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Koutsiaris AG, Batis V, Liakopoulou G, Tachmitzi SV, Detorakis ET, Tsironi EE. Optical Coherence Tomography Angiography (OCTA) of the eye: A review on basic principles, advantages, disadvantages and device specifications. Clin Hemorheol Microcirc 2022; 83:247-271. [PMID: 36502308 DOI: 10.3233/ch-221634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Optical Coherence Tomography Angiography (OCTA) is a relatively new imaging technique in ophthalmology for the visualization of the retinal microcirculation and other tissues of the human eye. This review paper aims to describe the basic definitions and principles of OCT and OCTA in the most straightforward possible language without complex mathematical and engineering analysis. This is done to help health professionals of various disciplines improve their understanding of OCTA and design further clinical research more efficiently. First, the basic technical principles of OCT and OCTA and related terminology are described. Then, a list of OCTA advantages and disadvantages, with a special reference to blood flow quantification limitations. Finally, an updated list of the basic hardware and software specifications of some of the commercially available OCTA devices is presented.
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Affiliation(s)
- Aristotle G. Koutsiaris
- Medical Informatics Laboratory, Faculty of Medicine, School of Health Sciences, University of Thessaly, Biopolis, Larissa, Greece
| | - Vasilios Batis
- Jules Gonin Eye Hospital Lausanne, Switzerland
- Department of Ophthalmology, University Hospital of Heraklion, Crete, Greece
| | - Georgia Liakopoulou
- Medical Informatics Laboratory, Faculty of Medicine, School of Health Sciences, University of Thessaly, Biopolis, Larissa, Greece
| | | | | | - Evangelia E. Tsironi
- Department of Ophthalmology, University Hospital of Larissa, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece
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2
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High speed photo-mediated ultrasound therapy integrated with OCTA. Sci Rep 2022; 12:19916. [PMID: 36402801 PMCID: PMC9675827 DOI: 10.1038/s41598-022-23188-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 10/26/2022] [Indexed: 11/20/2022] Open
Abstract
Photo-mediated Ultrasound Therapy (PUT), as a new anti-vascular technique, can promote cavitation activity to selectively destruct blood vessels with a significantly lower amount of energy when compared to energy level required by other laser and ultrasound treatment therapies individually. Here, we report the development of a high speed PUT system based on a 50-kHz pulsed laser to achieve faster treatment, decreasing the treatment time by a factor of 20. Furthermore, we integrated it with optical coherence tomography angiography (OCTA) for real time monitoring. The feasibility of the proposed OCTA-guided PUT was validated through in vivo rabbit experiments. The addition of OCTA to PUT allows for quantitative prescreening and real time monitoring of treatment response, thereby enabling implementation of individualized treatment strategies.
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3
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Wang X, Fu Y, Liu Y, Nie W, Su X, Zou X, Meng R, Li Y, Tao J. Non-invasive detection technology in port-wine stain treatment. Chin Med J (Engl) 2022; 135:2535-2537. [PMID: 36583915 PMCID: PMC9944340 DOI: 10.1097/cm9.0000000000002124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Indexed: 12/31/2022] Open
Affiliation(s)
- Xue Wang
- Department of Dermatology, The First Affiliated Hospital, Medical College of Shihezi University, Shihezi, Xinjiang 832008, China
| | - Yangxue Fu
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430022, China
- Hubei Engineering Research Center for Skin Repair and Theranostics, Wuhan, Hubei 430022, China
| | - Yan Liu
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430022, China
- Hubei Engineering Research Center for Skin Repair and Theranostics, Wuhan, Hubei 430022, China
| | - Wenjia Nie
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430022, China
- Hubei Engineering Research Center for Skin Repair and Theranostics, Wuhan, Hubei 430022, China
| | - Xingyu Su
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430022, China
- Hubei Engineering Research Center for Skin Repair and Theranostics, Wuhan, Hubei 430022, China
| | - Xianbiao Zou
- Department of Dermatology of the Fourth Medical Center of People's Liberation Army General Hospital, Beijing 100048, China
| | - Rusong Meng
- Department of Dermatology, Specialty Medical Center of the Air Force, People's Liberation Army, Beijing 100142, China
| | - Yan Li
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430022, China
- Hubei Engineering Research Center for Skin Repair and Theranostics, Wuhan, Hubei 430022, China
| | - Juan Tao
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430022, China
- Hubei Engineering Research Center for Skin Repair and Theranostics, Wuhan, Hubei 430022, China
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4
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Yang C, Zhu J, Zhu L, Fan F, Ma Z, Zhang F. Rapid estimations of intensity standard deviations for optical coherence tomography angiography. JOURNAL OF BIOPHOTONICS 2022; 15:e202100340. [PMID: 34951745 DOI: 10.1002/jbio.202100340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 11/22/2021] [Accepted: 12/22/2021] [Indexed: 06/14/2023]
Abstract
Optical coherence tomography angiography (OCTA) can map microvascular networks and quantify blood flow velocities with high resolution by calculating intensity standard deviations of time-series signals. However, statistical calculations of the standard deviations need much processing time and reduce the analysis efficiency. In this study, we proposed three optimized OCTA algorithms incorporating rapid estimations of the intensity standard deviations, including the range algorithm, the mean absolute error algorithm and the maximum absolute error algorithm. The abilities of the optimized algorithms to quantify the flow velocities were validated by a flow phantom. After a rat cerebral cortex was imaged, the optimized OCTA algorithms were compared with the conventional relative standard deviation algorithm in the metrics of imaging quality and processing time. The results show that the optimized algorithms incorporating rapid estimations of the intensity standard deviations have faster processing speeds with equivalent image quality.
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Affiliation(s)
- Chaojiang Yang
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
- Beijing Laboratory of Biomedical Testing Technology and Instruments, Beijing Information Science and Technology University, Beijing, China
| | - Jiang Zhu
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
- Beijing Laboratory of Biomedical Testing Technology and Instruments, Beijing Information Science and Technology University, Beijing, China
| | - Lianqing Zhu
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
- Beijing Key Laboratory of Optoelectronic Measurement Technology, Beijing Information Science and Technology University, Beijing, China
| | - Fan Fan
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
- Beijing Laboratory of Biomedical Testing Technology and Instruments, Beijing Information Science and Technology University, Beijing, China
| | - Zongqing Ma
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
- Beijing Laboratory of Biomedical Testing Technology and Instruments, Beijing Information Science and Technology University, Beijing, China
| | - Fan Zhang
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
- Beijing Laboratory of Biomedical Testing Technology and Instruments, Beijing Information Science and Technology University, Beijing, China
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5
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Bouma B, de Boer J, Huang D, Jang I, Yonetsu T, Leggett C, Leitgeb R, Sampson D, Suter M, Vakoc B, Villiger M, Wojtkowski M. Optical coherence tomography. NATURE REVIEWS. METHODS PRIMERS 2022; 2:79. [PMID: 36751306 PMCID: PMC9901537 DOI: 10.1038/s43586-022-00162-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Optical coherence tomography (OCT) is a non-contact method for imaging the topological and internal microstructure of samples in three dimensions. OCT can be configured as a conventional microscope, as an ophthalmic scanner, or using endoscopes and small diameter catheters for accessing internal biological organs. In this Primer, we describe the principles underpinning the different instrument configurations that are tailored to distinct imaging applications and explain the origin of signal, based on light scattering and propagation. Although OCT has been used for imaging inanimate objects, we focus our discussion on biological and medical imaging. We examine the signal processing methods and algorithms that make OCT exquisitely sensitive to reflections as weak as just a few photons and that reveal functional information in addition to structure. Image processing, display and interpretation, which are all critical for effective biomedical imaging, are discussed in the context of specific applications. Finally, we consider image artifacts and limitations that commonly arise and reflect on future advances and opportunities.
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Affiliation(s)
- B.E. Bouma
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA,Institute for Medical Engineering and Physics, Massachusetts Institute of Technology, Cambridge, MA, USA,Harvard Medical School, Boston, MA, USA,Corresponding author:
| | - J.F. de Boer
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - D. Huang
- Casey Eye Institute, Oregon Health and Science University, Portland, OR, USA
| | - I.K. Jang
- Harvard Medical School, Boston, MA, USA,Cardiology Division, Massachusetts General Hospital, Boston, MA, USA
| | - T. Yonetsu
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University
| | - C.L. Leggett
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | - R. Leitgeb
- Institute of Medical Physics, University of Vienna, Wien, Austria
| | - D.D. Sampson
- School of Physics and School of Biosciences and Medicine, University of Surrey, Guildford, United Kingdom
| | - M. Suter
- Harvard Medical School, Boston, MA, USA,Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - B. Vakoc
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA,Harvard Medical School, Boston, MA, USA
| | - M. Villiger
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA,Harvard Medical School, Boston, MA, USA
| | - M. Wojtkowski
- Institute of Physical Chemistry and International Center for Translational Eye Research, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland,Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Torun, Poland
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6
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Fan F, Zhang J, Zhu L, Ma Z, Zhu J. Improving cerebral microvascular image quality of optical coherence tomography angiography with deep learning-based segmentation. JOURNAL OF BIOPHOTONICS 2021; 14:e202100171. [PMID: 34382744 DOI: 10.1002/jbio.202100171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 08/07/2021] [Accepted: 08/09/2021] [Indexed: 06/13/2023]
Abstract
Optical coherence tomography angiography (OCTA) can map the microvascular networks of the cerebral cortices with micrometer resolution and millimeter penetration. However, the high scattering of the skull and the strong noise in the deep imaging region will distort the vasculature projections and decrease the OCTA image quality. Here, we proposed a deep learning-based segmentation method based on a U-Net convolutional neural network to extract the cortical region from the OCT image. The vascular networks were then visualized by three OCTA algorithms. The image quality of the vasculature projections was assessed by two metrics, including the peak signal-to-noise ratio (PSNR) and the contrast-to-noise ratio (CNR). The results show the accuracy of the cortical segmentation was 96.07%. The PSNR and CNR values increased significantly in the projections of the selected cortical regions. The OCTA incorporating the deep learning-based cortical segmentation can efficiently improve the image quality and enhance the vasculature clarity.
