1
|
Ong JX, Bou Ghanem GO, Nesper PL, Moonjely J, Fawzi AA. Optical Coherence Tomography Angiography of Volumetric Arteriovenous Relationships in the Healthy Macula and Their Derangement in Disease. Invest Ophthalmol Vis Sci 2023; 64:6. [PMID: 37133834 PMCID: PMC10166119 DOI: 10.1167/iovs.64.5.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 04/09/2023] [Indexed: 05/04/2023] Open
Abstract
Purpose To characterize relative arteriovenous connectivity of the healthy macula imaged by optical coherence tomography angiography (OCTA) using a new volumetric tool. Methods OCTA volumes were obtained for 20 healthy controls (20 eyes). Two graders identified superficial arterioles and venules. We implemented a custom watershed algorithm to identify capillaries most closely connected to arterioles and venules by using the large vessels as seeds to flood the vascular network. We calculated ratios of arteriolar- to venular-connected capillaries (A/V ratios) and adjusted flow indices (AFIs) for superficial capillary plexuses (SCPs), middle capillary plexuses (MCPs), and deep capillary plexuses (DCPs). We also analyzed two eyes with proliferative diabetic retinopathy (PDR) and one eye with macular telangiectasia (MacTel) to evaluate the utility of this method in visualizing pathological vascular connectivity. Results In healthy eyes, the MCP showed a greater proportion of arteriolar-connected vessels than the SCP and DCP (all P < 0.001). In the SCP, the arteriolar-connected AFI exceeded the venular-connected AFI, but this pattern reversed in the MCP and DCP, with higher venular-connected AFI (all P < 0.001). In PDR eyes, preretinal neovascularization originated from venules, whereas intraretinal microvascular abnormalities were heterogeneous, with some originating from venules and others representing dilated MCP capillary loops. In MacTel, diving SCP venules formed the epicenter of the outer retinal anomalous vascular network. Conclusions Healthy eyes showed a higher MCP A/V ratio but relatively slower arteriolar vs. venular flow velocity in the MCP and DCP, which may explain deep retinal vulnerability to ischemia. In eyes with complex vascular pathology, our connectivity findings were consistent with histopathologic studies.
Collapse
Affiliation(s)
- Janice X Ong
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Ghazi O Bou Ghanem
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Peter L Nesper
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Jessica Moonjely
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Amani A Fawzi
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| |
Collapse
|
2
|
Abtahi M, Le D, Ebrahimi B, Dadzie AK, Lim JI, Yao X. An open-source deep learning network AVA-Net for arterial-venous area segmentation in optical coherence tomography angiography. COMMUNICATIONS MEDICINE 2023; 3:54. [PMID: 37069396 PMCID: PMC10110614 DOI: 10.1038/s43856-023-00287-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 04/06/2023] [Indexed: 04/19/2023] Open
Abstract
BACKGROUND Differential artery-vein (AV) analysis in optical coherence tomography angiography (OCTA) holds promise for the early detection of eye diseases. However, currently available methods for AV analysis are limited for binary processing of retinal vasculature in OCTA, without quantitative information of vascular perfusion intensity. This study is to develop and validate a method for quantitative AV analysis of vascular perfusion intensity. METHOD A deep learning network AVA-Net has been developed for automated AV area (AVA) segmentation in OCTA. Seven new OCTA features, including arterial area (AA), venous area (VA), AVA ratio (AVAR), total perfusion intensity density (T-PID), arterial PID (A-PID), venous PID (V-PID), and arterial-venous PID ratio (AV-PIDR), were extracted and tested for early detection of diabetic retinopathy (DR). Each of these seven features was evaluated for quantitative evaluation of OCTA images from healthy controls, diabetic patients without DR (NoDR), and mild DR. RESULTS It was observed that the area features, i.e., AA, VA and AVAR, can reveal significant differences between the control and mild DR. Vascular perfusion parameters, including T-PID and A-PID, can differentiate mild DR from control group. AV-PIDR can disclose significant differences among all three groups, i.e., control, NoDR, and mild DR. According to Bonferroni correction, the combination of A-PID and AV-PIDR can reveal significant differences in all three groups. CONCLUSIONS AVA-Net, which is available on GitHub for open access, enables quantitative AV analysis of AV area and vascular perfusion intensity. Comparative analysis revealed AV-PIDR as the most sensitive feature for OCTA detection of early DR. Ensemble AV feature analysis, e.g., the combination of A-PID and AV-PIDR, can further improve the performance for early DR assessment.
