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Liang C, Xu Y, Xia Q, Xiao D, Gu J, Zhu X, Chen C, Chen Z, Hua D. Assessment of retinal and choroidal microvasculature in night shift medical workers by OCT angiography. Sci Rep 2024; 14:12718. [PMID: 38830921 PMCID: PMC11148059 DOI: 10.1038/s41598-024-62863-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 05/22/2024] [Indexed: 06/05/2024] Open
Abstract
This study evaluated retinal and choroidal microvascular changes in night shift medical workers and its correlation with melatonin level. Night shift medical workers (group A, 25 workers) and non-night shift workers (group B, 25 workers) were recruited. The images of macula and optic nerve head were obtained by swept-source OCT-angiography. Vessel density of retina, choriocapillaris (CC), choriocapillaris flow deficit (CC FD), choroidal thickness (CT) and choroidal vascularity index (CVI) were measured. 6-sulfatoxymelatonin concentration was analyzed from the morning urine. CC FD and CVI were significantly decreased and CT was significantly increased in group A (all P < 0.05). 6-sulfatoxymelatonin concentration was significantly lower in group A (P < 0.05), which was significantly positively correlated with CC FD size (r = 0.318, P = 0.024) and CVI of the most regions (maximum r-value was 0.482, P < 0.001), and was significantly negatively associated with CT of all regions (maximum r-value was - 0.477, P < 0.001). In night shift medical workers, the reduction of melatonin was significantly correlated with CT thickening, CVI reduction and CC FD reduction, which suggested that they might have a higher risk of eye diseases. CC FD could be a sensitive and accurate indicator to reflect CC perfusion.
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Affiliation(s)
- Congbi Liang
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuchang District, Wuhan, 430060, Hubei, China
| | - Yishuang Xu
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuchang District, Wuhan, 430060, Hubei, China
| | - Qinyun Xia
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuchang District, Wuhan, 430060, Hubei, China
| | - Di Xiao
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuchang District, Wuhan, 430060, Hubei, China
| | - Jingsai Gu
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuchang District, Wuhan, 430060, Hubei, China
| | - Xiangxiang Zhu
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuchang District, Wuhan, 430060, Hubei, China
| | - Changzheng Chen
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuchang District, Wuhan, 430060, Hubei, China.
| | - Zhen Chen
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuchang District, Wuhan, 430060, Hubei, China.
| | - Dihao Hua
- Eye Center, Renmin Hospital of Wuhan University, 238 Jiefang Road, Wuchang District, Wuhan, 430060, Hubei, China.
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Zhang X, Jiang J, Kong K, Li F, Chen S, Wang P, Song Y, Lin F, Lin TPH, Zangwill LM, Ohno-Matsui K, Jonas JB, Weinreb RN, Lam DSC. Optic neuropathy in high myopia: Glaucoma or high myopia or both? Prog Retin Eye Res 2024; 99:101246. [PMID: 38262557 DOI: 10.1016/j.preteyeres.2024.101246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 01/17/2024] [Accepted: 01/19/2024] [Indexed: 01/25/2024]
Abstract
Due to the increasing prevalence of high myopia around the world, structural and functional damages to the optic nerve in high myopia has recently attracted much attention. Evidence has shown that high myopia is related to the development of glaucomatous or glaucoma-like optic neuropathy, and that both have many common features. These similarities often pose a diagnostic challenge that will affect the future management of glaucoma suspects in high myopia. In this review, we summarize similarities and differences in optic neuropathy arising from non-pathologic high myopia and glaucoma by considering their respective structural and functional characteristics on fundus photography, optical coherence tomography scanning, and visual field tests. These features may also help to distinguish the underlying mechanisms of the optic neuropathies and to determine management strategies for patients with high myopia and glaucoma.
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Affiliation(s)
- Xiulan Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, 510060, China.
| | - Jingwen Jiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, 510060, China.
| | - Kangjie Kong
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, 510060, China.
| | - Fei Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, 510060, China.
| | - Shida Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, 510060, China.
| | - Peiyuan Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, 510060, China.
| | - Yunhe Song
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, 510060, China.
| | - Fengbin Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, 510060, China.
| | - Timothy P H Lin
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.
| | - Linda M Zangwill
- Hamilton Glaucoma Center, Viterbi Family Department of Ophthalmology and Shiley Eye Institute, University of California San Diego, La Jolla, CA, USA.
| | - Kyoko Ohno-Matsui
- Department of Ophthalmology and Visual Science, Tokyo Medical and Dental University, Tokyo, Japan.
| | - Jost B Jonas
- Department of Ophthalmology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland.
| | - Robert N Weinreb
- Hamilton Glaucoma Center, Viterbi Family Department of Ophthalmology and Shiley Eye Institute, University of California San Diego, La Jolla, CA, USA.
| | - Dennis S C Lam
- The International Eye Research Institute of the Chinese University of Hong Kong (Shenzhen), Shenzhen, China; The C-MER Dennis Lam & Partners Eye Center, C-MER International Eye Care Group, Hong Kong, China.
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3
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Abu-Qamar O, Lewis W, Mendonca LSM, De Sisternes L, Chin A, Alibhai AY, Gendelman I, Reichel E, Magazzeni S, Kubach S, Durbin M, Witkin AJ, Baumal CR, Duker JS, Waheed NK. Pseudoaveraging for denoising of OCT angiography: a deep learning approach for image quality enhancement in healthy and diabetic eyes. Int J Retina Vitreous 2023; 9:62. [PMID: 37822004 PMCID: PMC10568842 DOI: 10.1186/s40942-023-00486-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 08/02/2023] [Indexed: 10/13/2023] Open
Abstract
BACKGROUND This study aimed to develop a deep learning (DL) algorithm that enhances the quality of a single-frame enface OCTA scan to make it comparable to 4-frame averaged scan without the need for the repeated acquisitions required for averaging. METHODS Each of the healthy eyes and eyes from diabetic subjects that were prospectively enrolled in this cross-sectional study underwent four repeated 6 × 6 mm macular scans (PLEX Elite 9000 SS-OCT), and the repeated scans of each eye were co-registered to produce 4-frame averages. This prospective dataset of original (single-frame) enface scans and their corresponding averaged scans was divided into a training dataset and a validation dataset. In the training dataset, a DL algorithm (named pseudoaveraging) was trained using original scans as input and 4-frame averages as target. In the validation dataset, the pseudoaveraging algorithm was applied to single-frame scans to produce pseudoaveraged scans, and the single-frame and its corresponding averaged and pseudoaveraged scans were all qualitatively compared. In a separate retrospectively collected dataset of single-frame scans from eyes of diabetic subjects, the DL algorithm was applied, and the produced pseudoaveraged scan was qualitatively compared against its corresponding original. RESULTS This study included 39 eyes that comprised the prospective dataset (split into 5 eyes for training and 34 eyes for validating the DL algorithm), and 105 eyes that comprised the retrospective test dataset. Of the total 144 study eyes, 58% had any level of diabetic retinopathy (with and without diabetic macular edema), and the rest were from healthy eyes or eyes of diabetic subjects but without diabetic retinopathy and without macular edema. Grading results in the validation dataset showed that the pseudoaveraged enface scan ranked best in overall scan quality, background noise reduction, and visibility of microaneurysms (p < 0.05). Averaged scan ranked best for motion artifact reduction (p < 0.05). Grading results in the test dataset showed that pseudoaveraging resulted in enhanced small vessels, reduction of background noise, and motion artifact in 100%, 82%, and 98% of scans, respectively. Rates of false-positive/-negative perfusion were zero. CONCLUSION Pseudoaveraging is a feasible DL approach to more efficiently improve enface OCTA scan quality without introducing notable image artifacts.
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Affiliation(s)
- Omar Abu-Qamar
- New England Eye Center, Tufts Medical Center, 800 Washington St., Box 450, Boston, MA, 02111, USA
| | - Warren Lewis
- Research and Development, Carl Zeiss Meditec, Dublin, CA, 94568, USA
| | - Luisa S M Mendonca
- New England Eye Center, Tufts Medical Center, 800 Washington St., Box 450, Boston, MA, 02111, USA
- Department of Ophthalmology, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Luis De Sisternes
- Research and Development, Carl Zeiss Meditec, Dublin, CA, 94568, USA
| | - Adam Chin
- New England Eye Center, Tufts Medical Center, 800 Washington St., Box 450, Boston, MA, 02111, USA
| | - A Yasin Alibhai
- Boston Image Reading Center, 55 Causeway street, Boston, MA, 02114, USA
| | - Isaac Gendelman
- New England Eye Center, Tufts Medical Center, 800 Washington St., Box 450, Boston, MA, 02111, USA
| | - Elias Reichel
- New England Eye Center, Tufts Medical Center, 800 Washington St., Box 450, Boston, MA, 02111, USA
| | | | - Sophie Kubach
- Research and Development, Carl Zeiss Meditec, Dublin, CA, 94568, USA
| | - Mary Durbin
- Research and Development, Carl Zeiss Meditec, Dublin, CA, 94568, USA
| | - Andre J Witkin
- New England Eye Center, Tufts Medical Center, 800 Washington St., Box 450, Boston, MA, 02111, USA
| | - Caroline R Baumal
- New England Eye Center, Tufts Medical Center, 800 Washington St., Box 450, Boston, MA, 02111, USA
| | - Jay S Duker
- New England Eye Center, Tufts Medical Center, 800 Washington St., Box 450, Boston, MA, 02111, USA
| | - Nadia K Waheed
- New England Eye Center, Tufts Medical Center, 800 Washington St., Box 450, Boston, MA, 02111, USA.
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Cabral D, Fradinho AC, Zhang Y, Zhou H, Ramtohul P, Ramakrishnan MS, Pereira T, Wang RK, Freund KB. Quantitative assessment of choriocapillaris flow deficits and type 1 macular neovascularization growth in age-related macular degeneration. Sci Rep 2023; 13:8572. [PMID: 37236984 DOI: 10.1038/s41598-023-35080-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 05/12/2023] [Indexed: 05/28/2023] Open
Abstract
During the past 15 years, new treatment paradigms for neovascular age-related macular degeneration (nvAMD) have evolved due to the advent of intravitreal anti-vascular endothelial growth factor (VEGF) therapy and rapid advances in retinal imaging. Recent publications describe eyes with type 1 macular neovascularization (MNV) as showing more resistance to macular atrophy than eyes with other lesion types. We sought to explore whether the perfusion status of the native choriocapillaris (CC) surrounding type 1 MNV influences its pattern of growth. To evaluate this effect, we analyzed a case series of 22 eyes from 19 nvAMD patients with type 1 MNV exhibiting growth on swept-source optical coherence tomography angiography (SS-OCTA) over a minimum follow-up of 12 months. We observed an overall weak correlation between type 1 MNV growth and CC flow deficits (FDs) average size (τ = 0.17, 95% CI [- 0.20, 0.62]) and a moderate correlation with CC FD % (τ = 0.21, 95% CI [- 0.16, 0.68]). Type 1 MNV was located beneath the fovea in most of the eyes (86%) and median visual acuity was 20/35 Snellen equivalent. Our results support that type 1 MNV recapitulates areas of CC blood flow impairment while serving to preserve foveal function.
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Affiliation(s)
- Diogo Cabral
- Vitreous Retina Macula Consultants of New York, 950 Third Ave, New York, NY, 10022, USA
- iNOVA4Health, NOVA Medical School I Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisbon, Portugal
- Department of Ophthalmology, NYU Grossman School of Medicine, New York, NY, USA
| | - Ana C Fradinho
- iNOVA4Health, NOVA Medical School I Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Yi Zhang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Hao Zhou
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Prithvi Ramtohul
- Vitreous Retina Macula Consultants of New York, 950 Third Ave, New York, NY, 10022, USA
- Department of Ophthalmology, NYU Grossman School of Medicine, New York, NY, USA
| | - Meera S Ramakrishnan
- Vitreous Retina Macula Consultants of New York, 950 Third Ave, New York, NY, 10022, USA
- Department of Ophthalmology, NYU Grossman School of Medicine, New York, NY, USA
| | - Telmo Pereira
- iNOVA4Health, NOVA Medical School I Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Department of Ophthalmology, University of Washington, Seattle, WA, USA
| | - K Bailey Freund
- Vitreous Retina Macula Consultants of New York, 950 Third Ave, New York, NY, 10022, USA.
