Engineering, University of Craiova, 200585, Craiova, Romania
| | | | - Benjamin J Vakoc
- Department of Dermatology and Wellman Center of Photomedicine, Harvard Medical School and Massachusetts General Hospital, Boston, 02114, USA
| | - Timothy P Padera
- Department of Radiation Oncology, Edwin L. Steele Laboratory for Tumor Biology, Massachusetts General Hospital and Harvard Medical School, Boston, 02114, USA
| | - Lance L Munn
- Department of Radiation Oncology, Edwin L. Steele Laboratory for Tumor Biology, Massachusetts General Hospital and Harvard Medical School, Boston, 02114, USA.
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3
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Gruionu G, Baish J, McMahon S, Blauvelt D, Gruionu LG, Lenco MO, Vakoc BJ, Padera TP, Munn LL. Experimental and Theoretical Model of Single Vessel Minimally Invasive Micro-Laser Ablation: Inducing Microvascular Network Remodeling and Blood Flow Redistribution Without Compromising Host Tissue Function. RESEARCH SQUARE 2023:rs.3.rs-3754775. [PMID: 38196660 PMCID: PMC10775362 DOI: 10.21203/rs.3.rs-3754775/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Overly dense microvascular networks are treated by selective reduction of vascular elements. Inappropriate manipulation of microvessels could result in loss of host tissue function or a worsening of the clinical problem. Here, experimental, and computational models were developed to induce blood flow changes via selective artery and vein laser ablation and study the compensatory collateral flow redistribution and vessel diameter remodeling. The microvasculature was imaged non-invasively by bright-field and multi-photon laser microscopy, and Optical Coherence Tomography pre-ablation and up to 30 days post-ablation. A theoretical model of network remodeling was developed to compute blood flow and intravascular pressure and identify vessels most susceptible to changes in flow direction. The skin microvascular remodeling patterns were consistent among the five specimens studied. Significant remodeling occurred at various time points, beginning as early as days 1-3 and continuing beyond day 20. The remodeling patterns included collateral development, venous and arterial reopening, and both outward and inward remodeling, with variations in the time frames for each mouse. In a representative specimen, immediately post-ablation, the average artery and vein diameters increased by 14% and 23%, respectively. At day 20 post-ablation, the maximum increases in arterial and venous diameters were 2.5x and 3.3x, respectively. By day 30, the average artery diameter remained 11% increased whereas the vein diameters returned to near pre-ablation values. Some arteries regenerated across the ablation sites via endothelial cell migration, while veins either reconnected or rerouted flow around the ablation site, likely depending on local pressure driving forces. In the intact network, the theoretical model predicts that the vessels that act as collaterals after flow disruption are those most sensitive to distant changes in pressure. The model results match the post-ablation microvascular remodeling patterns.
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Affiliation(s)
- Gabriel Gruionu
- Indiana University School of Medicine, Krannert Cardiovascular Research Center, Department of Medicine, Indianapolis, 46202, USA
- Massachusetts General Hospital and Harvard Medical School, Edwin L. Steele Laboratory for Tumor Biology, Department of Radiation Oncology, Boston, 02114, USA
- University of Craiova, Department of Mechanical Engineering, Craiova, 200585, Romania
| | - James Baish
- Bucknell University, Department of Biomedical Engineering, Lewisburg, 17837, USA
| | - Sean McMahon
- Virginia Tech, Department of Physics, Blacksburg, 24060, USA
| | - David Blauvelt
- Boston Children’s Hospital, Department of Anesthesia, Critical Care, and Pain Medicine, Boston, 02115, USA
| | - Lucian G. Gruionu
- University of Craiova, Department of Mechanical Engineering, Craiova, 200585, Romania
| | | | - Benjamin J. Vakoc
- Harvard Medical School and Massachusetts General Hospital, Department of Dermatology and Wellman Center of Photomedicine, Boston, 02114, USA
| | - Timothy P. Padera
- Massachusetts General Hospital and Harvard Medical School, Edwin L. Steele Laboratory for Tumor Biology, Department of Radiation Oncology, Boston, 02114, USA
| | - Lance L. Munn
- Massachusetts General Hospital and Harvard Medical School, Edwin L. Steele Laboratory for Tumor Biology, Department of Radiation Oncology, Boston, 02114, USA
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4
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Han L, Tan B, Schmetterer L, Bizheva K. Localized transverse flow measurement with dynamic light scattering line-scan OCT. BIOMEDICAL OPTICS EXPRESS 2023; 14:883-905. [PMID: 36874477 PMCID: PMC9979667 DOI: 10.1364/boe.484257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 01/06/2023] [Indexed: 06/18/2023]
Abstract
A novel decorrelation-based approach for measuring localized transverse flow velocity using line-scan (LS) optical coherence tomography (OCT) is proposed. The new approach allows for separation of the flow velocity component along the line-illumination direction of the imaging beam from other orthogonal velocity components, from particle diffusion motion, and from noise-induced distortion in the OCT signal's temporal autocorrelation. The new method was verified by imaging flow in a glass capillary and a microfluidic device and mapping the spatial distribution of the flow velocity within the beam's illumination plane. This method can be extended in the future to map the three-dimensional flow velocity fields for both ex-vivo and in-vivo applications.