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Affiliation(s)
- Fan Fan
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
- Beijing Laboratory for Biomedical Detection Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
| | - Jisheng Zhang
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
- Beijing Laboratory for Biomedical Detection Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
| | - Lianqing Zhu
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
- Beijing Laboratory for Biomedical Detection Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
| | - Zongqing Ma
- Beijing Laboratory for Biomedical Detection Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
| | - Jiang Zhu
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
- Beijing Laboratory for Biomedical Detection Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
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7
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Doppler Optical Coherence Tomography for Otology Applications: From Phantom Simulation to In Vivo Experiment. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11125711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In otology, visualization and vibratory analysis have been crucial to enhance the success of diagnosis and surgical operation. Optical coherence tomography (OCT) has been employed in otology to obtain morphological structure of tissues non-invasively, owing to the ability of measuring the entire region of tympanic membrane, which compensates the limitations of conventional methods. As a functional extension of OCT, Doppler OCT, which enables the measurement of the motion information with structural data of tissue, has been applied in otology. Over the years, Doppler OCT systems have been evolved in various forms to enhance the measuring sensitivity of phase difference. In this review, we provide representative algorithms of Doppler OCT and various applications in otology from preclinical analysis to clinical experiments and discuss future developments.
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8
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Postnov DD, Tang J, Erdener SE, Kılıç K, Boas DA. Dynamic light scattering imaging. SCIENCE ADVANCES 2020; 6:6/45/eabc4628. [PMID: 33158865 PMCID: PMC7673709 DOI: 10.1126/sciadv.abc4628] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 09/17/2020] [Indexed: 05/18/2023]
Abstract
We introduce dynamic light scattering imaging (DLSI) to enable the wide-field measurement of the speckle temporal intensity autocorrelation function. DLSI uses the full temporal sampling of speckle fluctuations and a comprehensive model to identify the dynamic scattering regime and obtain a quantitative image of the scatterer dynamics. It reveals errors in the traditional theory of laser Doppler flowmetry and laser speckle contrast imaging and provides guidance on the best model to use in cerebral blood flow imaging.
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Affiliation(s)
- Dmitry D Postnov
- Neurophotonics Center, Boston University, Boston, MA 02215, USA
- Biomedical Sciences Institute, Faculty of Health and Medical Sciences, Copenhagen University, Copenhagen 2200, Denmark
| | - Jianbo Tang
- Neurophotonics Center, Boston University, Boston, MA 02215, USA
| | | | - Kıvılcım Kılıç
- Neurophotonics Center, Boston University, Boston, MA 02215, USA
| | - David A Boas
- Neurophotonics Center, Boston University, Boston, MA 02215, USA.
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9
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Zhu J, Liu J, Zhu L, Wang C, Fan F, Yang Q, Zhang F. Optical coherence tomography angiography for mapping cerebral microvasculature based on normalized differentiation analysis. JOURNAL OF BIOPHOTONICS 2020; 13:e202000245. [PMID: 32639617 DOI: 10.1002/jbio.202000245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/02/2020] [Accepted: 07/04/2020] [Indexed: 06/11/2023]
Abstract
Optical coherence tomography angiography (OCTA) is a label-free, noninvasive biomedical imaging modality for mapping microvascular networks and quantifying blood flow velocities in vivo. Simple computation and fast processing are critical for the OCTA in some applications. Herein, we report on a normalized differentiation method for mapping cerebral microvasculature with the advantages of simple analysis and high image quality, benefitting from computation of differentiation and characteristics of normalization. Normalized differentiation values are validated to have a nearly linear relationship with flow velocities in a range using a flow phantom. The measurements in a rat cerebral cortex show that the OCTA based on the normalized differentiation analysis can generate microvascular images with high quality and monitor spatiotemporal dynamics of blood flow with simple computation and fast processing before and after localized ischemia induced by arterial occlusion.
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Affiliation(s)
- Jiang Zhu
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
- Beijing Laboratory of Biomedical Testing Technology and Instruments, Beijing Information Science and Technology University, Beijing, China
| | - Jianting Liu
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
- Beijing Laboratory of Biomedical Testing Technology and Instruments, Beijing Information Science and Technology University, Beijing, China
| | - Lianqing Zhu
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
- Beijing Key Laboratory of Optoelectronic Measurement Technology, Beijing Information Science and Technology University, Beijing, China
| | - Chongyang Wang
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
- Beijing Laboratory of Biomedical Testing Technology and Instruments, Beijing Information Science and Technology University, Beijing, China
| | - Fan Fan
- Beijing Laboratory of Biomedical Testing Technology and Instruments, Beijing Information Science and Technology University, Beijing, China
| | - Qiang Yang
- Beijing Laboratory of Biomedical Testing Technology and Instruments, Beijing Information Science and Technology University, Beijing, China
| | - Fan Zhang
- Beijing Laboratory of Biomedical Testing Technology and Instruments, Beijing Information Science and Technology University, Beijing, China
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10
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Liu J, Zhu J, Zhu L, Yang Q, Fan F, Zhang F. Quantitative assessment of optical coherence tomography angiography algorithms for neuroimaging. JOURNAL OF BIOPHOTONICS 2020; 13:e202000181. [PMID: 32542943 DOI: 10.1002/jbio.202000181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 06/11/2020] [Accepted: 06/11/2020] [Indexed: 06/11/2023]
Abstract
Optical coherence tomography (OCT) angiography can noninvasively map microvascular networks and quantify blood flow in a cerebral cortex with a resolution of 1 to 10 μm and a penetration depth of 2 to 3 mm incorporating OCT signals and angiography algorithms. Different angiography algorithms have been developed in recent years; however, the performance of the algorithms has not been assessed quantitatively for neuroimaging applications. In this paper, we developed four metrics including vascular connectivity, contrast-to-noise ratio, signal-to-noise ratio and processing time to quantitatively assess the performance of OCT angiography algorithms in image quality and computation speed. After the imaging of a rat cortex using an OCT system, the cerebral microvascular networks were visualized by seven algorithms, and the performance of the algorithms was quantified and compared. Quantitative performance assessment of the algorithms can provide suggestions for the selection of appropriate OCT angiography algorithms in neuroimaging.
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Affiliation(s)
- Jianting Liu
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
- Beijing Laboratory of Biomedical Testing Technology and Instruments, Beijing Information Science and Technology University, Beijing, China
| | - Jiang Zhu
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
- Beijing Laboratory of Biomedical Testing Technology and Instruments, Beijing Information Science and Technology University, Beijing, China
| | - Lianqing Zhu
- Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science and Technology University, Beijing, China
- Beijing Key Laboratory of Optoelectronic Measurement Technology, Beijing Information Science and Technology University, Beijing, China
| | - Qiang Yang
- Beijing Laboratory of Biomedical Testing Technology and Instruments, Beijing Information Science and Technology University, Beijing, China
| | - Fan Fan
- Beijing Laboratory of Biomedical Testing Technology and Instruments, Beijing Information Science and Technology University, Beijing, China
| | - Fan Zhang
- Beijing Laboratory of Biomedical Testing Technology and Instruments, Beijing Information Science and Technology University, Beijing, China
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11
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Chen C, Shi W, Yang VXD. Real-time en-face Gabor optical coherence tomographic angiography on human skin using CUDA GPU. BIOMEDICAL OPTICS EXPRESS 2020; 11:2794-2805. [PMID: 32499961 PMCID: PMC7249826 DOI: 10.1364/boe.392499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 04/17/2020] [Accepted: 04/19/2020] [Indexed: 05/18/2023]
Abstract
We recently proposed an optical coherence tomographic angiography (OCTA) algorithm, Gabor optical coherence tomographic angiography (GOCTA), which can extract microvascular signals from a spectral domain directly with lower computational complexity compared to other algorithms. In this manuscript, we combine a programmable swept source, an OCT complex signal detecting unit, and graphics process units (GPU) to achieve a real-time en-face GOCTA system for human skin microvascular imaging. The programmable swept source can balance the A-scan rate and the spectral tuning range; the polarization-modulation based complex signal detecting unit can double the imaging depth range, and the GPU can accelerate data processing. C++ and CUDA are used as the programming platform where five parallel threads are created for galvo-driving signal generation, data acquisition, data transfer, data processing, and image display, respectively. Two queues (for the raw data and en-face images, respectively) are used to improve the data exchange efficiency among different devices. In this study, the data acquisition time and data processing time for each 3D complex volume (256×304×608 pixels,) are 405.3 and 173.7 milliseconds respectively. To the best of our knowledge, this is the first time to show en-face microvascular images covering 3×3 mm2 at a refresh rate of 2.5 Hz.
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Affiliation(s)
- Chaoliang Chen
- Biophotonics and Bioengineering Lab, Department of Electrical, Computer, and Biomedical Engineering, Ryerson University, Toronto, Ontario, Canada
| | - Weisong Shi
- Biophotonics and Bioengineering Lab, Department of Electrical, Computer, and Biomedical Engineering, Ryerson University, Toronto, Ontario, Canada
- Department of Optical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, China
| | - Victor X. D. Yang
- Biophotonics and Bioengineering Lab, Department of Electrical, Computer, and Biomedical Engineering, Ryerson University, Toronto, Ontario, Canada
- Division of Neurosurgery, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
- Division of Neurosurgery, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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12
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Chen C, Shi W, Ramjist J, Yang VXD. Gabor optical coherence tomographic angiography (GOCTA) (Part II): theoretical basis of sensitivity improvement and optimization for processing speed. BIOMEDICAL OPTICS EXPRESS 2020; 11:227-239. [PMID: 32010512 PMCID: PMC6968745 DOI: 10.1364/boe.380287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 12/05/2019] [Accepted: 12/05/2019] [Indexed: 05/29/2023]
Abstract
We previously proposed a Gabor optical coherence tomography angiography (GOCTA) algorithm for spectral domain optical coherence tomography (SDOCT) to extract microvascular signals from spectral fringes directly, with speed improvement of 4 to 20 times over existing methods. In this manuscript, we explored the theoretical basis of GOCTA with comparison of experimental data using solid and liquid displacement sample targets, demonstrating that the majority of the GOCTA sensitivity advantage over speckle variance based techniques was in the small displacement range (< 10 ∼ 20 µm) of the moving target (such as red blood cells). We further normalized GOCTA signal by root-mean-square (RMS) of original fringes, achieving a more uniform image quality, especially at edges of blood vessels where slow flow could occur. Furthermore, by transecting the spectral fringes and using skipped convolution, the data processing speed could be further improved. We quantified the trade-off in signal-to-noise-ratio (SNR) and contrast-to-noise-ratio (CNR) under various sub-spectral bands and found an optimized condition using 1/4 spectral band for minimal angiography image quality degradation, yet achieving a further 26.7 and 34 times speed improvement on GPU and CPU, respectively. Our optimized GOCTA algorithm has a speed advantage of over 140 times compared to existing speckle variance OCT (SVOCT) method.