- Department of Ophthalmology, NYU Grossman School of Medicine, New York, NY, USA.
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5
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Li J, Liu Z, Lu J, Shen M, Cheng Y, Siddiqui N, Zhou H, Zhang Q, Liu J, Herrera G, Hiya FE, Gregori G, Wang RK, Rosenfeld PJ. Decreased Macular Choriocapillaris Perfusion in Eyes With Macular Reticular Pseudodrusen Imaged With Swept-Source OCT Angiography. Invest Ophthalmol Vis Sci 2023; 64:15. [PMID: 37052925 PMCID: PMC10103727 DOI: 10.1167/iovs.64.4.15] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023] Open
Abstract
Purpose To determine if macular reticular pseudodrusen (RPD) were associated with markers of impaired macular choroidal perfusion, we investigated measurements of macular choriocapillaris (CC) flow deficits (FDs), CC thickness, and mean choroidal thickness (MCT) in eyes with macular RPD compared with normal eyes and eyes with soft drusen. Methods Eyes with intermediate age-related macular degeneration (iAMD) and normal eyes underwent 6 × 6 mm swept-source optical coherence tomography angiography (SS-OCTA) imaging to diagnose macular RPD, occupying over 25% of the fovea-centered 5 mm diameter circle, and measure outer retinal layer (ORL) thickness, CC FDs, CC thickness, MCT, and choroidal vascularity index (CVI) using previously published strategies within the same fovea-centered 5 mm circle. Results Ninety eyes were included; 30 normal eyes, 30 eyes with soft drusen, and 30 eyes with macular RPD. The RPD eyes showed higher macular CC FDs than normal eyes (P < 0.001) and soft drusen eyes (P = 0.019). Macular CC thickness was decreased in RPD eyes compared with normal eyes (P < 0.001) and soft drusen eyes (P = 0.016). Macular MCT in RPD eyes was thinner than normal eyes (P = 0.005) and soft drusen eyes (P < 0.001). No statistically and clinically significant differences were found in the ORL thickness and CVI measurements between RPD eyes and the other two groups (all P > 0.05). Conclusions Eyes with macular RPD had decreased macular CC perfusion, decreased CC thickness, and decreased MCT measurements compared with normal and soft drusen eyes, suggesting that RPD may result from impaired choroidal perfusion.
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Affiliation(s)
- Jianqing Li
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
- Department of Ophthalmology, First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Ziyu Liu
- Department of Bioengineering, University of Washington, Seattle, Washington, United States
| | - Jie Lu
- Department of Bioengineering, University of Washington, Seattle, Washington, United States
| | - Mengxi Shen
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
| | - Yuxuan Cheng
- Department of Bioengineering, University of Washington, Seattle, Washington, United States
| | - Nadia Siddiqui
- Department of Bioengineering, University of Washington, Seattle, Washington, United States
| | - Hao Zhou
- Department of Bioengineering, University of Washington, Seattle, Washington, United States
| | - Qinqin Zhang
- Research and Development, Carl Zeiss Meditec, Inc., Dublin, California, United States
| | - Jeremy Liu
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
| | - Gissel Herrera
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
| | - Farhan E Hiya
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
| | - Giovanni Gregori
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, United States
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Philip J Rosenfeld
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
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Lal B, Alonso-Caneiro D, Read SA, Carkeet A. Diurnal changes in choroidal optical coherence tomography angiography indices over 24 hours in healthy young adults. Sci Rep 2023; 13:3551. [PMID: 36864086 PMCID: PMC9981752 DOI: 10.1038/s41598-023-30433-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 02/22/2023] [Indexed: 03/04/2023] Open
Abstract
This prospective study investigated the magnitude and pattern of variation in choroidal optical coherence tomography angiography (OCT-A) indices every 4 h over 24 h in healthy young myopic (n = 24) and non-myopic (n = 20) adults. Choriocapillaris and deep choroid en-face images from macular OCT-A scans were analysed from each session to extract magnification-corrected vascular indices including choriocapillaris flow deficit number, size and density and deep choroid perfusion density in the sub-foveal, sub-parafoveal, and sub-perifoveal regions. Choroidal thickness was also obtained from structural OCT scans. Significant variations over 24 h (P < 0.05) were observed in most of the choroidal OCT-A indices excluding sub-perifoveal flow deficit number, with peaks observed between 2 to 6 AM. For myopes, peaks occurred significantly earlier (3-5 h), and the diurnal amplitude was significantly greater for sub-foveal flow deficit density (P = 0.02) and deep choroidal perfusion density (P = 0.03) compared with non-myopes. Choroidal thickness also showed significant diurnal changes (P < 0.05) with peaks between 2 to 4 AM. Significant correlations were found between diurnal amplitudes or acrophases of choroidal OCT-A indices and choroidal thickness, intraocular pressure, and systemic blood pressure. This provides the first comprehensive diurnal assessment of choroidal OCT-A indices over 24 h.
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Affiliation(s)
- Barsha Lal
- Centre for Vision and Eye Research, School of Optometry and Vision Science, Queensland University of Technology, Kelvin Grove, Brisbane, Australia.
| | - David Alonso-Caneiro
- Centre for Vision and Eye Research, School of Optometry and Vision Science, Queensland University of Technology, Kelvin Grove, Brisbane, Australia
| | - Scott A Read
- Centre for Vision and Eye Research, School of Optometry and Vision Science, Queensland University of Technology, Kelvin Grove, Brisbane, Australia
| | - Andrew Carkeet
- Centre for Vision and Eye Research, School of Optometry and Vision Science, Queensland University of Technology, Kelvin Grove, Brisbane, Australia
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López-Varela E, de Moura J, Novo J, Fernández-Vigo JI, Moreno-Morillo FJ, Ortega M. Fully automatic segmentation and monitoring of choriocapillaris flow voids in OCTA images. Comput Med Imaging Graph 2023; 104:102172. [PMID: 36630796 DOI: 10.1016/j.compmedimag.2022.102172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 11/10/2022] [Accepted: 12/27/2022] [Indexed: 01/11/2023]
Abstract
Optical coherence tomography angiography (OCTA) is a non-invasive ophthalmic imaging modality that is widely used in clinical practice. Recent technological advances in OCTA allow imaging of blood flow deeper than the retinal layers, at the level of the choriocapillaris (CC), where a granular image is obtained showing a pattern of bright areas, representing blood flow, and a pattern of small dark regions, called flow voids (FVs). Several clinical studies have reported a close correlation between abnormal FVs distribution and multiple diseases, so quantifying changes in FVs distribution in CC has become an area of interest for many clinicians. However, CC OCTA images present very complex features that make it difficult to correctly compare FVs during the monitoring of a patient. In this work, we propose fully automatic approaches for the segmentation and monitoring of FVs in CC OCTA images. First, a baseline approach, in which a fully automatic segmentation methodology based on local contrast enhancement and global thresholding is proposed to segment FVs and measure changes in their distribution in a straightforward manner. Second, a robust approach in which, prior to the use of our segmentation methodology, an unsupervised trained neural network is used to perform a deformable registration that aligns inconsistencies between images acquired at different time instants. The proposed approaches were tested with CC OCTA images collected during a clinical study on the response to photodynamic therapy in patients affected by chronic central serous chorioretinopathy (CSC), demonstrating their clinical utility. The results showed that both approaches are accurate and robust, surpassing the state of the art, therefore improving the efficacy of FVs as a biomarker to monitor the patient treatments. This gives great potential for the clinical use of our methods, with the possibility of extending their use to other pathologies or treatments associated with this type of imaging.
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Affiliation(s)
- Emilio López-Varela
- VARPA Group, Biomedical Research Institute of A Coruña (INIBIC), University of A Coruña, A Coruña, Spain; CITIC-Research Center of Information and Communication Technologies, University of A Coruña, A Coruña, Spain.
| | - Joaquim de Moura
- VARPA Group, Biomedical Research Institute of A Coruña (INIBIC), University of A Coruña, A Coruña, Spain; CITIC-Research Center of Information and Communication Technologies, University of A Coruña, A Coruña, Spain.
| | - Jorge Novo
- VARPA Group, Biomedical Research Institute of A Coruña (INIBIC), University of A Coruña, A Coruña, Spain; CITIC-Research Center of Information and Communication Technologies, University of A Coruña, A Coruña, Spain.
| | - José Ignacio Fernández-Vigo
- Departamento de Oftalmología, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria (IdISSC), Madrid, Spain; Centro Internacional de Oftalmología Avanzada, Madrid, Spain.
| | | | - Marcos Ortega
- VARPA Group, Biomedical Research Institute of A Coruña (INIBIC), University of A Coruña, A Coruña, Spain; CITIC-Research Center of Information and Communication Technologies, University of A Coruña, A Coruña, Spain.
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Ashimatey BS, Zhou X, Chu Z, Alluwimi M, Wang RK, Kashani AH. Variability of Vascular Reactivity in the Retina and Choriocapillaris to Oxygen and Carbon Dioxide Using Optical Coherence Tomography Angiography. Invest Ophthalmol Vis Sci 2023; 64:9. [PMID: 36745450 PMCID: PMC9910388 DOI: 10.1167/iovs.64.2.9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Purpose To investigate the regional and layer-specific vascular reactivity of the healthy human retina and choriocapillaris to changes in systemic carbon dioxide or oxygen. Methods High-resolution 3 × 3-mm2 optical coherence tomography angiography (OCTA) images were acquired from the central macula, temporal macula, and peripapillary retina while participants were exposed to three gas breathing conditions-room air, 5%CO2, and 100% O2. OCTA from all three regions were extracted and the apparent skeletonized vessel density (VSD) was assessed. The mean flow deficit sizes (MFDSs) of the choriocapillaris were also assessed. Repeated-measures analysis of variance was used to compare the ratio of intrasubject VSD change induced by the gas conditions from baseline in the superficial retinal layer (SRL) and deep retinal layer (DRL) for each retinal region independently, as well as the MFDS of the choriocapillaris. We also compared the vessel reactivity between the retinal capillaries and the choriocapillaris. Results The cumulative intrasubject response to the gas conditions differed significantly among regions of the SRL (F(2, 7) = 28.22, P < 0.001), with the temporal macula showing the largest response (15%) compared to the macula (8%) and radial peripapillary capillaries (7%). A similar trend was found in the DRL. The choriocapillaris reactivity was similar between the macula (5.8%) and temporal macula (5.6%). There was also a significant heterogeneity in the layer-specific gas responses, with the DRL showing the largest response (28.2%) and the choriocapillaris showing the smallest response (2.8%). Conclusions Capillary reactivity to changes in inhaled O2 and CO2 is spatially heterogeneous across the retina but not choriocapillaris.
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Affiliation(s)
- Bright S. Ashimatey
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Xiao Zhou
- Department of Bioengineering, University of Washington, Seattle, Washington, United States
| | - Zhongdi Chu
- Department of Bioengineering, University of Washington, Seattle, Washington, United States
| | - Muhammed Alluwimi
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, United States,Department of Ophthalmology, University of Washington Seattle, Washington, United States
| | - Amir H. Kashani
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
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9
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Cabral D, Ramtohul P, Fradinho AC, Freund KB. Volume Rendering of Deep Retinal Age-Related Microvascular Anomalies. Ophthalmol Retina 2022; 6:1185-1193. [PMID: 35772694 DOI: 10.1016/j.oret.2022.06.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 06/09/2022] [Accepted: 06/15/2022] [Indexed: 06/15/2023]
Abstract
PURPOSE To characterize and distinguish non-neovascular deep retinal age-related microvascular anomalies (DRAMA) from type 3 macular neovascularization (MNV) using volume rendering of OCT and OCT angiography (OCTA). DESIGN Retrospective, consecutive case series. SUBJECTS Consecutive patients with age-related macular degeneration (AMD) exhibiting de novo non-neovascular abnormalities within the deep vascular plexus (DCP), as detected using high-resolution (High-Res) spectral-domain (SD) and swept-source (SS) OCT or OCTA. Patients with retinal vascular alterations attributable to other disease entities were excluded. METHODS Complete ophthalmic examination and multimodal imaging, including confocal fundus photography (CFP), SD-OCT, High-Res SD-OCT and OCTA, and volume-averaged SS-OCTA. The volume renderings of High-Res OCTA and averaged SS-OCTA were used to analyze capillary abnormalities and inflow or outflow connectivity pathways. MAIN OUTCOME MEASURES The primary outcomes were the characteristics of capillary abnormalities (number, size, shape, reflectivity, and location) and inflow or outflow connectivity pathways. The secondary outcomes were nearby changes in CFP and structural OCT (hyperreflective foci [HRF], outer retinal atrophy, and retinal pigment epithelium [RPE] atrophy). RESULTS From 8 eyes of 8 patients, 2 subtypes of DRAMA were identified: small-diameter perifoveal capillary dilations with hyperreflective walls within the inner nuclear layer (type 1, n = 4) and vascular outpouchings, typically multiple, extending posteriorly into the Henle fiber layer, with reflectivity similar to adjacent normal retinal capillaries (type 2, n = 10). Four eyes had both subtypes of DRAMA. The 3-dimensional visualization of OCTA data demonstrated DRAMA corresponding to the dilations of DCP capillaries without direct inflow or outflow connections to the superficial plexus. Fundus photographs showed circular red dots in 3 eyes, all corresponding to type 1 DRAMA. In all the cases, DRAMA colocalized with HRF. No lesions were found anterior to the areas of the RPE or outer retina atrophy. Asymptomatic intraretinal exudation varied through a follow-up duration of up to 6 years, with no lesions progressing to type 3 MNV. CONCLUSIONS In eyes with non-neovascular AMD, DRAMA include 2 types of capillary dilations occurring without the remodeling of the surrounding vascular network. Deep retinal age-related microvascular anomalies can resemble microvascular changes due to other causes and can masquerade as type 3 MNV. Mild intraretinal exudation can vary during follow-up, without progression to type 3 MNV.
