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Poddar R, Shukla V, Alam Z, Mohan M. Automatic segmentation of layers in chorio-retinal complex using Graph-based method for ultra-speed 1.7 MHz wide field swept source FDML optical coherence tomography. Med Biol Eng Comput 2024; 62:1375-1393. [PMID: 38191981 DOI: 10.1007/s11517-023-03007-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 12/20/2023] [Indexed: 01/10/2024]
Abstract
The posterior segment of the human eye complex contains two discrete microstructure and vasculature network systems, namely, the retina and choroid. We present a single segmentation framework technique for segmenting the entire layers present in the chorio-retinal complex of the human eye using optical coherence tomography (OCT) images. This automatic program is based on the graph theory method. This single program is capable of segmenting seven layers of the retina and choroid scleral interface. The graph theory was utilized to find the probability matrix and subsequent boundaries of different layers. The program was also implemented to segment angiographic maps of different chorio-retinal layers using "segmentation matrices." The method was tested and successfully validated on OCT images from six normal human eyes as well as eyes with non-exudative age-related macular degeneration (AMD). The thickness of microstructure and microvasculature for different layers located in the chorio-retinal segment of the eye was also generated and compared. A decent efficiency in terms of processing time, sensitivity, and accuracy was observed compared to the manual segmentation and other existing methods. The proposed method automatically segments whole OCT images of chorio-retinal complex with augmented probability maps generation in OCT volume dataset. We have also evaluated the segmentation results using quantitative metrics such as Dice coefficient and Hausdorff distance This method realizes a mean descent Dice similarity coefficient (DSC) value of 0.82 (range, 0.816-0.864) for RPE and CSI layer.
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Affiliation(s)
- Raju Poddar
- Biophotonics Lab, Department of Bioengineering & Biotechnology, Birla Institute of Technology-Mesra, Ranchi, JH, 835 215, India.
| | - Vinita Shukla
- Biophotonics Lab, Department of Bioengineering & Biotechnology, Birla Institute of Technology-Mesra, Ranchi, JH, 835 215, India
| | - Zoya Alam
- Biophotonics Lab, Department of Bioengineering & Biotechnology, Birla Institute of Technology-Mesra, Ranchi, JH, 835 215, India
| | - Muktesh Mohan
- Biophotonics Lab, Department of Bioengineering & Biotechnology, Birla Institute of Technology-Mesra, Ranchi, JH, 835 215, India
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Tombolini B, Crincoli E, Sacconi R, Battista M, Fantaguzzi F, Servillo A, Bandello F, Querques G. Optical Coherence Tomography Angiography: A 2023 Focused Update on Age-Related Macular Degeneration. Ophthalmol Ther 2024; 13:449-467. [PMID: 38180632 PMCID: PMC10787708 DOI: 10.1007/s40123-023-00870-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 12/05/2023] [Indexed: 01/06/2024] Open
Abstract
Optical coherence tomography angiography (OCTA) has extensively enhanced our comprehension of eye microcirculation and of its associated diseases. In this narrative review, we explored the key concepts behind OCTA, as well as the most recent evidence in the pathophysiology of age-related macular degeneration (AMD) made possible by OCTA. These recommendations were updated since the publication in 2020, and are targeted for 2023. Importantly, as a future perspective in OCTA technology, we will discuss how artificial intelligence has been applied to OCTA, with a particular emphasis on its application to AMD study.
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Affiliation(s)
- Beatrice Tombolini
- School of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Division of Head and Neck, Ophthalmology Unit, Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy
| | - Emanuele Crincoli
- School of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Division of Head and Neck, Ophthalmology Unit, Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy
| | - Riccardo Sacconi
- School of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Division of Head and Neck, Ophthalmology Unit, Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy
| | - Marco Battista
- School of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Division of Head and Neck, Ophthalmology Unit, Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy
| | - Federico Fantaguzzi
- School of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Division of Head and Neck, Ophthalmology Unit, Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy
| | - Andrea Servillo
- School of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Division of Head and Neck, Ophthalmology Unit, Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy
| | - Francesco Bandello
- School of Medicine, Vita-Salute San Raffaele University, Milan, Italy
- Division of Head and Neck, Ophthalmology Unit, Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy
| | - Giuseppe Querques
- School of Medicine, Vita-Salute San Raffaele University, Milan, Italy.
- Division of Head and Neck, Ophthalmology Unit, Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy.
