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Lavia C, Bonnin S, Maule M, Erginay A, Tadayoni R, Gaudric A. VESSEL DENSITY OF SUPERFICIAL, INTERMEDIATE, AND DEEP CAPILLARY PLEXUSES USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY. Retina 2019; 39:247-258. [PMID: 30550527 PMCID: PMC6358199 DOI: 10.1097/iae.0000000000002413] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To provide values of retinal vessel density (VD) in the three retinal capillary plexuses, foveal avascular zone (FAZ) area, and retinal layer thickness in a cohort of healthy subjects. METHODS The optical coherence tomography angiography maps of 148 eyes of 84 healthy subjects, aged 22 to 76 years, were analyzed for measuring VD of the retinal capillary plexuses, using the Optovue device comprising a projection artifact removal algorithm. Foveal avascular zone metrics were measured, and the relationship between optical coherence tomography angiography findings and age, sex, and image quality was studied. RESULTS The deep capillary plexus showed the lowest VD (31.6% ± 4.4%) in all macular areas and age groups compared with the superficial vascular plexus (47.8% ± 2.8%) and intermediate capillary plexus (45.4% ± 4.2%). The mean VD decreased by 0.06%, 0.06%, and 0.08% per year, respectively, in the superficial vascular plexus, intermediate capillary plexus, and deep capillary plexus. Mean FAZ area, FAZ acircularity index, and capillary density in a 300-µm area around the FAZ were 0.25 ± 0.1 mm, 1.1 ± 0.05, and 50.8 ± 3.4%, respectively. The yearly increase in FAZ area was 0.003 mm (P < 0.001). CONCLUSION The deep capillary plexus, a single monoplanar capillary plexus located in the outer plexiform layer, has the lowest VD, a significant finding that might be used to evaluate retinal vascular diseases. Vascular density decreased with age in the three capillary plexuses.
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Affiliation(s)
- Carlo Lavia
- Service d'Ophtalmologie, Hôpital Lariboisière, AP-HP, Assistance Publique-Hôpitaux de Paris, Université Paris Diderot, Sorbonne Paris Cité, France
- Department of Surgical Sciences, Eye Clinic, University of Turin, Turin, Italy; and
| | - Sophie Bonnin
- Service d'Ophtalmologie, Hôpital Lariboisière, AP-HP, Assistance Publique-Hôpitaux de Paris, Université Paris Diderot, Sorbonne Paris Cité, France
| | - Milena Maule
- Department of Medical Sciences, CPO-Piemonte, AOU Città della Salute e della Scienza di Torino, University of Turin, Turin, Italy
| | - Ali Erginay
- Service d'Ophtalmologie, Hôpital Lariboisière, AP-HP, Assistance Publique-Hôpitaux de Paris, Université Paris Diderot, Sorbonne Paris Cité, France
| | - Ramin Tadayoni
- Service d'Ophtalmologie, Hôpital Lariboisière, AP-HP, Assistance Publique-Hôpitaux de Paris, Université Paris Diderot, Sorbonne Paris Cité, France
| | - Alain Gaudric
- Service d'Ophtalmologie, Hôpital Lariboisière, AP-HP, Assistance Publique-Hôpitaux de Paris, Université Paris Diderot, Sorbonne Paris Cité, France
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Chlebiej M, Gorczynska I, Rutkowski A, Kluczewski J, Grzona T, Pijewska E, Sikorski BL, Szkulmowska A, Szkulmowski M. Quality improvement of OCT angiograms with elliptical directional filtering. BIOMEDICAL OPTICS EXPRESS 2019; 10:1013-1031. [PMID: 30800529 PMCID: PMC6377873 DOI: 10.1364/boe.10.001013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 01/09/2019] [Accepted: 01/09/2019] [Indexed: 05/06/2023]
Abstract
We present a method of OCT angiography (OCTA) data filtering for noise suppression and improved visualization of the retinal vascular networks in en face projection images. In our approach, we use a set of filters applied in three orthogonal axes in the three-dimensional (3-D) data sets. Minimization of artifacts generated in B-scan-wise data processing is accomplished by filtering the cross-sections along the slow scanning axis. A-scans are de-noised by axial filtering. The core of the method is the application of directional filtering to the C-scans, i.e. one-pixel thick sections of the 3-D data set, perpendicular to the direction of the scanning OCT beam. The method uses a concept of structuring, directional kernels of shapes matching the geometry of the image features. We use rotating ellipses to find the most likely local orientation of the vessels and use the best matching ellipses for median filtering of the C-scans. We demonstrate our approach in the imaging of a normal human eye with laboratory-grade spectral-domain OCT setup. The "field performance" is demonstrated in imaging of diabetic retinopathy cases with a commercial OCT device. The absolute complex differences method is used for the generation of OCTA images from the data collected in the most noise-wise unfavorable OCTA scanning regime-two frame scanning.
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Affiliation(s)
- Michał Chlebiej
- Faculty of Mathematics and Computer Science, Nicolaus Copernicus University in Torun, Chopina 12/18, 87-100 Torun, Poland
- AM2M Ltd. L.P., Mickiewicza 7/17, 87-100 Torun, Poland
| | | | - Andrzej Rutkowski
- Faculty of Mathematics and Computer Science, Nicolaus Copernicus University in Torun, Chopina 12/18, 87-100 Torun, Poland
- AM2M Ltd. L.P., Mickiewicza 7/17, 87-100 Torun, Poland
| | - Jakub Kluczewski
- Faculty of Mathematics and Computer Science, Nicolaus Copernicus University in Torun, Chopina 12/18, 87-100 Torun, Poland
- AM2M Ltd. L.P., Mickiewicza 7/17, 87-100 Torun, Poland
| | - Tomasz Grzona
- Faculty of Mathematics and Computer Science, Nicolaus Copernicus University in Torun, Chopina 12/18, 87-100 Torun, Poland
- AM2M Ltd. L.P., Mickiewicza 7/17, 87-100 Torun, Poland
| | - Ewelina Pijewska
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
| | - Bartosz L. Sikorski
- Department of Ophthalmology, Nicolaus Copernicus University in Torun, 9 M. Sklodowskiej-Curie St., Bydgoszcz, Poland
- Oculomedica Eye Centre, 9 Broniewskiego St. Bydgoszcz, Poland
| | | | - Maciej Szkulmowski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
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153
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Enders C, Lang GE, Dreyhaupt J, Loidl M, Lang GK, Werner JU. Quantity and quality of image artifacts in optical coherence tomography angiography. PLoS One 2019; 14:e0210505. [PMID: 30682050 PMCID: PMC6347178 DOI: 10.1371/journal.pone.0210505] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 12/24/2018] [Indexed: 11/30/2022] Open
Abstract
Objective To analyze quality and frequency of OCTA artifacts and to evaluate their impact on the interpretability of OCTA images. Design 75 patients with diabetic retinopathy (DR), retinal artery occlusion (RAO), retinal vein occlusion (RVO), or neovascular age-related macular degeneration (nAMD) and healthy controls were enrolled in this cross-sectional study in the outpatient department of a tertiary eye care center. Methods All participants underwent an OCTA examination (spectral domain OCT Cirrus 5000 equipped with the AngioPlex module). OCTA scans were analyzed independently by two experienced ophthalmologists. Frequency of various artifacts for the entire OCTA scan and for different segmentation layers and the grading of OCTA interpretability were investigated. Results The analysis of 75 eyes of 38 women and 37 men between 24 and 94 years were included. Six eyes had no retinal disease, 19 eyes had nAMD, 16 had DR, 19 eyes had RVO, and 15 eyes showed RAO. A macular edema (ME) was present in 40 of the diseased eyes. Projection artifacts occurred in all eyes in any structure below the superficial retinal vessel layer, segmentation and motion artifacts were found in 55% (41/75) and 49% (37/75) of eyes, respectively. Other artifacts occurred less frequently. Segmentation artifacts were significantly more frequent in diseased than in healthy eyes (p<0.01). Qualitative assessment of OCTA images was graded as excellent in 65% and sufficient in 25% of cases, adding up to 91% images deemed acceptable for examination. Presence of ME was associated with a significantly poorer interpretability (p<0.01). Conclusion and Relevance Various artifacts appear at different frequencies in OCTA images. Nevertheless, a qualitative assessment of the OCTA images is almost always possible. Good knowledge of possible artifacts and critical analysis of the complete OCTA dataset are essential for correct clinical interpretation and determining a precise clinical diagnosis.
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Affiliation(s)
- Christian Enders
- Department of Ophthalmology, Ulm University, Ulm, Germany
- * E-mail:
| | | | - Jens Dreyhaupt
- Institute of Epidemiology and Medical Biometry, Ulm University, Ulm, Germany
| | - Max Loidl
- Department of Ophthalmology, Ulm University, Ulm, Germany
| | | | - Jens U. Werner
- Department of Ophthalmology, Ulm University, Ulm, Germany
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154
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Ling Y, Meiniel W, Singh-Moon R, Angelini E, Olivo-Marin JC, Hendon CP. Compressed sensing-enabled phase-sensitive swept-source optical coherence tomography. OPTICS EXPRESS 2019; 27:855-871. [PMID: 30696165 PMCID: PMC6410915 DOI: 10.1364/oe.27.000855] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 11/30/2018] [Accepted: 12/21/2018] [Indexed: 05/21/2023]
Abstract
Here we present a novel phase-sensitive swept-source optical coherence tomography (PhS-SS-OCT) system. The simultaneously recorded calibration signal, which is commonly used in SS-OCT to stabilize the phase, is randomly sub-sampled during the acquisition, and it is later reconstructed based on the Compressed Sensing (CS) theory. We first mathematically investigated the method, and verified it through computer simulations. We then conducted a vibrational frequency test and a flow velocity measurement in phantoms to demonstrate the system's capability of handling phase-sensitive tasks. The proposed scheme shows excellent phase stability with greatly discounted data bandwidth compared with conventional procedures. We further showcased the usefulness of the system in biological samples by detecting the blood flow in ex vivo swine left marginal artery. The proposed system is compatible with most of the existing SS-OCT systems and could be a preferred solution for future high-speed phase-sensitive applications.