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Affiliation(s)
- Diogo Cabral
- Vitreous Retina Macula Consultants of New York, New York, New York; Nova Medical School Research, Nova Medical School, Universidade Nova de Lisboa, Lisbon, Portugal; Department of Ophthalmology, New York University Grossman School of Medicine, New York, New York
| | - Prithvi Ramtohul
- Vitreous Retina Macula Consultants of New York, New York, New York; Department of Ophthalmology, New York University Grossman School of Medicine, New York, New York
| | - Ana C Fradinho
- Nova Medical School Research, Nova Medical School, Universidade Nova de Lisboa, Lisbon, Portugal
| | - K Bailey Freund
- Vitreous Retina Macula Consultants of New York, New York, New York; Department of Ophthalmology, New York University Grossman School of Medicine, New York, New York.
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10
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Kakihara S, Hirano T, Kitahara J, Matsuda Y, Imai A, Miyahara T, Murata T. Application of optical coherence tomography angiography to assess systemic severity in patients with hereditary transthyretin amyloidosis. PLoS One 2022; 17:e0275180. [PMID: 36156600 PMCID: PMC9512205 DOI: 10.1371/journal.pone.0275180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 09/12/2022] [Indexed: 11/19/2022] Open
Abstract
Hereditary transthyretin amyloidosis is an autosomal dominant form of amyloidosis caused by an abnormality in transthyretin, with various ocular manifestations. Among these, ocular amyloid angiopathy has attracted attention because of its direct link to visual impairment and its correlation with systemic severity. We hypothesized that optical coherence tomography angiographic parameters would be useful biomarkers of amyloidosis systemic severity and investigated their correlation with the systemic severity score. The primary outcome was the correlation between the systemic severity score and choriocapillaris flow deficit percentage. Secondary outcomes were the correlations between the systemic severity score and retinal optical coherence tomography angiographic parameters, including foveal avascular zone size and circularity and superficial/deep/total retinal perfusion and vessel densities. The choroidal and retinal vasculature was quantified in 36 eyes from 36 patients (age, 51.8±12.1 years; disease duration, 13.4±6.2 years). Ten eyes had a history of vitrectomy for vitreous opacity. Choriocapillaris flow deficit percentage was not significantly correlated with the systemic severity score (Spearman’s rank correlation: r = 2.96×10−2, p = 0.863). Similarly, foveal avascular zone size and circularity, and superficial/deep/total retinal perfusion and vessel densities were not significantly correlated with the systemic severity score. These results may indicate that optical coherence tomography angiographic parameters are not sufficient to predict amyloidosis severity.
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Affiliation(s)
- Shinji Kakihara
- Department of Ophthalmology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
- * E-mail:
| | - Takao Hirano
- Department of Ophthalmology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Junya Kitahara
- Department of Ophthalmology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Yorishige Matsuda
- Department of Ophthalmology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Akira Imai
- Department of Ophthalmology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Teruyoshi Miyahara
- Department of Ophthalmology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
| | - Toshinori Murata
- Department of Ophthalmology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
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11
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Swept-Source Optical Coherence Tomography Detection of Bruch's Membrane and Choriocapillaris Abnormalities in Sorsby Macular Dystrophy. Retina 2022; 42:1645-1654. [PMID: 35483032 DOI: 10.1097/iae.0000000000003515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Swept-source optical coherence tomography angiography (SS-OCTA) was used to analyze Bruch's membrane (BM) and choriocapillaris (CC) abnormalities in undiagnosed family members with Sorsby macular dystrophy (SMD). METHODS In a family with SMD (TIMP3 Tyr191Cys), SS-OCTA imaging was performed using the 6X6mm scan patter and previously validated algorithms to detect abnormalities in BM and the CC, as well as the presence of reticular pseudodrusen (RPD) and macular neovascularization (MNV). Genetic analyses were performed for TIMP3 mutations. RESULTS Of eight family members, two were previously diagnosed with SMD and six were asymptomatic. SS-OCTA imaging of the 33-year-old proband revealed type 1 MNV in the left eye and bilateral RPD, thickening of BM, CC thinning, and increases in CC flow deficits (FDs). A TIMP3 mutation was confirmed. His niece, despite having no clinical evidence of SMD, showed BM thickening and CC thinning on SS-OCTA. A TIMP3 mutation was confirmed. The proband's younger nephew and niece also carried the TIMP3 mutation without clinical evidence of SMD. Two additional members had normal exams, unremarkable SS-OCTA findings, and no TIMP3 mutation. CONCLUSIONS SS-OCTA imaging can detect BM and CC abnormalities in vivo in subjects unaware of their TIMP3 status in a family with SMD.
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12
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Li J, Zhou H, Feinstein M, Wong J, Wang RK, Chan L, Dai Y, Porco T, Duncan JL, Schwartz DM. Choriocapillaris Changes in Myopic Macular Degeneration. Transl Vis Sci Technol 2022; 11:37. [PMID: 35201337 PMCID: PMC8883151 DOI: 10.1167/tvst.11.2.37] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Purpose Myopic macular degeneration (MMD) can cause irreversible vision loss. Thinner choroid is associated with increased MMD severity. This cross-sectional study analyzed choriocapillaris (CC) alterations in MMD. Methods Axial length (AL), best-corrected visual acuity (BCVA), fundus photography, and swept-source optical coherence tomography angiography (SS-OCTA) were assessed in controls and high myopes (spherical equivalent ≤ −6 diopters). Myopic patients with grade 2 MMD (macular diffuse chorioretinal atrophy [MDCA]), high axial myopia (AL ≥ 26.5 mm), and BCVA ≥ 20/40 were compared with controls without MMD. CC mean thickness was measured from 3 × 3-mm SS-OCTA scans by identifying CC peaks in A-scan intensity profiles. CC flow deficit percent (CC FD%) was quantified using a fuzzy C-mean local thresholding method on en face OCTA images. Multivariate regressions compared CC thickness and CC FD% between myopic patients and controls, correcting for age and other confounders. Results Sixteen eyes with MDCA (AL, 26.96–33.93 mm; ages, 40–78 years) were compared with 51 control eyes (AL, 21.65–25.84 mm; ages, 19–88 years). CC thickness in patients with MDCA was 66% lower than that in controls (5.23 ± 0.68 µm [mean ± SD] vs. 15.46 ± 1.82 µm; P < 0.001). CC FD% in patients with MDCA was 237% greater than in controls (26.5 ± 4.3 vs. 11.2 ± 4.6; P < 0.001). Conclusions Patients with MDCA with good visual acuity had thinner CC and increased CC FD%, or reduced CC flow, compared with controls. Patients with grade 2 MMD and good visual acuity demonstrated significant choriocapillaris alterations, suggesting that choriocapillaris perfusion defects contribute to the pathogenesis of MMD. Translational Relevance Given the potential vascular etiology for MMD, current research about revascularization of ischemic retina likely has implications for the treatment of MMD.
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Affiliation(s)
- Jonathan Li
- Department of Ophthalmology, University of California, San Francisco, CA, USA.,Singapore National Eye Centre, Singapore
| | - Hao Zhou
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Max Feinstein
- Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Jessica Wong
- Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Lawrence Chan
- Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Yining Dai
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Travis Porco
- Department of Ophthalmology, University of California, San Francisco, CA, USA.,Francis I. Proctor Foundation, University of California, San Francisco, CA, USA
| | - Jacque L Duncan
- Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Daniel M Schwartz
- Department of Ophthalmology, University of California, San Francisco, CA, USA
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13
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Corvi F, Corradetti G, Sadda SR. Comparison Between Different Segmentation Strategies for the Choriocapillaris Using Optical Coherence Tomography Angiography. Ophthalmic Surg Lasers Imaging Retina 2021; 52:642-649. [PMID: 34908487 DOI: 10.3928/23258160-20211123-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND AND OBJECTIVE To assess the relationship between retinal pigment epithelium (RPE) and RPE fit-based segmentations of the choriocapillaris (CC) and its expected anatomic location. PATIENTS AND METHODS Consecutive healthy participants' eyes were imaged with optical coherence tomography angiography (PLEX Elite) with 3 × 3-mm and 6 × 6-mm scan. Ground-truth images were generated using 16-μm-thick slabs starting from 4 μm below the automatically segmented Bruch's membrane (BM) band. A series of slabs positioned below the RPE band and RPE fit were also generated, and CC flow deficit percentage was compared with the ground-truth segmentation. RESULTS Twenty-six eyes of 26 participants were analyzed. For both scans, the 21 to 37-μm slab offset from the RPE band most closely matched the BM-based ground-truth slab with mean differences of 0.78% and 0.36%. CONCLUSION The CC flow deficit percentage from the RPE band correlated strongly with BM-based CC slabs, with the closest approximation observed with slab offset 21 to 37 μm from the RPE band centerline. [Ophthalmic Surg Lasers Imaging. 2021;52:642-649.].
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14
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Untracht GR, Matos RS, Dikaios N, Bapir M, Durrani AK, Butsabong T, Campagnolo P, Sampson DD, Heiss C, Sampson DM. OCTAVA: An open-source toolbox for quantitative analysis of optical coherence tomography angiography images. PLoS One 2021; 16:e0261052. [PMID: 34882760 PMCID: PMC8659314 DOI: 10.1371/journal.pone.0261052] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 11/24/2021] [Indexed: 12/15/2022] Open
Abstract
Optical coherence tomography angiography (OCTA) performs non-invasive visualization and characterization of microvasculature in research and clinical applications mainly in ophthalmology and dermatology. A wide variety of instruments, imaging protocols, processing methods and metrics have been used to describe the microvasculature, such that comparing different study outcomes is currently not feasible. With the goal of contributing to standardization of OCTA data analysis, we report a user-friendly, open-source toolbox, OCTAVA (OCTA Vascular Analyzer), to automate the pre-processing, segmentation, and quantitative analysis of en face OCTA maximum intensity projection images in a standardized workflow. We present each analysis step, including optimization of filtering and choice of segmentation algorithm, and definition of metrics. We perform quantitative analysis of OCTA images from different commercial and non-commercial instruments and samples and show OCTAVA can accurately and reproducibly determine metrics for characterization of microvasculature. Wide adoption could enable studies and aggregation of data on a scale sufficient to develop reliable microvascular biomarkers for early detection, and to guide treatment, of microvascular disease.