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Affiliation(s)
- Le Han
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Bingyao Tan
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 639798, Singapore
- SERI-NTU Advanced Ocular Engineering (STANCE), 639798, Singapore
- Singapore Eye Research Institute, Singapore National Eye Center, 169856, Singapore
| | - Leopold Schmetterer
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 639798, Singapore
- SERI-NTU Advanced Ocular Engineering (STANCE), 639798, Singapore
- Singapore Eye Research Institute, Singapore National Eye Center, 169856, Singapore
- Ophthalmology & Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore
- Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
- Department of Clinical Pharmacology, Medical University Vienna, Vienna, Austria
- Center for Medical Physics and Biomedical Engineering, Medical University Vienna, Vienna, Austria
| | - Kostadinka Bizheva
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- Dept. of Systems Design Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- School of Optometry and Vision Sciences, Univ. of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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5
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Cheishvili K, Kalkman J. Sub-diffusion flow velocimetry with number fluctuation optical coherence tomography. OPTICS EXPRESS 2023; 31:3755-3773. [PMID: 36785361 DOI: 10.1364/oe.474279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 12/27/2022] [Indexed: 06/18/2023]
Abstract
We have implemented number fluctuation dynamic light scattering optical coherence tomography (OCT) for measuring extremely slow, sub-diffusion flows of dilute particle suspensions using the second-order autocovariance function. Our method has a lower minimum measurable velocity than conventional correlation-based OCT or phase-resolved Doppler OCT, as the velocity estimation is not affected by the particle diffusion. Similar to non-dilute correlation-based OCT, our technique works for any Doppler angle. With our analysis we can quantitatively determine the concentration of particles under flow. Finally, we demonstrate 2D sub-diffusion flow imaging with a scanning OCT system at high rate by performing number fluctuation correlation analysis on subsequent B-scans.
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6
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Nam AS, Braaf B, Vakoc BJ. Using the dynamic forward scattering signal for optical coherence tomography based blood flow quantification. OPTICS LETTERS 2022; 47:3083-3086. [PMID: 35709056 PMCID: PMC9580005 DOI: 10.1364/ol.455475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
To our knowledge, all existing optical coherence tomography approaches for quantifying blood flow, whether Doppler-based or decorrelation-based, analyze light that is back-scattered by moving red blood cells (RBCs). This work investigates the potential advantages of basing these measurements on light that is forward-scattered by RBCs, i.e., by looking at the signals back-scattered from below the vessel. We show experimentally that flowmetry based on forward-scattering is insensitive to vessel orientation for vessels that are approximately orthogonal to the imaging beam. We further provide proof-of-principle demonstrations of dynamic forward-scattering (DFS) flowmetry in human retinal and choroidal vessels.