Collapse
Affiliation(s)
- Mansour Abtahi
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - David Le
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Behrouz Ebrahimi
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Albert K Dadzie
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Jennifer I Lim
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Xincheng Yao
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, 60607, USA.
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, 60612, USA.
| |
Collapse
|
3
|
Xu X, Yang P, Wang H, Xiao Z, Xing G, Zhang X, Wang W, Xu F, Zhang J, Lei J. AV-casNet: Fully Automatic Arteriole-Venule Segmentation and Differentiation in OCT Angiography. IEEE TRANSACTIONS ON MEDICAL IMAGING 2023; 42:481-492. [PMID: 36227826 DOI: 10.1109/tmi.2022.3214291] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Automatic segmentation and differentiation of retinal arteriole and venule (AV), defined as small blood vessels directly before and after the capillary plexus, are of great importance for the diagnosis of various eye diseases and systemic diseases, such as diabetic retinopathy, hypertension, and cardiovascular diseases. Optical coherence tomography angiography (OCTA) is a recent imaging modality that provides capillary-level blood flow information. However, OCTA does not have the colorimetric and geometric differences between AV as the fundus photography does. Various methods have been proposed to differentiate AV in OCTA, which typically needs the guidance of other imaging modalities. In this study, we propose a cascaded neural network to automatically segment and differentiate AV solely based on OCTA. A convolutional neural network (CNN) module is first applied to generate an initial segmentation, followed by a graph neural network (GNN) to improve the connectivity of the initial segmentation. Various CNN and GNN architectures are employed and compared. The proposed method is evaluated on multi-center clinical datasets, including 3 ×3 mm2 and 6 ×6 mm2 OCTA. The proposed method holds the potential to enrich OCTA image information for the diagnosis of various diseases.
Collapse
|
4
|
Berlin A, Cabral D, Chen L, Messinger JD, Balaratnasingam C, Mendis R, Ferrara D, Freund KB, Curcio CA. Histology of type 3 macular neovascularization and microvascular anomalies in treated age-related macular degeneration: a case study. OPHTHALMOLOGY SCIENCE 2023; 3:100280. [PMID: 36970117 PMCID: PMC10033755 DOI: 10.1016/j.xops.2023.100280] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 01/16/2023] [Accepted: 01/30/2023] [Indexed: 02/11/2023]
Abstract
Purpose To investigate intraretinal neovascularization and microvascular anomalies by correlating in vivo multimodal imaging with corresponding ex vivo histology in a single patient. Design A case study comprising clinical imaging from a community-based practice, and histologic analysis at a university-based research laboratory (clinicopathologic correlation). Participants A White woman in her 90s treated with numerous intravitreal anti-VEGF injections for bilateral type 3 macular neovascularization (MNV) secondary to age-related macular degeneration (AMD). Methods Clinical imaging comprised serial infrared reflectance, eye-tracked spectral-domain OCT, OCT angiography, and fluorescein angiography. Eye tracking, applied to the 2 preserved donor eyes, enabled the correlation of clinical imaging signatures with high-resolution histology and transmission electron microscopy. Main Outcome Measures Histologic/ultrastructural descriptions and diameters of vessels seen in clinical imaging. Results Six vascular lesions were histologically confirmed (type 3 MNV, n = 3; deep retinal age-related microvascular anomalies [DRAMAs], n = 3). Pyramidal (n = 2) or tangled (n = 1) morphologies of type 3 MNV originated at the deep capillary plexus (DCP) and extended posteriorly to approach without penetrating persistent basal laminar deposit. They did not enter the subretinal pigment epithelium (RPE)-basal laminar space or cross the Bruch membrane. Choroidal contributions were not found. The neovascular complexes included pericytes and nonfenestrated endothelial cells, within a