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Affiliation(s)
- Gavrielle R. Untracht
- Optical+Biomedical Engineering Laboratory, School of Electrical, Electronic and Computer Engineering, The University of Western Australia, Perth, Western Australia, Australia
- Surrey Biophotonics, Advanced Technology Institute, School of Physics and School of Biosciences and Medicine, University of Surrey, Guildford, Surrey, United Kingdom
- * E-mail:
| | - Rolando S. Matos
- Department of Biochemical Sciences and Department of Clinical and Experimental Medicine, School of Biosciences and Medicine, University of Surrey, Guildford, Surrey, United Kingdom
| | | | - Mariam Bapir
- Department of Biochemical Sciences and Department of Clinical and Experimental Medicine, School of Biosciences and Medicine, University of Surrey, Guildford, Surrey, United Kingdom
| | - Abdullah K. Durrani
- Surrey Biophotonics, Advanced Technology Institute, School of Physics and School of Biosciences and Medicine, University of Surrey, Guildford, Surrey, United Kingdom
| | - Teemapron Butsabong
- Department of Biochemical Sciences and Department of Clinical and Experimental Medicine, School of Biosciences and Medicine, University of Surrey, Guildford, Surrey, United Kingdom
| | - Paola Campagnolo
- Department of Biochemical Sciences and Department of Clinical and Experimental Medicine, School of Biosciences and Medicine, University of Surrey, Guildford, Surrey, United Kingdom
| | - David D. Sampson
- Surrey Biophotonics, Advanced Technology Institute, School of Physics and School of Biosciences and Medicine, University of Surrey, Guildford, Surrey, United Kingdom
| | - Christian Heiss
- Department of Biochemical Sciences and Department of Clinical and Experimental Medicine, School of Biosciences and Medicine, University of Surrey, Guildford, Surrey, United Kingdom
- Surrey and Sussex Healthcare NHS Trust, East Surrey Hospital, Redhill, Surrey, United Kingdom
| | - Danuta M. Sampson
- Department of Biochemical Sciences and Department of Clinical and Experimental Medicine, School of Biosciences and Medicine, University of Surrey, Guildford, Surrey, United Kingdom
- Surrey Biophotonics, Centre for Vision, Speech and Signal Processing and School of Biosciences and Medicine, The University of Surrey, Guildford, United Kingdom
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15
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Kalra G, Zarranz-Ventura J, Chahal R, Bernal-Morales C, Lupidi M, Chhablani J. Optical coherence tomography (OCT) angiolytics: a review of OCT angiography quantitative biomarkers. Surv Ophthalmol 2021; 67:1118-1134. [PMID: 34748794 DOI: 10.1016/j.survophthal.2021.11.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 10/29/2021] [Accepted: 11/01/2021] [Indexed: 02/08/2023]
Abstract
Optical coherence tomography angiography (OCTA) provides a non-invasive method to obtain angiography of the chorioretinal vasculature leading to its recent widespread adoption. With a growing number of studies exploring the use of OCTA, various biomarkers quantifying the vascular characteristics have come to light. In the current report, we summarize the biomarkers currently described for retinal and choroidal vasculature using OCTA systems and the methods used to obtain them. Further, we present a critical review of these methods and key findings in common retinal diseases and appraise future directions, including applications of artificial intelligence in OCTA .
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Affiliation(s)
- Gagan Kalra
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA; Government Medical College and Hospital, Chandigarh, India
| | - Javier Zarranz-Ventura
- Institut Clinic d'Oftalmologia (ICOF) Hospital Clinic, Barcelona, Spain; Institut de Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Rutvi Chahal
- Government Medical College and Hospital, Chandigarh, India
| | - Carolina Bernal-Morales
- Institut Clinic d'Oftalmologia (ICOF) Hospital Clinic, Barcelona, Spain; Institut de Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Marco Lupidi
- Department of Surgical and Biomedical Sciences, University of Perugia, S.Maria della Misericordia Hospital, Perugia, Italy
| | - Jay Chhablani
- University of Pittsburgh Medical Center Eye Center, University of Pittsburgh, Pittsburgh, PA, USA.
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16
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McKay KM, Chu Z, Kim JB, Legocki A, Zhou X, Tian M, Munk MR, Wang RK, Pepple KL. Automated Quantification of Choriocapillaris Lesion Area in Patients With Posterior Uveitis. Am J Ophthalmol 2021; 231:179-193. [PMID: 34107308 PMCID: PMC8608733 DOI: 10.1016/j.ajo.2021.06.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 04/26/2021] [Accepted: 06/01/2021] [Indexed: 11/28/2022]
Abstract
PURPOSE To validate a custom algorithm for automated identification and quantification of clinically relevant inflammatory choriocapillaris (CC) lesions from en face swept-source optical coherence tomography (SS-OCTA) images. DESIGN Observational case series. METHODS Twenty eyes of 14 patients with posterior uveitis were imaged. The machine-generated en face OCTA CC slabs were exported to a computing platform, where a custom algorithm performed unsupervised lesion boundary delineation and area quantification. Lesions identified by the algorithm (AG) were compared to those identified by 2 masked human graders (HG1 and HG2), using the Sørensen-Dice coefficient (DSC) and intraclass correlation coefficient (ICC). Intragrader and intravisit reliability were determined by coefficient of variation (CV) and DSC. RESULTS The AG demonstrated excellent agreement with both HGs in determination of lesion area (HG1 vs AG ICC 0.92, 95% CI 0.81-0.97, HG2 vs AG ICC 0.91, 95% CI 0.78-0.97). The AG demonstrated good spatial overlap (DSC ≥0.70) with both HGs in 14 of 20 (70%) eyes and at least 1 HG in 16 of 20 (80%) eyes. Poor spatial overlap (DSC between 0.31 and 0.69) was associated with the presence of a choroidal neovascular membrane and low-contrast lesion boundaries. Intravisit repeatability for the AG was superior to both HGs (CV 2.6% vs >5%). CONCLUSION This custom algorithm demonstrated a high degree of agreement with HGs in identification of inflammatory CC lesions and outperformed HGs in reproducibility. Automated CC lesion delineation will support the development of objective and quantitative biomarker of disease activity in patients with posterior uveitis.
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Affiliation(s)
- K Matthew McKay
- Department of Ophthalmology, University of Washington, Seattle, Washington, USA
| | - Zhongdi Chu
- Departments of Ophthalmology and Bioengineering, University of Washington, Seattle, Washington, USA
| | - Joon-Bom Kim
- Department of Ophthalmology, University of Washington, Seattle, Washington, USA
| | - Alex Legocki
- Department of Ophthalmology, University of Washington, Seattle, Washington, USA
| | - Xiao Zhou
- Departments of Ophthalmology and Bioengineering, University of Washington, Seattle, Washington, USA
| | - Meng Tian
- Department of Ophthalmology and Bern Photographic Reading Center, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Marion R Munk
- Department of Ophthalmology and Bern Photographic Reading Center, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Ruikang K Wang
- Department of Ophthalmology, University of Washington, Seattle, Washington, USA; Departments of Ophthalmology and Bioengineering, University of Washington, Seattle, Washington, USA
| | - Kathryn L Pepple
- Department of Ophthalmology, University of Washington, Seattle, Washington, USA.
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17
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Loria O, Kodjikian L, Denis P, Vartin C, Dimassi S, Gervolino L, Maignan A, Kermarrec R, Chambard C, Pradat P, Mathis T. QUANTITATIVE ANALYSIS OF CHORIOCAPILLARIS ALTERATIONS IN SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN DIABETIC PATIENTS. Retina 2021; 41:1809-1818. [PMID: 33411469 DOI: 10.1097/iae.0000000000003102] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
PURPOSE To evaluate quantitative alterations of the choriocapillaris in swept-source optical coherence tomography angiography in diabetic patients. METHODS We included normal patients and diabetic patients with and without diabetic retinopathy (DR), excluding patients with macular edema. Angiograms in 3 × 3 mm were acquired with Plexelite 9000 swept-source optical coherence tomography angiography. Choroidal flow voids were analyzed after removal of projection artifacts. The main evaluation was the correlation between choroidal flow voids area (FVA-CC) and DR stage. RESULTS A total of 120 eyes of 72 patients were analyzed. There were 17 eyes from healthy subjects, 30 eyes without DR, 22 eyes with minimal nonproliferative DR, 30 eyes with moderate nonproliferative DR, 16 eyes with severe nonproliferative DR, and 5 eyes with proliferative DR (PDR). The percentage of FVA-CC for each group was, respectively, 10.9 ± 3.4%, 14.6 ± 4.8%, 17.6 ± 3.5%, 20.7 ± 5.9%, 19.9 ± 2.9%, and 26.6 ± 4.4%. FVA-CC and DR stage significantly correlated (P < 0.0001). FVA-CC was significantly increased in diabetic patients without DR compared with healthy subjects (P = 0.008). CONCLUSION Diabetes is associated with quantifiable choriocapillaris alterations in swept-source optical coherence tomography angiography. These alterations precede clinical signs of DR and are correlated with DR stage.
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Affiliation(s)
- Olivier Loria
- Service d'Ophtalmologie, Hôpital universitaire de la Croix-Rousse, Hospices Civils de Lyon, France
| | - Laurent Kodjikian
- Service d'Ophtalmologie, Hôpital universitaire de la Croix-Rousse, Hospices Civils de Lyon, France
- Laboratoire UMR-CNRS 5510 Matéis, Villeurbane, France
| | - Philippe Denis
- Service d'Ophtalmologie, Hôpital universitaire de la Croix-Rousse, Hospices Civils de Lyon, France
| | - Christine Vartin
- Service d'Ophtalmologie, Hôpital universitaire de la Croix-Rousse, Hospices Civils de Lyon, France
| | - Sarra Dimassi
- Service d'Ophtalmologie, Groupe Hospitalier Public Sud de l'Oise, Creil, France
| | - Lucas Gervolino
- Institut des Sciences et Techniques de la Réadaptation-Orthoptie, Lyon, France; and
| | - Antoine Maignan
- Institut des Sciences et Techniques de la Réadaptation-Orthoptie, Lyon, France; and
| | - Ronan Kermarrec
- Institut des Sciences et Techniques de la Réadaptation-Orthoptie, Lyon, France; and
| | - Claudine Chambard
- Service d'Ophtalmologie, Hôpital universitaire de la Croix-Rousse, Hospices Civils de Lyon, France
- Institut des Sciences et Techniques de la Réadaptation-Orthoptie, Lyon, France; and
| | - Pierre Pradat
- Centre de Recherche Clinique, Hôpital universitaire de la Croix-Rousse, Hospices Civils de Lyon, France
| | - Thibaud Mathis
- Service d'Ophtalmologie, Hôpital universitaire de la Croix-Rousse, Hospices Civils de Lyon, France
- Laboratoire UMR-CNRS 5510 Matéis, Villeurbane, France
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18
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Ng DSC, Chan LKY, Ng CM, Lai TYY. Visualising the choriocapillaris: Histology, imaging modalities and clinical research - A review. Clin Exp Ophthalmol 2021; 50:91-103. [PMID: 34387023 DOI: 10.1111/ceo.13984] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 08/09/2021] [Indexed: 01/02/2023]
Abstract
The choriocapillaris plays a considerable role in the normal physiology of the eye as well as in various diseases. Assessing the changes in the choriocapillaris can therefore provide important information about normal ageing and pathogenesis of visual impairment, and even some systemic diseases. In vivo imaging of the choriocapillaris has evolved from non-depth resolved, dye-based angiography to advanced, high-resolution optical coherence tomography angiography (OCTA). However, the intricate microvascular networks within the choriocapillaris are still beyond the resolving limits of most OCTA instruments. Knowledge of histology, meticulous image acquisition methods, recognition of artefact and post-acquisition processing techniques are necessary for optimising OCTA choriocapillaris images. Qualitative and quantitative analyses of the choriocapillaris provide clinical information in age-related macular degeneration (AMD), diabetic retinopathy (DR), pathologic myopia and central serous chorioretinopathy (CSC). Furthermore, studies have revealed choriocapillaris changes in posterior uveitis that are correlated with treatment outcome and have important prognostic significance. In addition to retinal diseases, choriocapillaris changes have been observed in systemic vascular diseases and complications associated with pregnancy.