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Miao Y, Siadati M, Song J, Ma D, Jian Y, Beg MF, Sarunic MV, Ju MJ. Phase-corrected buffer averaging for enhanced OCT angiography using FDML laser. Opt Lett 2021; 46:3833-3836. [PMID: 34388753 DOI: 10.1364/ol.430915] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 07/07/2021] [Indexed: 05/18/2023]
Abstract
Megahertz-rate optical coherence tomography angiography (OCTA) is highly anticipated as an ultrafast imaging tool in clinical settings. However, shot-noise-limited sensitivity is inevitably reduced in high-speed imaging systems. In this Letter, we present a coherent buffer averaging technique for use with a Fourier-domain mode-locked (FDML) laser to improve OCTA contrast at 1060 nm MHz-rate retinal imaging. Full characterization of spectral variations among the FDML buffers and a numerical correction method are also presented, with the results demonstrating a 10-fold increase in the phase alignment among buffers. Coherent buffer averaging provided better OCTA contrast than the conventional multi-frame averaging approach with a faster acquisition time.
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Greig EC, Laver NV, Mendonca LS, Levine ES, Baumal CR, Waheed NK, Duker JS. SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN SMALL CHOROIDAL MELANOMAS AND CHOROIDAL NEVI. Retina 2021; 41:1182-1192. [PMID: 33315830 PMCID: PMC8140669 DOI: 10.1097/iae.0000000000003053] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE To evaluate the use of swept-source optical coherence tomography angiography to detect distinct vascular features in small choroidal melanomas and choroidal nevi. METHODS Patients with a choroidal nevus or a treatment-naïve choroidal melanoma were imaged with color fundus photography, ultrasound, and swept-source optical coherence tomography angiography (12 × 12 mm). High-risk features including overlying fluid, orange pigment, shaggy photoreceptors, acoustic hollowness, depth >2 mm, and basal diameter >5 mm were assessed. Optical coherence tomography angiography vascular markers included: choroidal vessel visualization, choroidal vessel depth, and choriocapillaris flow signal, assessed qualitatively by comparison with surrounding, unaffected choriocapillaris. RESULTS Twenty-nine lesions were included in this study, seven flat choroidal nevi, 17 elevated choroidal nevi, and 5 choroidal melanomas. Distinct vascular patterns were noted between flat nevi, elevated nevi, and small choroidal melanomas. Choroidal melanomas displayed two types of vasculature: "nevus-like" vasculature with straight parallel vessels and complex vasculature with vascular loops and crosslinking. Visualized choroidal vessels were significantly deeper in melanomas (110 µm) than elevated (84 µm) or flat nevi (70 µm). In a size-matched subanalysis of 5 elevated choroidal nevi and 5 choroidal melanomas, choroidal melanomas had increased mean choroidal vessel depth (P = 0.015), deepest choroidal vessel visualized (P = 0.034), and presence of a deep choroidal vessel >155 µm (P = 0.048). CONCLUSION Swept-source optical coherence tomography angiography may detect distinct vascular features in choroidal nevi and small choroidal melanomas.
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Affiliation(s)
- Eugenia Custo Greig
- Department of Ophthalmology, New England Eye Center, Tufts Medical Center, Boston, Massachusetts
- Yale School of Medicine, New Haven, Connecticut; and
| | - Nora V. Laver
- Department of Ophthalmology, New England Eye Center, Tufts Medical Center, Boston, Massachusetts
| | - Luisa S.M. Mendonca
- Department of Ophthalmology, New England Eye Center, Tufts Medical Center, Boston, Massachusetts
- Department of Ophthalmology, Federal University of Sao Paulo, Sao Paulo, Brazil.
| | - Emily S. Levine
- Department of Ophthalmology, New England Eye Center, Tufts Medical Center, Boston, Massachusetts
| | - Caroline R. Baumal
- Department of Ophthalmology, New England Eye Center, Tufts Medical Center, Boston, Massachusetts
| | - Nadia K. Waheed
- Department of Ophthalmology, New England Eye Center, Tufts Medical Center, Boston, Massachusetts
| | - Jay S. Duker
- Department of Ophthalmology, New England Eye Center, Tufts Medical Center, Boston, Massachusetts
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Abstract
Optical coherence tomography (OCT) is a non-invasive investigative technique that is used to obtain high-resolution three-dimensional (3D) images of biological structures. This method is useful in diagnosing diseases of specific organs like the eye, where a direct biopsy cannot be conducted. Since its inception, significant advancements have been made in its technology. Apart from its initial application in ophthalmology for retinal imaging, substantial technological innovations in OCT brought by the research community have enabled its utilization beyond its original scope and allowed its application in many new clinical areas. This review presents a summary of the clinical applications of OCT in the field of medicine (ophthalmology, cardiology, otology, and dermatology) and dentistry (tissue imaging, detection of caries, analysis of dental polymer composite restorations, imaging of root canals, and diagnosis of oral cancer). In addition, potential advantages and disadvantages of OCT are also discussed.