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Affiliation(s)
- Yuye Ling
- Department of Electrical Engineering, Columbia University, 500 W 120th St., New York, New York 10027,
USA
| | - William Meiniel
- Institut Mines-Telecom, Telecom-ParisTech, CNRS LTCI, Paris,
France
- Institut Pasteur, BioImage Analysis unit, CNRS UMR 3691, Paris,
France
| | - Rajinder Singh-Moon
- Department of Electrical Engineering, Columbia University, 500 W 120th St., New York, New York 10027,
USA
| | - Elsa Angelini
- Institut Mines-Telecom, Telecom-ParisTech, CNRS LTCI, Paris,
France
- NIHR Imperial BRC, ITMAT Data Science Group, Imperial College, London,
United Kingdom
- Department of Biomedical Engineering, Columbia University, 500 W 120th St., New York, New York 10027,
USA
| | | | - Christine P. Hendon
- Department of Electrical Engineering, Columbia University, 500 W 120th St., New York, New York 10027,
USA
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155
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Devarajan K, Di Lee W, Ong HS, Lwin NC, Chua J, Schmetterer L, Mehta JS, Ang M. Vessel density and En-face segmentation of optical coherence tomography angiography to analyse corneal vascularisation in an animal model. EYE AND VISION 2019; 6:2. [PMID: 30656178 PMCID: PMC6330743 DOI: 10.1186/s40662-018-0128-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 12/24/2018] [Indexed: 11/10/2022]
Abstract
Background Optical coherence tomography angiography (OCTA) is a novel non-invasive angiography technology that has recently been extensively studied for its utility in anterior segment imaging. In this study, we compared a split-spectrum amplitude decorrelation angiography (SSADA) OCTA and an Complex OCT signal difference angiography [corrected] (CODAA SD) [corrected] OCTA system to current angiographic technique, indocyanine green angiography (ICGA), to assess corneal vascularisation in an animal model. Methods We imaged 16 rabbits, (one eye per animal) with corneal vascularisation using SSADA OCTA (AngioVue; Optovue Inc., USA), CODAA OCTA [corrected] (Angioscan; RS-3000 Nidek Co. Ltd., Japan) and ICGA in the same region of interest of the cornea at successive time-points. We then analysed all scanned images for vessel density measurements and used paired t-tests and Bland-Altman plots to examine for significant differences. The en-face segmentation images from each of the OCTA scans were also extracted and were matched at every 50 μm segmentation to be compared for vessel density at the respective depths. Results Bland-Altman plots revealed a good agreement between all three imaging techniques (P > 0.05) for all vessel density measurements computed, and the ranges of 95% limit of agreement were acceptable from a clinical perspective. No significant difference was reported, with ICGA (μ = 16.52 ± 8.94%) being more comparable to the CODAA [corrected] OCTA (μ = 16.23 ± 9.51%; p = 0.50) than the SSADA OCTA (μ = 17.09 ± 7.34%; p = 0.33) system. Also, a good correlation value (r > 0.9) was obtained when comparing the vessel density measurements of the en-face segmentations between the OCTA systems. Conclusions Comparable vessel density quantification between the two OCTA systems, and with ICGA was obtained. Segmentation analysis of the vasculature at different depths showed varied performance in the two OCTA systems relative to each other. The implications of the study may help to aid in the development of better OCTA algorithms for the anterior segment and its use in clinical translational research.
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Affiliation(s)
| | - Wen Di Lee
- 1Singapore Eye Research Institute, Singapore, Singapore
| | - Hon Shing Ong
- 1Singapore Eye Research Institute, Singapore, Singapore.,2Singapore National Eye Center, Singapore, Singapore
| | - Nyein C Lwin
- 1Singapore Eye Research Institute, Singapore, Singapore
| | - Jacqueline Chua
- 1Singapore Eye Research Institute, Singapore, Singapore.,3Eye-ACP, Duke-NUS Graduate Medical School, Singapore, Singapore
| | - Leopold Schmetterer
- 1Singapore Eye Research Institute, Singapore, Singapore.,4Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,5Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,6Nanyang Technological University, Singapore, Singapore
| | - Jodhbir S Mehta
- 1Singapore Eye Research Institute, Singapore, Singapore.,2Singapore National Eye Center, Singapore, Singapore.,3Eye-ACP, Duke-NUS Graduate Medical School, Singapore, Singapore.,6Nanyang Technological University, Singapore, Singapore
| | - Marcus Ang
- 1Singapore Eye Research Institute, Singapore, Singapore.,2Singapore National Eye Center, Singapore, Singapore.,3Eye-ACP, Duke-NUS Graduate Medical School, Singapore, Singapore
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156
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Park HJ, Lim HB, Lee MW, Jo YJ, Kim JY. Interocular Symmetry of Optical Coherence Tomography Angiography Parameters in Normal Eyes of Korean Adults. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2019. [DOI: 10.3341/jkos.2019.60.7.676] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Hye Jin Park
- Department of Ophthalmology, Chungnam National University Hospital, Daejeon, Korea
| | - Hyung Bin Lim
- Department of Ophthalmology, Chungnam National University Hospital, Daejeon, Korea
- Department of Ophthalmology, Armed Forces Capital Hospital, Seongnam, Korea
| | - Min Woo Lee
- Department of Ophthalmology, Chungnam National University Hospital, Daejeon, Korea
| | - Young Joon Jo
- Department of Ophthalmology, Chungnam National University Hospital, Daejeon, Korea
| | - Jung Yeul Kim
- Department of Ophthalmology, Chungnam National University Hospital, Daejeon, Korea
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157
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Mujat M, Lu Y, Maguluri G, Zhao Y, Iftimia N, Ferguson RD. Visualizing the vasculature of the entire human eye posterior hemisphere without a contrast agent. BIOMEDICAL OPTICS EXPRESS 2019; 10:167-180. [PMID: 30775091 PMCID: PMC6363207 DOI: 10.1364/boe.10.000167] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 11/17/2018] [Accepted: 11/26/2018] [Indexed: 05/07/2023]
Abstract
The platform described here combines the non-invasive measurement of the retina/choroid structure and ocular blood flow based on optical coherence tomography (OCT) and wide-field semi-quantitative global flow visualization using line-scanning Doppler flowmetry (LSDF). The combination of these two imaging modalities within the same platform enables comprehensive assessment of blood flow in the retina and choroid in animals and human subjects for diagnostic purposes. Ultra-widefield vasculature visualization is demonstrated here for the first time without injecting additional contrast agents and based only on the motion of particles within the vasculature.
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158
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Xu J, Li Y, Song S, Cepurna W, Morrison J, Wang RK. Evaluating changes of blood flow in retina, choroid, and outer choroid in rats in response to elevated intraocular pressure by 1300 nm swept-source OCT. Microvasc Res 2019; 121:37-45. [PMID: 30267716 PMCID: PMC6286199 DOI: 10.1016/j.mvr.2018.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 09/23/2018] [Accepted: 09/25/2018] [Indexed: 01/06/2023]
Abstract
We report the development of a 1300 nm swept-source optical coherence tomography (SS-OCT) system specifically designed to perform OCT imaging and optical microangiography (OMAG) in rat eyes in vivo and its use in evaluating the effects of intraocular pressure (IOP) elevation on ocular circulation. The swept laser is operated in single longitude mode with a 90 nm bandwidth centered at 1300 nm and 200 kHz A-line rate, providing remarkable sensitivity fall-off performance along the imaging depth, a larger field of view of 2.5 × 2.5 mm2 (approximately 35°), and more time-efficient imaging acquisition. The advantage of the SS-OCT/OMAG is highlighted by an increased imaging depth of the entire posterior thickness of optic nerve head (ONH) and its surrounding vascular anatomy, to include, for the first time in vivo, the vasculature at the scleral opening, allowing visualization of the circle of Zinn-Haller and posterior ciliary arteries (PCAs). Furthermore, the capillary-level resolution angiograms achieved at the retinal and choroidal layers over a larger field of view enable a significantly improved quantification of the response of vascular area density (VAD) to elevated IOP. The results indicate that reduction in perfusion of the choroid in response to elevated IOP is delayed compared to that seen in the retina; while choroidal VAD doesn't reach 50% of baseline until ~70 mmHg, the same effect is seen for the retinal VAD at ~60 mmHg. The superior image quality offered by SS-OCT may allow more comprehensive investigation of IOP-related ocular perfusion changes and their pathological roles in glaucomatous optic nerve damage.
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Affiliation(s)
- Jingjiang Xu
- University of Washington, Department of Bioengineering, Seattle, WA 98195, USA
| | - Yuandong Li
- University of Washington, Department of Bioengineering, Seattle, WA 98195, USA
| | - Shaozhen Song
- University of Washington, Department of Bioengineering, Seattle, WA 98195, USA
| | - William Cepurna
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - John Morrison
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Ruikang K Wang
- University of Washington, Department of Bioengineering, Seattle, WA 98195, USA; University of Washington, Department of Ophthalmology, Seattle, WA 98104, USA.
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159
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Karti O, Saatci AO. Optical Coherence Tomography Angiography in Eyes with Non-infectious Posterior Uveitis; Some Practical Aspects. MEDICAL HYPOTHESIS, DISCOVERY & INNOVATION OPHTHALMOLOGY JOURNAL 2019; 8:312-322. [PMID: 31788494 PMCID: PMC6778673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Optical coherence tomography angiography (OCTA) is an innovative imaging technology enabling clinicians to learn more about the pathophysiology of disease processes as it facilitates visualization of the retinal and choroidal circulation without injection of a dye. Also it provides ample qualitative and quantitative data on the vascular supply. OCTA has become an important tool nowadays in the diagnosis and follow-up of patients with age-related macular degeneration, inherited chorioretinal diseases, diabetic retinopathy, retinal vascular occlusive diseases and optic nerve disorders. However, its place is relatively less known in non-infectious posterior uveitis (NIPU). OCTA may help mainly in assessing macular and peripheric retinal perfusion status, detection of retinal and/or disc neovascularization, diagnose of inflammatory choroidal neovascularization and visualizing the uveitic white-dot lesions. This mini-review describes the use of OCTA in patients with NIPU and summarizes some practical points in several uveitic entities.
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Affiliation(s)
- Omer Karti
- Department of Ophthalmology, Bozyaka Training and Research Hospital, İzmir, Turkey
| | - Ali Osman Saatci
- Department of Ophthalmology, DokuzEylul University Medical Faculty, İzmir, Turkey
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160
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Im JC. Measurement of Vessel Density Using Optical Coherence Tomography-angiography in Normal Subjects: Difference by Analysis Area. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2019. [DOI: 10.3341/jkos.2019.60.4.355] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Jong Chan Im
- Department of Ophthalmology, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea
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161
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Abstract
PURPOSE OF REVIEW Diabetic retinopathy is the most common microvascular complication of diabetes mellitus and a leading cause of blindness throughout the world. Ocular imaging continues to play a vital role in the diagnosis, management and monitoring of diabetic retinopathy. Major technological advancements in imaging over the past decade have improved our understanding and knowledge of diabetic retinopathy and therefore a multimodal approach to imaging has become the standard of care. RECENT FINDINGS Updates to traditional technologies such as digital fundus photography along with recent advancements in optical coherence tomography (OCT) and OCT angiography (OCTA) have provided clinicians with new information and improved efficiency. SUMMARY In this review, we describe the benefits and clinical applications of several imaging techniques in diabetic retinopathy including color photography, fluorescein angiography, OCT, OCTA and adaptive optics. Understanding the indications and limitations of each technology allows clinicians to gain the most information from each modality and thereby optimize patient care.