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Affiliation(s)
- Danny Siu-Chun Ng
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.,Hong Kong Eye Hospital, Mong Kok, Hong Kong
| | - Leo Ka-Yu Chan
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.,Hong Kong Eye Hospital, Mong Kok, Hong Kong
| | - Ching Man Ng
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Timothy Y Y Lai
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.,2010 Retina & Macula Centre, Kowloon, Hong Kong
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19
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Hacker V, Reiter GS, Schranz M, Told R, Reumüller A, Hofer D, Steiner I, Schmidt-Erfurth U, Sacu S. Impact of large choroidal vessels on choriocapillaris flow deficit analyses in optical coherence tomography angiography. PLoS One 2021; 16:e0254955. [PMID: 34343177 PMCID: PMC8330935 DOI: 10.1371/journal.pone.0254955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 07/06/2021] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To investigate the impact of large choroidal vessels (LCV) on Choriocapillaris (CC) flow deficit (FD) analyses with swept-source optical coherence tomography angiography (SS-OCTA). DESIGN Prospective, cross-sectional study. METHODS Macular 6x6mm SS-OCTA scans were obtained from intermediate age-related macular degeneration (iAMD) and healthy eyes. Images were captured and processed according to most common standards and analyzed for percentage of flow-deficits (FD%) within four 1x1mm squares at the corners of each image. Choroidal thickness (CT), iris color and refraction error were considered as potential influential factors for LCV visibility. A linear mixed model and logistic regression models were calculated for statistical evaluation. RESULTS Sixty-nine iAMD and 49 age-matched healthy eyes were enrolled. LCV were visible in at least one sector in 52% of iAMD and 47% of healthy eyes. Within the iAMD group FD% were significantly lower in areas containing LCV (p = 0.0029). Increasing CT resulted in an odds ratio decrease of LCV (OR: 0.94, p<0.0001). Below a CT value of ≤118μm LCV could be expected with a sensitivity of 86% and a specificity of 85%. CONCLUSIONS LCV can significantly affect CC FD analyses of SS-OCTA images. Their visibility is negatively associated with CT. The impact of LCV should be taken into account when performing CC FD assessments, especially in patients where reduced CT is to be expected and inclusion of affected areas should be considered carefully.
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Affiliation(s)
- Valentin Hacker
- Vienna Clinical Trial Center (VTC), Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Gregor Sebastian Reiter
- Christian Doppler Laboratory for Ophthalmic Image Analysis, Vienna Reading Center, Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Markus Schranz
- Vienna Clinical Trial Center (VTC), Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Reinhard Told
- Vienna Clinical Trial Center (VTC), Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Adrian Reumüller
- Vienna Clinical Trial Center (VTC), Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Dominik Hofer
- Vienna Reading Center (VRC), Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Irene Steiner
- Center for Medical Statistics, Informatics and Intelligent Systems, Section for Medical Statistics, Medical University of Vienna, Vienna, Austria
| | - Ursula Schmidt-Erfurth
- Vienna Clinical Trial Center (VTC), Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
- Christian Doppler Laboratory for Ophthalmic Image Analysis, Vienna Reading Center, Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
- Vienna Reading Center (VRC), Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
| | - Stefan Sacu
- Vienna Clinical Trial Center (VTC), Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria
- * E-mail:
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20
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Bhalla M, Heisler M, Mammo Z, Ju MJ, Sarunic MV, Navajas EV, Warner S, Schendel S, Gill KS. Investigation of the Peripapillary Choriocapillaris in Normal Tension Glaucoma, Primary Open-angle Glaucoma, and Control Eyes. J Glaucoma 2021; 30:682-689. [PMID: 33927150 DOI: 10.1097/ijg.0000000000001861] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 04/01/2021] [Indexed: 11/26/2022]
Abstract
PRECIS The peripapillary choriocapillaris (CC) was observed to be significantly impaired in normal tension glaucoma (NTG) subjects compared with normal controls using optical coherence tomography angiography (OCTA). PURPOSE The aim was to quantitatively evaluate the peripapillary CC in NTG, primary open-angle glaucoma (POAG), and control eyes using OCTA. MATERIALS AND METHODS Ninety eyes (30 controls, 30 NTG, and 30 POAG) from 73 patients were imaged using the Zeiss Plex Elite 9000. Five repeat 3×3 mm OCTA scans were acquired both nasally and temporally to the optic disc and subsequently averaged. Four CC flow deficit (FD) measures were calculated using the fuzzy C-means approach: FD density (FDD), mean FD size (MFDS), FD number (FDN), and FD area (FDA). RESULTS Temporal NTG CC parameters were associated with visual field index and mean deviation (P<0.05). The control group showed a significantly lower nasal FDD (nasal: 3.79±1.26%, temporal: 4.48±1.73%, P=0.03), FDN (nasal: 156.43±38.44, temporal: 178.40±45.68, P=0.02), and FDA (nasal: 0.22±0.08, temporal: 0.26±0.10, P=0.03) when compared with temporal optic disc. The NTG group showed a significantly higher FDD (NTG: 5.04±2.38%, control: 3.79±1.26%, P=0.03), FDN (NTG: 185.90±56.66, control: 156.43±38.44, P=0.04), and FDA (NTG: 0.30±0.14 mm2, control: 0.22±0.08 mm2, P=0.03) nasal to the optic disc compared with controls. CONCLUSIONS Association between CC parameters and glaucoma severity in NTG, but not POAG subjects, suggests vascular abnormalities may be a potential factor in the multifactorial process of glaucoma damage in NTG patients.
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Affiliation(s)
| | - Morgan Heisler
- School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
| | - Zaid Mammo
- Department of Ophthalmology and Visual Sciences
| | - Myeong Jin Ju
- Department of Ophthalmology and Visual Sciences
- School of Biomedical Engineering, University of British Columbia, Vancouver
| | - Marinko V Sarunic
- School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
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21
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Lejoyeux R, Benillouche J, Ong J, Errera MH, Rossi EA, Singh SR, Dansingani KK, da Silva S, Sinha D, Sahel JA, Freund KB, Sadda SR, Lutty GA, Chhablani J. Choriocapillaris: Fundamentals and advancements. Prog Retin Eye Res 2021; 87:100997. [PMID: 34293477 DOI: 10.1016/j.preteyeres.2021.100997] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 07/02/2021] [Accepted: 07/13/2021] [Indexed: 12/19/2022]
Abstract
The choriocapillaris is the innermost structure of the choroid that directly nourishes the retinal pigment epithelium and photoreceptors. This article provides an overview of its hemovasculogenesis development to achieve its final architecture as a lobular vasculature, and also summarizes the current histological and molecular knowledge about choriocapillaris and its dysfunction. After describing the existing state-of-the-art tools to image the choriocapillaris, we report the findings in the choriocapillaris encountered in the most frequent retinochoroidal diseases including vascular diseases, inflammatory diseases, myopia, pachychoroid disease spectrum disorders, and glaucoma. The final section focuses on the development of imaging technology to optimize visualization of the choriocapillaris as well as current treatments of retinochoroidal disorders that specifically target the choriocapillaris. We conclude the article with pertinent unanswered questions and future directions in research for the choriocapillaris.
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Affiliation(s)
| | | | - Joshua Ong
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Marie-Hélène Errera
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Ethan A Rossi
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA 15213, USA
| | - Sumit R Singh
- Jacobs Retina Center, Shiley Eye Institute, University of California San Diego, San Diego, CA, USA
| | - Kunal K Dansingani
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Susana da Silva
- Department of Ophthalmology and Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Debasish Sinha
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Cell Biology and Center for Biologic Imaging, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - José-Alain Sahel
- Rothschild Foundation, 75019, Paris, France; Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France; CHNO des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, France
| | - K Bailey Freund
- LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear, and Throat Hospital, New York, NY, USA; Vitreous Retina Macula Consultants of New York, New York, NY, USA; Department of Ophthalmology, New York University of Medicine, New York, NY, USA; Edward S. Harkness Eye Institute, Columbia University Medical Center, New York, NY, USA
| | - SriniVas R Sadda
- Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, CA, 90033, USA; Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Gerard A Lutty
- Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, MD, 21287, USA
| | - Jay Chhablani
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
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22
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Xue W, Lin S, Chen X, Jia Y, Fang X, Suo Y, Ma Y, Wang Y, Zou H. In vivo noninvasive imaging and quantitative analysis of iris vessels. Ophthalmic Res 2021; 64:754-761. [PMID: 33887742 DOI: 10.1159/000516553] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 04/02/2021] [Indexed: 11/19/2022]
Affiliation(s)
- Wenwen Xue
- Department of Ophthalmology, Shanghai Eye Disease Prevention & Treatment Center/Shanghai Eye Hospital, Shanghai, China,
| | - Senlin Lin
- Department of Ophthalmology, Shanghai Eye Disease Prevention & Treatment Center/Shanghai Eye Hospital, Shanghai, China
| | - Xia Chen
- Department of Ophthalmology, Shanghai Eye Disease Prevention & Treatment Center/Shanghai Eye Hospital, Shanghai, China
| | - Yanwen Jia
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaoling Fang
- Department of Ophthalmology, Shanghai Eye Disease Prevention & Treatment Center/Shanghai Eye Hospital, Shanghai, China
| | - Yan Suo
- Department of Ophthalmology, Shanghai Eye Disease Prevention & Treatment Center/Shanghai Eye Hospital, Shanghai, China
| | - Yingyan Ma
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yulan Wang
- Department of Ophthalmology, Shanghai Eye Disease Prevention & Treatment Center/Shanghai Eye Hospital, Shanghai, China
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Haidong Zou
- Department of Ophthalmology, Shanghai Eye Disease Prevention & Treatment Center/Shanghai Eye Hospital, Shanghai, China
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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23
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Ringel MJ, Tang EM, Tao YK. Advances in multimodal imaging in ophthalmology. Ther Adv Ophthalmol 2021; 13:25158414211002400. [PMID: 35187398 PMCID: PMC8855415 DOI: 10.1177/25158414211002400] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 02/23/2021] [Indexed: 12/12/2022] Open
Abstract
Multimodality ophthalmic imaging systems aim to enhance the contrast, resolution, and functionality of existing technologies to improve disease diagnostics and therapeutic guidance. These systems include advanced acquisition and post-processing methods using optical coherence tomography (OCT), combined scanning laser ophthalmoscopy and OCT systems, adaptive optics, surgical guidance, and photoacoustic technologies. Here, we provide an overview of these ophthalmic imaging systems and their clinical and basic science applications.
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Affiliation(s)
- Morgan J. Ringel
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Eric M. Tang
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Yuankai K. Tao
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
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24
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Cheng Y, Chu Z, Wang RK. Robust three-dimensional registration on optical coherence tomography angiography for speckle reduction and visualization. Quant Imaging Med Surg 2021; 11:879-894. [PMID: 33654662 PMCID: PMC7829160 DOI: 10.21037/qims-20-751] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 08/18/2020] [Indexed: 11/06/2022]
Abstract
BACKGROUND In the clinical applications of optical coherence tomography angiography (OCTA), the repeated scanning and averaging method can provide better contrast with reduced speckle noises in the final results, which are useful for visualizing and quantifying vascular components with high accuracy, reproducibility, and reliability. However, the inevitable patient motion presents a challenge to this method. The objective of this study is to meet this challenge by introducing a 3D registration method to register optical coherence tomography (OCT)/OCTA scans for precise volume averaging of multiple scans to improve the signal-to-noise ratio (SNR) and increase quantification accuracy. METHODS The proposed method utilized both rigid affine transformation and non-rigid B-spline transformation in which their parameters were optimized and calculated by the average stochastic gradient descent on OCT structural images. In addition, we also introduced a multi-level resolution approach to further improve the robustness and computational speed of our proposed method. The imaging performance was tested on in vivo imaging of human skin and eye and assessed by SNR, peak signal-to-noise ratio (PSNR) and normalized correlation coefficient (NCC). RESULTS Five subjects were enrolled in this study for obtaining in vivo images of skin and retina. The proposed registration and averaging method provided substantial improvements of the imaging performance in terms of vessel connectivity and signal to noise ratio. The increase of repeated volume numbers in the averaging improves all the metrics assessed, i.e., SNR, PSNR and NCC. An improvement of the SNR from 10 to 40 dB after 10 repeated volumetric averaging was achieved. CONCLUSIONS The proposed 3D registration and averaging method is effective in reducing speckle noises and suppressing motion artifacts, thereby improving SNR, PSNR and NCC metrics for final averaged images. It is expected that the proposed algorithm would be practically useful in better visualization and more reliable quantification of in vivo OCT and OCTA data, which would be beneficial to OCT clinical applications.