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Affiliation(s)
- Saqib Ali
- Department of Biomedical Dental Sciences, College of Dentistry, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Saqlain Bin Syed Gilani
- Department of Oral Biology, Islamic International Dental College, Riphah International University, Islamabad, Pakistan
| | - Juzer Shabbir
- Department of Operative Dentistry and Endodontics, Liaquat College of Medicine and Dentistry, Karachi, Pakistan
| | - Khalid S Almulhim
- Department of Restorative Dental Sciences, College of Dentistry, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Amr Bugshan
- Department of Biomedical Dental Sciences, College of Dentistry, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Imran Farooq
- Faculty of Dentistry, University of Toronto, Toronto, ON, M5G 1G6, Canada
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Athwal A, Balaratnasingam C, Yu DY, Heisler M, Sarunic MV, Ju MJ. Optimizing 3D retinal vasculature imaging in diabetic retinopathy using registration and averaging of OCT-A. Biomed Opt Express 2021; 12:553-570. [PMID: 33659089 PMCID: PMC7899521 DOI: 10.1364/boe.408590] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/06/2020] [Accepted: 12/07/2020] [Indexed: 05/29/2023]
Abstract
High resolution visualization of optical coherence tomography (OCT) and OCT angiography (OCT-A) data is required to fully take advantage of the imaging modality's three-dimensional nature. However, artifacts induced by patient motion often degrade OCT-A data quality. This is especially true for patients with deteriorated focal vision, such as those with diabetic retinopathy (DR). We propose a novel methodology for software-based OCT-A motion correction achieved through serial acquisition, volumetric registration, and averaging. Motion artifacts are removed via a multi-step 3D registration process, and visibility is significantly enhanced through volumetric averaging. We demonstrate that this method permits clear 3D visualization of retinal pathologies and their surrounding features, 3D visualization of inner retinal capillary connections, as well as reliable visualization of the choriocapillaris layer.
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Affiliation(s)
- Arman Athwal
- School of Engineering Science, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Chandrakumar Balaratnasingam
- Centre for Ophthalmology and Visual Science, University of Western Australia, Perth, Australia
- Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Dao-Yi Yu
- Centre for Ophthalmology and Visual Science, University of Western Australia, Perth, Australia
- Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Morgan Heisler
- School of Engineering Science, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Marinko V. Sarunic
- School of Engineering Science, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Myeong Jin Ju
- School of Engineering Science, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
- University of British Columbia, Department of Ophthalmology and Visual Sciences, 2550 Willow Street, Vancouver, BC, V5Z 3N9, Canada
- University of British Columbia, School of Biomedical Engineering, 251–2222 Health Sciences Mall, Vancouver, BC, V6 T 1Z3, Canada
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7
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Greig EC, Duker JS, Waheed NK. A practical guide to optical coherence tomography angiography interpretation. Int J Retina Vitreous 2020; 6:55. [PMID: 33292740 PMCID: PMC7666474 DOI: 10.1186/s40942-020-00262-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 11/05/2020] [Indexed: 12/16/2022] Open
Abstract
Background Optical coherence tomography angiography (OCTA) can image the retinal vasculature in vivo, without the need for contrast dye. This technology has been commercially available since 2014, however, much of its use has been limited to the research setting. Over time, more clinical practices have adopted OCTA imaging. While countless publications detail OCTA’s use for the study of retinal microvasculature, few studies outline OCTA’s clinical utility. Body This review provides an overview of OCTA imaging and details tips for successful interpretation. The review begins with a summary of OCTA technology and artifacts that arise from image acquisition. New methods and best practices to prevent image artifacts are discussed. OCTA has the unique ability among retinovascular imaging modalities to individually visualize each retinal plexus. Slabs offered in standard OCTA devices are reviewed, and clinical uses for each slab are outlined. Lastly, the use of OCTA for the clinical interpretation of retinal pathology, such as diabetic retinopathy and age-related macular degeneration, is discussed. Conclusion OCTA is evolving from a scientific tool to a clinical imaging device. This review provides a toolkit for successful image interpretation in a clinical setting.