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Affiliation(s)
- Khoi Tran
- Department of Ophthalmology, University of British Columbia, Vancouver, British Columbia, Canada
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162
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Le NM, Song S, Zhou H, Xu J, Li Y, Sung CE, Sadr A, Chung KH, Subhash HM, Kilpatrick L, Wang RK. A noninvasive imaging and measurement using optical coherence tomography angiography for the assessment of gingiva: An in vivo study. JOURNAL OF BIOPHOTONICS 2018; 11:e201800242. [PMID: 30112807 DOI: 10.1002/jbio.201800242] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 08/13/2018] [Indexed: 05/20/2023]
Abstract
Gingiva is the soft tissue that surrounds and protects the teeth. Healthy gingiva provides an effective barrier to periodontal insults to deeper tissue, thus is an important indicator to a patient's periodontal health. Current methods in assessing gingival tissue health, including visual observation and physical examination with probing on the gingiva, are qualitative and subjective. They may become cumbersome when more complex cases are involved, such as variations in gingival biotypes where feature and thickness of the gingiva are considered. A noninvasive imaging technique providing depth-resolved structural and vascular information is necessary for an improved assessment of gingival tissue and more accurate diagnosis of periodontal status. We propose a three-dimensional (3D) imaging technique, optical coherence tomography (OCT), to perform in situ imaging on human gingiva. Ten volunteers (five male, five female, age 25-35) were recruited; and the labial gingival tissues of upper incisors were scanned using the combined use of state-of-the-art swept-source OCT and OCT angiography (OCTA). Information was collected describing the 3D tissue microstructure and capillary vasculature of the gingiva within a penetration depth of up to 2 mm. Results indicate significant structural and vascular differences between the two extreme gingival biotypes (ie, thick and thin gingiva), and demonstrate special features of vascular arrangement and characteristics in gingival inflammation. Within the limit of this study, the OCT/OCTA technique is feasible in quantifying different attributes of gingival biotypes and the severity of gingival inflammation.
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Affiliation(s)
- Nhan M Le
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Shaozhen Song
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Hao Zhou
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Jingjiang Xu
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Yuandong Li
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Cheng-En Sung
- Department of Periodontology, School of Dentistry, Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan
- Department of Restorative Dentistry, University of Washington, Seattle, Washington
| | - Alireza Sadr
- Department of Restorative Dentistry, University of Washington, Seattle, Washington
| | - Kwok-Hung Chung
- Department of Restorative Dentistry, University of Washington, Seattle, Washington
| | - Hrebesh M Subhash
- Clinical Method Development - Oral Care, Colgate-Palmolive Company, Piscataway, New Jersey
| | - Latonya Kilpatrick
- Clinical Method Development - Oral Care, Colgate-Palmolive Company, Piscataway, New Jersey
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, Washington
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163
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Yao X, Son T, Kim TH, Lu Y. Functional optical coherence tomography of retinal photoreceptors. Exp Biol Med (Maywood) 2018; 243:1256-1264. [PMID: 30482040 DOI: 10.1177/1535370218816517] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
IMPACT STATEMENT Retinal photoreceptors are the primary target of age-related macular degeneration (AMD) which is the leading cause of severe vision loss and legal blindness. An objective method for functional assessment of photoreceptor physiology can benefit early detection and better treatment evaluation of AMD and other eye diseases that are known to cause photoreceptor dysfunctions. This article summarizes in vitro study of IOS mechanisms and in vivo demonstration of IOS imaging of intact animals. Further development of the functional IOS imaging may provide a revolutionary solution to achieve objective assessment of human photoreceptors.
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Affiliation(s)
- Xincheng Yao
- 1 Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA.,2 Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Taeyoon Son
- 1 Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Tae-Hoon Kim
- 1 Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Yiming Lu
- 1 Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
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164
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Li XX, Wu W, Zhou H, Deng JJ, Zhao MY, Qian TW, Yan C, Xu X, Yu SQ. A quantitative comparison of five optical coherence tomography angiography systems in clinical performance. Int J Ophthalmol 2018; 11:1784-1795. [PMID: 30450309 DOI: 10.18240/ijo.2018.11.09] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 07/06/2018] [Indexed: 01/21/2023] Open
Abstract
AIM To compare the clinical performance of 4 spectral-domain (SD) optical coherence tomography angiography (OCTA) systems: AngioVue™, AngioPlex™, Spectralis® OCTA, AngioScan, and 1 swept-source (SS) OCTA SS OCT Angio™. METHODS Twenty-seven undilated right eyes of 27 participants underwent OCTA examination using five different systems respectively for both 3×3 and 6×6 mm2 scan pattern (Spectralis OCTA for 3×3 mm2 scan only). Image quality, including vessel valid visibility and the number of motion artifacts, and acquisition time were evaluated. Repeated measures analysis of variance (ANOVA) with Bonferroni's post-test and Friedman test with Dunn's post-test were used to compare measurements. RESULTS The age of the subjects was 28.19±5.55y (range, 23-49y). The spherical equivalent refraction was -2.55±1.84 D (range, 0.00 to -5.25 D). Significant difference was observed in the evaluation of vessel valid visibility (AngioVue the highest: 0.111±0.031 for 3×3 mm2 scan and 0.128±0.020 for 6×6 mm2 scan), number of motion artifacts (AngioVue the fewest: 0.778±1.086 for 3×3 mm2 scan and 0.333±0.620 for 6×6 mm2 scan) and acquisition time (AngioPlex the shortest: 8.537±1.921s for 3×3 mm2 scan and 8.298±1.741s for 6×6 mm2 scan; all P<0.001). CONCLUSION There is poor agreement of measurements among systems. AngioVue provides images with the highest vessel valid visibility and the fewest motion artifacts. AngioPlex achieves the shortest acquisition.
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Affiliation(s)
- Xin-Xin Li
- Department of Ophthalmology, Shanghai General Hospital Affiliated to Shanghai Jiao Tong University, Shanghai 200080, China.,Shanghai Key Laboratory of Ocular Fundus Disease, Shanghai 200080, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai 200080, China
| | - Wei Wu
- Department of Mathematics, Eidgenössische Technische Hochschule Zürich, Zurich 8092, Switzerland
| | - Hao Zhou
- Department of Ophthalmology, Shanghai General Hospital Affiliated to Shanghai Jiao Tong University, Shanghai 200080, China
| | - Jun-Jie Deng
- Department of Ophthalmology, Shanghai General Hospital Affiliated to Shanghai Jiao Tong University, Shanghai 200080, China.,Shanghai Key Laboratory of Ocular Fundus Disease, Shanghai 200080, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai 200080, China
| | - Meng-Ya Zhao
- Department of Ophthalmology, Shanghai General Hospital Affiliated to Shanghai Jiao Tong University, Shanghai 200080, China.,Shanghai Key Laboratory of Ocular Fundus Disease, Shanghai 200080, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai 200080, China
| | - Tian-Wei Qian
- Department of Ophthalmology, Shanghai General Hospital Affiliated to Shanghai Jiao Tong University, Shanghai 200080, China.,Shanghai Key Laboratory of Ocular Fundus Disease, Shanghai 200080, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai 200080, China
| | - Chen Yan
- Department of Ophthalmology, Shanghai General Hospital Affiliated to Shanghai Jiao Tong University, Shanghai 200080, China
| | - Xun Xu
- Department of Ophthalmology, Shanghai General Hospital Affiliated to Shanghai Jiao Tong University, Shanghai 200080, China.,Shanghai Key Laboratory of Ocular Fundus Disease, Shanghai 200080, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai 200080, China
| | - Su-Qin Yu
- Department of Ophthalmology, Shanghai General Hospital Affiliated to Shanghai Jiao Tong University, Shanghai 200080, China
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165
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Chu Z, Zhou H, Cheng Y, Zhang Q, Wang RK. Improving visualization and quantitative assessment of choriocapillaris with swept source OCTA through registration and averaging applicable to clinical systems. Sci Rep 2018; 8:16826. [PMID: 30429502 PMCID: PMC6235855 DOI: 10.1038/s41598-018-34826-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 10/24/2018] [Indexed: 12/25/2022] Open
Abstract
Choriocapillaris (CC) visualization and quantification remains challenging. We propose an innovative three-step registration and averaging approach using repeated swept source optical coherence tomography angiography (SS-OCTA) scans to conduct automatic quantitative assessment on CC. Six subjects were enrolled, each imaged at several locations with SS-OCTA from macular to equatorial regions using 3 mm × 3 mm scanning pattern. Five repeated volumes were collected for each subject. The complex optical microangiography (OMAG) algorithm was applied to identify blood flow in CC slab. An automatic three-step registration of translation, affine and B-Spline was applied to en face OCTA images of CC, followed with averaging. A fuzzy clustering approach was used to segment vasculature and flow deficits from the averaged images. The improvement in visualization of CC was evaluated and the average intercapillary distance was estimated by calculating the averaged capillary lumen spacing. A series of quantitative indices of flow deficit density, number, size, complexity index and aspect ratio index (FDD, FDN, FDS, FDCI and FDARI) were designed and validated with the increase of repeated scan numbers for averaging. Quantitative assessment was applied and compared on CC in macular and equatorial regions. The intercapillary distance was observed to be around 24 µm at macula and increased toward equatorial regions. All five quantitative indices (FDD, FDN, FDS, FDCI and FDARI) showed significant changes with multiple averaging and tend to become stable with repeated number of 4. Our proposed registration and averaging algorithm significantly improved the visualization of CC with SS-OCTA. The designed five indices for CC provide more options in the quantitative assessment of CC and are of great potentials in assisting the understanding of disease pathology, early diagnosis and treatment monitoring.
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Affiliation(s)
- Zhongdi Chu
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Hao Zhou
- 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
| | - 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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167
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Classification of burn injury using Raman spectroscopy and optical coherence tomography: An ex-vivo study on porcine skin. Burns 2018; 45:659-670. [PMID: 30385061 DOI: 10.1016/j.burns.2018.10.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 08/16/2018] [Accepted: 10/04/2018] [Indexed: 11/20/2022]
Abstract
Accurate depth assessment of burn wounds is a critical task to provide the right treatment and care. Currently, laser Doppler imaging is able to provide better accuracy compared to the standard clinical evaluation. However, its clinical applicability is limited by factors like scanning distance, time, and cost. Precise diagnosis of burns requires adequate structural and functional details. In this work, we evaluated the combined potential of two non-invasive optical modalities, optical coherence tomography (OCT) and Raman spectroscopy (RS), to identify degrees of burn wounds (superficial partial-thickness (SPT), deep partial-thickness (DPT), and full-thickness (FT)). OCT provides morphological information, whereas, RS provides biochemical aspects. OCT images and Raman spectra were obtained from burns created on ex-vivo porcine skin. Algorithms were developed to segment skin region and extract textural features from OCT images, and derive spectral wave features from RS. These computed features were fed into machine learning classifiers for categorization of burns. Histological results obtained from trichrome staining were used as ground-truth. The combined performance of RS-OCT reported an overall average accuracy of 85% and ROC-AUC=0.94, in distinguishing the burn wounds. The significant performance on ex vivo skin motivates to assess the feasibility of combined RS-OCT in in vivo models.