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Affiliation(s)
- Chaoliang Chen
- Biophotonics and Bioengineering Lab, Department of Electrical, Computer, and Biomedical Engineering, Ryerson University, Toronto, Ontario, Canada
| | - Weisong Shi
- Biophotonics and Bioengineering Lab, Department of Electrical, Computer, and Biomedical Engineering, Ryerson University, Toronto, Ontario, Canada
- Department of Optical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, China
| | - Joel Ramjist
- Biophotonics and Bioengineering Lab, Department of Electrical, Computer, and Biomedical Engineering, Ryerson University, Toronto, Ontario, Canada
| | - Victor X. D. Yang
- Biophotonics and Bioengineering Lab, Department of Electrical, Computer, and Biomedical Engineering, Ryerson University, Toronto, Ontario, Canada
- Division of Neurosurgery, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
- Division of Neurosurgery, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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13
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Li Y, Chen J, Chen Z. Advances in Doppler optical coherence tomography and angiography. TRANSLATIONAL BIOPHOTONICS 2019; 1:e201900005. [PMID: 33005888 PMCID: PMC7523705 DOI: 10.1002/tbio.201900005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 11/14/2019] [Indexed: 12/22/2022] Open
Abstract
Since the first demonstration of Doppler optical coherence tomography (OCT) in 1997, several functional extensions of Doppler OCT have been developed, including velocimetry, angiogram, and optical coherence elastography. These functional techniques have been widely used in research and clinical applications, particularly in ophthalmology. Here, we review the principles, representative methods, and applications of different Doppler OCT techniques, followed by discussion on the innovations, limitations, and future directions of each of these techniques.
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Affiliation(s)
- Yan Li
- Beckman Laser Institute, University of California, Irvine, California
- Department of Biomedical Engineering, University of California, Irvine, California
| | - Jason Chen
- Beckman Laser Institute, University of California, Irvine, California
- Department of Biomedical Engineering, University of California, Irvine, California
| | - Zhongping Chen
- Beckman Laser Institute, University of California, Irvine, California
- Department of Biomedical Engineering, University of California, Irvine, California
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14
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Zhu J, Hancock AM, Qi L, Telkmann K, Shahbaba B, Chen Z, Frostig RD. Spatiotemporal dynamics of pial collateral blood flow following permanent middle cerebral artery occlusion in a rat model of sensory-based protection: a Doppler optical coherence tomography study. NEUROPHOTONICS 2019; 6:045012. [PMID: 31824979 PMCID: PMC6903432 DOI: 10.1117/1.nph.6.4.045012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 11/19/2019] [Indexed: 05/05/2023]
Abstract
There is a growing recognition regarding the importance of pial collateral flow in the protection from impending ischemic stroke both in preclinical and clinical studies. Collateral flow is also a major player in sensory stimulation-based protection from impending ischemic stroke. Doppler optical coherence tomography has been employed to image spatiotemporal patterns of collateral flow within the dorsal branches of the middle cerebral artery (MCA) as it provides a powerful tool for quantitative in vivo flow parameters imaging (velocity, flux, direction of flow, and radius of imaged branches). It was employed prior to and following dorsal permanent MCA occlusion (pMCAo) in rat models of treatment by protective sensory stimulation, untreated controls, or sham surgery controls. Unexpectedly, following pMCAo in the majority of subjects, some MCA branches continued to show anterograde blood flow patterns over time despite severing of the MCA. Further, in the presence of protective sensory stimulation, the anterograde velocity and flux were stronger and lasted longer than in retrograde flow branches, even within different branches of single subjects, but stimulated retrograde branches showed stronger flow parameters at 24 h. Our study suggests that the spatiotemporal patterns of collateral-based dorsal MCA flow are dynamic and provide a detailed description on the differential effects of protective sensory stimulation.
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Affiliation(s)
- Jiang Zhu
- University of California Irvine, Beckman Laser Institute, Irvine, California, United States
| | - Aneeka M. Hancock
- University of California Irvine, Department of Neurobiology and Behavior, Irvine, California, United States
| | - Li Qi
- University of California Irvine, Beckman Laser Institute, Irvine, California, United States
| | - Klaus Telkmann
- University of California Irvine, Department of Statistics, Irvine, California, United States
| | - Babak Shahbaba
- University of California Irvine, Department of Statistics, Irvine, California, United States
| | - Zhongping Chen
- University of California Irvine, Beckman Laser Institute, Irvine, California, United States
- University of California Irvine, Department of Biomedical Engineering, Irvine, California, United States
- Address all correspondence to Ron D. Frostig, E-mail: ; Zhongping Chen, E-mail:
| | - Ron D. Frostig
- University of California Irvine, Department of Neurobiology and Behavior, Irvine, California, United States
- University of California Irvine, Department of Biomedical Engineering, Irvine, California, United States
- University of California Irvine, Center for the Neurobiology of Learning and Memory, Irvine, California, United States
- Address all correspondence to Ron D. Frostig, E-mail: ; Zhongping Chen, E-mail:
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15
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Abstract
Despite our understanding that the microvasculature plays a multifaceted role in the development and progression of various conditions, we know little about the extent of this involvement. A need exists for non-invasive, clinically meaningful imaging modalities capable of elucidating microvascular information to aid in our understanding of disease, and to aid in the diagnosis/monitoring of disease for more patient-specific care. In this review article, a number of imaging techniques are summarized that have been utilized to investigate the microvasculature of skin, along with their advantages, disadvantages and future perspectives in preclinical and clinical settings. These techniques include dermoscopy, capillaroscopy, Doppler sonography, laser Doppler flowmetry (LDF) and perfusion imaging, laser speckle contrast imaging (LSCI), optical coherence tomography (OCT), including its Doppler and dynamic variant and the more recently developed OCT angiography (OCTA), photoacoustic imaging, and spatial frequency domain imaging (SFDI). Attention is largely, but not exclusively, placed on optical imaging modalities that use intrinsic optical signals to contrast the microvasculature. We conclude that whilst each imaging modality has been successful in filling a particular niche, there is no one, all-encompassing modality without inherent flaws. Therefore, the future of cutaneous microvascular imaging may lie in utilizing a multi-modal approach that will counter the disadvantages of individual systems to synergistically augment our imaging capabilities.
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Affiliation(s)
- Anthony J Deegan
- Department of Bioengineering, University of Washington, 3720 15th Ave. NE., Seattle, WA 98195, United States of America
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16
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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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17
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Holmes J, Schuh S, Bowling FL, Mani R, Welzel J. Dynamic Optical Coherence Tomography Is a New Technique for Imaging Skin Around Lower Extremity Wounds. INT J LOW EXTR WOUND 2019; 18:65-74. [DOI: 10.1177/1534734618821015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Chronic wounds such as venous leg ulcers invariably heal slowly and recur. In the case of venous leg ulcers, poor healing of chronic wounds is variously attributed to ambulatory hypertension, impaired perfusion and diffusion, presence of chronic inflammation at wound sites, lipodermatosclerosis, and senescence. The aim of this study was to investigate whether a new technique, optical coherence tomography (OCT), which permits imaging of blood capillaries in the peri-wound skin, can provide new insights into the pathology. OCT and its recent variant, dynamic OCT, permit rapid noninvasive depth-resolved imaging of the capillaries in the superficial dermis via a handheld probe, showing the morphology and density of vessels down to 20 µm in diameter. We used dynamic OCT to investigate 15 chronic wounds and assess characteristics of the vessels at the 4 poles around the wounds, the wound bed, adjacent dermatosclerosis, and unaffected skin. The results of the study show that both vessel morphology and density in the wound edges are dramatically different from that in healthy skin, showing clusters of glomuleri-like vessels (knot-like forms or clumps) and an absence of linear branching vessels, and also greater blood perfusion. Such vessel shapes are reported to be associated with tissue growth. The OCT imaging procedure was rapid and well tolerated by patients and provided new information not available from other devices. Thus, OCT appears to have great promise as a tool for the evaluation and study of chronic ulcers.
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Affiliation(s)
- Jon Holmes
- Michelson Diagnostics Ltd, Maidstone, Kent, UK
| | | | | | - Raj Mani
- University of Southampton, Southampton, UK
- Chiang Mai University, Chiang Mai, Thailand
- Shanghai Jiao Tong University, Shanghai, China
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18
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Zhu J, He X, Chen Z. Acoustic radiation force optical coherence elastography for elasticity assessment of soft tissues. APPLIED SPECTROSCOPY REVIEWS 2019; 54:457-481. [PMID: 31749516 PMCID: PMC6867804 DOI: 10.1080/05704928.2018.1467436] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Biomechanical properties of soft tissues are important indicators of tissue functions which can be used for clinical diagnosis and disease monitoring. Elastography, incorporating the principles of elasticity measurements into imaging modalities, provides quantitative assessment of elastic properties of biological tissues. Benefiting from high-resolution, noninvasive and three-dimensional optical coherence tomography (OCT), optical coherence elastography (OCE) is an emerging optical imaging modality to characterize and map biomechanical properties of soft tissues. Recently, acoustic radiation force (ARF) OCE has been developed for elasticity measurements of ocular tissues, detection of vascular lesions and monitoring of blood coagulation based on remote and noninvasive ARF excitation to both internal and superficial tissues. Here, we describe the advantages of the ARF-OCE technique, the measurement methods in ARF-OCE, the applications in biomedical detection, current challenges and advances. ARF-OCE technology has the potential to become a powerful tool for in vivo elasticity assessment of biological samples in a non-contact, non-invasive and high-resolution nature.