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Affiliation(s)
- Yuxuan Cheng
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Zhongdi Chu
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Department of Ophthalmology, University of Washington, Seattle, WA, USA
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25
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Optical Coherence Tomography Angiography of the Choriocapillaris in Age-Related Macular Degeneration. J Clin Med 2021; 10:jcm10040751. [PMID: 33668537 PMCID: PMC7918036 DOI: 10.3390/jcm10040751] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/09/2021] [Accepted: 02/10/2021] [Indexed: 12/11/2022] Open
Abstract
The advent of optical coherence tomography angiography (OCTA) has allowed for remarkable advancements in our understanding of the role of the choriocapillaris in age-related macular degeneration (AMD). As a relatively new imaging modality, techniques to analyze and quantify choriocapillaris images are still evolving. Quantification of the choriocapillaris requires careful consideration of many factors, including the type of OCTA device, segmentation of the choriocapillaris slab, image processing techniques, and thresholding method. OCTA imaging shows that the choriocapillaris is impaired in intermediate non-neovascular AMD, and the severity of impairment may predict the advancement of disease. In advanced atrophic AMD, the choriocapillaris is severely impaired underneath the area of geographic atrophy, and the level of impairment surrounding the lesion predicts the rate of atrophy enlargement. Macular neovascularization can be readily identified and classified using OCTA, but it is still unclear if neovascularization features with OCTA can predict the lesion’s level of activity. The choriocapillaris surrounding macular neovascularization is impaired while the more peripheral choriocapillaris is spared, implying that choriocapillaris disruption may drive neovascularization growth. With continued innovation in OCTA image acquisition and analysis methods, advancement in clinical applications and pathophysiologic discoveries in AMD are set to follow.
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26
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Chu Z, Zhang Q, Gregori G, Rosenfeld PJ, Wang RK. Guidelines for Imaging the Choriocapillaris Using OCT Angiography. Am J Ophthalmol 2021; 222:92-101. [PMID: 32891694 DOI: 10.1016/j.ajo.2020.08.045] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/12/2020] [Accepted: 08/28/2020] [Indexed: 01/23/2023]
Abstract
PURPOSE To provide guidance on how to appropriately quantitate various choriocapillaris (CC) parameters with optical coherence tomography angiography (OCTA). DESIGN Evidence-based perspective. METHODS Review of literature and experience of authors. RESULTS Accurate and reliable quantification of CC using OCTA requires that CC can be visualized and that the measurements of various CC parameters are validated. For accurate visualization, the selected CC slab must be physiologically sound, must produce images consistent with histology, and must yield qualitatively similar images when viewing repeats of the same scan or scans of different sizes. For accurate quantification, the measured intercapillary distances (ICDs) should be consistent with known measurements using histology and adaptive optics and/or OCTA, the selected CC parameters must be physiologically and physically meaningful based on the resolution of the instrument and the density of the scans, the selected algorithm for CC binarization must be appropriate and generate meaningful results, and the CC measurements calculated from multiple scans of the same and different sizes should be quantitatively similar. If the Phansalkar local thresholding method is used, then its parameters must be optimized for CC based on the OCTA instrument and scan patterns used. It is recommended that the window radius used in the Phansalkar method should be related to the expected average ICD in normal eyes. CONCLUSIONS Quantitative analysis of CC using commercially available OCTA instruments is complicated, and researchers need to tailor their strategies based on the instrument, scan patterns, anatomy, and thresholding strategies to achieve accurate and reliable measurements.
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27
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Maltsev DS, Fomin AV, Kulikov AN, Vasiliev AS. [Evaluation of choriocapillaris with high-speed spectral-domain optical coherence tomography angiography and image averaging]. Vestn Oftalmol 2021; 137:76-84. [PMID: 34156781 DOI: 10.17116/oftalma202113703176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
PURPOSE To study the capabilities of high-speed spectral-domain optical coherence tomography angiography (SD-OCTA) with image averaging in the evaluation of choriocapillaries in healthy individuals and patients with central serous chorioretinopathy (CSC). MATERIAL AND METHODS All participants underwent OCTA examination on the SOLIX tomograph (Optovue, USA) using quadruplicate 3×3 mm scan with image averaging. Image analysis was performed in 9-µm custom slab with Phansalkar auto local threshold algorithm and calculation of flow voids larger than 5000 µm2 and 10 000 µm2. The optimal slab depth was determined in healthy eyes by consecutive analysis of the slabs with a 3-µm shift from zero position to 33 µm below Bruch's membrane. RESULTS The study included 18 eyes of 18 healthy volunteers (40.4±6.0 years old) and 18 fellow eyes of 18 unilateral CSC patients (37.4±10.7 years old). The slab 12 µm below the Bruch's membrane showed the minimal number of flow voids (23.1±7.0 of >5000 µm2 voids per scan) and was chosen for further analysis. The number of flow voids of >5000 µm2 in healthy paired eyes of CSC patients was statistically significantly higher than in the eyes of healthy individuals (32.7±10.7 and 25.3±8.1 voids/scan, respectively; p=0.022). The number of flow voids of >10000 µm2 was also statistically significantly higher in CSC eyes compared to healthy eyes (5.6±3.3 and 3.5±1.9 voids/scan, respectively; p=0.045). There was no statistically significant difference in total area of the voids between the eyes of healthy individuals and CSC patients (96406.1±3924.5 µm2 and 95395.7 ± 3615.1 µm2, respectively; p=0.42). CONCLUSION The optimal settings for choriocapillaris imaging on the SOLIX tomograph include 9-µm slab 9 to 18 µm below the Bruch's membrane. Using a 9-µm slab 12 µm below the Bruch's membrane, a substantial difference was found in choriocapillaris perfusion between eyes of healthy individuals and CSC patients.
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Affiliation(s)
- D S Maltsev
- S.M. Kirov Military Medical Academy, Saint Petersburg, Russia
| | | | - A N Kulikov
- S.M. Kirov Military Medical Academy, Saint Petersburg, Russia
| | - A S Vasiliev
- S.M. Kirov Military Medical Academy, Saint Petersburg, Russia
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28
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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. BIOMEDICAL OPTICS 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] [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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29
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Shi Y, Chu Z, Wang L, Zhang Q, Feuer W, de Sisternes L, Durbin MK, Gregori G, Wang RK, Rosenfeld PJ. Validation of a Compensation Strategy Used to Detect Choriocapillaris Flow Deficits Under Drusen With Swept Source OCT Angiography. Am J Ophthalmol 2020; 220:115-127. [PMID: 32621895 DOI: 10.1016/j.ajo.2020.06.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/14/2020] [Accepted: 06/19/2020] [Indexed: 12/19/2022]
Abstract
PURPOSE A compensation strategy that was developed to measure the choriocapillaris (CC) flow deficits (FDs) under drusen was tested in eyes with large drusen from age-related macular degeneration (AMD) before and after the drusen spontaneously resolved without evidence of disease progression. DESIGN Prospective, observational consecutive case series. METHODS Patients with AMD were enrolled in a prospective swept-source optical coherence tomography (SS-OCT) imaging study. Consecutive eyes with large drusen were followed, and eyes that underwent spontaneous collapse of drusen without evidence of disease progression were identified retrospectively. The drusen-resolved regions were manually outlined. CC FDs were measured using a previously published compensation strategy that adjusted for the decreased signal intensity underlying drusen. Both the percentage of FDs (FD%) and the mean FD sizes (MFDSs) were measured before and after drusen resolution. RESULTS Resolution of drusen was identified in 8 eyes from 8 patients. The average interval between the 2 visits was 7.8 months. The average drusen volumes measured between visits were 0.23 and 0.04 mm3, respectively. After the drusen resolved, the average follow-up time without evidence of disease progression was 10.1 months. When the 2 visits were compared, there were no statistically significant differences in any of the CC parameters within the drusen resolved regions once the compensation strategy was applied (all P values >.22). CONCLUSIONS In this naturally occurring experiment in which drusen collapsed without evidence of disease progression, the CC parameters were similar once our compensation strategy was applied both before and after the drusen resolved.
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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
| | - Zhongdi Chu
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Liang Wang
- 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
| | - William Feuer
- 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
| | - 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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30
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Corvi F, Su L, Sadda SR. Evaluation of the inner choroid using OCT angiography. Eye (Lond) 2020; 35:110-120. [PMID: 33046831 DOI: 10.1038/s41433-020-01217-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 09/16/2020] [Accepted: 09/29/2020] [Indexed: 12/26/2022] Open
Abstract
The advent of optical coherence tomography angiography (OCTA) has allowed a qualitative and quantitative analysis of the retinal vasculature and the choriocapillaris. With the use of OCTA, several studies evaluated the changes in the choriocapillaris showing how this vascular structure plays a significant role in the pathogenesis of different conditions. This article reviews the current methods of analysis of the choriocapillaris and the relevant findings in different chorioretinal diseases.
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Affiliation(s)
- Federico Corvi
- Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, CA, USA.,Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,Eye Clinic, Department of Biomedical and Clinical Science "Luigi Sacco", Sacco Hospital, University of Milan, Milan, Italy
| | - Li Su
- Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, CA, USA.,Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.,Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of medicine, Shanghai, China
| | - Srinivas R Sadda
- Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, CA, USA. .,Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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31
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Laiginhas R, Cabral D, Falcão M. Evaluation of the different thresholding strategies for quantifying choriocapillaris using optical coherence tomography angiography. Quant Imaging Med Surg 2020; 10:1994-2005. [PMID: 33014731 DOI: 10.21037/qims-20-340] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background In this paper, we evaluate the different thresholding strategies that have been used for the quantification of the choriocapillaris (CC) and explore their repeatability and the interchangeability of the measurements resulting from its application. Methods Observational study. Eighteen eyes from nine healthy volunteers aged >18 years were imaged four consecutive times with a SD-OCTA system (Heidelberg Engineering, Germany) using a 10°×10° high-resolution protocol centered on the fovea. Projection artifacts were removed, and the CC was bracketed between 10 and 30 µm below Bruch's membrane. For the quantification of CC, we used four flow deficits (FD) parameters: FD number, mean FD size, total FD area and FD density. We performed a systematic review of literature to collect the thresholding methods that have been used for the quantification of CC. The CC quantification parameters were then evaluated after applying each of the thresholding strategies. Intraclass correlation coefficient (ICC) and Pearson's correlation analysis were used to compare the repeatability and interchangeability among the different thresholding strategies for quantifying the CC. Results A total of 72 optical coherence tomography angiography (OCTA) examinations were considered. The systematic review allowed us to conclude that three local thresholding strategies (Phansalkar, mean and Niblack) and three global thresholding strategies (mean, default, Otsu) have been used for CC quantification. These strategies were evaluated in our observational study. We found a high agreement within the same method in the quantification of FD number, mean FD size, total FD area and FD density but a poor agreement with different strategies. Local strategies achieved a significantly superior ICC than global ones in CC quantification. Conclusions In conclusion, the interchangeability of the CC quantification using different thresholding strategies is low, and direct comparisons should not be performed. Local thresholding strategies are significantly superior to global ones for quantifying CC and should be preferred. There is an unmet need for a uniform strategy to quantify CC in future studies.
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Affiliation(s)
- Rita Laiginhas
- Department of Ophthalmology, CHEDV, Portugal.,PDICSS, Faculty of Medicine of the University of Porto, Porto, Portugal
| | - Diogo Cabral
- CEDOC, NOVA Medical School I Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisbon, Portugal.,Instituto de Oftalmologia Dr. Gama Pinto, Lisboa, Portugal
| | - Manuel Falcão
- Department of Ophthalmology, Centro Hospitalar e Universitário de São João, Porto, Portugal.,Department of Surgery and Physiology, Faculty of Medicine of the University of Porto, Porto, Portugal
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32
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Chu Z, Weinstein JE, Wang RK, Pepple KL. Quantitative Analysis of the Choriocapillaris in Uveitis Using En Face Swept-Source Optical Coherence Tomography Angiography. Am J Ophthalmol 2020; 218:17-27. [PMID: 32413411 DOI: 10.1016/j.ajo.2020.05.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 05/04/2020] [Accepted: 05/05/2020] [Indexed: 11/18/2022]
Abstract
PURPOSE To perform a quantitative analysis of choriocapillaris (CC) flow deficits (FDs) in patients with uveitis. DESIGN Retrospective cross-sectional study. METHODS Swept-source optical coherence tomography based angiography (SS-OCTA) macular volume scans (3 × 3 mm and 6 × 6 mm) were obtained using the Plex Elite 9000. En face CC images were generated and analyzed using an automated FD identification algorithm. Three quantitative metrics were determined for each eye: FD number (FDN), mean FD size (MFDS), and FD density (FDD). Quantitative metrics were compared between uveitis and control eyes. The uveitis cohort was further subdivided by the presence or absence of choroidal involvement, and quantitative metrics were compared between subgroups and normal control subjects. RESULTS A total of 38 eyes from 38 control subjects and 73 eyes from 73 uveitis subjects were included in this study. Eyes with uveitis have significantly larger CC MFDS (3- × 3-mm scans; P < .0001; 6- × 6-mm scans; P < .0001) and higher FDD (P = .0002; P = .0076, respectively) compared to control eyes. Additional analysis determined that these differences were due to the choroidal disease subgroup, which demonstrates significantly larger MFDS (3 × 3 = 1,108 μm2; 6 × 6 = 1,104 μm2) compared to both normal control eyes (752 μm2; P < .0001; 802 μm2; P < .0001, respectively) and uveitis patients without choroidal involvement (785 μm2; P < .0001; 821 μm2; P < .0001, respectively). No significant differences were found between the quantitative metrics of control subjects and patients without choroidal involvement. CONCLUSIONS Automated quantification of CC can identify pathological FDs and provide quantitative metrics describing such lesions in patients with uveitis. Posterior uveitis patients have significantly larger CC FDs than patients with other forms of uveitis.