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168
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Rodríguez FJ, Staurenghi G, Gale R. The role of OCT-A in retinal disease management. Graefes Arch Clin Exp Ophthalmol 2018; 256:2019-2026. [PMID: 30175386 PMCID: PMC6208724 DOI: 10.1007/s00417-018-4109-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 06/25/2018] [Accepted: 07/26/2018] [Indexed: 01/18/2023] Open
Abstract
Optical coherence tomography angiography (OCT-A) is a non-invasive, non-dye-based imaging modality that has the potential to enhance our understanding of retinal diseases. While this rapidly advancing imaging modality offers great potential, there is a need for community-wide understanding of the range of technologies and methods for interpreting the images, as well as a need to enhance understanding of images from disease-free eyes for reference when screening for retinal diseases. Importantly, clinical trials have been designed without OCT-A-based endpoints; therefore, caution is required when making treatment decisions based on OCT-A imaging alone. With this in mind, a full understanding of the advantages and limitations of OCT-A will be vital for effective development of the technique within the field of ophthalmology. On behalf of the Vision Academy Steering Committee (sponsored by Bayer), this publication summarizes the views of the authors on the current use of OCT-A imaging and explores its potential for future applications in research and clinical practice.
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Affiliation(s)
- Francisco J Rodríguez
- Fundación Oftalmológica Nacional, Calle 50, #13-50, Bogotá, Colombia. .,Department of Ophthalmology, University of Rosario School of Medicine, Bogotá, Colombia.
| | - Giovanni Staurenghi
- University Eye Clinic, Department of Biomedical and Clinical Sciences 'Luigi Sacco', University of Milan, Milan, Italy
| | - Richard Gale
- Department of Ophthalmology, York Teaching Hospital NHS Foundation Trust, York, UK.,Department of Health Sciences, University of York, York, UK
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169
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Mitsui T, Aoki K. Dynamically enhanced low-coherence interferometry. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:094302. [PMID: 30278758 DOI: 10.1063/1.5025859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 09/05/2018] [Indexed: 06/08/2023]
Abstract
In the investigations of inhomogeneous media, availability of methods to study the interior of the material without affecting it is valuable. Optical coherence tomography provides such a functionality by providing depth resolved images of semi-transparent objects non-invasively. This is especially useful in medicine and is used not only in research but also in clinical practice. Optical coherence tomography characterizes each cross section by its reflectance. The basic physics principle underlying optical coherence tomography is low-coherence interferometry, which is combined with lateral scanning to produce cross sections. It is clearly desirable to obtain more detailed information regarding each cross section, if available. We have developed a system which measures the fluctuation spectra at all depths in low-coherence interferometry. By providing more information for each cross section, this can in principle be effective in tissue characterization and pathological diagnosis. The system uses the time dependence of the low-coherence interferometry data to obtain the fluctuation spectrum at each depth. Additionally, noise reduction is applied to obtain the spectra without unwanted noise, such as shot-noise, which can swamp the signal. The measurement system is applied to samples with no external stimuli, and depth resolved thermal fluctuation spectra of the samples are obtained. These spectra are compared with their corresponding theoretical expectations and are found to agree. The measurement system requires dualizing the detectors in the low-coherence interferometer but otherwise requires little additional equipment. The measurements were performed in ten to a hundred seconds.
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Affiliation(s)
- Takahisa Mitsui
- Research and Education Center for Natural Sciences and Department of Physics, Hiyoshi, Keio University, Yokohama 223-8521, Japan
| | - Kenichiro Aoki
- Research and Education Center for Natural Sciences and Department of Physics, Hiyoshi, Keio University, Yokohama 223-8521, Japan
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170
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Zhang Q, Rezaei KA, Saraf SS, Chu Z, Wang F, Wang RK. Ultra-wide optical coherence tomography angiography in diabetic retinopathy. Quant Imaging Med Surg 2018; 8:743-753. [PMID: 30306055 DOI: 10.21037/qims.2018.09.02] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Background To implement an ultra-wide optical coherence tomography angiography imaging (UW-OCTA) modality in eyes with diabetic retinopathy (DR) with the aim of quantifying the burden of microvascular disease at baseline and subsequent clinic visits. Methods UW-OCTA was implemented on a 1,060 nm swept source (SS) OCTA engine running at 100 kHz A-line rate with a motion tracking mechanism. A montage scanning protocol was used to capture a 100-degree field of view (FOV) using a 4×4 grid of sixteen total individual 6×6 mm2 scans. Typical OCTA images with a FOV of 3×3, 6×6 and 12×12 mm2 were obtained for comparison. DR patients were scanned at baseline and follow-up. They were treated at the clinician's discretion. Vessel density and non-perfusion area maps were calculated based on the UW-OCTA images. Results Three proliferative DR patients were included in the study. UW-OCTA images provided more detailed visualization of vascular networks compared to 50-degree fluorescein angiography (FA) and showed higher burden of pathology in the retinal periphery that was not captured by typical OCTA. Neovascularization complexes were clearly detected in the two patients with active PDR. Vessel density and non-perfusion maps were used to measure progressive capillary non-perfusion and regression of neovascularization between visits. Conclusions UW-OCTA provides approximately 100-degree OCTA images of the fundus comparable to that of wide-angle fundus photography, and may be more applicable in conditions such as DR which affect the peripheral retina in contrast to standard OCTA.
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Affiliation(s)
- Qinqin Zhang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Kasra A Rezaei
- Department of Ophthalmology, University of Washington Eye Institute, Seattle, Washington, USA
| | - Steven S Saraf
- Department of Ophthalmology, University of Washington Eye Institute, Seattle, Washington, USA
| | - Zhongdi Chu
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Fupeng Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA.,Department of Ophthalmology, University of Washington Eye Institute, Seattle, Washington, USA
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171
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Ang M, Baskaran M, Werkmeister RM, Chua J, Schmidl D, Aranha dos Santos V, Garhöfer G, Mehta JS, Schmetterer L. Anterior segment optical coherence tomography. Prog Retin Eye Res 2018; 66:132-156. [DOI: 10.1016/j.preteyeres.2018.04.002] [Citation(s) in RCA: 216] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 02/20/2018] [Accepted: 04/04/2018] [Indexed: 02/03/2023]
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172
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The Importance of Signal Strength in Quantitative Assessment of Retinal Vessel Density Using Optical Coherence Tomography Angiography. Sci Rep 2018; 8:12897. [PMID: 30150636 PMCID: PMC6110792 DOI: 10.1038/s41598-018-31321-9] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 08/17/2018] [Indexed: 11/20/2022] Open
Abstract
The quality of the scan image is important in microvascular circulation analysis using optical coherence tomography (OCTA). We aimed to investigate the effect of signal strength (SS) on OCTA metrics and minimum SS level that could be considered optimal. Macular 6 × 6 mm angiography images were acquired, and all subjects were divided into four groups according to the SS (SS 7, SS 8, SS 9, and SS 10) of the OCTA image. Vessel density (VD), perfusion density (PD), and foveal avascular zone (FAZ) metrics of the superficial capillary plexus were compared. In total, 446 eyes from young healthy subjects were included. As the SS increased from 7 to 10, the VD and PD of the total area, and the FAZ area increased significantly (all, p < 0.001), but there were no significant difference between SS 9 and SS 10 in all metrics. Correlation analysis between the SS and each parameter showed a high correlation coefficient (VD, r = 0.668; PD, r = 0.671; FAZ area, r = 0.570; all, p < 0.001). The measurements of VD, PD, and FAZ using OCTA varied significantly with the SS, and at least 9 of SS is recommended. The physician should be careful in the analyses of OCTA measurements showing different values of the SS.
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173
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Gao W. Quantitative depth-resolved microcirculation imaging with optical coherence tomography angiography (Part ΙΙ): Microvascular network imaging. Microcirculation 2018; 25:e12376. [DOI: 10.1111/micc.12376] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 04/11/2017] [Indexed: 11/28/2022]
Affiliation(s)
- Wanrong Gao
- Department of Optical Engineering; Nanjing University of Science and Technology; Nanjing Jiangsu China
- MIIT Key Laboratory of Advanced Solid Laser; Nanjing University of Science and Technology; Nanjing Jiangsu China
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174
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DIRECTIONAL CHANGES IN TISSUE REFLECTIVITY MAY INFLUENCE FLOW DETECTION ON OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY. Retina 2018; 38:739-747. [PMID: 28426631 DOI: 10.1097/iae.0000000000001656] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To determine if directional or anatomical changes in tissue reflectivity of Henle fiber layer (HFL) may influence flow detection on optical coherence tomography angiography (OCT-A). METHODS Cross-sectional analysis of consecutive cases undergoing OCT-A. Directional changes in visualization of HFL were either produced manually by moving the beam entrance within the pupil or observed occurring naturally because of tilting of the OCT line-scan within a myopic staphyloma. Areas of enhanced HFL visualization were identified on cross-sectional and en face structural OCT scans. Visualization of OCT-A flow within the superficial and the deep capillary plexuses were compared in areas with and without enhanced HFL reflectivity. RESULTS Fifteen eyes from 9 patients were included, with a mean age of 49.6 ± 17.9 years. On OCT-A, retinal areas with enhanced HFL reflectivity produced manually or by scan tilting within myopic staphylomas showed no changes in the superficial capillary plexus flow. However, deep capillary plexus flow was altered by variable projection of the superficial flow onto the deeper retinal layers. CONCLUSION Directional changes in HFL reflectivity can alter the detection of deep capillary plexus flow imaged with OCT-A by influencing the projection of superficial flow onto the deeper retinal layers. We recommend that clinicians minimize scan tilting during scan acquisition and be aware of this phenomenon in eyes with posterior staphyloma.
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175
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Pakzad-Vaezi K, Khaksari K, Chu Z, Van Gelder RN, Wang RK, Pepple KL. Swept-Source OCT Angiography of Serpiginous Choroiditis. Ophthalmol Retina 2018; 2:712-719. [PMID: 30148243 PMCID: PMC6103638 DOI: 10.1016/j.oret.2017.11.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
PURPOSE To examine and quantify choriocapillaris lesions in active and quiescent serpiginous choroiditis (SC) using swept-source optical coherence tomography angiography (SS-OCTA) and en-face image analysis. DESIGN Prospective observational case series. PARTICIPANTS Patients with a clinical diagnosis of SC. METHODS A SS-OCTA prototype was used to image active and quiescent serpiginous lesions longitudinally before and after anti-inflammatory treatment. En-face slabs of choriocapillaris flow (CC-slab) or outer nuclear layer structure (ONL-slab) were generated from OCTA and OCT data, respectively. MAIN OUTCOME MEASURES Qualitative and quantitative analyses on lesion boundary and area using a semi-automated MATLAB algorithm. Lesions were also compared to traditional multimodal imaging. RESULTS Six eyes of three patients were imaged. Choroidal lesions were identified and analyzed in four of six eyes. Lesions with well-defined boundaries were identified in the CC-slab in areas of both active and inactive choroiditis. CC-slab lesion size and shape showed good correlation with lesions identified on indocyanine green angiography. CC-slab lesion area increased with disease activity and decreased with corticosteroid treatment. During active disease, the CC-slab lesion area was larger than both the ONL-slab and fundus autofluorescence lesion areas. Active CC-slab lesions not associated with corresponding abnormal autofluorescence resolved without clinical scarring after treatment. In inactive scars, the areas of retinal and choriocapillaris lesions were similar and did not change over time. CONCLUSIONS En-face analysis of SS-OCTA choriocapillaris flow voids provide a non-invasive method for the detection of lesions in patients with SC. The presence of lesions in the choriocapillaris in the absence of retinal pigment epithelium and outer retinal abnormalities supports the hypothesis that choriocapillaris is the primary site of pathology in SC, and may be a sensitive early sign of disease activity. We propose a simple grading system of SC lesions based on SS-OCTA and fundus autofluorescence findings. SS-OCTA is a promising non-invasive method for monitoring patients with SC.
