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Saeed A, Hadoux X, van Wijngaarden P. Hyperspectral retinal imaging biomarkers of ocular and systemic diseases. Eye (Lond) 2024:10.1038/s41433-024-03135-9. [PMID: 38778136 DOI: 10.1038/s41433-024-03135-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 02/20/2024] [Accepted: 05/07/2024] [Indexed: 05/25/2024] Open
Abstract
Hyperspectral imaging is a frontier in the field of medical imaging technology. It enables the simultaneous collection of spectroscopic and spatial data. Structural and physiological information encoded in these data can be used to identify and localise typically elusive biomarkers. Studies of retinal hyperspectral imaging have provided novel insights into disease pathophysiology and new ways of non-invasive diagnosis and monitoring of retinal and systemic diseases. This review provides a concise overview of recent advances in retinal hyperspectral imaging.
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Affiliation(s)
- Abera Saeed
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, 3002, VIC, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, 3002, VIC, Australia
| | - Xavier Hadoux
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, 3002, VIC, Australia
| | - Peter van Wijngaarden
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, 3002, VIC, Australia.
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, 3002, VIC, Australia.
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Past, present and future role of retinal imaging in neurodegenerative disease. Prog Retin Eye Res 2021; 83:100938. [PMID: 33460813 PMCID: PMC8280255 DOI: 10.1016/j.preteyeres.2020.100938] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 12/11/2020] [Accepted: 12/17/2020] [Indexed: 02/08/2023]
Abstract
Retinal imaging technology is rapidly advancing and can provide ever-increasing amounts of information about the structure, function and molecular composition of retinal tissue in humans in vivo. Most importantly, this information can be obtained rapidly, non-invasively and in many cases using Food and Drug Administration-approved devices that are commercially available. Technologies such as optical coherence tomography have dramatically changed our understanding of retinal disease and in many cases have significantly improved their clinical management. Since the retina is an extension of the brain and shares a common embryological origin with the central nervous system, there has also been intense interest in leveraging the expanding armamentarium of retinal imaging technology to understand, diagnose and monitor neurological diseases. This is particularly appealing because of the high spatial resolution, relatively low-cost and wide availability of retinal imaging modalities such as fundus photography or OCT compared to brain imaging modalities such as magnetic resonance imaging or positron emission tomography. The purpose of this article is to review and synthesize current research about retinal imaging in neurodegenerative disease by providing examples from the literature and elaborating on limitations, challenges and future directions. We begin by providing a general background of the most relevant retinal imaging modalities to ensure that the reader has a foundation on which to understand the clinical studies that are subsequently discussed. We then review the application and results of retinal imaging methodologies to several prevalent neurodegenerative diseases where extensive work has been done including sporadic late onset Alzheimer's Disease, Parkinson's Disease and Huntington's Disease. We also discuss Autosomal Dominant Alzheimer's Disease and cerebrovascular small vessel disease, where the application of retinal imaging holds promise but data is currently scarce. Although cerebrovascular disease is not generally considered a neurodegenerative process, it is both a confounder and contributor to neurodegenerative disease processes that requires more attention. Finally, we discuss ongoing efforts to overcome the limitations in the field and unmet clinical and scientific needs.
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Lemmens S, Van Eijgen J, Van Keer K, Jacob J, Moylett S, De Groef L, Vancraenendonck T, De Boever P, Stalmans I. Hyperspectral Imaging and the Retina: Worth the Wave? Transl Vis Sci Technol 2020; 9:9. [PMID: 32879765 PMCID: PMC7442879 DOI: 10.1167/tvst.9.9.9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 06/23/2020] [Indexed: 02/07/2023] Open
Abstract
Purpose Hyperspectral imaging is gaining attention in the biomedical field because it generates additional spectral information to study physiological and clinical processes. Several technologies have been described; however an independent, systematic literature overview is lacking, especially in the field of ophthalmology. This investigation is the first to systematically overview scientific literature specifically regarding retinal hyperspectral imaging. Methods A systematic literature review was conducted, in accordance with PRISMA Statement 2009 criteria, in four bibliographic databases: Medline, Embase, Cochrane Database of Systematic Reviews, and Web of Science. Results Fifty-six articles were found that meet the review criteria. A range of techniques was reported: Fourier analysis, liquid crystal tunable filters, tunable laser sources, dual-slit monochromators, dispersive prisms and gratings, computed tomography, fiber optics, and Fabry-Perrot cavity filter covered complementary metal oxide semiconductor. We present a narrative synthesis and summary tables of findings of the included articles, because methodologic heterogeneity and diverse research topics prevented a meta-analysis being conducted. Conclusions Application in ophthalmology is still in its infancy. Most previous experiments have been performed in the field of retinal oximetry, providing valuable information in the diagnosis and monitoring of various ocular diseases. To date, none of these applications have graduated to clinical practice owing to the lack of sufficiently large validation studies. Translational Relevance Given the promising results that smaller studies show for hyperspectral imaging (e.g., in Alzheimer's disease), advanced research in larger validation studies is warranted to determine its true clinical potential.