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Affiliation(s)
- Ahhyun Stephanie Nam
- Wellman Center for Photomedicine, Massachusetts General Hospital, 40 Blossom St, Boston, MA 02114 USA
- Harvard Medical School, 25 Shattuck St, Boston, MA 02115 USA
| | - Boy Braaf
- Wellman Center for Photomedicine, Massachusetts General Hospital, 40 Blossom St, Boston, MA 02114 USA
- Harvard Medical School, 25 Shattuck St, Boston, MA 02115 USA
| | - Benjamin J. Vakoc
- Wellman Center for Photomedicine, Massachusetts General Hospital, 40 Blossom St, Boston, MA 02114 USA
- Harvard Medical School, 25 Shattuck St, Boston, MA 02115 USA
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7
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Tang J, Postnov DD, Kilic K, Erdener SE, Lee B, Giblin JT, Szabo TL, Boas DA. Functional Ultrasound Speckle Decorrelation-Based Velocimetry of the Brain. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2001044. [PMID: 32999839 PMCID: PMC7509671 DOI: 10.1002/advs.202001044] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 05/20/2020] [Indexed: 05/25/2023]
Abstract
A high-speed, contrast-free, quantitative ultrasound velocimetry (vUS) for blood flow velocity imaging throughout the rodent brain is developed based on the normalized first-order temporal autocorrelation function of the ultrasound field signal. vUS is able to quantify blood flow velocity in both transverse and axial directions, and is validated with numerical simulation, phantom experiments, and in vivo measurements. The functional imaging ability of vUS is demonstrated by monitoring the blood flow velocity changes during whisker stimulation in awake mice. Compared to existing Power-Doppler- and Color-Doppler-based functional ultrasound imaging techniques, vUS shows quantitative accuracy in estimating both axial and transverse flow speeds and resistance to acoustic attenuation and high-frequency noise.
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Affiliation(s)
- Jianbo Tang
- Neurophotonics CenterDepartment of Biomedical EngineeringBoston UniversityBostonMA02215USA
| | - Dmitry D. Postnov
- Neurophotonics CenterDepartment of Biomedical EngineeringBoston UniversityBostonMA02215USA
- Biomedical Sciences InstituteCopenhagen UniversityCopenhagen2200Denmark
| | - Kivilcim Kilic
- Neurophotonics CenterDepartment of Biomedical EngineeringBoston UniversityBostonMA02215USA
| | - Sefik Evren Erdener
- Neurophotonics CenterDepartment of Biomedical EngineeringBoston UniversityBostonMA02215USA
| | - Blaire Lee
- Neurophotonics CenterDepartment of Biomedical EngineeringBoston UniversityBostonMA02215USA
| | - John T. Giblin
- Neurophotonics CenterDepartment of Biomedical EngineeringBoston UniversityBostonMA02215USA
| | - Thomas L. Szabo
- Neurophotonics CenterDepartment of Biomedical EngineeringBoston UniversityBostonMA02215USA
| | - David A. Boas
- Neurophotonics CenterDepartment of Biomedical EngineeringBoston UniversityBostonMA02215USA
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8
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Braaf B, Donner S, Uribe-Patarroyo N, Bouma BE, Vakoc BJ. A Neural Network Approach to Quantify Blood Flow from Retinal OCT Intensity Time-Series Measurements. Sci Rep 2020; 10:9611. [PMID: 32541887 PMCID: PMC7295995 DOI: 10.1038/s41598-020-66158-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 05/12/2020] [Indexed: 12/31/2022] Open
Abstract
Many diseases of the eye are associated with alterations in the retinal vasculature that are possibly preceded by undetected changes in blood flow. In this work, a robust blood flow quantification framework is presented based on optical coherence tomography (OCT) angiography imaging and deep learning. The analysis used a forward signal model to simulate OCT blood flow data for training of a neural network (NN). The NN was combined with pre- and post-processing steps to create an analysis framework for measuring flow rates from individual blood vessels. The framework’s accuracy was validated using both blood flow phantoms and human subject imaging, and across flow speed, vessel angle, hematocrit levels, and signal-to-noise ratio. The reported flow rate of the calibrated NN framework was measured to be largely independent of vessel angle, hematocrit levels, and measurement signal-to-noise ratio. In vivo retinal flow rate measurements were self-consistent across vascular branch points, and approximately followed a predicted power-law dependence on the vessel diameter. The presented OCT-based NN flow rate estimation framework addresses the need for a robust, deployable, and label-free quantitative retinal blood flow mapping technique.
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Affiliation(s)
- Boy Braaf
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA.,Harvard Medical School, Boston, MA, USA
| | | | - Néstor Uribe-Patarroyo
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA.,Harvard Medical School, Boston, MA, USA
| | - Brett E Bouma
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA.,Harvard Medical School, Boston, MA, USA.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Benjamin J Vakoc
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA. .,Harvard Medical School, Boston, MA, USA.