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Affiliation(s)
| | - Kosar Khaksari
- Department of Bioengineering, University of Washington, Seattle, WA
98195
| | - Zhongdi Chu
- Department of Bioengineering, University of Washington, Seattle, WA
98195
| | - Russell N Van Gelder
- Department of Ophthalmology, University of Washington, Seattle, WA
98104
- Department of Pathology, University of Washington, Seattle, WA
98195
- Department of Biological Structure, University of Washington,
Seattle, WA 98195
| | - Ruikang K Wang
- Department of Ophthalmology, University of Washington, Seattle, WA
98104
- Department of Bioengineering, University of Washington, Seattle, WA
98195
| | - Kathryn L Pepple
- Department of Ophthalmology, University of Washington, Seattle, WA
98104
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176
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Dense B-Scan Optical Coherence Tomography Angiography. Am J Ophthalmol 2018; 190:78-88. [PMID: 29601820 DOI: 10.1016/j.ajo.2018.03.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 03/13/2018] [Accepted: 03/20/2018] [Indexed: 11/21/2022]
Abstract
PURPOSE To describe a novel imaging technique, which we call "dense B-scan optical coherence tomography angiography" (DB OCTA), in which thin dense raster scans are used to produce highly resolved structural B-scans with superimposed flow signal that provide precise correlation between retinal microstructure and blood flow. DESIGN Observational case series. METHODS Normal eyes and eyes with macular findings of interest were imaged with DB OCTA in which 150-400 OCT B-scans were acquired within a narrow area (from a single line to 1 degree) with a width of 10-30 degrees. B-scans containing 5-7 consecutive frames were processed for OCTA signal and then combined and visualized post-acquisition by application of a Gaussian filter across neighboring scans. The result was a single, smoothed, high-resolution image that contained both structural and flow information. Tracked follow-up DB OCTA was used to detect subtle changes in pathology over time. RESULTS Two hundred and thirty-seven eyes from 205 subjects aged 18-100 years (mean 72.88 ± 14.74 years) with a diverse range of macular findings were imaged with DB OCTA. Highly resolved scans showing precise localization of flow signal were readily obtained, even in patients with poor visual acuity and/or poor fixation. We present clinical examples that demonstrate the utility of DB OCTA for visualizing the associations between retinal microstructure and blood flow. CONCLUSIONS DB OCTA enables precise correlation between retinal microstructure and blood flow. The ability to obtain accurately aligned follow-up DB OCTA studies has the potential to refine the understanding and clinical management of a wide range of macular diseases.
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177
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Men S, Wong JM, Welch EJ, Xu J, Song S, Deegan AJ, Ravichander A, Casavant B, Berthier E, Wang RK. OCT-based angiography of human dermal microvascular reactions to local stimuli: Implications for increasing capillary blood collection volumes. Lasers Surg Med 2018; 50:908-916. [PMID: 29799134 DOI: 10.1002/lsm.22944] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2018] [Indexed: 12/22/2022]
Abstract
OBJECTIVES To measure and compare microvascular responses within the skin of the upper arm to local stimuli, such as heating or rubbing, through the use of optical coherence tomography angiography (OCTA), and to investigate its impact on blood volume collection. MATERIALS AND METHODS With the use of heat packs or rubbing, local stimulation was applied to the skin of either the left or right upper arm. Data from the stimulated sites were obtained using OCTA comparing pre- and post-stimulation microvascular parameters, such as vessel density, mean vessel diameter, and mean avascular pore size. Additionally, blood was collected using a newly designed collection device and volume was recorded to evaluate the effect of the skin stimulation. RESULTS Nineteen subjects were recruited for local stimulation study (including rubbing and heating) and 21 subjects for blood drawn study. Of these subjects, 14 agreed to participate in both studies. OCTA was successful in monitoring and measuring minute changes in the microvasculature of the stimulated skin. Compared to baseline, significant changes after local heating and rubbing were respectively found in vessel density (16% [P = 0.0004] and 33% [P < 0.0001] increase), mean vessel diameter (14% and 11% increase) and mean avascular pore size (5% [P = 0.0068] and 8% [P = 0.0005] decrease) after stimulations. A gradual recovery was recorded for each parameter, with no difference being measured after 30 minutes. Blood collection volumes significantly increased after stimulations of heating (48% increase; P = 0.049) and rubbing (78% increase; P = 0.048). Significant correlations were found between blood volume and microvascular parameters except mean avascular pore size under the heating condition. CONCLUSIONS OCTA can provide important information regarding microvascular adaptations to local stimuli. With that, both heating and rubbing of the skin have positive effects on blood collection capacity, with rubbing having the most significant effect. Lasers Surg. Med. 50:908-916, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Shaojie Men
- Department of Bioengineering, University of Washington, 3720 15th Ave. NE., Seattle 98195, Washington
| | - Jennifer Manyu Wong
- Department of Bioengineering, University of Washington, 3720 15th Ave. NE., Seattle 98195, Washington
| | - Emily J Welch
- Tasso, Inc., 1631 15th Ave. W., Suite 105, Seattle 98119, Washington
| | - Jingjiang Xu
- Department of Bioengineering, University of Washington, 3720 15th Ave. NE., Seattle 98195, Washington
| | - Shaozhen Song
- Department of Bioengineering, University of Washington, 3720 15th Ave. NE., Seattle 98195, Washington
| | - Anthony J Deegan
- Department of Bioengineering, University of Washington, 3720 15th Ave. NE., Seattle 98195, Washington
| | | | - Benjamin Casavant
- Tasso, Inc., 1631 15th Ave. W., Suite 105, Seattle 98119, Washington
| | - Erwin Berthier
- Tasso, Inc., 1631 15th Ave. W., Suite 105, Seattle 98119, Washington
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, 3720 15th Ave. NE., Seattle 98195, Washington
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Abstract
PURPOSE To provide the reader with information on the principal techniques of optical coherence tomography angiography (OCTA); the current literature on OCTA reproducibility; its applications to glaucoma detection and monitoring of progression; and the role of OCTA in the assessment of the vascular component in glaucoma pathogenesis. METHODS A literature review of the pertinent publications for the OCTA in relation to the development, techniques, and its use in glaucoma was carried out. RESULTS Rapid improvements in optical coherence tomography (OCT) technology have allowed for enhancement of both image resolution and scanning speed, and the development of vascular assessment modality. OCTA is the non-invasive in vivo imaging of the vasculature located within the retina and optic nerve head area. The principle of OCTA is to use the variations in OCT signals caused by moving particles as the contrast mechanism for imaging of flow. Several algorithms which aim to maximize the contrast signal and minimize the noise have been developed including the phase-based techniques, intensity-based techniques (e.g., split-spectrum amplitude decorrelation angiography (SSADA)), and complex-based techniques (e.g., optical microangiography (OMAG)). With its reliable technique, high image resolution, and current availability, OCTA has been widely used in the assessment of posterior segment diseases including glaucoma in which ocular perfusion dysfunction has been proposed as a pathophysiological mechanism. CONCLUSION OCTA may enhance our knowledge of glaucoma pathogenesis and offer an improvement in our ability to detect glaucomatous change.
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Affiliation(s)
- Sunee Chansangpetch
- a Department of Ophthalmology , University of California San Francisco , San Francisco , CA , USA.,b Department of Ophthalmology , Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross , Bangkok , Thailand
| | - Shan C Lin
- a Department of Ophthalmology , University of California San Francisco , San Francisco , CA , USA
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Akahori T, Iwase T, Yamamoto K, Ra E, Kawano K, Ito Y, Terasaki H. Macular Displacement After Vitrectomy in Eyes With Idiopathic Macular Hole Determined by Optical Coherence Tomography Angiography. Am J Ophthalmol 2018; 189:111-121. [PMID: 29505776 DOI: 10.1016/j.ajo.2018.02.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 02/18/2018] [Accepted: 02/23/2018] [Indexed: 11/16/2022]
Abstract
PURPOSE To determine whether the macula is displaced after vitrectomy with internal limiting membrane (ILM) peeling in eyes with an idiopathic macular hole. DESIGN A retrospective, observational case series. METHODS Optical coherence tomography angiography was used to obtain 3 mm × 3 mm en face images before and 2, 4, and 8 weeks after the vitrectomy with ILM peeling for 20 eyes of 20 patients with an idiopathic macular hole. The displacements of easily identifiable retinal vessel bifurcations were measured relative to the fovea and the optic disc. RESULTS The distance between the optic disc and vessel bifurcations was significantly shorter in all 4 quadrants throughout the postoperative period (P < .001). This distance was significantly greater in the temporal quadrant (P < .001). The distance of the bifurcations was significantly correlated with the preoperative distance from the optic disc (r = -0.579, P < .001). A significantly greater downward displacement was observed in the superior quadrant (P < .001). The change in the angle of bifurcations was significantly correlated with the preoperative angle to the optic disc (r = -0.632, P < .001). The change in the distance in the inner region was significantly greater than that in the outer region in all quadrants. A significant reduction was observed in the mean foveal avascular zone area during the follow-up period. CONCLUSIONS The retina in the macular region was displaced nasally, probably owing to movement of the retina toward the optic disc because of a contraction after the ILM removal. There is also a possibility of a rotation downward by buoyancy from gas tamponade, and centripetal contraction during the process of hole closure.