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Affiliation(s)
- Sophie Lemmens
- University Hospitals UZ Leuven, Department of Ophthalmology, Leuven, Belgium
- KU Leuven, Biomedical Sciences Group, Department of Neurosciences, Research Group Ophthalmology, Leuven, Belgium
- VITO (Flemish Institute for Technological Research), Health Unit, Boeretang, Belgium
| | - Jan Van Eijgen
- University Hospitals UZ Leuven, Department of Ophthalmology, Leuven, Belgium
- KU Leuven, Biomedical Sciences Group, Department of Neurosciences, Research Group Ophthalmology, Leuven, Belgium
- VITO (Flemish Institute for Technological Research), Health Unit, Boeretang, Belgium
| | - Karel Van Keer
- University Hospitals UZ Leuven, Department of Ophthalmology, Leuven, Belgium
- KU Leuven, Biomedical Sciences Group, Department of Neurosciences, Research Group Ophthalmology, Leuven, Belgium
| | - Julie Jacob
- University Hospitals UZ Leuven, Department of Ophthalmology, Leuven, Belgium
- KU Leuven, Biomedical Sciences Group, Department of Neurosciences, Research Group Ophthalmology, Leuven, Belgium
| | - Sinéad Moylett
- Department of Psychiatry, University of Cambridge School of Clinical Medicine, Cambridge Biomedical Campus, Cambridge, UK
| | - Lies De Groef
- Neural Circuit Development and Regeneration Research Group, Department of Biology, KU Leuven, Leuven, Belgium
| | - Toon Vancraenendonck
- VITO (Flemish Institute for Technological Research), Health Unit, Boeretang, Belgium
| | - Patrick De Boever
- VITO (Flemish Institute for Technological Research), Health Unit, Boeretang, Belgium
- Hasselt University, Centre of Environmental Sciences, Agoralaan, Belgium
| | - Ingeborg Stalmans
- University Hospitals UZ Leuven, Department of Ophthalmology, Leuven, Belgium
- KU Leuven, Biomedical Sciences Group, Department of Neurosciences, Research Group Ophthalmology, Leuven, Belgium
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Zhu Z, He C, Zhang Y, Yue X, Ba D. Mathematical method for analysis of the asymmetric retinal vascular networks. Eur J Ophthalmol 2018; 29:538-546. [PMID: 30270647 DOI: 10.1177/1120672118802952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The purpose of this study was to quantitatively investigate the haemodynamics and oxygen transmission of the retina. METHODS Considering the effect of Fåhraeus-Lindqvist effect on the apparent viscosity of blood and the actual haematocrit in blood vessels, this study used the currently known retinal parameters (e.g. blood flow obtained by Doppler Fourier domain optical coherence tomography, FD-OCT for short) to construct a retinal blood circulation model consisting of an asymmetric vascular network system. RESULTS The blood flow velocity and the vascular diameter in the retinal blood vessels satisfied the exponential relationship. The wall shear stress was related to the release of nitric oxide synthase and endothelin-1 by endothelial cells and played an important role in retinal blood flow regulation. In the retinal arteries, the oxygen tension ranged from 98 to 65 mmHg, and the oxygen saturation ranged from 97.3% to 92.2%. In the retinal veins, the oxygen tension was approximately 41.8 mmHg, and the oxygen saturation ranged from 79.2% to 77.3%. The difference in oxygen content of the arteriovenous network was 5.4 (ml O2/dl blood), and the oxygen extraction of the superior temporal arteriovenous network was 86 (μl/min*ml O2/dl blood). CONCLUSION Compared with previous relevant experimental data, the numerical model established in this article demonstrates reliability. It also helps advance our understanding of the retinal pathological processes related to hemodynamics and metabolism.
