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Valmaggia P, Cattin PC, Sandkühler R, Inglin N, Otto TP, Aumann S, Teussink MM, Spaide RF, Scholl HPN, Maloca PM. Time-Resolved Dynamic Optical Coherence Tomography for Retinal Blood Flow Analysis. Invest Ophthalmol Vis Sci 2024; 65:9. [PMID: 38837167 PMCID: PMC11160951 DOI: 10.1167/iovs.65.6.9] [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: 11/01/2023] [Accepted: 05/16/2024] [Indexed: 06/06/2024] Open
Abstract
Purpose Optical coherence tomography (OCT) representations in clinical practice are static and do not allow for a dynamic visualization and quantification of blood flow. This study aims to present a method to analyze retinal blood flow dynamics using time-resolved structural OCT. Methods We developed novel imaging protocols to acquire video-rate time-resolved OCT B-scans (1024 × 496 pixels, 10 degrees field of view) at four different sensor integration times (integration time of 44.8 µs at a nominal A-scan rate of 20 kHz, 22.4 µs at 40 kHz, 11.2 µs at 85 kHz, and 7.24 µs at 125 kHz). The vessel centers were manually annotated for each B-scan and surrounding subvolumes were extracted. We used a velocity model based on signal-to-noise ratio (SNR) drops due to fringe washout to calculate blood flow velocity profiles in vessels within five optic disc diameters of the optic disc rim. Results Time-resolved dynamic structural OCT revealed pulsatile SNR changes in the analyzed vessels and allowed the calculation of potential blood flow velocities at all integration times. Fringe washout was stronger in acquisitions with longer integration times; however, the ratio of the average SNR to the peak SNR inside the vessel was similar across all integration times. Conclusions We demonstrated the feasibility of estimating blood flow profiles based on fringe washout analysis, showing pulsatile dynamics in vessels close to the optic nerve head using structural OCT. Time-resolved dynamic OCT has the potential to uncover valuable blood flow information in clinical settings.
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Affiliation(s)
- Philippe Valmaggia
- Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), Basel, Basel, Switzerland
- Department of Ophthalmology, University Hospital Basel, Basel, Switzerland
| | - Philippe C. Cattin
- Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
| | - Robin Sandkühler
- Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland
| | - Nadja Inglin
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), Basel, Basel, Switzerland
| | | | - Silke Aumann
- Heidelberg Engineering GmbH, Heidelberg, Germany
| | | | - Richard F. Spaide
- Vitreous Retina Macula Consultants of New York, New York, United States
| | - Hendrik P. N. Scholl
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), Basel, Basel, Switzerland
- Department of Ophthalmology, University Hospital Basel, Basel, Switzerland
| | - Peter M. Maloca
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), Basel, Basel, Switzerland
- Department of Ophthalmology, University Hospital Basel, Basel, Switzerland
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Feu-Basilio S, Maloca PM, Hasler P, Scholl HPN, Marin-Martinez S, Rosinés-Fonoll J, Suarez-Valero X, Reich M, Lange C, Egan C, Zweifel S, Tufail A, Spaide RF, Zarranz-Ventura J. Retinal vessel volume reference database derived from volume-rendered optical coherence tomography angiography. Sci Rep 2024; 14:2721. [PMID: 38302574 PMCID: PMC10834445 DOI: 10.1038/s41598-024-53000-8] [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: 11/12/2023] [Accepted: 01/25/2024] [Indexed: 02/03/2024] Open
Abstract
Optical coherence tomography angiography (OCTA) enables three-dimensional reconstruction of the functional blood vessels in the retina. Therefore, it enables the quantification of 3D retinal vessel parameters such as surface area and vessel volume. In spite of the widespread use of OCTA, no representative volume-rendered vessel volume (VV) data are published to date. In this study, OCTA 3 × 3 mm macular cubes were processed with volume-rendering techniques to measure VV in 203 eyes from 107 healthy volunteers. Generalized linear models (GLM) were constructed to assess the impact of age, gender, visual acuity (VA), spherical equivalent (SE), and axial length (AL) on VV. Overall mean VV was 0.23 ± 0.05mm3. Age and axial length showed a negative correlation with VV. However, GLM model analysis found that AL exerted the most pronounced influence on VV. No statistically significant associations were identified between gender or between left and right eyes. This is the first study to assess 3D OCTA VV and its naturally occurring variations in a large series of healthy subjects. It offers novel insights into the characterization of normal retinal vascular anatomy in healthy individuals, contributing to a valuable reference for future research in this field.