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9
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Maltais-Tariant R, Boudoux C, Uribe-Patarroyo N. Real-time co-localized OCT surveillance of laser therapy using motion corrected speckle decorrelation. BIOMEDICAL OPTICS EXPRESS 2020; 11:2925-2950. [PMID: 32637233 PMCID: PMC7316020 DOI: 10.1364/boe.385654] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 03/19/2020] [Accepted: 04/09/2020] [Indexed: 05/27/2023]
Abstract
We present a system capable of real-time delivery and monitoring of laser therapy by imaging with optical coherence tomography (OCT) through a double-clad fiber (DCF). A double-clad fiber coupler is used to inject and collect OCT light into the core of a DCF and inject the therapy light into its larger inner cladding, allowing for both imaging and therapy to be perfectly coregistered. Monitoring of treatment depth is achieved by calculating the speckle intensity decorrelation occurring during tissue coagulation. Furthermore, an analytical noise correction was used on the correlation to extend the maximum monitoring depth. We also present a method for correcting motion-induced decorrelation using a lookup table. Using the value of the noise- and motion-corrected correlation coefficient in a novel approach, our system is capable of identifying the depth of thermal coagulation in real time and automatically shut the therapy laser off when the targeted depth is reached. The process is demonstrated ex vivo in rat tongue and abdominal muscles for depths ranging from 500 µm to 1000 µm with induced motion in real time.
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Affiliation(s)
- Raphaël Maltais-Tariant
- Polytechnique Montréal, Department of Engineering Physics, 2900 Boulevard Edouard-Montpetit, Montreal, Qc, Canada
| | - Caroline Boudoux
- Polytechnique Montréal, Department of Engineering Physics, 2900 Boulevard Edouard-Montpetit, Montreal, Qc, Canada
- Castor Optics Inc., 361 Boul Montpellier, St-Laurent, Qc, Canada
| | - Néstor Uribe-Patarroyo
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 40 Blossom Street, Boston, Massachusetts 02114, USA
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10
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Uribe-Patarroyo N, Post AL, Ruiz-Lopera S, Faber DJ, Bouma BE. Noise and bias in optical coherence tomography intensity signal decorrelation. OSA CONTINUUM 2020; 3:709-741. [PMID: 34085035 PMCID: PMC8171193 DOI: 10.1364/osac.385431] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Functional optical coherence tomography (OCT) imaging based on the decorrelation of the intensity signal has been used extensively in angiography and is finding use in flowmetry and therapy monitoring. In this work, we present a rigorous analysis of the autocorrelation function, introduce the concepts of contrast bias, statistical bias and variability, and identify the optimal definition of the second-order autocorrelation function (ACF) g (2) to improve its estimation from limited data. We benchmark different averaging strategies in reducing statistical bias and variability. We also developed an analytical correction for the noise contributions to the decorrelation of the ACF in OCT that extends the signal-to-noise ratio range in which ACF analysis can be used. We demonstrate the use of all the tools developed in the experimental determination of the lateral speckle size depth dependence in a rotational endoscopic probe with low NA, and we show the ability to more accurately determine the rotational speed of an endoscopic probe to implement NURD detection. We finally present g (2)-based angiography of the finger nailbed, demonstrating the improved results from noise correction and the optimal bias mitigation strategies.