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Affiliation(s)
- Zhongdi Chu
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Jessica E Weinstein
- Department of Ophthalmology, University of Washington, Seattle, Washington, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA; Department of Ophthalmology, University of Washington, Seattle, Washington, USA
| | - Kathryn L Pepple
- Department of Ophthalmology, University of Washington, Seattle, Washington, USA.
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33
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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. ANNALS OF TRANSLATIONAL MEDICINE 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] [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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34
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Wang G, Le NM, Hu X, Cheng Y, Jacques SL, Subhash H, Wang RK. Semi-automated registration and segmentation for gingival tissue volume measurement on 3D OCT images. BIOMEDICAL OPTICS EXPRESS 2020; 11:4536-4547. [PMID: 32923062 PMCID: PMC7449737 DOI: 10.1364/boe.396599] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/28/2020] [Accepted: 07/17/2020] [Indexed: 05/17/2023]
Abstract
The change in gingival tissue volume may be used to indicate changes in gingival inflammation, which may be useful for the clinical assessment of gingival health. Properly quantifying gingival tissue volume requires a robust technique for accurate registration and segmentation of longitudinally captured 3-dimensional (3D) images. In this paper, a semi-automated registration and segmentation method for micrometer resolution measurement of gingival-tissue volume is proposed for 3D optical coherence tomography (OCT) imaging. For quantification, relative changes in gingiva tissue volume are measured based on changes in the gingiva surface height using the tooth surface as a reference. This report conducted repeatability tests on this method drawn from repeated scans in one patient, indicating an error of the point cloud registration method for oral OCT imaging is 63.08 ± 4.52µm (1σ), and the measurement error of the gingival tissue average thickness is -3.40 ± 21.85µm (1σ).
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Affiliation(s)
- Geng Wang
- University of Washington, Department of
Bioengineering, Seattle, WA 98195, USA
| | - Nhan Minh Le
- University of Washington, Department of
Bioengineering, Seattle, WA 98195, USA
| | - Xiaohui Hu
- University of Washington, Department of
Bioengineering, Seattle, WA 98195, USA
| | - Yuxuan Cheng
- University of Washington, Department of
Bioengineering, Seattle, WA 98195, USA
| | - Steven L. Jacques
- University of Washington, Department of
Bioengineering, Seattle, WA 98195, USA
| | - Hrebesh Subhash
- Clinical Method Development - Oral Care,
Colgate-Palmolive Company, Piscataway, NJ 08854, USA
| | - Ruikang K. Wang
- University of Washington, Department of
Bioengineering, Seattle, WA 98195, USA
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35
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Clinical Utility of Triplicate En Face Image Averaging for Optical Coherence Tomography Angiography in Glaucoma and Glaucoma Suspects. J Glaucoma 2020; 29:823-830. [PMID: 32496464 DOI: 10.1097/ijg.0000000000001570] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PRéCIS:: Averaging triplicate en face angiograms of the radial peripapillary capillary (RPC) plexus with optical coherence tomography angiography (OCTA) improves vessel visualization, reduces vessel density parameters, and increases the diagnostic accuracy for glaucoma of one such parameter. PURPOSE The purpose of this study was to test the hypothesis that triplicate averaging of the RPC layer improves visualization and diagnostic accuracy of OCTA for glaucoma. MATERIALS AND METHODS This is a cross-sectional study involving 63 primary open-angle glaucoma patients and 70 age-matched glaucoma suspects. Triplicate 6×6 mm OCTA scans of the optic nerve head were acquired, and the RPC layer was extracted. RPC en face images were registered and averaged. Parameters of global entropy, global standard deviation, local texture correlation, local homogeneity, signal-to-noise ratio, and intercapillary distance were used to measure the change in visualization with averaging. Vessel area density (VAD), vessel skeleton density (VSD), and flux parameters were calculated in a 2.8 mm annulus excluding the optic disc. The diagnostic accuracy of these parameters for glaucoma was assessed by calculating the area under the receiver operating curve (AUC) values. RESULTS Three-frame averaging resulted in decreased global entropy and global standard deviation (Ps<0.001), and increased local texture correlation, local homogeneity, signal-to-noise ratio, and intercapillary distance (Ps<0.001). Averaged images also had reduced VAD, VSD, and flux (Ps<0.001). AUC was significantly increased for VSD after image averaging (P=0.018), while no significant change in AUC was observed for VAD (P=0.229) or flux (P=0.193). CONCLUSIONS Triplicate averaging improves visualization of the RPC layer and the diagnostic accuracy of VSD for glaucoma. The impact of image averaging on OCTA diagnostic performance and other potential applications warrants further exploration.
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Nattagh K, Zhou H, Rinella N, Zhang Q, Dai Y, Foote KG, Keiner C, Deiner M, Duncan JL, Porco TC, Wang RK, Schwartz DM. OCT Angiography to Predict Geographic Atrophy Progression using Choriocapillaris Flow Void as a Biomarker. Transl Vis Sci Technol 2020; 9:6. [PMID: 32832213 PMCID: PMC7414606 DOI: 10.1167/tvst.9.7.6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 02/10/2020] [Indexed: 01/04/2023] Open
Abstract
Purpose To investigate the relationship between choriocapillaris (CC) flow void (FV) percentage and geographic atrophy (GA) growth rate, and study how variations in FV percentage surrounding GA predict regional GA growth. Methods This prospective, longitudinal study enrolled subjects with GA secondary to nonexudative age-related macular degeneration. Optical coherence tomography angiography imaged the CC and FV percentage was evaluated using a validated algorithm. GA growth rate was measured as the difference in the square root of GA area divided by the months between baseline and follow-up imaging. Results Twelve eyes from 7 subjects with a mean age of 80 ± 5 years (range 74-86) were studied once at baseline and 7 to 16 months later. GA expansion rate was positively correlated with increased CC FV percentage (Spearman rank correlation coefficient r = 0.69 [P = 0.038] and 0.76 [P = 0.013]) within the 6 x 6 mm scanned macular region and the 2° margin surrounding each GA lesion, respectively. Regions with CC FV at baseline located within 480 µm from the GA margin showed 33% greater chance of becoming atrophic compared with regions within 480 µm from the GA margin that did not show CC FV at baseline. Conclusions GA expansion rate and CC FV density throughout the macular region and surrounding the GA margin were significantly correlated. The regional magnitude of FV immediately surrounding GA was associated with GA growth into that region. Translational Relevance CC FV analysis may facilitate prediction of GA growth over time for patients with advanced nonneovascular age-related macular degeneration.
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Affiliation(s)
- Khashayar Nattagh
- Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Hao Zhou
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Nicholas Rinella
- Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Qinqin Zhang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Yining Dai
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Katharina G. Foote
- Department of Ophthalmology, University of California, San Francisco, CA, USA
- School of Optometry and Vision Science Graduate Group, University of California- Berkeley, Berkeley, CA, USA
| | - Cathrine Keiner
- Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Michael Deiner
- Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Jacque L. Duncan
- Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Travis C. Porco
- Department of Ophthalmology, University of California, San Francisco, CA, USA
- Francis I. Proctor Foundation, University of California, San Francisco, CA, USA
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Daniel M. Schwartz
- Department of Ophthalmology, University of California, San Francisco, CA, USA
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37
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Chu Z, Cheng Y, Zhang Q, Zhou H, Dai Y, Shi Y, Gregori G, Rosenfeld PJ, Wang RK. Quantification of Choriocapillaris with Phansalkar Local Thresholding: Pitfalls to Avoid. Am J Ophthalmol 2020; 213:161-176. [PMID: 32059979 DOI: 10.1016/j.ajo.2020.02.003] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 01/31/2020] [Accepted: 02/01/2020] [Indexed: 01/01/2023]
Abstract
PURPOSE To demonstrate the proper use of the Phansalkar local thresholding method (Phansalkar method) in choriocapillaris (CC) quantification with optical coherence tomography angiography (OCTA). DESIGN Retrospective, observational case series. METHODS Swept source OCTA imaging was performed using 3×3 mm and 6×6 mm scanning patterns. The CC slab was extracted after semiautomatic segmentation of the retinal pigment epithelium/Bruch membrane complex. Retinal projection artifacts were removed before further analysis, and CC OCTA images from drusen eyes were compensated using a previously published strategy. CC flow deficits (FDs) were segmented with 2 previously published algorithms: the fuzzy C-means approach (FCM method) and the Phansalkar method. With the Phansalkar method, different parameters were tested and a local window radius of 1 to 15 pixels was used. FD density, mean FD size, and FD number were calculated for comparison. RESULTS Six normal eyes from 6 subjects and 6 eyes with drusen secondary to age-related macular degeneration from 6 subjects were analyzed. With both 3×3 mm and 6×6 mm scans from all eyes, the FD metrics were highly dependent on the selection of the local window radius when using the Phansalkar method. Larger window radii resulted in higher FD density values. FD number increased with the increase in the window radius but then decreased, with an inflection point at about 1 to 2 intercapillary distances. Mean FD size decreased then increased with increasing window radii. CONCLUSIONS Multiple parameters, especially the local window radius, should be optimized before using the Phansalkar method for the quantification of CC FDs with OCTA imaging. It is recommended that the proper use of the Phansalkar method should include the selection of the window radius that is related to the expected intercapillary distance in normal eyes.
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Affiliation(s)
- Zhongdi Chu
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Yuxuan Cheng
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Qinqin Zhang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Hao Zhou
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Yining Dai
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Yingying Shi
- 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
| | - Philip J Rosenfeld
- 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; Department of Ophthalmology, University of Washington, Seattle, Washington, USA.
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38
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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] [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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39
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Chu Z, Gregori G, Rosenfeld PJ, Wang RK. Quantification of Choriocapillaris with Optical Coherence Tomography Angiography: A Comparison Study. Am J Ophthalmol 2019; 208:111-123. [PMID: 31323202 DOI: 10.1016/j.ajo.2019.07.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 06/19/2019] [Accepted: 07/11/2019] [Indexed: 12/19/2022]
Abstract
PURPOSE To demonstrate the variation in quantitative choriocapillaris (CC) metrics with various binarization approaches using optical coherence tomography angiography (OCTA). DESIGN Retrospective, observational, cross-sectional case series. METHODS Macular OCTA scans, 3- × 3-mm and 6- × 6-mm, were obtained from normal eyes and from eyes with drusen secondary to age-related macular degeneration (AMD). The CC slab was extracted, and the CC flow deficits (FDs) were segmented with 2 previously published algorithms: the fuzzy C-means approach (FCM method) and Phansalkar's local thresholding (Phansalkar method). Four different values for the radius were used in order to investigate the effect on the FD segmentation when using the Phansalkar method. FD density (FDD), mean FD size (MFDS), FD number (FDN), FD area (FDA) and intercapillary distance (ICD) were calculated for comparison. Repeatability was assessed as coefficient of variation (CV), and Pearson's correlation analysis was conducted. RESULTS Six eyes from 6 subjects with normal eyes and 6 eyes from 6 subjects with drusen secondary to AMD were scanned. The 3- × 3-mm scans resulted in higher repeatability than the 6- × 6-mm scans. For the Phansalkar method, larger values of the radius resulted in higher repeatability. ANOVA tests resulted in significant differences (P < 0.001) among the FCM method and the Phansalkar method with different radius options for all CC metrics and scan sizes investigated. In 3- × 3-mm scans, significant correlation was found between the FCM method and the Phansalkar method for all quantitative CC metrics other than FDN (all P < 0.001; 0.90 < r <0.99). CONCLUSIONS Quantitative CC analysis with commercially available OCTA is complicated and researchers need to pay close attention to how they conduct such analyses.