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Affiliation(s)
- Tomohiko Akahori
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Takeshi Iwase
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
| | - Kentaro Yamamoto
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Eimei Ra
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Kenichi Kawano
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yasuki Ito
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroko Terasaki
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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180
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Quantitative comparisons between optical coherence tomography angiography and matched histology in the human eye. Exp Eye Res 2018; 170:13-19. [DOI: 10.1016/j.exer.2018.02.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 01/24/2018] [Accepted: 02/09/2018] [Indexed: 11/18/2022]
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181
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Ju MJ, Heisler M, Athwal A, Sarunic MV, Jian Y. Effective bidirectional scanning pattern for optical coherence tomography angiography. BIOMEDICAL OPTICS EXPRESS 2018; 9:2336-2350. [PMID: 29760992 PMCID: PMC5946793 DOI: 10.1364/boe.9.002336] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/17/2018] [Accepted: 04/17/2018] [Indexed: 05/18/2023]
Abstract
We demonstrate the utility of a novel scanning method for optical coherence tomography angiography (OCTA). Although raster scanning is commonly used for OCTA imaging, a bidirectional approach would lessen the distortion caused by galvanometer-based scanners as sources continue to increase sweep rates. As shown, a unidirectional raster scan approach has a lower effective scanning time than bidirectional approaches; however, a strictly bidirectional approach causes contrast variation along the B-scan direction due to the non-uniform time interval between B-scans. Therefore, a stepped bidirectional approach is introduced and successfully applied to retinal imaging in normal controls and in a pathological subject with diabetic retinopathy.
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182
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Raghunathan R, Wu C, Singh M, Liu CH, Miranda RC, Larin KV. Evaluating the effects of maternal alcohol consumption on murine fetal brain vasculature using optical coherence tomography. JOURNAL OF BIOPHOTONICS 2018; 11:e201700238. [PMID: 29292845 PMCID: PMC6292438 DOI: 10.1002/jbio.201700238] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 12/28/2017] [Indexed: 05/09/2023]
Abstract
Prenatal alcohol exposure (PAE) can result in a range of anomalies including brain and behavioral dysfunctions, collectively termed fetal alcohol spectrum disorder. PAE during the 1st and 2nd trimester is common, and research in animal models has documented significant neural developmental deficits associated with PAE during this period. However, little is known about the immediate effects of PAE on fetal brain vasculature. In this study, we used in utero speckle variance optical coherence tomography, a high spatial- and temporal-resolution imaging modality, to evaluate dynamic changes in microvasculature of the 2nd trimester equivalent murine fetal brain, minutes after binge-like maternal alcohol exposure. Acute binge-like PAE resulted in a rapid (<1 hour) and significant decrease (P < .001) in vessel diameter as compared to the sham group. The data show that a single binge-like maternal alcohol exposure resulted in swift vasoconstriction in fetal brain vessels during the critical period of neurogenesis.
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Affiliation(s)
- Raksha Raghunathan
- Department of Biomedical Engineering, University of Houston, Houston, Texas
| | - Chen Wu
- Department of Biomedical Engineering, University of Houston, Houston, Texas
| | - Manmohan Singh
- Department of Biomedical Engineering, University of Houston, Houston, Texas
| | - Chih-Hao Liu
- Department of Biomedical Engineering, University of Houston, Houston, Texas
| | - Rajesh C. Miranda
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, College of Medicine, College Station, Texas
| | - Kirill V. Larin
- Department of Biomedical Engineering, University of Houston, Houston, Texas
- Interdisciplinary Laboratory of Biophotonics, Tomsk State University, Tomsk, Russia
- Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas
- Correspondence: Kirill V. Larin, Department of Biomedical Engineering, University of Houston, Houston, TX.
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183
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Bhende M, Shetty S, Parthasarathy MK, Ramya S. Optical coherence tomography: A guide to interpretation of common macular diseases. Indian J Ophthalmol 2018; 66:20-35. [PMID: 29283118 PMCID: PMC5778576 DOI: 10.4103/ijo.ijo_902_17] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Optical coherence tomography is a quick, non invasive and reproducible imaging tool for macular lesions and has become an essential part of retina practice. This review address the common protocols for imaging the macula, basics of image interpretation, features of common macular disorders with clues to differentiate mimickers and an introduction to choroidal imaging. It includes case examples and also a practical algorithm for interpretation.
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Affiliation(s)
- Muna Bhende
- Shri Bhagwan Mahavir Vitreoretinal Services, Medical Research Foundation, Chennai, Tamil Nadu, India
| | - Sharan Shetty
- Shri Bhagwan Mahavir Vitreoretinal Services, Medical Research Foundation, Chennai, Tamil Nadu, India
| | - Mohana Kuppuswamy Parthasarathy
- Shri Bhagwan Mahavir Vitreoretinal Services, Medical Research Foundation, Chennai, Tamil Nadu, India; School of Optometry and Vision Science, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - S Ramya
- Shri Bhagwan Mahavir Vitreoretinal Services, Medical Research Foundation, Chennai, Tamil Nadu, India
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184
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Optical coherence tomography angiography in the management of age-related macular degeneration. Curr Opin Ophthalmol 2018. [PMID: 29538181 DOI: 10.1097/icu.0000000000000469] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
PURPOSE OF REVIEW Optical coherence tomography angiography (OCT-A) provides rapid, flow-based imaging of the retinal and choroidal vasculature in a noninvasive manner. This review contrasts this novel technique with conventional angiography and discusses its current uses and limitations in the management of age-related macular degeneration (AMD). RECENT FINDINGS Initial work with OCT-A has focused on its ability to identify choriocapillaris flow alterations in dry AMD and to sensitively detect choroidal neovascular membranes (CNVs) in neovascular AMD. Reduced choriocapillaris flow beyond the borders of geographic atrophy seen on OCT-A suggests a primary vascular cause in geographic atrophy. Longitudinal OCT-A analysis of CNV morphology has demonstrated the transition from an immature to mature CNV phenotype following treatment. Current clinical applications of OCT-A include identification of asymptomatic CNV and monitoring for CNV development in the setting of an acquired vitelliform lesion. SUMMARY OCT-A remains a promising diagnostic tool but one still very much in evolution. Larger studies will be needed to more accurately describe its sensitivity and specificity for CNV detection and to better characterize longitudinal CNV morphologic changes. Anticipated hardware and software updates including swept-source light sources, automated montaging, and manual adjustment of interscan timing should enhance the capabilities of OCT-A in the management of AMD.
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185
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Deegan AJ, Wang W, Men S, Li Y, Song S, Xu J, Wang RK. Optical coherence tomography angiography monitors human cutaneous wound healing over time. Quant Imaging Med Surg 2018; 8:135-150. [PMID: 29675355 DOI: 10.21037/qims.2018.02.07] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Background In vivo imaging of the complex cascade of events known to be pivotal elements in the healing of cutaneous wounds is a difficult but essential task. Current techniques are highly invasive, or lack the level of vascular and structural detail required for accurate evaluation, monitoring and treatment. We aimed to use an advanced optical coherence tomography (OCT)-based angiography (OCTA) technique for the non-invasive, high resolution imaging of cutaneous wound healing. Methods We used a clinical prototype OCTA to image, identify and track key vascular and structural adaptations known to occur throughout the healing process. Specific vascular parameters, such as diameter and density, were measured to aid our interpretations under a spatiotemporal framework. Results We identified multiple distinct, yet overlapping stages, hemostasis, inflammation, proliferation, and remodeling, and demonstrated the detailed vascularization and anatomical attributes underlying the multifactorial processes of dermatologic wound healing. Conclusions OCTA provides an opportunity to both qualitatively and quantitatively assess the vascular response to acute cutaneous damage and in the future, may help to ascertain wound severity and possible healing outcomes; thus, enabling more effective treatment options.
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Affiliation(s)
- Anthony J Deegan
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Wendy Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Shaojie Men
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Yuandong Li
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Shaozhen Song
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Jingjiang Xu
- Department of Bioengineering, 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
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186
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de Oliveira Dias JR, Zhang Q, Garcia JMB, Zheng F, Motulsky EH, Roisman L, Miller A, Chen CL, Kubach S, de Sisternes L, Durbin MK, Feuer W, Wang RK, Gregori G, Rosenfeld PJ. Natural History of Subclinical Neovascularization in Nonexudative Age-Related Macular Degeneration Using Swept-Source OCT Angiography. Ophthalmology 2018; 125:255-266. [PMID: 28964581 PMCID: PMC11402511 DOI: 10.1016/j.ophtha.2017.08.030] [Citation(s) in RCA: 145] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 08/10/2017] [Accepted: 08/22/2017] [Indexed: 01/12/2023] Open
Abstract
PURPOSE Swept-source (SS) OCT angiography (OCTA) was used to determine the prevalence, incidence, and natural history of subclinical macular neovascularization (MNV) in eyes with nonexudative age-related macular degeneration (AMD). DESIGN Prospective, observational, consecutive case series. PARTICIPANTS Patients with intermediate AMD (iAMD) or geographic atrophy (GA) secondary to nonexudative AMD in 1 eye and exudative AMD in the fellow eye. METHODS All patients were imaged using both the 3×3 mm and 6×6 mm SS OCTA fields of view (PLEX Elite 9000; Carl Zeiss Meditec, Inc, Dublin, CA). The en face slab used to detect the MNV extended from the outer retina to the choriocapillaris, and projection artifacts were removed using a proprietary algorithm. MAIN OUTCOME MEASURES Prevalence of subclinical MNV and time to exudation with Kaplan-Meier cumulative estimates of exudation at 1 year. RESULTS From August 2014 through March 2017, 160 patients underwent SS OCTA (110 eyes with iAMD and 50 eyes with GA). Swept-source OCTA identified subclinical MNV at the time of first imaging in 23 of 160 eyes, for a prevalence of 14.4%. Six eyes demonstrated subclinical MNV during the follow-up. Of 134 eyes with follow-up visits, a total of 13 eyes demonstrated exudation, and of these 13 eyes, 10 eyes were found to have pre-existing subclinical MNV. By 12 months, the Kaplan-Meier cumulative incidence of exudation for all 134 eyes was 6.8%. For eyes with subclinical MNV at the time of first SS OCTA imaging, the incidence was 21.1%, and for eyes without subclinical MNV, the incidence was 3.6%. There was no difference in the cumulative incidence of exudation from pre-existing MNV in eyes with iAMD or GA (P = 0.847, log-rank test). After the detection of subclinical MNV, the risk of exudation was 15.2 times (95% confidence interval, 4.2-55.4) greater compared with eyes without subclinical MNV. CONCLUSIONS By 12 months, the risk of exudation was greater for eyes with documented subclinical MNV compared with eyes without detectable MNV. For eyes with subclinical MNV, recommendations include more frequent follow-up and home monitoring. Intravitreal therapy is not recommended until prospective studies are performed.
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Affiliation(s)
- João R de Oliveira Dias
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Qinqin Zhang
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - José M B Garcia
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Fang Zheng
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida; Department of Ophthalmology, Tianjin Medical University General Hospital, Tianjin Medical University, Tianjin, China
| | - Elie H Motulsky
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Luiz Roisman
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Andrew Miller
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Chieh-Li Chen
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Sophie Kubach
- Research and Development (R&D), Carl Zeiss Meditec, Inc, Dublin, California
| | - Luis de Sisternes
- Research and Development (R&D), Carl Zeiss Meditec, Inc, Dublin, California
| | - Mary K Durbin
- Research and Development (R&D), Carl Zeiss Meditec, Inc, Dublin, California
| | - William Feuer
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Ruikang K Wang
- 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
| | - Philip J Rosenfeld
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida.