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Affiliation(s)
- Néstor Uribe-Patarroyo
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 40 Blossom Street, MA 02114, USA
| | - Anouk L. Post
- Amsterdam UMC, University of Amsterdam, Department of Biomedical Engineering and Physics, Cancer Center Amsterdam, Amsterdam Cardiovascular Sciences, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
- These authors contributed equally to this work and are listed in alphabetical order
| | - Sebastián Ruiz-Lopera
- Applied Optics Group, Universidad EAFIT, Carrera 49 # 7 Sur-50, Medellín, Colombia
- These authors contributed equally to this work and are listed in alphabetical order
| | - Dirk J. Faber
- Amsterdam UMC, University of Amsterdam, Department of Biomedical Engineering and Physics, Cancer Center Amsterdam, Amsterdam Cardiovascular Sciences, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Brett E. Bouma
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 40 Blossom Street, MA 02114, USA
- Institute for Medical Engineering and Science, Massachussets Institute of Technology, Cambridge, MA 02142, USA
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11
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Ferris NG, Cannon TM, Villiger M, Bouma BE, Uribe-Patarroyo N. Forward multiple scattering dominates speckle decorrelation in whole-blood flowmetry using optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2020; 11:1947-1966. [PMID: 32341859 PMCID: PMC7173878 DOI: 10.1364/boe.384539] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 03/06/2020] [Accepted: 03/06/2020] [Indexed: 05/22/2023]
Abstract
Quantitative blood flow measurements using optical coherence tomography (OCT) have a wide potential range of medical research and clinical applications. Flowmetry based on the temporal dynamics of the OCT signal may have the ability to measure three-dimensional flow profiles regardless of the flow direction. State-of-the-art models describing the OCT signal temporal statistics are based on dynamic light scattering (DLS), a model which is inherently limited to single scattering regimes. DLS methods continue to be applied to OCT despite the knowledge that red blood cells produce strong forward multiple scattering. Here, we postulate that forward multiple scattering is the primary mechanism causing the rate of speckle-decorrelation derived from data acquired in vivo to deviate from the rate of decorrelation determined in phantom experiments. We also postulate that multiple scattering contributions to decorrelation are only present when the sample exhibits velocity field inhomogeneities larger than the scale of a resolution volume and are thus absent in rigid bulk motion. To test these hypotheses, we performed a systematic study of the effects of forward multiple scattering on OCT signal decorrelation with phantom experiments under physiologically relevant flow conditions and relative bulk motion. Our experimental results confirm that the amount of forward multiple scattering affects the proportionality between lateral flow and decorrelation. We propose that multiply scattered light carries information from different locations in the sample and each location imprints scattering dynamics on the scattered light causing increased decorrelation rates. Our analysis confirms that the detection of forward scattered light inside the vessel lumen causes an increase in the rate of decorrelation which results in an overestimation of blood flow velocities at depths as shallow as 40 µm into whole blood for OCT systems with typical numerical apertures used in retinal imaging.
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Affiliation(s)
- Natalie G. Ferris
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 40 Blossom Street, Boston, Massachusetts 02114, USA
- Harvard-MIT Program in Health Sciences and Technology, Cambridge, Massachusetts 02139, USA
- Harvard Graduate Program in Biophysics, Harvard University Cambridge, Massachusetts 02139, USA
| | - Taylor M. Cannon
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 40 Blossom Street, Boston, Massachusetts 02114, USA
- Harvard-MIT Program in Health Sciences and Technology, Cambridge, Massachusetts 02139, USA
| | - Martin Villiger
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 40 Blossom Street, Boston, Massachusetts 02114, USA
| | - Brett E. Bouma
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 40 Blossom Street, Boston, Massachusetts 02114, USA
- Harvard-MIT Program in Health Sciences and Technology, Cambridge, Massachusetts 02139, USA
- Institute for Medical Engineering and Science, MIT, Massachusetts 02139, USA
| | - Néstor Uribe-Patarroyo
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 40 Blossom Street, Boston, Massachusetts 02114, USA
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12
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Gräfe MGO, Nadiarnykh O, De Boer JF. Optical coherence tomography velocimetry based on decorrelation estimation of phasor pair ratios (DEPPAIR). BIOMEDICAL OPTICS EXPRESS 2019; 10:5470-5485. [PMID: 31799025 PMCID: PMC6865093 DOI: 10.1364/boe.10.005470] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 09/17/2019] [Accepted: 09/20/2019] [Indexed: 05/13/2023]
Abstract
Quantitative velocity estimations in optical coherence tomography requires the estimation of the axial and lateral flow components. Optical coherence tomography measures the depth resolved complex field reflected from a sample. While the axial velocity component can be determined from the Doppler shift or phase shift between a pair of consecutive measurements at the same location, the estimation of the lateral component for in vivo applications is still challenging. One approach to determine lateral velocity is multiple simultaneous measurements at different angles. In another approach the lateral component can be retrieved through repeated measurements at (nearly) the same location by an analysis of the decorrelation over time. In this paper we follow the latter approach. We describe a model for the complex field changes between consecutive measurements and use it to predict the uncertainties for amplitude-based, phase-based and complex algorithms. The uncertainty of the flow estimations follows from a statistical analysis and is determined by the number of available measurements and the applied analysis method. The model is verified in phantom measurements and the dynamic range of velocity estimations is investigated. We demonstrate that phase-based and complex (phasor) based lateral flow estimation methods are superior to amplitude-based algorithms.