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Affiliation(s)
- Zhipeng Zhu
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Chao He
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Yingli Zhang
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Xiangji Yue
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Dechun Ba
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
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Hyperspectral Image Mapping Spectrometry for Retinal Oximetry Measurements in Four Diseased Eyes. Int Ophthalmol Clin 2018; 56:25-38. [PMID: 27575756 DOI: 10.1097/iio.0000000000000139] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Keilani C, Halalchi A, Wakpi Djeugue D, Regis A, Abada S. Retinal oximetry during treatment of retinal vein occlusion by ranibizumab in patients with high blood pressure and dyslipidemia. J Fr Ophtalmol 2016; 39:816-821. [PMID: 27865689 DOI: 10.1016/j.jfo.2016.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 06/22/2016] [Accepted: 08/01/2016] [Indexed: 12/16/2022]
Abstract
INTRODUCTION In the present study, we examined retinal vascular oxygen saturation in patients with retinal vein occlusion (RVO), high blood pressure (HBP) and dyslipidemia, before and during intravitreal vascular endothelial growth factor (VEGF) injection (ranibizumab). METHODS We retrospectively reviewed the medical records of six patients with visual acuity (VA) reduced by macular edema (ME) secondary to RVO with HBP and dyslipidemia, who underwent intravitreal anti-VEGF injection between October 2014 and February 2015 in the department of ophthalmology of François-Quesnay Hospital at Mantes-la-Jolie (France). The main inclusion criterion was the presence of RVO with ME and decreased VA. The primary endpoint was improvement of retinal venous oxygen saturation in patients with RVO before and 3 months after intravitreal ranibizumab injection. Secondary outcomes were improvement of retinal arterial oxygen saturation, improvement of best-corrected visual acuity (BCVA) on the Early Treatment Diabetic Retinopathy Study (ETDRS) scale, regression of ME measured by the central macular thickness (CMT) in nm and studying the correlation between blood pressure (BP) and retinal venous oxygen saturation before and after ranibizumab. RESULTS Six eyes of six patients were included. Before treatment, the mean (standard deviation [SD]) of the retinal venous saturation (%) was 38.1±14.2. Three months after the injections, the mean (SD) of the retinal venous saturation (%) increased statistically significantly 49.2±11 (P=0.03). CONCLUSION In this study, retinal venous oxygen saturation in patients with RVO, HBP and dyslipidemia was partially normalized during intravitreal ranibizumab treatment.
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Affiliation(s)
- C Keilani
- Department of vascular neurology, faculty of medicine, hôpital universitaire de la Pitié-Salpêtrière, Pierre-et-Marie-Curie (Paris VI), 47-83, boulevard de l'Hôpital, 75013 Paris, France.
| | - A Halalchi
- Department of ophthalmology, hôpital François-Quesnay, 2, boulevard Sully, 78201 Mantes-la-Jolie cedex, France
| | - D Wakpi Djeugue
- Department of ophthalmology, hôpital François-Quesnay, 2, boulevard Sully, 78201 Mantes-la-Jolie cedex, France
| | - A Regis
- Department of ophthalmology, hôpital François-Quesnay, 2, boulevard Sully, 78201 Mantes-la-Jolie cedex, France
| | - S Abada
- Department of ophthalmology, hôpital François-Quesnay, 2, boulevard Sully, 78201 Mantes-la-Jolie cedex, France
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Noninvasive assessment of retinal vascular oxygen content among normal and diabetic human subjects: a study using hyperspectral computed tomographic imaging spectroscopy. Retina 2015; 34:1854-60. [PMID: 24732694 DOI: 10.1097/iae.0000000000000146] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE This pilot study was aimed to demonstrate the clinical feasibility of using hyperspectral computed tomographic spectroscopy to measure blood oxygen content in human retinal vessels. METHODS All procedures were performed under a University of Southern California Institutional Review Board-approved protocol and after obtaining informed consent. Fifty-seven subjects with and without diabetic retinopathy were dilated for standard fundus photography. Fundus photographs and retinal vascular oxygen measurements (oximetry) were made using a custom-made hyperspectral computed tomographic imaging spectrometer coupled to a standard fundus camera. Oximetry measurements were made along arteries (Aox) and veins (Vox) within vessel segments that were 1 to 2 disk diameters from the optic disk. RESULTS For all control subjects (n = 45), mean Aox and Vox were 93 ± 7% and 65 ± 5% (P = 0.001), respectively. For all diabetic subjects (n = 12), mean Aox and Vox were 90 ± 7% and 68 ± 5% (P = 0.001), respectively. In subjects with proliferative diabetic retinopathy, Aox was significantly lower, and Vox was significantly higher than other groups (85 ± 4% and 71 ± 4%, respectively; P = 0.04, analysis of variance). There was a highly significant difference in the arteriovenous difference between subjects with proliferative diabetic retinopathy and those in the control group (14 vs. 26%, P = 0.003). CONCLUSION Hyperspectral computed tomographic spectroscopy is a clinically feasible method for measurement and analysis of vascular oxygen content in retinal health and disease. This study uses the techniques relevant to oximetry; however, the breadth of spectral data available through this method may be applicable to study other anatomical and functional features of the retina in health and disease.
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