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187
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Lyu S, Zhang M, Wang RK, Gao Y, Zhang Q, Min X. Analysis of the characteristics of optical coherence tomography angiography for retinal cavernous hemangioma: A case report. Medicine (Baltimore) 2018; 97:e9940. [PMID: 29443780 PMCID: PMC5839856 DOI: 10.1097/md.0000000000009940] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
RATIONALE Retinal cavernous hemangioma is a rare congenital vascular malformation with typical fundus changes. Optical coherence tomography angiography (OCTA), which is in rise in the recent years, is a rapid and noninvasive technology to assist in obtaining information regarding the blood flow changes in the fundus lesions from different layers without injecting a contrast agent. PATIENT CONCERNS A 40-year-old male patient with visual occlusion in the right eye for >1 month was reported. DIAGNOSES Retinal cavernous hemangioma was diagnosed by fundus examination, fluorescein angiography (FA) and OCTA, and the characteristics of OCTA images were analyzed. INTERVENTIONS The lesion occurred outside the macula, the central vision remained basically normal, and no significant complications were noted in this patient. Therefore, we preferred to regularly follow-up without therapeutic intervention. CONCLUSIONS OCTA can display fundus blood flow and vascular lesions noninvasively and rapidly. On OCTA, retinal cavernous hemangiomas showed characteristic changes and have good correspondence with fundus imaging and FA examinations. Moreover, OCTA remains more sensitive to vascular abnormalities, and imaging remains clearer, providing new diagnosis and follow-up route for this disease.
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Affiliation(s)
- Shuyuan Lyu
- Department of Ophthalmology, West China Hospital of Sichuan University, Wuhou District, Chengdu, Sichuan, China
| | - Ming Zhang
- Department of Ophthalmology, West China Hospital of Sichuan University, Wuhou District, Chengdu, Sichuan, China
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Yunxia Gao
- Department of Ophthalmology, West China Hospital of Sichuan University, Wuhou District, Chengdu, Sichuan, China
| | - Qinqin Zhang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Xiaoxue Min
- Department of Ophthalmology, West China Hospital of Sichuan University, Wuhou District, Chengdu, Sichuan, China
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188
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Tan ACS, Tan GS, Denniston AK, Keane PA, Ang M, Milea D, Chakravarthy U, Cheung CMG. An overview of the clinical applications of optical coherence tomography angiography. Eye (Lond) 2018; 32:262-286. [PMID: 28885606 PMCID: PMC5811700 DOI: 10.1038/eye.2017.181] [Citation(s) in RCA: 122] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 07/15/2017] [Indexed: 12/15/2022] Open
Abstract
Optical coherence tomography angiography (OCTA) has emerged as a novel, non-invasive imaging modality that allows the detailed study of flow within the vascular structures of the eye. Compared to conventional dye angiography, OCTA can produce more detailed, higher resolution images of the vasculature without the added risk of dye injection. In our review, we discuss the advantages and disadvantages of this new technology in comparison to conventional dye angiography. We provide an overview of the current OCTA technology available, compare the various commercial OCTA machines technical specifications and discuss some future software improvements. An approach to the interpretation of OCTA images by correlating images to other multimodal imaging with attention to identifying potential artefacts will be outlined and may be useful to ophthalmologists, particularly those who are currently still unfamiliar with this new technology. This review is based on a search of peer-reviewed published papers relevant to OCTA according to our current knowledge, up to January 2017, available on the PubMed database. Currently, many of the published studies have focused on OCTA imaging of the retina, in particular, the use of OCTA in the diagnosis and management of common retinal diseases such as age-related macular degeneration and retinal vascular diseases. In addition, we describe clinical applications for OCTA imaging in inflammatory diseases, optic nerve diseases and anterior segment diseases. This review is based on both the current literature and the clinical experience of our individual authors, with an emphasis on the clinical applications of this imaging technology.
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Affiliation(s)
- A C S Tan
- Singapore National Eye Center, Singapore Eye Research Institute, Singapore, Singapore
- Singapore Eye Research Institute, Singapore Singapore
- Duke-NUS Medical School, Singapore, Singapore
| | - G S Tan
- Singapore National Eye Center, Singapore Eye Research Institute, Singapore, Singapore
- Singapore Eye Research Institute, Singapore Singapore
- Duke-NUS Medical School, Singapore, Singapore
| | - A K Denniston
- Department of Ophthalmology, University Hospitals of Birmingham NHS Foundation Trust, Birmingham, UK
- Academic Unit of Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
| | - P A Keane
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
| | - M Ang
- Singapore National Eye Center, Singapore Eye Research Institute, Singapore, Singapore
- Singapore Eye Research Institute, Singapore Singapore
- Duke-NUS Medical School, Singapore, Singapore
| | - D Milea
- Singapore National Eye Center, Singapore Eye Research Institute, Singapore, Singapore
- Singapore Eye Research Institute, Singapore Singapore
- Duke-NUS Medical School, Singapore, Singapore
| | - U Chakravarthy
- Department of Ophthalmology, Queen's University of Belfast, Royal Victoria Hospital, Belfast, Northern Ireland
| | - C M G Cheung
- Singapore National Eye Center, Singapore Eye Research Institute, Singapore, Singapore
- Singapore Eye Research Institute, Singapore Singapore
- Duke-NUS Medical School, Singapore, Singapore
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189
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Optical coherence tomography angiography: a review of current and future clinical applications. Graefes Arch Clin Exp Ophthalmol 2018; 256:237-245. [DOI: 10.1007/s00417-017-3896-2] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 12/20/2017] [Accepted: 12/28/2017] [Indexed: 10/18/2022] Open
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190
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Xu J, Song S, Li Y, Wang RK. Complex-based OCT angiography algorithm recovers microvascular information better than amplitude- or phase-based algorithms in phase-stable systems. Phys Med Biol 2017; 63:015023. [PMID: 29049034 DOI: 10.1088/1361-6560/aa94bc] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Optical coherence tomography angiography (OCTA) is increasingly becoming a popular inspection tool for biomedical imaging applications. By exploring the amplitude, phase and complex information available in OCT signals, numerous algorithms have been proposed that contrast functional vessel networks within microcirculatory tissue beds. However, it is not clear which algorithm delivers optimal imaging performance. Here, we investigate systematically how amplitude and phase information have an impact on the OCTA imaging performance, to establish the relationship of amplitude and phase stability with OCT signal-to-noise ratio (SNR), time interval and particle dynamics. With either repeated A-scan or repeated B-scan imaging protocols, the amplitude noise increases with the increase of OCT SNR; however, the phase noise does the opposite, i.e. it increases with the decrease of OCT SNR. Coupled with experimental measurements, we utilize a simple Monte Carlo (MC) model to simulate the performance of amplitude-, phase- and complex-based algorithms for OCTA imaging, the results of which suggest that complex-based algorithms deliver the best performance when the phase noise is < ~40 mrad. We also conduct a series of in vivo vascular imaging in animal models and human retina to verify the findings from the MC model through assessing the OCTA performance metrics of vessel connectivity, image SNR and contrast-to-noise ratio. We show that for all the metrics assessed, the complex-based algorithm delivers better performance than either the amplitude- or phase-based algorithms for both the repeated A-scan and the B-scan imaging protocols, which agrees well with the conclusion drawn from the MC simulations.
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Affiliation(s)
- Jingjiang Xu
- Department of Bioengineering, University of Washington, Seattle, WA 98195, United States of America
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191
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Glittenberg C, Reisman C, Ansari-Shahrezaei S. Introduction to swept source optical coherence tomography angiography. SPEKTRUM DER AUGENHEILKUNDE 2017. [DOI: 10.1007/s00717-017-0366-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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192
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Le N, Song S, Zhang Q, Wang RK. Robust principal component analysis in optical micro-angiography. Quant Imaging Med Surg 2017; 7:654-667. [PMID: 29312870 DOI: 10.21037/qims.2017.12.05] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Background Recent development of optical micro-angiography (OMAG) utilizes principal component analysis (PCA), where linear-regression filter is employed to separate static and blood flow signals within optical coherence tomography (OCT). While PCA is relatively simple and computationally efficient, the technique is sensitive to and easily skewed by outliers. In this paper, robust PCA (RPCA) is thus introduced to tackle this issue in traditional PCA. Methods We first provide brief theoretical background of PCA and RPCA in the context of OMAG where coherent (complex) OCT signals are utilized to contrast blood flow. We then compare PCA and RPCA on sets of 4D-OCT complex data (3 dimensions in space and 1 dimension in time), which are collected from microfluidic phantoms and in vivo nail-fold tissue. Results In phantom experiments, both analyses perform relatively well since there are little motion within our observation time window, albeit small tail-noise artifacts from PCA. In nail-fold experiment, PCA suffers from tissue motion, from which RPCA does not seem to be affected. Results from RPCA also show enhancements of other dynamic signals, which are likely from the intercellular fluid. This unwanted result is yet to be proven useful for clinical applications. Conclusions Traditional PCA method employs linear-regression filter and is sensitive to outliers (tail-noise and motion artifacts). RPCA method is robust against outliers, but is currently computationally expensive.
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Affiliation(s)
- Nhan Le
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Shaozhen Song
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Qinqin Zhang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
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193
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Tremoleda JL, Alvarez K, Aden A, Donnan R, Michael-Titus AT, Tomlins PH. Heart-rate sensitive optical coherence angiography for measuring vascular changes due to posttraumatic brain injury in mice. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:1-6. [PMID: 29210221 DOI: 10.1117/1.jbo.22.12.121710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 11/09/2017] [Indexed: 06/07/2023]
Abstract
Traumatic brain injury (TBI) results in direct vascular disruption, triggering edema, and reduction in cerebral blood flow. Therefore, understanding the pathophysiology of brain microcirculation following TBI is important for the development of effective therapies. Optical coherence angiography (OCA) is a promising tool for evaluating TBI in rodent models. We develop an approach to OCA that uses the heart-rate frequency to discriminate between static tissue and vasculature. This method operates on intensity data and is therefore not phase sensitive. Furthermore, it does not require spatial overlap of voxels and thus can be applied to pre-existing datasets for which oversampling may not have been explicitly considered. Heart-rate sensitive OCA was developed for dynamic assessment of mouse microvasculature post-TBI. Results show changes occurring at 5-min intervals within the first 50 min of injury.