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13
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Popov I, Weatherbee A, Vitkin A. Impact of velocity gradient in Poiseuille flow on the statistics of coherent radiation scattered by flowing Brownian particles in optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-7. [PMID: 31562708 PMCID: PMC6997670 DOI: 10.1117/1.jbo.24.9.097001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 08/23/2019] [Indexed: 05/22/2023]
Abstract
A closed-form expression is obtained for the temporal correlation function of the scattered radiation detected in optical coherence tomography (OCT), taking into account the flow velocity gradient across the OCT detection volume in the suspension of flowing Brownian particles. The analytical approach we use includes both the laser beam and wavefront curvature radii changing over the depth. Also, we compare our results with a previously obtained theoretical model, partially an empirical approach. Our findings suggest the importance of the flow velocity gradient for accurate measurements of flow velocity vector, particle diffusivity, shear-induced diffusion, and potentially other OCT applications.
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Affiliation(s)
- Ivan Popov
- University of Toronto, Department of Medical Biophysics, Toronto Medical Discovery Tower, Toronto, Ontario, Canada
- Address all correspondence to Ivan Popov, E-mail:
| | - Andrew Weatherbee
- University of Toronto, Department of Medical Biophysics, Toronto Medical Discovery Tower, Toronto, Ontario, Canada
| | - Alex Vitkin
- University of Toronto, Department of Medical Biophysics, Toronto Medical Discovery Tower, Toronto, Ontario, Canada
- University of Toronto, Department of Radiation Oncology, Toronto, Ontario, Canada
- Ontario Cancer Institute/University Health Network, Division of Biophysics and Bioimaging, Toronto, Ontario, Canada
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Tang J, Erdener SE, Sunil S, Boas DA. Normalized field autocorrelation function-based optical coherence tomography three-dimensional angiography. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-8. [PMID: 30868803 PMCID: PMC6414735 DOI: 10.1117/1.jbo.24.3.036005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 02/06/2019] [Indexed: 05/02/2023]
Abstract
Optical coherence tomography angiography (OCTA) has been widely used for en face visualization of the microvasculature, but is challenged for real three-dimensional (3-D) topologic imaging due to the "tail" artifacts that appear below large vessels. Further, OCTA is generally incapable of differentiating descending arterioles from ascending venules. We introduce a normalized field autocorrelation function-based OCTA (g1-OCTA), which minimizes the tail artifacts and is capable of distinguishing penetrating arterioles from venules in the 3-D image. g1 ( τ ) is calculated from repeated optical coherence tomography (OCT) acquisitions for each spatial location. The decay amplitude of g1 ( τ ) is retrieved to represent the dynamics for each voxel. To account for the small g1 ( τ ) decay in capillaries where red blood cells are flowing slowly and discontinuously, Intralipid is injected to enhance the OCT signal. We demonstrate that the proposed technique realizes 3-D OCTA with negligible tail projections and the penetrating arteries are readily identified. In addition, compared to regular OCTA, the proposed g1-OCTA largely increased the depth-of-field. This technique provides a more accurate rendering of the vascular 3-D anatomy and has the potential for more quantitative characterization of vascular networks.
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Affiliation(s)
- Jianbo Tang
- Boston University, Neurophotonics Center, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts, United States
- Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States
- Address all correspondence to Jianbo Tang, E-mail:
| | - Sefik Evren Erdener
- Boston University, Neurophotonics Center, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts, United States
- Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States
| | - Smrithi Sunil
- Boston University, Neurophotonics Center, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - David A. Boas
- Boston University, Neurophotonics Center, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts, United States
- Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States
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Pijewska E, Gorczynska I, Szkulmowski M. Computationally effective 2D and 3D fast phase unwrapping algorithms and their applications to Doppler optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2019; 10:1365-1382. [PMID: 30891352 PMCID: PMC6420292 DOI: 10.1364/boe.10.001365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 01/20/2019] [Accepted: 01/22/2019] [Indexed: 05/07/2023]
Abstract
We propose a simplification for a robust and easy to implement fast phase unwrapping (FPU) algorithm that is used to solve the phase wrapping problem encountered in various fields of optical imaging and metrology. We show that the number of necessary computations using the algorithm can be reduced compared to its original version. FPU can be easily extended from two to three spatial dimensions. We demonstrate the applicability of the two- and three-dimensional FPU algorithm for Doppler optical coherence tomography (DOCT) in numerical simulations, and in the imaging of a flow phantom and blood flow in the human retina in vivo. We introduce an FPU applicability plot for use as a guide in the selection of the most suitable version of the algorithm depending on the phase noise in the acquired data. This plot uses the circular standard deviation of the wrapped phase distribution as a measure of noise and relates it to the root-mean-square error of the recovered, unwrapped phase.