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Affiliation(s)
- Jiang Zhu
- Beckman Laser Institute, University of California, Irvine, Irvine, California 92612, USA
| | - Xingdao He
- Key Laboratory of Nondestructive Test (Ministry of Education), Nanchang Hangkong University, Nanchang 330063, China
| | - Zhongping Chen
- Beckman Laser Institute, University of California, Irvine, Irvine, California 92612, USA
- Key Laboratory of Nondestructive Test (Ministry of Education), Nanchang Hangkong University, Nanchang 330063, China
- Department of Biomedical Engineering, University of California, Irvine, Irvine, California 92697, USA
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19
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Akif A, Walek K, Polucha C, Lee J. Doppler OCT clutter rejection using variance minimization and offset extrapolation. BIOMEDICAL OPTICS EXPRESS 2018; 9:5340-5352. [PMID: 30460132 PMCID: PMC6238902 DOI: 10.1364/boe.9.005340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 10/05/2018] [Accepted: 10/05/2018] [Indexed: 05/02/2023]
Abstract
Doppler optical coherence tomography (OCT) is widely used for high-resolution mapping of flow velocities and is based on analysis of temporal changes in the phase of an OCT signal (i.e., how fast the OCT signal rotates in the complex plane). Determination of the rate of phase change or rotation speed critically depends on the center of rotation. Here, we demonstrate the bias in high-pass filtering, the current widely used method to determine the center of rotation, and propose two advanced methods for Doppler OCT clutter rejection. The bias in the high-pass filtering method becomes increasingly significant with lower velocities or larger signal noise. Two novel methods based on variance minimization and offset extrapolation can potentially reduce this bias and thereby improve the accuracy of Doppler OCT measurements of flow velocities, even for low-velocity and/or high-noise signals. The two novel methods and the current standard method (high-pass filtering) have been tested in combination with several currently used velocity measurement algorithms: Kasai, autocorrelation function fitting, and maximum likelihood estimation. The newly proposed methods are shown to improve the accuracy in both the center of rotation and resultant velocity by up to 60 percentage points and reduce the flow conservation error by 30% when applied to in vivo cerebral blood flow imaging of the rodent brain cortex.
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Affiliation(s)
- Adil Akif
- Center for Biomedical Engineering, School of Engineering, Brown University, Providence, RI 02906, USA
| | - Konrad Walek
- Department of Neuroscience, Brown University, Providence, RI 02906, USA
- Warren A. Alpert Medical School, Brown University, Providence, RI 02906, USA
| | - Collin Polucha
- Center for Biomedical Engineering, School of Engineering, Brown University, Providence, RI 02906, USA
| | - Jonghwan Lee
- Center for Biomedical Engineering, School of Engineering, Brown University, Providence, RI 02906, USA
- Carney Institute for Brain Science, Brown University, Providence, RI 02906, USA
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20
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Leitgeb RA, Baumann B. Multimodal Optical Medical Imaging Concepts Based on Optical Coherence Tomography. FRONTIERS IN PHYSICS 2018; 6. [PMID: 0 DOI: 10.3389/fphy.2018.00114] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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21
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Gao W. Quantitative depth-resolved microcirculation imaging with optical coherence tomography angiography (Part ΙΙ): Microvascular network imaging. Microcirculation 2018; 25:e12376. [DOI: 10.1111/micc.12376] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 04/11/2017] [Indexed: 11/28/2022]
Affiliation(s)
- Wanrong Gao
- Department of Optical Engineering; Nanjing University of Science and Technology; Nanjing Jiangsu China
- MIIT Key Laboratory of Advanced Solid Laser; Nanjing University of Science and Technology; Nanjing Jiangsu China
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22
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Chen C, Yang VXD. Gabor optical coherence tomographic angiography (GOCTA) (Part I): human retinal imaging in vivo. BIOMEDICAL OPTICS EXPRESS 2017; 8:5724-5734. [PMID: 29296500 PMCID: PMC5745115 DOI: 10.1364/boe.8.005724] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 08/26/2017] [Accepted: 09/01/2017] [Indexed: 05/29/2023]
Abstract
Recently, parallel high A-line speed and wide field imaging for optical coherence tomography angiography (OCTA) has become more prevalent, resulting in a dramatic increase of data quantity which poses a challenge for real time imaging even for GPU in data processing. In this manuscript, we propose a new OCTA processing technique, Gabor optical coherence tomographic angiography (GOCTA), for label-free human retinal angiography imaging. In spectral domain optical coherence tomography (SDOCT), k-space resampling and Fourier transform (FFT) are required for the entire data set of interference fringes to calculate blood flow information in previous OCTA algorithms, which are computationally intensive. As adults' eye anterior-posterior radii are nearly constant, only 3 A-scan lines need to be processed to obtain the gross orientation of the retina by using a sphere model. Subsequently, the en face microvascular images can be obtained by using the GOCTA algorithm from interference fringes directly without the steps of k-space resampling, numerical dispersion compensation, FFT, and maximum (mean) projection, resulting in a significant improvement of the data processing speed by 4 to 20 times faster than the existing methods. GOCTA is potentially suitable for SDOCT systems in en face preview applications requiring real-time microvascular imaging.
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Affiliation(s)
- Chaoliang Chen
- Biophotonics and Bioengineering Lab, Department of Electrical and Computer Engineering, Ryerson University, Toronto, Ontario, Canada
| | - Victor X. D. Yang
- Biophotonics and Bioengineering Lab, Department of Electrical and Computer Engineering, Ryerson University, Toronto, Ontario, Canada
- Division of Neurosurgery, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
- Division of Neurosurgery, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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23
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Zhu J, Zhang B, Qi L, Wang L, Yang Q, Zhu Z, Huo T, Chen Z. Quantitative angle-insensitive flow measurement using relative standard deviation OCT. APPLIED PHYSICS LETTERS 2017; 111:181101. [PMID: 29151604 PMCID: PMC5663647 DOI: 10.1063/1.5009200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 10/13/2017] [Indexed: 05/09/2023]
Abstract
Incorporating different data processing methods, optical coherence tomography (OCT) has the ability for high-resolution angiography and quantitative flow velocity measurements. However, OCT angiography cannot provide quantitative information of flow velocities, and the velocity measurement based on Doppler OCT requires the determination of Doppler angles, which is a challenge in a complex vascular network. In this study, we report on a relative standard deviation OCT (RSD-OCT) method which provides both vascular network mapping and quantitative information for flow velocities within a wide range of Doppler angles. The RSD values are angle-insensitive within a wide range of angles, and a nearly linear relationship was found between the RSD values and the flow velocities. The RSD-OCT measurement in a rat cortex shows that it can quantify the blood flow velocities as well as map the vascular network in vivo.
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Affiliation(s)
- Jiang Zhu
- Beckman Laser Institute, University of California, Irvine, Irvine, California 92612, USA
| | | | - Li Qi
- Beckman Laser Institute, University of California, Irvine, Irvine, California 92612, USA
| | | | - Qiang Yang
- Beckman Laser Institute, University of California, Irvine, Irvine, California 92612, USA
| | | | - Tiancheng Huo
- Beckman Laser Institute, University of California, Irvine, Irvine, California 92612, USA
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24
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McLean JP, Ling Y, Hendon CP. Frequency-constrained robust principal component analysis: a sparse representation approach to segmentation of dynamic features in optical coherence tomography imaging. OPTICS EXPRESS 2017; 25:25819-25830. [PMID: 29041245 PMCID: PMC5644470 DOI: 10.1364/oe.25.025819] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 10/05/2017] [Accepted: 10/05/2017] [Indexed: 05/18/2023]
Abstract
Sparse representation theory is an exciting area of research with recent applications in medical imaging and detection, segmentation, and quantitative analysis of biological processes. We present a variant on the robust-principal component analysis (RPCA) algorithm, called frequency constrained RPCA (FC-RPCA), for selectively segmenting dynamic phenomena that exhibit spectra within a user-defined range of frequencies. The algorithm lacks subjective parameter tuning and demonstrates robust segmentation in datasets containing multiple motion sources and high amplitude noise. When tested on 17 ex-vivo, time lapse optical coherence tomography (OCT) B-scans of human ciliated epithelium, segmentation accuracies ranged between 91-99% and consistently out-performed traditional RPCA.
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25
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Zhu J, Merkle CW, Bernucci MT, Chong SP, Srinivasan VJ. Can OCT Angiography Be Made a Quantitative Blood Measurement Tool? APPLIED SCIENCES-BASEL 2017; 7. [PMID: 30009045 PMCID: PMC6042878 DOI: 10.3390/app7070687] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Optical Coherence Tomography Angiography (OCTA) refers to a powerful class of OCT scanning protocols and algorithms that selectively enhance the imaging of blood vessel lumens, based mainly on the motion and scattering of red blood cells (RBCs). Though OCTA is widely used in clinical and basic science applications for visualization of perfused blood vessels, OCTA is still primarily a qualitative tool. However, more quantitative hemodynamic information would better delineate disease mechanisms, and potentially improve the sensitivity for detecting early stages of disease. Here, we take a broader view of OCTA in the context of microvascular hemodynamics and light scattering. Paying particular attention to the unique challenges presented by capillaries versus larger supplying and draining vessels, we critically assess opportunities and challenges in making OCTA a quantitative tool.
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Affiliation(s)
- Jun Zhu
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, USA
| | - Conrad W. Merkle
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, USA
| | - Marcel T. Bernucci
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, USA
| | - Shau Poh Chong
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, USA
| | - Vivek J. Srinivasan
- Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, USA
- Department of Ophthalmology and Vision Science, School of Medicine, University of California Davis, Sacramento, CA 95817, USA
- Correspondence: ; Tel.: +1-530-752-9277
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26
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de Boer JF, Leitgeb R, Wojtkowski M. Twenty-five years of optical coherence tomography: the paradigm shift in sensitivity and speed provided by Fourier domain OCT [Invited]. BIOMEDICAL OPTICS EXPRESS 2017; 8:3248-3280. [PMID: 28717565 PMCID: PMC5508826 DOI: 10.1364/boe.8.003248] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 04/26/2017] [Accepted: 05/22/2017] [Indexed: 05/19/2023]
Abstract
Optical coherence tomography (OCT) has become one of the most successful optical technologies implemented in medicine and clinical practice mostly due to the possibility of non-invasive and non-contact imaging by detecting back-scattered light. OCT has gone through a tremendous development over the past 25 years. From its initial inception in 1991 [Science254, 1178 (1991)] it has become an indispensable medical imaging technology in ophthalmology. Also in fields like cardiology and gastro-enterology the technology is envisioned to become a standard of care. A key contributor to the success of OCT has been the sensitivity and speed advantage offered by Fourier domain OCT. In this review paper the development of FD-OCT will be revisited, providing a single comprehensive framework to derive the sensitivity advantage of both SD- and SS-OCT. We point out the key aspects of the physics and the technology that has enabled a more than 2 orders of magnitude increase in sensitivity, and as a consequence an increase in the imaging speed without loss of image quality. This speed increase provided a paradigm shift from point sampling to comprehensive 3D in vivo imaging, whose clinical impact is still actively explored by a large number of researchers worldwide.