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Affiliation(s)
- Silvia Feu-Basilio
- Hospital Clínic de Barcelona, University of Barcelona, Carrer de Sabino Arana, 1, 08028, Barcelona, Spain
| | - Peter M Maloca
- Institute of Molecular and Clinical Ophthalmology Basel, 4031, Basel, Switzerland
- Department of Ophthalmology, University Hospital Basel, 4031, Basel, Switzerland
- Moorfields Eye Hospital NHS Foundation Trust, London, EC1V 2PD, UK
| | - Pascal Hasler
- Institute of Molecular and Clinical Ophthalmology Basel, 4031, Basel, Switzerland
| | - Hendrik P N Scholl
- Institute of Molecular and Clinical Ophthalmology Basel, 4031, Basel, Switzerland
- Department of Ophthalmology, University Hospital Basel, 4031, Basel, Switzerland
| | - Sara Marin-Martinez
- Hospital Clínic de Barcelona, University of Barcelona, Carrer de Sabino Arana, 1, 08028, Barcelona, Spain
| | - Josep Rosinés-Fonoll
- Hospital Clínic de Barcelona, University of Barcelona, Carrer de Sabino Arana, 1, 08028, Barcelona, Spain
| | - Xavier Suarez-Valero
- Hospital Clínic de Barcelona, University of Barcelona, Carrer de Sabino Arana, 1, 08028, Barcelona, Spain
| | - Michael Reich
- Faculty of Medicine, Eye Center, Albert-Ludwig University Freiburg, 79085, Freiburg, Germany
- Augenärzte Am Städel, Hans-Thoma-Strasse 24, 60596, Frankfurt Am Main, Germany
| | - Clemens Lange
- Faculty of Medicine, Eye Center, Albert-Ludwig University Freiburg, 79085, Freiburg, Germany
- Department of Ophthalmology, St. Franziskus Hospital, 48145, Münster, Germany
| | - Catherine Egan
- Moorfields Eye Hospital NHS Foundation Trust, London, EC1V 2PD, UK
| | - Sandrine Zweifel
- Department of Ophthalmology, University Hospital Zurich, 8006, Zurich, Switzerland
- University of Zurich, 8006, Zurich, Switzerland
| | - Adnan Tufail
- Moorfields Eye Hospital NHS Foundation Trust, London, EC1V 2PD, UK
| | - Richard F Spaide
- Vitreous, Retina, Macula Consultants of New York, New York, NY, USA
| | - Javier Zarranz-Ventura
- Hospital Clínic de Barcelona, University of Barcelona, Carrer de Sabino Arana, 1, 08028, Barcelona, Spain.
- Moorfields Eye Hospital NHS Foundation Trust, London, EC1V 2PD, UK.
- Institut de Investigacions Biomediques August Pi i Sunyer (IDIBAPS), 08036, Barcelona, Spain.
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Ong CJT, Wong MYZ, Cheong KX, Zhao J, Teo KYC, Tan TE. Optical Coherence Tomography Angiography in Retinal Vascular Disorders. Diagnostics (Basel) 2023; 13:diagnostics13091620. [PMID: 37175011 PMCID: PMC10178415 DOI: 10.3390/diagnostics13091620] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 04/28/2023] [Accepted: 05/01/2023] [Indexed: 05/15/2023] Open
Abstract
Traditionally, abnormalities of the retinal vasculature and perfusion in retinal vascular disorders, such as diabetic retinopathy and retinal vascular occlusions, have been visualized with dye-based fluorescein angiography (FA). Optical coherence tomography angiography (OCTA) is a newer, alternative modality for imaging the retinal vasculature, which has some advantages over FA, such as its dye-free, non-invasive nature, and depth resolution. The depth resolution of OCTA allows for characterization of the retinal microvasculature in distinct anatomic layers, and commercial OCTA platforms also provide automated quantitative vascular and perfusion metrics. Quantitative and qualitative OCTA analysis in various retinal vascular disorders has facilitated the detection of pre-clinical vascular changes, greater understanding of known clinical signs, and the development of imaging biomarkers to prognosticate and guide treatment. With further technological improvements, such as a greater field of view and better image quality processing algorithms, it is likely that OCTA will play an integral role in the study and management of retinal vascular disorders. Artificial intelligence methods-in particular, deep learning-show promise in refining the insights to be gained from the use of OCTA in retinal vascular disorders. This review aims to summarize the current literature on this imaging modality in relation to common retinal vascular disorders.