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Affiliation(s)
- Eugenia Custo Greig
- New England Eye Center, Tufts Medical Center, 800 Washington Street, Box 450, Boston, MA, 02111, USA.,Yale School of Medicine, New Haven, CT, USA
| | - Jay S Duker
- New England Eye Center, Tufts Medical Center, 800 Washington Street, Box 450, Boston, MA, 02111, USA
| | - Nadia K Waheed
- New England Eye Center, Tufts Medical Center, 800 Washington Street, Box 450, Boston, MA, 02111, USA.
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8
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Tan B, Sim R, Chua J, Wong DWK, Yao X, Garhöfer G, Schmidl D, Werkmeister RM, Schmetterer L. Approaches to quantify optical coherence tomography angiography metrics. Ann Transl Med 2020; 8:1205. [PMID: 33241054 PMCID: PMC7576021 DOI: 10.21037/atm-20-3246] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Optical coherence tomography (OCT) has revolutionized the field of ophthalmology in the last three decades. As an OCT extension, OCT angiography (OCTA) utilizes a fast OCT system to detect motion contrast in ocular tissue and provides a three-dimensional representation of the ocular vasculature in a non-invasive, dye-free manner. The first OCT machine equipped with OCTA function was approved by U.S. Food and Drug Administration in 2016 and now it is widely applied in clinics. To date, numerous methods have been developed to aid OCTA interpretation and quantification. In this review, we focused on the workflow of OCTA-based interpretation, beginning from the generation of the OCTA images using signal decorrelation, which we divided into intensity-based, phase-based and phasor-based methods. We further discussed methods used to address image artifacts that are commonly observed in clinical settings, to the algorithms for image enhancement, binarization, and OCTA metrics extraction. We believe a better grasp of these technical aspects of OCTA will enhance the understanding of the technology and its potential application in disease diagnosis and management. Moreover, future studies will also explore the use of ocular OCTA as a window to link ocular vasculature to the function of other organs such as the kidney and brain.
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Affiliation(s)
- Bingyao Tan
- Institute for Health Technologies, Nanyang Technological University, Singapore, Singapore.,Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE) Program, Nanyang Technological University, Singapore, Singapore
| | - Ralene Sim
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Jacqueline Chua
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore
| | - Damon W K Wong
- Institute for Health Technologies, Nanyang Technological University, Singapore, Singapore.,Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE) Program, Nanyang Technological University, Singapore, Singapore
| | - Xinwen Yao
- Institute for Health Technologies, Nanyang Technological University, Singapore, Singapore.,Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE) Program, Nanyang Technological University, Singapore, Singapore
| | - Gerhard Garhöfer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Doreen Schmidl
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - René M Werkmeister
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Leopold Schmetterer
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE) Program, Nanyang Technological University, Singapore, Singapore.,Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore.,Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore, Singapore.,Department of Ophthalmology, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.,Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
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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. Biomed Opt 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] [What about the content of this article? (0)] [Affiliation(s)] [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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10
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Shi Y, Zhang Q, Zheng F, Russell JF, Motulsky EH, Banta JT, Chu Z, Zhou H, Patel NA, de Sisternes L, Durbin MK, Feuer W, Gregori G, Wang RK, Rosenfeld PJ. Correlations Between Different Choriocapillaris Flow Deficit Parameters in Normal Eyes Using Swept Source OCT Angiography. Am J Ophthalmol 2020; 209:18-26. [PMID: 31562858 PMCID: PMC7017580 DOI: 10.1016/j.ajo.2019.09.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 09/16/2019] [Accepted: 09/17/2019] [Indexed: 11/24/2022]
Abstract
PURPOSE Choriocapillaris (CC) imaging of normal eyes with swept-source optical coherence tomographic angiography (SS-OCTA) was performed, and the percentage of CC flow deficits (FD%) and the average area of CC flow deficits (FDa) were compared within the given macular regions. DESIGN A prospective, cross-sectional study. METHODS Subjects with normal eyes ranging in age from their 20s through their 80s were imaged with SS-OCTA (PLEX Elite 9000; Carl Zeiss Meditec, Dublin, California, USA) using both 3×3-mm and 6×6-mm macular scan patterns. The CC images were generated using a previously published and validated algorithm. In both 3×3-mm and 6×6-mm scans, the CC FD% and FDa were measured in circular regions centered on the fovea with diameters as 1 mm and 2.5 mm (C1 and C2.5). In 6×6-mm scans, the FD% and FDa were measured within an additional circular region with diameter as 5 mm (C5). The correlations between FD% and FDa from each region were analyzed with Pearson correlation coefficients. RESULTS A total of 164 eyes were analyzed. There was excellent correlation between CC FDa and FD% measurements from each region. In the 3×3-mm scans, the correlations in the C1 and C2.5 regions were 0.83 and 0.90, respectively. In the 6×6-mm scans, the correlations in C1, C2.5, and C5 regions were 0.90, 0.89, and 0.89, respectively. CONCLUSIONS When measuring CC FDs, we found excellent correlations between FDa and FD% in regions from 3×3-mm and 6×6-mm scans. Further studies are needed to determine if one parameter is more useful when studying diseased eyes.