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Affiliation(s)
- Johannes F. de Boer
- Department of Physics and Astronomy and LaserLaB Amsterdam, VU University, De Boelelaan 1105, 1081 HV Amsterdam, Department of Ophthalmology, VU Medical Center, Amsterdam, The Netherlands
- Authors are listed in alphabetical order and contributed equally
| | - Rainer Leitgeb
- Christian Doppler Laboratory OPTRAMED, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
- Authors are listed in alphabetical order and contributed equally
| | - Maciej Wojtkowski
- Physical Optics and Biophotonics Group, Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52 01-224 Warsaw, Poland
- Authors are listed in alphabetical order and contributed equally
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27
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Gao SS, Jia Y, Zhang M, Su JP, Liu G, Hwang TS, Bailey ST, Huang D. Optical Coherence Tomography Angiography. Invest Ophthalmol Vis Sci 2017; 57:OCT27-36. [PMID: 27409483 PMCID: PMC4968919 DOI: 10.1167/iovs.15-19043] [Citation(s) in RCA: 238] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Optical coherence tomography angiography (OCTA) is a noninvasive approach that can visualize blood vessels down to the capillary level. With the advent of high-speed OCT and efficient algorithms, practical OCTA of ocular circulation is now available to ophthalmologists. Clinical investigations that used OCTA have increased exponentially in the past few years. This review will cover the history of OCTA and survey its most important clinical applications. The salient problems in the interpretation and analysis of OCTA are described, and recent advances are highlighted.
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28
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Optical Coherence Tomography Visualization of a Port-Wine Stain in a Patient With Sturge-Weber Syndrome. Dermatol Surg 2017; 43:889-891. [PMID: 28541265 DOI: 10.1097/dss.0000000000001055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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29
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Gao W. Quantitative depth-resolved microcirculation imaging with optical coherence tomography angiography (Part Ι): Blood flow velocity imaging. Microcirculation 2017; 25:e12375. [PMID: 28419622 DOI: 10.1111/micc.12375] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 04/11/2017] [Indexed: 12/20/2022]
Abstract
The research goal of the microvascular network imaging with OCT angiography is to achieve depth-resolved blood flow and vessel imaging in vivo in the clinical management of patents. In this review, we review the main phenomena that have been explored in OCT to image the blood flow velocity vector and the vessels of the microcirculation within living tissues. Parameters that limit the accurate measurements of blood flow velocity are then considered. Finally, initial clinical diagnosis applications and future developments of OCT flow images are discussed.
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Affiliation(s)
- Wanrong Gao
- Department of Optical Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, China.,MIIT Key Laboratory of Advanced soIid Laser, Nanjing University of science and Technology, Nanjing, Jiangsu, China
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30
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Chen C, Cheng KHY, Jakubovic R, Jivraj J, Ramjist J, Deorajh R, Gao W, Barnes E, Chin L, Yang VXD. High speed, wide velocity dynamic range Doppler optical coherence tomography (Part V): Optimal utilization of multi-beam scanning for Doppler and speckle variance microvascular imaging. OPTICS EXPRESS 2017; 25:7761-7777. [PMID: 28380895 DOI: 10.1364/oe.25.007761] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this paper, a multi-beam scanning technique is proposed to optimize the microvascular images of human skin obtained with Doppler effect based methods and speckle variance processing. Flow phantom experiments were performed to investigate the suitability for combining multi-beam data to achieve enhanced microvascular imaging. To our surprise, the highly variable spot sizes (ranging from 13 to 77 μm) encountered in high numerical aperture multi-beam OCT system imaging the same target provided reasonably uniform Doppler variance and speckle variance responses as functions of flow velocity, which formed the basis for combining them to obtain better microvascular imaging without scanning penalty. In vivo 2D and 3D imaging of human skin was then performed to further demonstrate the benefit of combining multi-beam scanning to obtain improved signal-to-noise ratio (SNR) in microvascular imaging. Such SNR improvement can be as high as 10 dB. To our knowledge, this is the first demonstration of combining different spot size, staggered multiple optical foci scanning, to achieve enhanced SNR for blood flow OCT imaging.
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31
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Chen CL, Wang RK. Optical coherence tomography based angiography [Invited]. BIOMEDICAL OPTICS EXPRESS 2017; 8:1056-1082. [PMID: 28271003 PMCID: PMC5330554 DOI: 10.1364/boe.8.001056] [Citation(s) in RCA: 263] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 01/16/2017] [Indexed: 05/18/2023]
Abstract
Optical coherence tomography (OCT)-based angiography (OCTA) provides in vivo, three-dimensional vascular information by the use of flowing red blood cells as intrinsic contrast agents, enabling the visualization of functional vessel networks within microcirculatory tissue beds non-invasively, without a need of dye injection. Because of these attributes, OCTA has been rapidly translated to clinical ophthalmology within a short period of time in the development. Various OCTA algorithms have been developed to detect the functional micro-vasculatures in vivo by utilizing different components of OCT signals, including phase-signal-based OCTA, intensity-signal-based OCTA and complex-signal-based OCTA. All these algorithms have shown, in one way or another, their clinical values in revealing micro-vasculatures in biological tissues in vivo, identifying abnormal vascular networks or vessel impairment zones in retinal and skin pathologies, detecting vessel patterns and angiogenesis in eyes with age-related macular degeneration and in skin and brain with tumors, and monitoring responses to hypoxia in the brain tissue. The purpose of this paper is to provide a technical oriented overview of the OCTA developments and their potential pre-clinical and clinical applications, and to shed some lights on its future perspectives. Because of its clinical translation to ophthalmology, this review intentionally places a slightly more weight on ophthalmic OCT angiography.
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Affiliation(s)
- Chieh-Li Chen
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA 98195, USA
- Department of Ophthalmology, University of Washington, 325 9th Ave, Seattle, WA 98104, USA
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA 98195, USA
- Department of Ophthalmology, University of Washington, 325 9th Ave, Seattle, WA 98104, USA
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Wang Y, Huang D, Su Y, Yao XS. Two-dimensional phase unwrapping in Doppler Fourier domain optical coherence tomography. OPTICS EXPRESS 2016; 24:26129-26145. [PMID: 27857350 DOI: 10.1364/oe.24.026129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
For phase-related imaging modalities using interferometric techniques, it is important to develop effective method to recover phase information that is mathematically wrapped. In this paper, we propose and demonstrate a two-dimensional (2D) method to achieve effective phase unwrapping in Doppler Fourier-domain (FD) optical coherence tomography (OCT), and recover the discontinuous phase distribution in retinal blood flow successfully for the first time in Doppler OCT studies. The proposed method is based on phase gradient approach in the axial dimension, with phase denoising performed through 2D window moving average in the sampled phase image using complex Doppler OCT data. The 2D unwrapping is carried out to correct phase discontinuities in the wrapped Doppler phase map, and the abrupt phase changes can be identified and corrected accurately. The proposed algorithm is computationally efficient and easy to be implemented.
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Cho YK, Zheng G, Augustine GJ, Hochbaum D, Cohen A, Knöpfel T, Pisanello F, Pavone FS, Vellekoop IM, Booth MJ, Hu S, Zhu J, Chen Z, Hoshi Y. Roadmap on neurophotonics. JOURNAL OF OPTICS (2010) 2016; 18:093007. [PMID: 28386392 PMCID: PMC5378317 DOI: 10.1088/2040-8978/18/9/093007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Mechanistic understanding of how the brain gives rise to complex behavioral and cognitive functions is one of science's grand challenges. The technical challenges that we face as we attempt to gain a systems-level understanding of the brain are manifold. The brain's structural complexity requires us to push the limit of imaging resolution and depth, while being able to cover large areas, resulting in enormous data acquisition and processing needs. Furthermore, it is necessary to detect functional activities and 'map' them onto the structural features. The functional activity occurs at multiple levels, using electrical and chemical signals. Certain electrical signals are only decipherable with sub-millisecond timescale resolution, while other modes of signals occur in minutes to hours. For these reasons, there is a wide consensus that new tools are necessary to undertake this daunting task. Optical techniques, due to their versatile and scalable nature, have great potentials to answer these challenges. Optical microscopy can now image beyond the diffraction limit, record multiple types of brain activity, and trace structural features across large areas of tissue. Genetically encoded molecular tools opened doors to controlling and detecting neural activity using light in specific cell types within the intact brain. Novel sample preparation methods that reduce light scattering have been developed, allowing whole brain imaging in rodent models. Adaptive optical methods have the potential to resolve images from deep brain regions. In this roadmap article, we showcase a few major advances in this area, survey the current challenges, and identify potential future needs that may be used as a guideline for the next steps to be taken.
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Affiliation(s)
- Yong Ku Cho
- Department of Chemical and Biomolecular Engineering, Institute for Systems Genomics, University of Connecticut, 191 Auditorium Rd, Storrs, CT 06269-3222, USA
| | - Guoan Zheng
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT 06269, USA
| | - George J Augustine
- Lee Kong Chian School of Medicine, Nanyang Technological University, 50 Nanyang Drive, Research Techno Plaza, Singapore 637553, Singapore
| | - Daniel Hochbaum
- Departments of Chemistry and Chemical Biology and Physics, Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA
| | - Adam Cohen
- Departments of Chemistry and Chemical Biology and Physics, Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA
| | - Thomas Knöpfel
- Division of Brain Sciences, Department of Medicine, Imperial College London, London W12 0NN, UK
| | - Ferruccio Pisanello
- Istituto Italiano di Tecnologia (IIT), Center for Biomolecular Nanotechnologies, Via Barsanti sn, I-73010 Arnesano (Lecce), Italy
| | - Francesco S Pavone
- European Laboratory for Non Linear Spectroscopy, University of Florence, Via N. Carrara 1, I-50019 Sesto Fiorentino (FI), Italy; Department of Physics, University of Florence, Via G. Sansone 1, I-50019 Sesto Fiorentino, Italy; Istituto Nazionale di Ottica, L.go E. fermi 2, I-50100 Firenze, Italy
| | - Ivo M Vellekoop
- Biomedical Photonic Imaging group, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Martin J Booth
- Centre for Neural Circuits and Behaviour, University of Oxford, Mansfield Road, Oxford OX1 3SR, UK; Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK
| | - Song Hu
- Department of Biomedical Engineering, University of Virginia, 415 Lane Road, Charlottesville, VA 22908, USA
| | - Jiang Zhu
- Beckman Laser Institute, University of California, Irvine, 1002 Health Sciences Road East, Irvine, CA 92617, USA
| | - Zhongping Chen
- Beckman Laser Institute, University of California, Irvine, 1002 Health Sciences Road East, Irvine, CA 92617, USA
| | - Yoko Hoshi
- Department of Biomedical Optics, Institute for Medical Photonics Research, Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192, Japan
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Wijesinghe RE, Park K, Kim DH, Jeon M, Kim J. In vivo imaging of melanoma-implanted magnetic nanoparticles using contrast-enhanced magneto-motive optical Doppler tomography. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:64001. [PMID: 27334932 DOI: 10.1117/1.jbo.21.6.064001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 06/01/2016] [Indexed: 06/06/2023]
Abstract
We conducted an initial feasibility study using real-time magneto-motive optical Doppler tomography (MM-ODT) with enhanced contrast to investigate the detection of superparamagnetic iron oxide (SPIO) magnetic nanoparticles implanted into in vivo melanoma tissue. The MM-ODT signals were detected owing to the phase shift of the implanted magnetic nanoparticles, which occurred due to the action of an applied magnetic field. An amplifier circuit-based solenoid was utilized for generating high-intensity oscillating magnetic fields. The MM-ODT system was confirmed as an effective in vivo imaging method for detecting melanoma tissue, with the performance comparable to those of conventional optical coherence tomography and optical Doppler tomography methods. Moreover, the optimal values of the SPIO nanoparticles concentration and solenoid voltage for obtaining the uppermost Doppler velocity were derived as well. To improve the signal processing speed for real-time imaging, we adopted multithread programming techniques and optimized the signal path. The results suggest that this imaging modality can be used as a powerful tool to identify the intracellular and extracellular SPIO nanoparticles in melanoma tissues in vivo.