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Tang J, Erdener SE, Li B, Fu B, Sakadzic S, Carp SA, Lee J, Boas DA. Shear-induced diffusion of red blood cells measured with dynamic light scattering-optical coherence tomography. JOURNAL OF BIOPHOTONICS 2018; 11:10.1002/jbio.201700070. [PMID: 28700129 PMCID: PMC5766442 DOI: 10.1002/jbio.201700070] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 06/05/2017] [Accepted: 07/05/2017] [Indexed: 05/18/2023]
Abstract
Quantitative measurements of intravascular microscopic dynamics, such as absolute blood flow velocity, shear stress and the diffusion coefficient of red blood cells (RBCs), are fundamental in understanding the blood flow behavior within the microcirculation, and for understanding why diffuse correlation spectroscopy (DCS) measurements of blood flow are dominantly sensitive to the diffusive motion of RBCs. Dynamic light scattering-optical coherence tomography (DLS-OCT) takes the advantages of using DLS to measure particle flow and diffusion within an OCT resolution-constrained three-dimensional volume, enabling the simultaneous measurements of absolute RBC velocity and diffusion coefficient with high spatial resolution. In this work, we applied DLS-OCT to measure both RBC velocity and the shear-induced diffusion coefficient within penetrating venules of the somatosensory cortex of anesthetized mice. Blood flow laminar profile measurements indicate a blunted laminar flow profile and the degree of blunting decreases with increasing vessel diameter. The measured shear-induced diffusion coefficient was proportional to the flow shear rate with a magnitude of ~0.1 to 0.5 × 10-6 mm2 . These results provide important experimental support for the recent theoretical explanation for why DCS is dominantly sensitive to RBC diffusive motion.
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Affiliation(s)
- Jianbo Tang
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
- Corresponding Author: Jianbo Tang,
| | - Sefik Evren Erdener
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Baoqiang Li
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Buyin Fu
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Sava Sakadzic
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Stefan A. Carp
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
| | - Jonghwan Lee
- School of Engineering, Institute for Brain Science, Brown University, Providence, Rhode Island 02912, USA
| | - David A. Boas
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
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Bouma BE, Villiger M, Otsuka K, Oh WY. Intravascular optical coherence tomography [Invited]. BIOMEDICAL OPTICS EXPRESS 2017; 8:2660-2686. [PMID: 28663897 PMCID: PMC5480504 DOI: 10.1364/boe.8.002660] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 04/10/2017] [Accepted: 04/11/2017] [Indexed: 05/03/2023]
Abstract
Shortly after the first demonstration of optical coherence tomography for imaging the microstructure of the human eye, work began on developing systems and catheters suitable for intravascular imaging in order to diagnose and investigate atherosclerosis and potentially to monitor therapy. This review covers the driving considerations of the clinical application and its constraints, the major engineering milestones that enabled the current, high-performance commercial imaging systems, the key studies that laid the groundwork for image interpretation, and the clinical research that traces intravascular optical coherence tomography (OCT) from early human pilot studies to current clinical trials.
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Affiliation(s)
- Brett E Bouma
- Harvard Medical School and Massachusetts General Hospital, Boston, MA 02171, USA
- Institute for Medical Engineering and Science, Cambridge, MA, 02139, USA
| | - Martin Villiger
- Harvard Medical School and Massachusetts General Hospital, Boston, MA 02171, USA
| | - Kenichiro Otsuka
- Harvard Medical School and Massachusetts General Hospital, Boston, MA 02171, USA
| | - Wang-Yuhl Oh
- Department of Mechanical Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, South Korea
- KI for Health Science and Technology, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, South Korea
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