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Affiliation(s)
- Jordi L Tremoleda
- Queen Mary University of London, Blizard Institute, Barts and the London School of Medicine and Dent, United Kingdom
| | - Karl Alvarez
- Queen Mary University of London, School of Electrical Engineering and Computer Science, London, United Kingdom
| | - Abdirahman Aden
- Queen Mary University of London, Institute of Dentistry, Barts and the London School of Medicine and, United Kingdom
| | - Robert Donnan
- Queen Mary University of London, School of Electrical Engineering and Computer Science, London, United Kingdom
| | - Adina T Michael-Titus
- Queen Mary University of London, Blizard Institute, Barts and the London School of Medicine and Dent, United Kingdom
| | - Peter H Tomlins
- Queen Mary University of London, Institute of Dentistry, Barts and the London School of Medicine and, United Kingdom
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Park KS, Choi WJ, Song S, Xu J, Wang RK. Multifunctional in vivo imaging for monitoring wound healing using swept-source polarization-sensitive optical coherence tomography. Lasers Surg Med 2017; 50:213-221. [PMID: 29193202 DOI: 10.1002/lsm.22767] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2017] [Indexed: 01/15/2023]
Abstract
BACKGROUND AND OBJECTIVE Wound healing involves a complex and dynamic biological process in response to tissue injury. Monitoring of the cascade of cellular events is useful for wound management and treatment. The aim of this study is to demonstrate the potential of multifunctional polarization-sensitive optical coherence tomography (PS-OCT) to longitudinally monitor the self-healing process in a murine cutaneous wound model. MATERIALS AND METHODS A multi-functional PS-OCT system based on swept source OCT configuration (1,310 nm central wavelength) was designed to obtain simultaneously microstructural, blood perfusion, and birefringent information of a biological tissue in vivo. A 1-mm-diameter wound was generated in a mouse pinna with a complete biopsy punch. Afterwards, the self-healing process of the injured tissue was observed every week over 6-week period using the multifunctional system to measure changes in the tissue birefringence. Further OCT angiography (OCTA) was used in post data processing to obtain blood perfusion information over the injured tissue. RESULTS Three complementary images indicating the changes in anatomical, vascular, and birefringent information of tissue around wound were simultaneously provided from a 3-dimensional (3-D) PS-OCT data set during the wound repair over 1 month. Specifically, inflammatory and proliferative phases of wound healing were characterized by thickened epidermal tissue (from OCT images) and angiogenesis (from OCT angiography images) around wound. Also, it was observed that the regenerating tissues had highly realigned birefringent structures (from PS-OCT images). CONCLUSION This preliminary study suggests that the proposed multi-functional imaging modality has a great potential to improve the understanding of wound healing through non-invasive, serial monitoring of vascular and tissue responses to injury. Lasers Surg. Med. 50:213-221, 2018. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Kwan S Park
- Department of Bioengineering, University of Washington, Seattle, Washington 98195
| | - Woo June Choi
- Department of Bioengineering, University of Washington, Seattle, Washington 98195
| | - Shaozhen Song
- Department of Bioengineering, University of Washington, Seattle, Washington 98195
| | - Jingjiang Xu
- Department of Bioengineering, University of Washington, Seattle, Washington 98195
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, Washington 98195
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195
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Veritti D, Sarao V, Francescutti L, Rota N, Loewenstein A, Borrelli E, Sadda SR, Lanzetta P. Optical coherence tomography angiography findings in diabetic retinopathy. EXPERT REVIEW OF OPHTHALMOLOGY 2017. [DOI: 10.1080/17469899.2017.1395698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Daniele Veritti
- Department of Medicine - Ophthalmology, University of Udine, Udine, Italy
- Istituto Europeo di Microchirurgia Oculare - IEMO, Udine, Italy
| | - Valentina Sarao
- Department of Medicine - Ophthalmology, University of Udine, Udine, Italy
- Istituto Europeo di Microchirurgia Oculare - IEMO, Udine, Italy
| | | | - Nestore Rota
- Department of Medicine - Ophthalmology, University of Udine, Udine, Italy
| | - Anat Loewenstein
- Ophthalmology Department, Tel Aviv Medical Center and The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Enrico Borrelli
- 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
- Ophthalmology Clinic, Department of Medicine and Science of Ageing, University G. D’Annunzio Chieti-Pescara, Chieti, Italy
| | - 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
| | - Paolo Lanzetta
- Department of Medicine - Ophthalmology, University of Udine, Udine, Italy
- Istituto Europeo di Microchirurgia Oculare - IEMO, Udine, Italy
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196
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Xu J, Song S, Men S, Wang RK. Long ranging swept-source optical coherence tomography-based angiography outperforms its spectral-domain counterpart in imaging human skin microcirculations. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:1-11. [PMID: 29185292 PMCID: PMC5712670 DOI: 10.1117/1.jbo.22.11.116007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 11/08/2017] [Indexed: 05/07/2023]
Abstract
There is an increasing demand for imaging tools in clinical dermatology that can perform in vivo wide-field morphological and functional examination from surface to deep tissue regions at various skin sites of the human body. The conventional spectral-domain optical coherence tomography-based angiography (SD-OCTA) system is difficult to meet these requirements due to its fundamental limitations of the sensitivity roll-off, imaging range as well as imaging speed. To mitigate these issues, we demonstrate a swept-source OCTA (SS-OCTA) system by employing a swept source based on a vertical cavity surface-emitting laser. A series of comparisons between SS-OCTA and SD-OCTA are conducted. Benefiting from the high system sensitivity, long imaging range, and superior roll-off performance, the SS-OCTA system is demonstrated with better performance in imaging human skin than the SD-OCTA system. We show that the SS-OCTA permits remarkable deep visualization of both structure and vasculature (up to ∼2 mm penetration) with wide field of view capability (up to 18×18 mm2), enabling a more comprehensive assessment of the morphological features as well as functional blood vessel networks from the superficial epidermal to deep dermal layers. It is expected that the advantages of the SS-OCTA system will provide a ground for clinical translation, benefiting the existing dermatological practice.
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Affiliation(s)
- Jingjiang Xu
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Shaozhen Song
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
| | - Shaojie Men
- University of Washington, Department of Bioengineering, Seattle, Washington, United States
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197
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Song S, Xu J, Men S, Shen TT, Wang RK. Robust numerical phase stabilization for long-range swept-source optical coherence tomography. JOURNAL OF BIOPHOTONICS 2017; 10:1398-1410. [PMID: 28485132 PMCID: PMC5831409 DOI: 10.1002/jbio.201700034] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 03/28/2017] [Accepted: 04/03/2017] [Indexed: 05/03/2023]
Abstract
A novel phase stabilization technique is demonstrated with significant improvement in the phase stability of a micro-electromechanical (MEMS) vertical cavity surface-emitting laser (VCSEL) based swept-source optical coherence tomography (SS-OCT) system. Without any requirements of hardware modifications, the new fully numerical phase stabilization technique features high tolerance to acquisition jitter, and significantly reduced budget in computational effort. We demonstrate that when measured with biological tissue, this technique enables a phase sensitivity of 89 mrad in highly scattering tissue, with image ranging distance of up to 12.5 mm at A-line scan rate of 100.3 kHz. We further compare the performances delivered by the phase-stabilization approach with conventional numerical approach for accuracy and computational efficiency. Imaging result of complex signal-based optical coherence tomography angiography (OCTA) and Doppler OCTA indicate that the proposed phase stabilization technique is robust, and efficient in improving the image contrast-to-noise ratio and extending OCTA depth range. The proposed technique can be universally applied to improve phase-stability in generic SS-OCT with different scale of scan rates without a need for special treatment.
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Affiliation(s)
- Shaozhen Song
- University of Washington, Department of Bioengineering, Seattle, WA 98195, USA
| | - Jingjiang Xu
- University of Washington, Department of Bioengineering, Seattle, WA 98195, USA
| | - Shaojie Men
- University of Washington, Department of Bioengineering, Seattle, WA 98195, USA
| | - Tueng T Shen
- University of Washington, Department of Bioengineering, Seattle, WA 98195, USA
- University of Washington, Department of Ophthalmology, Seattle, WA 98195, USA
| | - Ruikang K Wang
- University of Washington, Department of Bioengineering, Seattle, WA 98195, USA
- University of Washington, Department of Ophthalmology, Seattle, WA 98195, USA
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198
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The application of optical coherence tomography angiography in retinal diseases. Surv Ophthalmol 2017; 62:838-866. [DOI: 10.1016/j.survophthal.2017.05.006] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 05/18/2017] [Accepted: 05/19/2017] [Indexed: 01/30/2023]
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199
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Wei W, Choi WJ, Wang RK. Microvascular imaging and monitoring of human oral cavity lesions in vivo by swept-source OCT-based angiography. Lasers Med Sci 2017; 33:123-134. [PMID: 29038969 DOI: 10.1007/s10103-017-2350-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 10/01/2017] [Indexed: 01/23/2023]
Abstract
We report the development of optical coherence tomography- (OCT) based angiography (OCTA) to image blood flow within microcirculatory tissue beds in human oral cavity in vivo with a field of view at 10 mm × 10 mm. Three-dimensional (3D) structural and vascular images of labial mucosa tissue are obtained at a single 3D acquisition. Pathologic mucosal sites with mouth ulcers are examined using the OCT tomograms and angiograms, upon which to monitor the lesion healing process over a period of 2 weeks. Quantitative metrics of the capillary loop density within the lamina propria layer are evaluated, providing statistically significant difference between healthy and diseased conditions over time. Furthermore, tissue anatomy and vessel morphology of other susceptible sites to ulcer, such as tongue, alveolar mucosa, and labial frenulum, are also imaged to demonstrate the promise of the proposed method as a clinically useful tool for the diagnosis and monitoring of therapeutic treatment of oral tissue abnormalities.
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Affiliation(s)
- Wei Wei
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA, 98195, USA
| | - Woo June Choi
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA, 98195, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, 3720 15th Ave NE, Seattle, WA, 98195, USA.
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200
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Nesper PL, Soetikno BT, Zhang HF, Fawzi AA. OCT angiography and visible-light OCT in diabetic retinopathy. Vision Res 2017; 139:191-203. [PMID: 28601429 PMCID: PMC5723235 DOI: 10.1016/j.visres.2017.05.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Revised: 05/23/2017] [Accepted: 05/24/2017] [Indexed: 12/31/2022]
Abstract
In recent years, advances in optical coherence tomography (OCT) techniques have increased our understanding of diabetic retinopathy, an important microvascular complication of diabetes. OCT angiography is a non-invasive method that visualizes the retinal vasculature by detecting motion contrast from flowing blood. Visible-light OCT shows promise as a novel technique for quantifying retinal hypoxia by measuring the retinal oxygen delivery and metabolic rates. In this article, we discuss recent insights provided by these techniques into the vascular pathophysiology of diabetic retinopathy. The next milestones for these modalities are large multicenter studies to establish consensus on the most reliable and consistent outcome parameters to study diabetic retinopathy.
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Affiliation(s)
- Peter L Nesper
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, 645 N. Michigan Avenue, Suite 440, Chicago, IL 60611, USA.
| | - Brian T Soetikno
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, 645 N. Michigan Avenue, Suite 440, Chicago, IL 60611, USA; Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA; Medical Scientist Training Program, Feinberg School of Medicine, Northwestern University, 303 East Chicago Avenue, Chicago, IL 60611, USA.
| | - Hao F Zhang
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, 645 N. Michigan Avenue, Suite 440, Chicago, IL 60611, USA; Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA.
| | - Amani A Fawzi
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, 645 N. Michigan Avenue, Suite 440, Chicago, IL 60611, USA.
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