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Affiliation(s)
- Ruchire Eranga Wijesinghe
- Kyungpook National University, School of Electronics Engineering, College of IT Engineering, 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea
| | - Kibeom Park
- Kyungpook National University, School of Electronics Engineering, College of IT Engineering, 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea
| | - Dong-Hyeon Kim
- 3D Convergence Technology Center, 70 Dongnae-ro, Daegu 41061, Republic of Korea
| | - Mansik Jeon
- Kyungpook National University, School of Electronics Engineering, College of IT Engineering, 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea
| | - Jeehyun Kim
- Kyungpook National University, School of Electronics Engineering, College of IT Engineering, 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea
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Choi B, Tan W, Jia W, White SM, Moy WJ, Yang BY, Zhu J, Chen Z, Kelly KM, Nelson JS. The Role of Laser Speckle Imaging in Port-Wine Stain Research: Recent Advances and Opportunities. IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS : A PUBLICATION OF THE IEEE LASERS AND ELECTRO-OPTICS SOCIETY 2016; 2016:6800812. [PMID: 27013846 PMCID: PMC4800318 DOI: 10.1109/jstqe.2015.2493961] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Here, we review our current knowledge on the etiology and treatment of port-wine stain (PWS) birthmarks. Current treatment options have significant limitations in terms of efficacy. With the combination of 1) a suitable preclinical microvascular model, 2) laser speckle imaging (LSI) to evaluate blood-flow dynamics, and 3) a longitudinal experimental design, rapid preclinical assessment of new phototherapies can be translated from the lab to the clinic. The combination of photodynamic therapy (PDT) and pulsed-dye laser (PDL) irradiation achieves a synergistic effect that reduces the required radiant exposures of the individual phototherapies to achieve persistent vascular shutdown. PDL combined with anti-angiogenic agents is a promising strategy to achieve persistent vascular shutdown by preventing reformation and reperfusion of photocoagulated blood vessels. Integration of LSI into the clinical workflow may lead to surgical image guidance that maximizes acute photocoagulation, is expected to improve PWS therapeutic outcome. Continued integration of noninvasive optical imaging technologies and biochemical analysis collectively are expected to lead to more robust treatment strategies.
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Affiliation(s)
- Bernard Choi
- Departments of Biomedical Engineering and Surgery, the Beckman Laser Institute and Medical Clinic, and the Edwards Lifesciences Center for Advanced Cardiovascular Technology, all at University of California, Irvine 92612 USA
| | - Wenbin Tan
- Beckman Laser Institute and Medical Clinic, University of California, Irvine 92612 USA
| | - Wangcun Jia
- Beckman Laser Institute and Medical Clinic, University of California, Irvine 92612 USA
| | - Sean M. White
- Beckman Laser Institute and Medical Clinic, University of California, Irvine 92612 USA
| | - Wesley J. Moy
- Beckman Laser Institute and Medical Clinic, University of California, Irvine 92612 USA
| | - Bruce Y. Yang
- Beckman Laser Institute and Medical Clinic, University of California, Irvine 92612 USA
| | | | | | - Kristen M. Kelly
- Department of Dermatology and the Beckman Laser Institute and Medical Clinic, all at University of California, Irvine 92612 USA
| | - J. Stuart Nelson
- Departments of Biomedical Engineering and Surgery and the Beckman Laser Institute and Medical Clinic, all at University of California, Irvine 92612 USA
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Qi L, Zhu J, Hancock AM, Dai C, Zhang X, Frostig RD, Chen Z. Fully distributed absolute blood flow velocity measurement for middle cerebral arteries using Doppler optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2016; 7:601-15. [PMID: 26977365 PMCID: PMC4771474 DOI: 10.1364/boe.7.000601] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 01/08/2016] [Accepted: 01/08/2016] [Indexed: 05/03/2023]
Abstract
Doppler optical coherence tomography (DOCT) is considered one of the most promising functional imaging modalities for neuro biology research and has demonstrated the ability to quantify cerebral blood flow velocity at a high accuracy. However, the measurement of total absolute blood flow velocity (BFV) of major cerebral arteries is still a difficult problem since it is related to vessel geometry. In this paper, we present a volumetric vessel reconstruction approach that is capable of measuring the absolute BFV distributed along the entire middle cerebral artery (MCA) within a large field-of-view. The Doppler angle at each point of the MCA, representing the vessel geometry, is derived analytically by localizing the artery from pure DOCT images through vessel segmentation and skeletonization. Our approach could achieve automatic quantification of the fully distributed absolute BFV across different vessel branches. Experiments on rodents using swept-source optical coherence tomography showed that our approach was able to reveal the consequences of permanent MCA occlusion with absolute BFV measurement.
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Affiliation(s)
- Li Qi
- Institute of Optical Communication Engineering and College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu, 210093, China
- Beckman Laser Institute, University of California, Irvine, Irvine, California 92612, USA
| | - Jiang Zhu
- Beckman Laser Institute, University of California, Irvine, Irvine, California 92612, USA
- Department of Biomedical Engineering, University of California, Irvine, Irvine, California 92697, USA
| | - Aneeka M. Hancock
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, California, USA
- The Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, California, USA
| | - Cuixia Dai
- Beckman Laser Institute, University of California, Irvine, Irvine, California 92612, USA
| | - Xuping Zhang
- Institute of Optical Communication Engineering and College of Engineering and Applied Sciences, Nanjing University, Nanjing, Jiangsu, 210093, China
| | - Ron D. Frostig
- Department of Biomedical Engineering, University of California, Irvine, Irvine, California 92697, USA
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, California, USA
- The Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, California, USA
| | - Zhongping Chen
- Beckman Laser Institute, University of California, Irvine, Irvine, California 92612, USA
- Department of Biomedical Engineering, University of California, Irvine, Irvine, California 92697, USA
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Huang S, Piao Z, Zhu J, Lu F, Chen Z. In vivo microvascular network imaging of the human retina combined with an automatic three-dimensional segmentation method. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:76003. [PMID: 26169790 PMCID: PMC4572094 DOI: 10.1117/1.jbo.20.7.076003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 06/12/2015] [Indexed: 05/21/2023]
Abstract
Microvascular network of the retina plays an important role in diagnosis and monitoring of various retinal diseases. We propose a three-dimensional (3-D) segmentation method with intensity-based Doppler variance (IBDV) based on swept-source optical coherence tomography. The automatic 3-D segmentation method is used to obtain seven surfaces of intraretinal layers. The microvascular network of the retina, which is acquired by the IBDV method, can be divided into six layers. The microvascular network of the six individual layers is visualized, and the morphology and contrast images can be improved by using the segmentation method. This method has potential for earlier diagnosis and precise monitoring in retinal vascular diseases.
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Affiliation(s)
- Shenghai Huang
- Wenzhou Medical University, School of Optometry and Ophthalmology, 270 Xueyuan Road, Wenzhou 325027, China
- University of California, Irvine, Beckman Laser Institute, 1002 Health Sciences Road East, Irvine, California 92612, United States
| | - Zhonglie Piao
- University of California, Irvine, Beckman Laser Institute, 1002 Health Sciences Road East, Irvine, California 92612, United States
| | - Jiang Zhu
- University of California, Irvine, Beckman Laser Institute, 1002 Health Sciences Road East, Irvine, California 92612, United States
| | - Fan Lu
- Wenzhou Medical University, School of Optometry and Ophthalmology, 270 Xueyuan Road, Wenzhou 325027, China
| | - Zhongping Chen
- Wenzhou Medical University, School of Optometry and Ophthalmology, 270 Xueyuan Road, Wenzhou 325027, China
- University of California, Irvine, Beckman Laser Institute, 1002 Health Sciences Road East, Irvine, California 92612, United States
- University of California, Irvine, Department of Biomedical Engineering, Irvine, California 92697, United States
- Address all correspondence to: Zhongping Chen, E-mail:
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38
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Zhu J, Qu Y, Ma T, Li R, Du Y, Huang S, Shung KK, Zhou Q, Chen Z. Imaging and characterizing shear wave and shear modulus under orthogonal acoustic radiation force excitation using OCT Doppler variance method. OPTICS LETTERS 2015; 40:2099-102. [PMID: 25927794 PMCID: PMC4537318 DOI: 10.1364/ol.40.002099] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We report on a novel acoustic radiation force orthogonal excitation optical coherence elastography (ARFOE-OCE) technique for imaging shear wave and quantifying shear modulus under orthogonal acoustic radiation force (ARF) excitation using the optical coherence tomography (OCT) Doppler variance method. The ARF perpendicular to the OCT beam is produced by a remote ultrasonic transducer. A shear wave induced by ARF excitation propagates parallel to the OCT beam. The OCT Doppler variance method, which is sensitive to the transverse vibration, is used to measure the ARF-induced vibration. For analysis of the shear modulus, the Doppler variance method is utilized to visualize shear wave propagation instead of Doppler OCT method, and the propagation velocity of the shear wave is measured at different depths of one location with the M scan. In order to quantify shear modulus beyond the OCT imaging depth, we move ARF to a deeper layer at a known step and measure the time delay of the shear wave propagating to the same OCT imaging depth. We also quantitatively map the shear modulus of a cross-section in a tissue-equivalent phantom after employing the B scan.