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Affiliation(s)
- Charles Jit Teng Ong
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 168751, Singapore
| | - Mark Yu Zheng Wong
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 168751, Singapore
| | - Kai Xiong Cheong
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 168751, Singapore
| | - Jinzhi Zhao
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 168751, Singapore
| | - Kelvin Yi Chong Teo
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 168751, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program (EYE ACP), Duke-NUS Medical School, Singapore 169857, Singapore
| | - Tien-En Tan
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 168751, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program (EYE ACP), Duke-NUS Medical School, Singapore 169857, Singapore
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Maloca PM, Freichel C, Hänsli C, Valmaggia P, Müller PL, Zweifel S, Seeger C, Inglin N, Scholl HPN, Denk N. Cynomolgus monkey's choroid reference database derived from hybrid deep learning optical coherence tomography segmentation. Sci Rep 2022; 12:13276. [PMID: 35918392 PMCID: PMC9346135 DOI: 10.1038/s41598-022-17699-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 07/29/2022] [Indexed: 11/18/2022] Open
Abstract
Cynomolgus monkeys exhibit human-like features, such as a fovea, so they are often used in non-clinical research. Nevertheless, little is known about the natural variation of the choroidal thickness in relation to origin and sex. A combination of deep learning and a deterministic computer vision algorithm was applied for automatic segmentation of foveolar optical coherence tomography images in cynomolgus monkeys. The main evaluation parameters were choroidal thickness and surface area directed from the deepest point on OCT images within the fovea, marked as the nulla with regard to sex and origin. Reference choroid landmarks were set underneath the nulla and at 500 µm intervals laterally up to a distance of 2000 µm nasally and temporally, complemented by a sub-analysis of the central bouquet of cones. 203 animals contributed 374 eyes for a reference choroid database. The overall average central choroidal thickness was 193 µm with a coefficient of variation of 7.8%, and the overall mean surface area of the central bouquet temporally was 19,335 µm2 and nasally was 19,283 µm2. The choroidal thickness of the fovea appears relatively homogeneous between the sexes and the studied origins. However, considerable natural variation has been observed, which needs to be appreciated.
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Affiliation(s)
- Peter M Maloca
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), 4031, Basel, Switzerland. .,Department of Ophthalmology, University Hospital Basel, 4031, Basel, Switzerland. .,Moorfields Eye Hospital NHS Foundation Trust, London, EC1V 2PD, UK.
| | - Christian Freichel
- Pharma Research and Early Development (pRED), Pharmaceutical Sciences (PS), Roche, Innovation Center Basel, 4070, Basel, Switzerland
| | - Christof Hänsli
- Berner Augenklinik Am Lindenhofspital and University of Bern, Bern, Switzerland
| | - Philippe Valmaggia
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), 4031, Basel, Switzerland
| | - Philipp L Müller
- Moorfields Eye Hospital NHS Foundation Trust, London, EC1V 2PD, UK.,Department of Ophthalmology, University of Bonn, Bonn, Germany.,Makulazentrum Augsburg, Fachärzte Augenheilkunde, Augsburg, Germany
| | - Sandrine Zweifel
- University Hospital Zurich, Frauenklinikstrasse 24, 8091, Zurich, Switzerland.,University of Zurich, Rämistrasse 71, 8006, Zürich, Switzerland
| | - Christine Seeger
- Pharma Research and Early Development (pRED), Pharmaceutical Sciences (PS), Roche, Innovation Center Basel, 4070, Basel, Switzerland
| | - Nadja Inglin
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), 4031, Basel, Switzerland
| | - Hendrik P N Scholl
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), 4031, Basel, Switzerland.,Department of Ophthalmology, University Hospital Basel, 4031, Basel, Switzerland
| | - Nora Denk
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), 4031, Basel, Switzerland.,Pharma Research and Early Development (pRED), Pharmaceutical Sciences (PS), Roche, Innovation Center Basel, 4070, Basel, Switzerland
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