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Affiliation(s)
- Zhongdi Chu
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Giovanni Gregori
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Philip J Rosenfeld
- 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; Department of Ophthalmology, University of Washington, Seattle, Washington.
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40
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Marsh-Armstrong B, Migacz J, Jonnal R, Werner JS. Automated quantification of choriocapillaris anatomical features in ultrahigh-speed optical coherence tomography angiograms. BIOMEDICAL OPTICS EXPRESS 2019; 10:5337-5350. [PMID: 31646049 PMCID: PMC6788607 DOI: 10.1364/boe.10.005337] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 09/16/2019] [Accepted: 09/17/2019] [Indexed: 06/10/2023]
Abstract
In vivo visualization and quantification of choriocapillaris vascular anatomy is a fundamental step in understanding the relation between choriocapillaris degradation and atrophic retinopathies, including geographic atrophy. We describe a process utilizing ultrahigh-speed swept-source optical coherence tomography and a custom-designed "local min-max normalized masking" algorithm to extract in vivo anatomical metrics of the choriocapillaris. We used a swept-source optical coherence tomography system with a 1.6 MHz A-scan rate to image healthy retinas. With the postprocessing algorithm, we reduced noise, optimized visibility of vasculature, and skeletonized the vasculature within the images. These skeletonizations were in 89 % agreement with those made by skilled technicians and were, on average, completed in 18.6 s as compared to the 5.6 h technicians required. Anatomy within the processed images and skeletonizations was analyzed to identify average values ( mean ± SD ) of flow void radius ( 9.8 ± 0.7 µm ), flow void area ( 749 ± 110 µm 2 ), vessel radius ( 5.0 ± 0.3 µm ), branch-point to branch-point vessel length ( 26.8 ± 1.1 µm ), and branches per branch-point ( 3.1 ± 0.1 ) . To exemplify the uses of this tool a retina with geographic atrophy was imaged and processed to reveal statistically significant ( p < 0.05 ) increases in flow void radii and decreases in vessel radii under atrophic lesions as compared to atrophy-free regions on the same retina. Our results demonstrate a new avenue for quantifying choriocapillaris anatomy and studying vasculature changes in atrophic retinopathies.
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Age-Related Changes in Choroidal Thickness and the Volume of Vessels and Stroma Using Swept-Source OCT and Fully Automated Algorithms. Ophthalmol Retina 2019; 4:204-215. [PMID: 32033714 DOI: 10.1016/j.oret.2019.09.012] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 09/24/2019] [Accepted: 09/25/2019] [Indexed: 02/07/2023]
Abstract
PURPOSE To determine age-related changes in choroidal thickness and the volume of choroidal vessels and stroma using automated algorithms based on structural swept-source OCT (SS-OCT) scans. DESIGN Prospective and observational study. PARTICIPANTS The study included 144 normal participants with ages ranging from 20 to 88 years. METHODS A previously reported strategy was used to automatically segment the choroid using SS-OCT structural images. Attenuation correction was applied on B-scans to enhance the choroidal contrast and facilitate more accurate automatic segmentation of the 3-dimensional choroidal vessel and stroma. The parameters that we investigated included mean choroidal thickness (MCT), choroidal vessel volume (CVV), choroidal stroma volume (CSV), choroid vascularity index (CVI), and the choroidal stroma-to-vessel volume ratio (CSVR). Correlations between MCT and choroidal vessel metrics of CVV, CSV, CVI, and CSVR were studied. Regional distributions of MCT and CVI were analyzed using a grid centered on the fovea. Age-related changes in MCT, CVV, CSV, and CVI were studied in the entire scanning region, as well as in the subregions of the grids. MAIN OUTCOME MEASURES Age-related changes in MCT, CVV, CSV, and CVI using 6×6-mm and 12×12-mm SS-OCT scans. RESULTS The automated choroid segmentations were validated against manual segmentations, and MCT measurements were shown to be in good agreement (P < 0.0001). Choroidal vessel volume and CSV showed significant correlations with MCT (all P < 0.0001). Interestingly, CVI and CSVR were constant, with little variation among all participants regardless of age and MCT (61.1±1.8% and 0.64±0.05, respectively). Measurements on 12×12-mm and 6×6-mm scans showed excellent agreement in all scan regions (all P < 0.0001). While choroidal thickness and choroidal volume, which includes both choroidal vessels and stroma, decrease with age (all P < 0.0001), the CVI and CSVR vary little among all ages in all regions. CONCLUSIONS Whereas MCT, CVV, and CSV decrease with age, the CVI and CSVR remain constant in all regions with age. Ongoing studies are using these automated algorithms on SS-OCT structural datasets to investigate the diagnostic usefulness of these choroidal parameters in a myriad of ocular and systemic diseases.
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Features of the choriocapillaris on four different optical coherence tomography angiography devices. Int Ophthalmol 2019; 40:325-333. [DOI: 10.1007/s10792-019-01182-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 09/22/2019] [Indexed: 12/01/2022]
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Mehta N, Liu K, Alibhai AY, Gendelman I, Braun PX, Ishibazawa A, Sorour O, Duker JS, Waheed NK. Impact of Binarization Thresholding and Brightness/Contrast Adjustment Methodology on Optical Coherence Tomography Angiography Image Quantification. Am J Ophthalmol 2019; 205:54-65. [PMID: 30885708 DOI: 10.1016/j.ajo.2019.03.008] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/06/2019] [Accepted: 03/06/2019] [Indexed: 12/27/2022]
Abstract
PURPOSE Binarization is a critical technique in optical coherence tomography angiography (OCTA) image analysis, but there is no consistency in the method used in published OCTA studies. This study assessed whether differences in OCTA binarization and brightness and contrast adjustments affect quantification measurements. DESIGN Prospective cross-sectional validity study. METHODS This was a single-center study examining 21 eyes of 11 healthy individuals. All eyes were imaged using a swept-source OCTA (Zeiss), and quantitative measurements resulting from five binarization thresholding and five brightness/contrast adjustment methods were compared. All measurements were calculated for the superficial plexus and choriocapillaris (CC), as well as unaveraged and averaged en face OCTA images. RESULTS There were statistically significant differences between measurements from different binarization thresholding methods (P < 0.0001), as well as measurements from different histogram adjustments (P < 0.0001). The binarization thresholds yielded different measurements when combined with variable brightness/contrast adjustments. The method of analysis also affected the directionality of trends in imaging measurements between unaveraged and averaged CC images. CONCLUSIONS The method of OCTA image binarization thresholding and histogram adjustment significantly alters quantitative measurements and the directionality of trends. Results obtained from different OCTA binarization methods should be seen as valid only for that given method. This has significant consequences for clinical trials using OCTA measurements as outcome measurements. A consensus is needed across the research community for a consistent method for OCTA image quantification and greater attention paid to fully describing methods in published studies.
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Zhou K, Song S, Zhang Q, Chu Z, Huang Z, Wang RK. Visualizing choriocapillaris using swept-source optical coherence tomography angiography with various probe beam sizes. BIOMEDICAL OPTICS EXPRESS 2019; 10:2847-2860. [PMID: 31259055 PMCID: PMC6583358 DOI: 10.1364/boe.10.002847] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/02/2019] [Accepted: 05/09/2019] [Indexed: 05/29/2023]
Abstract
Imaging choriocapillaris (CC) is a long-term challenge for commercial OCT angiography (OCTA) systems due to limited transverse resolution. Effects of transverse resolution on the visualization of a CC microvascular network are explored and demonstrated in this paper. We use three probe beams with sizes of ~1.12 mm, ~2.51 mm and ~3.50 mm at the pupil plane, which deliver an estimated transverse resolution at the retina of 17.5 µm, 8.8 µm and 7.0 µm, respectively, to investigate the ability of OCTA to resolve the CC capillary vessels. The complex optical microangiography algorithm is applied to extract blood flow in the CC slab. Mean retinal pigment epithelium (RPE) to CC (RPE-CC) distance, mean CC inter-vascular spacing and the magnitude in the radially-averaged power spectrum are quantified. We demonstrate that a clearer CC lobular capillary network is resolved in the angiograms provided by a larger beam size. The image contrast of the CC angiogram with a large beam size of 3.50 mm is 114% higher than that with a small beam size of 1.12 mm. While the measurements of the mean RPE-CC distance and CC inter-vascular spacing are almost consistent regardless of the beam sizes, they are more reliable and stable with the larger beam size of 3.50 mm. We conclude that the beam size is a key parameter for CC angiography if the purpose of the investigation is to visualize the individual CC capillaries.
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Affiliation(s)
- Kanheng Zhou
- School of Science and Engineering, University of Dundee, Dundee DD1 4HN, UK
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Shaozhen Song
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Qinqin Zhang
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Zhongdi Chu
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Zhihong Huang
- School of Science and Engineering, University of Dundee, Dundee DD1 4HN, UK
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
- Department of Ophthalmology, University of Washington, Seattle, WA 98195, USA
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Chu Z, Zhang Q, Zhou H, Shi Y, Zheng F, Gregori G, Rosenfeld PJ, Wang RK. Quantifying choriocapillaris flow deficits using global and localized thresholding methods: a correlation study. Quant Imaging Med Surg 2018; 8:1102-1112. [PMID: 30701164 PMCID: PMC6328379 DOI: 10.21037/qims.2018.12.09] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 12/12/2018] [Indexed: 01/07/2023]
Abstract
BACKGROUND To investigate the correlation and agreement of two previously published choriocapillaris (CC) quantification methods using a normal database with swept-source optical coherence tomography angiography (SS-OCTA). METHODS Normal adult subjects from all age groups imaged by SS-OCTA were used in this study. Each subject was imaged with 3 mm × 3 mm and 6 mm × 6 mm scan patterns centered on fovea, upon which en face CC images were generated by segmenting volumetric OCTA data. After signal compensation and removal of projection artifacts and noise, CC images were analyzed to identify flow deficits (FD) using two published methods. The first method utilized standard deviation from a young normal database (SD method) as the global thresholding while the second method utilized fuzzy C-means algorithm (FCM method) with local thresholding. Both methods segmented FDs from CC images and quantified FD density (FDD) and mean FD size (MFDS). In each 3 mm × 3 mm scan, three regions were quantified: a 1 mm circle (C1), a 1.5 mm rim (R1.5) and a 2.5 mm circle (C2.5). In each 6 mm × 6 mm scan, five regions were quantified: C1, R1.5, C2.5, a 2.5 mm rim (R2.5) and a 5 mm circle (C5). Spearman correlation and Bland-Altman plot analyses were conducted to compare the two methods. RESULTS Data obtained from 164 normal subjects (age: 56±19, 59% females) were used in this study. Strong correlations were observed between the two methods in all comparisons (r: 0.78-0.94, all P<0.0001). Overall MFDS provided higher or comparable correlation coefficients (r) compared to FDD. We have also observed stronger correlations in the central macula compared to parafoveal and perifoveal regions for both FDD and MFDS. In regions of C1, R1.5 and C2.5, 6 mm × 6 mm scans resulted in better agreement (smaller mean bias, similar or tighter limit of agreement) between the two methods for both FDD and MFDS compared to 3 mm × 3 mm scans. CONCLUSIONS There are strong correlations and satisfactory agreement between SD method and FCM method. SD method requires the reference to a normal database for CC quantification while FCM does not. Both methods could be used for the analysis of CC FDs in clinical settings depending on specific study designs such as the availability of a normal database.
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Affiliation(s)
- Zhongdi Chu
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Qinqin Zhang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Hao Zhou
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Yingying Shi
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Fang Zheng
- 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
| | - Philip J. Rosenfeld
- 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
- Department of Ophthalmology, University of Washington, Seattle, Washington, USA
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