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Affiliation(s)
- Jiang Zhu
- Beckman Laser Institute, University of California, Irvine, 1002 Health Sciences Road East, Irvine, California 92612, USA
| | - Yueqiao Qu
- Beckman Laser Institute, University of California, Irvine, 1002 Health Sciences Road East, Irvine, California 92612, USA
- Department of Biomedical Engineering, University of California, Irvine, Irvine, California 92697, USA
| | - Teng Ma
- Department of Biomedical Engineering, NIH Ultrasonic Transducer Resource Center, University of Southern California, Los Angeles, California 90089, USA
| | - Rui Li
- Beckman Laser Institute, University of California, Irvine, 1002 Health Sciences Road East, Irvine, California 92612, USA
| | - Yongzhao Du
- Beckman Laser Institute, University of California, Irvine, 1002 Health Sciences Road East, Irvine, California 92612, USA
| | - Shenghai Huang
- Beckman Laser Institute, University of California, Irvine, 1002 Health Sciences Road East, Irvine, California 92612, USA
| | - K. Kirk Shung
- Department of Biomedical Engineering, NIH Ultrasonic Transducer Resource Center, University of Southern California, Los Angeles, California 90089, USA
| | - Qifa Zhou
- Department of Biomedical Engineering, NIH Ultrasonic Transducer Resource Center, University of Southern California, Los Angeles, California 90089, USA
| | - Zhongping Chen
- Beckman Laser Institute, University of California, Irvine, 1002 Health Sciences Road East, Irvine, California 92612, USA
- Department of Biomedical Engineering, University of California, Irvine, Irvine, California 92697, USA
- Corresponding author:
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39
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Proskurin SG, Potlov AY, Frolov SV. One specific velocity color mapping using optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:051034. [PMID: 25679878 DOI: 10.1117/1.jbo.20.5.051034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 01/19/2015] [Indexed: 06/04/2023]
Abstract
Depth resolved coherence gating along with Doppler shift detection of the carrier frequency is used for one predetermined velocity mapping in different flows. Bidirectional rapid scanning optical delay of optical coherence tomography system is applied in the reference arm. Tilted capillary entry is used as a hydrodynamic phantom to model a sign-variable flow with complex geometry. Structural and one specific velocity images are obtained from the scanning interferometer signal processing in the frequency domain using analog and digital filtering. A standard structural image is decomposed into three parts: stationary object, and positive and negative velocity distributions. The latter two show equivelocity maps of the flow. The final image is represented as the complexation of the three.
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40
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Poddar R, Kim DY, Werner JS, Zawadzki RJ. In vivo imaging of human vasculature in the chorioretinal complex using phase-variance contrast method with phase-stabilized 1-μm swept-source optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:126010. [PMID: 25517255 PMCID: PMC4269528 DOI: 10.1117/1.jbo.19.12.126010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 07/17/2014] [Accepted: 10/08/2014] [Indexed: 05/22/2023]
Abstract
We present a noninvasive phase-variance (pv)–based motion contrast method for depth-resolved imaging of the human chorioretinal complex microcirculation with a newly developed phase-stabilized high speed (100-kHz A-scans/s) 1-μm swept- ource optical coherence tomography (SSOCT) system. Compared to our previous spectral-domain (spectrometer based) pv-spectral domain OCT (SDOCT) system, this system has the advantages of higher sensitivity, reduced fringe wash-out for high blood flow speeds and deeper penetration in choroid. High phase stability SSOCT imaging was achieved by using a computationally efficient phase stabilization approach. This process does not require additional calibration hardware and complex numerical procedures. Our phase stabilization method is simple and can be employed in a variety of SSOCT systems. Examples of vasculature in the chorioretinal complex imaged by pv-SSOCT from normal as well as diseased eyes are presented and compared to retinal images of the same subjects acquired with fluorescein angiography and indocyanine green angiography. Observations of morphology of vascular perfusion in chorioretinal complex visualized by our method are listed.
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Affiliation(s)
- Raju Poddar
- University of California Davis, Department of Ophthalmology and Vision Science, Vision Science and Advanced Retinal Imaging Laboratory, Sacramento, California 95817, United States
- Birla Institute of Technology, Department of Biotechnology, Mesra, Ranchi, Jharkhand 835215, India
| | - Dae Yu Kim
- University of California Davis, Department of Ophthalmology and Vision Science, Vision Science and Advanced Retinal Imaging Laboratory, Sacramento, California 95817, United States
- Dankook University, Beckman Laser Institute Korea, Cheonan, Chungnam 330-715, Republic of Korea
| | - John S. Werner
- University of California Davis, Department of Ophthalmology and Vision Science, Vision Science and Advanced Retinal Imaging Laboratory, Sacramento, California 95817, United States
| | - Robert J. Zawadzki
- University of California Davis, Department of Ophthalmology and Vision Science, Vision Science and Advanced Retinal Imaging Laboratory, Sacramento, California 95817, United States
- Address all correspondence to: Robert J. Zawadzki, E-mail:
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Nam AS, Chico-Calero I, Vakoc BJ. Complex differential variance algorithm for optical coherence tomography angiography. BIOMEDICAL OPTICS EXPRESS 2014; 5:3822-32. [PMID: 25426313 PMCID: PMC4242020 DOI: 10.1364/boe.5.003822] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 08/07/2014] [Accepted: 08/15/2014] [Indexed: 05/17/2023]
Abstract
We describe a complex differential variance (CDV) algorithm for optical coherence tomography based angiography. The algorithm exploits both the intensity and phase changes of optical coherence tomography (OCT) signals from flowing blood to achieve high vascular contrast, and also intrinsically reject undesirable phase signals originating from small displacement axial bulk tissue motion and instrument synchronization errors. We present this algorithm within a broader discussion of the properties of OCT signal dynamics. The performance of the algorithm is compared against two other existing algorithms using both phantom measurements and in vivo data. We show that the algorithm provides better contrast for a given number of measurements and equivalent spatial averaging.
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Affiliation(s)
- Ahhyun S. Nam
- Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139,
USA
- Wellman Center for Photomedicine, Massachusetts General Hospital, 50 Blossom Street, Boston, Massachusetts 02114,
USA
| | - Isabel Chico-Calero
- Wellman Center for Photomedicine, Massachusetts General Hospital, 50 Blossom Street, Boston, Massachusetts 02114,
USA
- Harvard Medical School, 25 Shattuck Street, Boston, Massachusetts 02115,
USA
| | - Benjamin J. Vakoc
- Wellman Center for Photomedicine, Massachusetts General Hospital, 50 Blossom Street, Boston, Massachusetts 02114,
USA
- Harvard Medical School, 25 Shattuck Street, Boston, Massachusetts 02115,
USA
- Department of Health Sciences and Technology, Harvard-MIT, Cambridge, Massachusetts 02139,
USA
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42
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Liu Q, Li Y, Lu H, Tong S. Real-time high resolution laser speckle imaging of cerebral vascular changes in a rodent photothrombosis model. BIOMEDICAL OPTICS EXPRESS 2014; 5:1483-93. [PMID: 24877010 PMCID: PMC4025902 DOI: 10.1364/boe.5.001483] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 03/16/2014] [Accepted: 04/08/2014] [Indexed: 05/11/2023]
Abstract
The study of hemodynamic and vascular changes following ischemic stroke is of great importance in the understanding of physiological and pathological processes during the thrombus formation. The photothrombosis model is preferred by researchers in stroke study for its minimal invasiveness, controllable infarct volume and lesion location. Nevertheless, there is a lack in high spatiotemporal resolution techniques for real time monitoring of cerebral blood flow (CBF) changes in 2D-profile. In this study, we implemented a microscopic laser speckle imaging (LSI) system to detect CBF and other vascular changes in the rodent model of photothrombotic stroke. Using a high resolution and high speed CCD (640 × 480 pixels, 60 fps), online image registration technique, and automatic parabolic curve fitting, we obtained real time CBF and blood velocity profile (BVP) changes in cortical vessels. Real time CBF and BVP monitoring has been shown to reveal details of vascular disturbances and the stages of blood coagulation in photothrombotic stroke. Moreover, LSI also provides information on additional parameters including vessel morphologic size, blood flow centerline velocity and CBF spatiotemporal fluctuations, which are very important for understanding the physiology and neurovascular pathology in the photothrombosis model.
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43
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Reif R, Yousefi S, Choi WJ, Wang RK. Analysis of cross-sectional image filters for evaluating nonaveraged optical microangiography images. APPLIED OPTICS 2014; 53:806-15. [PMID: 24663258 PMCID: PMC3978384 DOI: 10.1364/ao.53.000806] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 12/20/2013] [Indexed: 05/07/2023]
Abstract
Optical microangiography (OMAG) is a method that enables the noninvasive extraction of blood vessels within biological tissues. OMAG B-frames are prone to noise; therefore, techniques such as B-frame averaging have been applied to reduce these effects. A drawback of this method is that the total acquisition time and amount of data collected are increased; hence, the data are susceptible to motion artifacts and decorrelation. In this paper we propose using an image filter on a nonaveraged OMAG B-frame to reduce its noise. Consequently, B-frames comparable to the averaged OMAG B-frame are obtained, while reducing the total acquisition and processing time. The method is tested with two different systems, a high-resolution spectral domain and a relatively low-resolution swept-source optical coherence tomography system. It is demonstrated that the weighted average filter produces the lowest B-frame error; however, all filters produce comparable results when quantifying the en face projection view image.