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Affiliation(s)
- Yingying Shi
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Qinqin Zhang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Fang Zheng
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Jonathan F Russell
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Elie H Motulsky
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - James T Banta
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Zhongdi Chu
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Hao Zhou
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Nimesh A Patel
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Luis de Sisternes
- Research and Development, Carl Zeiss Meditec, Inc, Dublin, California, USA
| | - Mary K Durbin
- Research and Development, Carl Zeiss Meditec, Inc, Dublin, California, USA
| | - William Feuer
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Giovanni Gregori
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Philip J Rosenfeld
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA.
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11
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Borrelli E, Sadda SR, Uji A, Querques G. Pearls and Pitfalls of Optical Coherence Tomography Angiography Imaging: A Review. Ophthalmol Ther 2019; 8:215-26. [PMID: 30868418 DOI: 10.1007/s40123-019-0178-6] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Indexed: 12/28/2022] Open
Abstract
Optical coherence tomography angiography (OCTA) has significantly expanded our knowledge of the ocular vasculature. Furthermore, this imaging modality has been widely adopted to investigate different ocular and systemic diseases. In this review, a discussion of the fundamental principles of OCTA is followed by the application of this imaging modality to study the retinal and choroidal vessels. A proper comprehension of this imaging modality is essential for the interpretation of OCTA imaging applications in retinal and choroidal disorders.
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12
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Rani PK, Prajapati RC. Role of OCT Angiography in the Detection of Retinal Vascular and Macular Abnormalities in Subjects with Asteroid Hyalosis. Semin Ophthalmol 2019; 34:42-46. [PMID: 30475665 DOI: 10.1080/08820538.2018.1551497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 11/15/2018] [Indexed: 10/27/2022]
Abstract
Purpose: To study the role of Optical coherence tomography (OCT) Angiography (OCTA) in detecting retinal vascular and macular abnormalities as compared to Fundus Fluorescein Angiography (FFA) in subjects with Asteroid hyalosis (AH).Methods: In a prospective study, patients with AH underwent OCTA and FFA. AH graded as Grade 1 in 8 (optic disc, second order vessels visible), Grade 2 in 4 (optic disc, first-order vessels visible), Grade 3 in 11 (hazy view of optic disc) and Grade 4 (no view of fundus) in 2 eyes.Results: A total of 20 patients (25 eyes) with AH were included. In comparison to FFA, OCTA was able to similarly detect Diabetic Retinopathy changes such as Neovascularization, microaneurysms, capillary dropout, and foveal avascular zone extent in vascular occlusion in all grades of AH.Conclusion: OCTA, a noninvasive imaging tool, could detect various retinal vascular and macular abnormalities in patients with all grades of AH in comparison to FFA.