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Affiliation(s)
- Roberto Reif
- Department of Bioengineering, University of Washington, 3720 15 Ave. NE, Seattle WA 98195, USA
| | - Siavash Yousefi
- Department of Bioengineering, University of Washington, 3720 15 Ave. NE, Seattle WA 98195, USA
| | - Woo June Choi
- Department of Bioengineering, University of Washington, 3720 15 Ave. NE, Seattle WA 98195, USA
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, 3720 15 Ave. NE, Seattle WA 98195, USA
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Watanabe Y, Takahashi Y, Numazawa H. Graphics processing unit accelerated intensity-based optical coherence tomography angiography using differential frames with real-time motion correction. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:021105. [PMID: 23846119 DOI: 10.1117/1.jbo.19.2.021105] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We demonstrate intensity-based optical coherence tomography (OCT) angiography using the squared difference of two sequential frames with bulk-tissue-motion (BTM) correction. This motion correction was performed by minimization of the sum of the pixel values using axial- and lateral-pixel-shifted structural OCT images. We extract the BTM-corrected image from a total of 25 calculated OCT angiographic images. Image processing was accelerated by a graphics processing unit (GPU) with many stream processors to optimize the parallel processing procedure. The GPU processing rate was faster than that of a line scan camera (46.9 kHz). Our OCT system provides the means of displaying structural OCT images and BTM-corrected OCT angiographic images in real time.
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Affiliation(s)
- Yuuki Watanabe
- Yamagata University, Bio-systems Engineering, Graduate School of Science and Engineering, 4-3-16 Johnan, Yonezawa, Yamagata 992-8510, Japan.
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The diagnostic function of OCT in diabetic maculopathy. Mediators Inflamm 2013; 2013:434560. [PMID: 24369444 PMCID: PMC3863575 DOI: 10.1155/2013/434560] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/25/2013] [Indexed: 01/16/2023] Open
Abstract
Diabetic maculopathy (DM) is one of the major causes of vision impairment in individuals with diabetes. The traditional approach to diagnosis of DM includes fundus ophthalmoscopy and fluorescein angiography. Although very useful clinically, these methods do not contribute much to the evaluation of retinal morphology and its thickness profile. That is why a new technique called optical coherence tomography (OCT) was utilized to perform cross-sectional imaging of the retina. It facilitates measuring the macular thickening, quantification of diabetic macular oedema, and detecting vitreoretinal traction. Thus, OCT may assist in patient selection with DM who can benefit from treatment, identify what treatment is indicated, guide its implementing, and allow precise monitoring of treatment response. It seems to be the technique of choice for the early detection of macular oedema and for the followup of DM.
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46
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Bouwens A, Szlag D, Szkulmowski M, Bolmont T, Wojtkowski M, Lasser T. Quantitative lateral and axial flow imaging with optical coherence microscopy and tomography. OPTICS EXPRESS 2013; 21:17711-29. [PMID: 23938644 DOI: 10.1364/oe.21.017711] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Optical coherence tomography (OCT) and optical coherence microscopy (OCM) allow the acquisition of quantitative three-dimensional axial flow by estimating the Doppler shift caused by moving scatterers. Measuring the velocity of red blood cells is currently the principal application of these methods. In many biological tissues, blood flow is often perpendicular to the optical axis, creating the need for a quantitative measurement of lateral flow. Previous work has shown that lateral flow can be measured from the Doppler bandwidth, albeit only for simplified optical systems. In this work, we present a generalized model to analyze the influence of relevant OCT/OCM system parameters such as light source spectrum, numerical aperture and beam geometry on the Doppler spectrum. Our analysis results in a general framework relating the mean and variance of the Doppler frequency to the axial and lateral flow velocity components. Based on this model, we present an optimized acquisition protocol and algorithm to reconstruct quantitative measurements of lateral and axial flow from the Doppler spectrum for any given OCT/OCM system. To validate this approach, Doppler spectrum analysis is employed to quantitatively measure flow in a capillary with both extended focus OCM and OCT.
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Affiliation(s)
- Arno Bouwens
- Laboratoire d’Optique Biomédicale, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
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Yousefi S, Qin J, Wang RK. Super-resolution spectral estimation of optical micro-angiography for quantifying blood flow within microcirculatory tissue beds in vivo. BIOMEDICAL OPTICS EXPRESS 2013; 4:1214-28. [PMID: 23847744 PMCID: PMC3704100 DOI: 10.1364/boe.4.001214] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 06/07/2013] [Accepted: 06/08/2013] [Indexed: 05/07/2023]
Abstract
In this paper, we propose a super-resolution spectral estimation technique to quantify microvascular hemodynamics using optical microangiography (OMAG) based on optical coherence tomography (OCT). The proposed OMAG technique uses both amplitude and phase information of the OCT signals which makes it sensitive to the axial and transverse flows. The scanning protocol for the proposed method is identical to three-dimensional ultrahigh sensitive OMAG, and is applicable for in vivo measurements. In contrast to the existing capillary flow quantification methods, the proposed method is less sensitive to tissue motion and does not have aliasing problems due fast flow within large blood vessels. This method is analogous to power Doppler in ultrasonography and estimates the number of red blood cells passing through the beam as opposed to the velocity of the particles. The technique is tested both qualitatively and quantitatively by using OMAG to image microcirculation within mouse ear flap in vivo.
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48
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Blatter C, Weingast J, Alex A, Grajciar B, Wieser W, Drexler W, Huber R, Leitgeb RA. In situ structural and microangiographic assessment of human skin lesions with high-speed OCT. BIOMEDICAL OPTICS EXPRESS 2012; 3:2636-46. [PMID: 23082302 PMCID: PMC3469999 DOI: 10.1364/boe.3.002636] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 08/30/2012] [Accepted: 09/11/2012] [Indexed: 05/17/2023]
Abstract
We demonstrate noninvasive structural and microvascular contrast imaging of different human skin diseases in vivo using an intensity difference analysis of OCT tomograms. The high-speed swept source OCT system operates at 1310 nm with 220 kHz A-scan rate. It provides an extended focus by employing a Bessel beam. The studied lesions were two cases of dermatitis and two cases of basal cell carcinoma. The lesions show characteristic vascular patterns that are significantly different from healthy skin. In case of inflammation, vessels are dilated and perfusion is increased. In case of basal cell carcinoma, the angiogram shows a denser network of unorganized vessels with large vessels close to the skin surface. Those results indicate that assessing vascular changes yields complementary information with important insight into the metabolic demand.
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Affiliation(s)
- Cedric Blatter
- Center of Medical Physics and Biomedical Engineering, Medical
University Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Jessika Weingast
- Department of Dermatology, Division of General Dermatology,
Medical University Vienna, Waehringer Guertel 18-20, 1090 Vienna,
Austria
| | - Aneesh Alex
- Center of Medical Physics and Biomedical Engineering, Medical
University Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Branislav Grajciar
- Center of Medical Physics and Biomedical Engineering, Medical
University Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Wolfgang Wieser
- Lehrstuhl für BioMolekulare Optik,
Ludwig-Maximilians-Universität München, Oettingenstraße 67, 80538 Munich,
Germany
| | - Wolfgang Drexler
- Center of Medical Physics and Biomedical Engineering, Medical
University Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Robert Huber
- Lehrstuhl für BioMolekulare Optik,
Ludwig-Maximilians-Universität München, Oettingenstraße 67, 80538 Munich,
Germany
| | - Rainer A. Leitgeb
- Center of Medical Physics and Biomedical Engineering, Medical
University Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
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49
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Liu G, Lin AJ, Tromberg BJ, Chen Z. A comparison of Doppler optical coherence tomography methods. BIOMEDICAL OPTICS EXPRESS 2012; 3:2669-80. [PMID: 23082305 PMCID: PMC3469988 DOI: 10.1364/boe.3.002669] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 09/11/2012] [Accepted: 09/19/2012] [Indexed: 05/17/2023]
Abstract
We compare, in detail, the phase-resolved color Doppler (PRCD), phase-resolved Doppler variance (PRDV) and intensity-based Doppler variance (IBDV) methods. All the methods are able to quantify flow speed when the flow rate is within a certain range, which is dependent on the adjacent A-line time interval. While PRCD is most sensitive when the flow direction is along the probing beam, PRDV and IBDV can be used to measure the flow when the flow direction is near perpendicular to the probing beam. However, the values of PRDV and IBDV are Doppler angle-dependent when the Doppler angle is above a certain threshold. The sensitivity of all the methods can be improved by increasing the adjacent A-line time interval while still maintaining a high sampling density level. We also demonstrate for the first time, to the best of our knowledge, high resolution inter-frame PRDV method. In applications where mapping vascular network such as angiogram is more important than flow velocity quantification, IBDV and PRDV images show better contrast than PRCD images. The IBDV and PRDV show very similar characteristics and demonstrate comparable results for vasculature mapping. However, the IBDV is less sensitive to bulk motion and with less post-processing steps, which is preferred for fast data processing situations. In vivo imaging of mouse brain with intact skull and human skin with the three methods were demonstrated and the results were compared. The IBDV method was found to be able to obtain high resolution image with a relative simple processing procedure.
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Affiliation(s)
- Gangjun Liu
- Beckman Laser Institute, University of California, Irvine, Irvine, CA 92617, USA
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92617, USA
| | - Alexander J. Lin
- Beckman Laser Institute, University of California, Irvine, Irvine, CA 92617, USA
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92617, USA
| | - Bruce J. Tromberg
- Beckman Laser Institute, University of California, Irvine, Irvine, CA 92617, USA
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92617, USA
| | - Zhongping Chen
- Beckman Laser Institute, University of California, Irvine, Irvine, CA 92617, USA
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92617, USA
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50
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Huang Y, Liu X, Kang JU. Real-time 3D and 4D Fourier domain Doppler optical coherence tomography based on dual graphics processing units. BIOMEDICAL OPTICS EXPRESS 2012; 3:2162-74. [PMID: 23024910 PMCID: PMC3447558 DOI: 10.1364/boe.3.002162] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 08/15/2012] [Accepted: 08/16/2012] [Indexed: 05/04/2023]
Abstract
We present real-time 3D (2D cross-sectional image plus time) and 4D (3D volume plus time) phase-resolved Doppler OCT (PRDOCT) imaging based on configuration of dual graphics processing units (GPU). A GPU-accelerated phase-resolving processing algorithm was developed and implemented. We combined a structural image intensity-based thresholding mask and average window method to improve the signal-to-noise ratio of the Doppler phase image. A 2D simultaneous display of the structure and Doppler flow images was presented at a frame rate of 70 fps with an image size of 1000 × 1024 (X × Z) pixels. A 3D volume rendering of tissue structure and flow images-each with a size of 512 × 512 pixels-was presented 64.9 milliseconds after every volume scanning cycle with a volume size of 500 × 256 × 512 (X × Y × Z) voxels, with an acquisition time window of only 3.7 seconds. To the best of our knowledge, this is the first time that an online, simultaneous structure and Doppler flow volume visualization has been achieved. Maximum system processing speed was measured to be 249,000 A-scans per second with each A-scan size of 2048 pixels.
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