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Affiliation(s)
- Padmaja Kumari Rani
- Smt. Kanuri Santhamma Retina Vitreous Centre, L V Prasad Eye Institute, Hyderabad, India
| | - Reena C Prajapati
- Smt. Kanuri Santhamma Retina Vitreous Centre, L V Prasad Eye Institute, Hyderabad, India
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Migacz JV, Gorczynska I, Azimipour M, Jonnal R, Zawadzki RJ, Werner JS. Megahertz-rate optical coherence tomography angiography improves the contrast of the choriocapillaris and choroid in human retinal imaging. Biomed Opt Express 2019; 10:50-65. [PMID: 30775082 PMCID: PMC6363198 DOI: 10.1364/boe.10.000050] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 11/25/2018] [Accepted: 11/27/2018] [Indexed: 05/03/2023]
Abstract
Angiographic imaging of the human eye with optical coherence tomography (OCT) is becoming an increasingly important tool in the scientific investigation and clinical management of several blinding diseases, including age-related macular degeneration and diabetic retinopathy. We have observed that OCT angiography (OCTA) of the human choriocapillaris and choroid with a 1.64 MHz A-scan rate swept-source laser yields higher contrast images as compared to a slower rate system operating at 100 kHz. This result is unexpected because signal sensitivity is reduced when acquisition rates are increased, and the incident illumination power is kept constant. The contrast of angiography images generated by acquiring multiple sequential frames and calculating the variation caused by blood flow, however, appears to be improved significantly when lower-contrast images are taken more rapidly. To demonstrate that the acquisition rate plays a role in the quality improvement, we have imaged five healthy subjects with a narrow field of view (1.2 mm) OCTA imaging system using two separate swept-source lasers of different A-line rates and compared the results quantitatively using the radially-averaged power spectrum. The average improvement in the contrast is 23.0% (+/-7.6%). Although the underlying cause of this enhancement is not explicitly determined here, we speculate that the higher-speed system suppresses the noise contribution from eye motion in subjects and operates with an inter-scan time that better discriminates the flow velocities present in the choroid and choriocapillaris. Our result informs OCT system developers on the merits of ultrahigh-speed acquisition in functional imaging applications.
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Affiliation(s)
- Justin V. Migacz
- Vison Science and Advanced Retinal Imaging Laboratory, Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA 95817, USA
| | - Iwona Gorczynska
- Vison Science and Advanced Retinal Imaging Laboratory, Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA 95817, USA
- Institute of Physics, Faculty of Physics, Astronomy, and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
| | - Mehdi Azimipour
- Vison Science and Advanced Retinal Imaging Laboratory, Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA 95817, USA
| | - Ravi Jonnal
- Vison Science and Advanced Retinal Imaging Laboratory, Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA 95817, USA
| | - Robert J. Zawadzki
- Vison Science and Advanced Retinal Imaging Laboratory, Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA 95817, USA
| | - John S. Werner
- Vison Science and Advanced Retinal Imaging Laboratory, Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA 95817, USA
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Abstract
Retinal imaging has undergone a revolution in the past 50 years to allow for better understanding of the eye in health and disease. Significant improvements have occurred both in hardware such as lasers and optics in addition to software image analysis. Optical imaging modalities include optical coherence tomography (OCT), OCT angiography (OCTA), photoacoustic microscopy (PAM), scanning laser ophthalmoscopy (SLO), adaptive optics (AO), fundus autofluorescence (FAF), and molecular imaging (MI). These imaging modalities have enabled improved visualization of retinal pathophysiology and have had a substantial impact on basic and translational medical research. These improvements in technology have translated into early disease detection, more accurate diagnosis, and improved management of numerous chorioretinal diseases. This article summarizes recent advances and applications of retinal optical imaging techniques, discusses current clinical challenges, and predicts future directions in retinal optical imaging.
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Affiliation(s)
- Yanxiu Li
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Xiaobo Xia
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Yannis M. Paulus
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48015, USA
- Correspondence: ; Tel.: +1-734-232-8105; Fax: +1-734-936-3815
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Abstract
Optical coherence tomography angiography (OCTA) is a novel non-invasive imaging modality for 3-dimensional visualization of retinal and optic nerve capillary networks. In this article, a comprehensive review of relevant original articles in the PubMed database was performed using the search terms "diabetic retinopathy," "diabetic macular edema," "diabetes mellitus," and "optical coherence tomography angiography." OCTA was found to detect microvascular changes early in diabetes mellitus, even before they become clinically evident. Morphological and qualitative assessment of vascular changes can help to determine the pathophysiological processes, activity, treatment, and follow-up of diabetic retinopathy (DR). Vessel density and foveal avascular zone are the most investigated quantified indices shown to be early predictors of DR, correlated to DR severity and visual function, and useful in predicting response to treatment. OCTA has shown to be a promising alternative to fluorescein angiography in the management of DR. Further studies are warranted to determine the role of OCTA in the routine clinical management of DR.
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Affiliation(s)
- Joobin Khadamy
- Eye Research Center, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Kaveh Abri Aghdam
- Eye Research Center, Rassoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran
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