collagenous sheath covered by dysmorphic RPE cells. Deep retinal age-related microvascular anomaly lesions extended posteriorly from the DCP into the Henle fiber and the outer nuclear layers without evidence of atrophy, exudation, or anti-VEGF responsiveness. Two DRAMAs lacked collagenous sheaths. External and internal diameters of type 3 MNV and DRAMA vessels were larger than comparison vessels in the index eyes and in aged normal and intermediate AMD eyes. Conclusions Type 3 MNV vessels reflect specializations of source capillaries and persist during anti-VEGF therapy. The collagenous sheath of type 3 MNV lesions may provide structural stabilization. If so, vascular characteristics may be useful in disease monitoring in addition to fluid and flow signal detection. Further investigation with longitudinal imaging before exudation onset will help determine if DRAMAs are part of the type 3 MNV progression sequence. Financial Disclosures Proprietary or commercial disclosure may be found after the references.
Collapse
|
5
|
Arrigo A, Aragona E, Battaglia Parodi M, Bandello F. Quantitative approaches in multimodal fundus imaging: State of the art and future perspectives. Prog Retin Eye Res 2023; 92:101111. [PMID: 35933313 DOI: 10.1016/j.preteyeres.2022.101111] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 07/16/2022] [Accepted: 07/19/2022] [Indexed: 02/01/2023]
Abstract
When it first appeared, multimodal fundus imaging revolutionized the diagnostic workup and provided extremely useful new insights into the pathogenesis of fundus diseases. The recent addition of quantitative approaches has further expanded the amount of information that can be obtained. In spite of the growing interest in advanced quantitative metrics, the scientific community has not reached a stable consensus on repeatable, standardized quantitative techniques to process and analyze the images. Furthermore, imaging artifacts may considerably affect the processing and interpretation of quantitative data, potentially affecting their reliability. The aim of this survey is to provide a comprehensive summary of the main multimodal imaging techniques, covering their limitations as well as their strengths. We also offer a thorough analysis of current quantitative imaging metrics, looking into their technical features, limitations, and interpretation. In addition, we describe the main imaging artifacts and their potential impact on imaging quality and reliability. The prospect of increasing reliance on artificial intelligence-based analyses suggests there is a need to develop more sophisticated quantitative metrics and to improve imaging technologies, incorporating clear, standardized, post-processing procedures. These measures are becoming urgent if these analyses are to cross the threshold from a research context to real-life clinical practice.
Collapse
Affiliation(s)
- Alessandro Arrigo
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy.
| | - Emanuela Aragona
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy
| | - Maurizio Battaglia Parodi
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy
| | - Francesco Bandello
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy
| |
Collapse
|
6
|
Cabral D, Ramtohul P, Fradinho AC, Freund KB. Volume Rendering of Deep Retinal Age-Related Microvascular Anomalies. Ophthalmol Retina 2022; 6:1185-1193. [PMID: 35772694 DOI: 10.1016/j.oret.2022.06.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 06/09/2022] [Accepted: 06/15/2022] [Indexed: 06/15/2023]
Abstract
PURPOSE To characterize and distinguish non-neovascular deep retinal age-related microvascular anomalies (DRAMA) from type 3 macular neovascularization (MNV) using volume rendering of OCT and OCT angiography (OCTA). DESIGN Retrospective, consecutive case series. SUBJECTS Consecutive patients with age-related macular degeneration (AMD) exhibiting de novo non-neovascular abnormalities within the deep vascular plexus (DCP), as detected using high-resolution (High-Res) spectral-domain (SD) and swept-source (SS) OCT or OCTA. Patients with retinal vascular alterations attributable to other disease entities were excluded. METHODS Complete ophthalmic examination and multimodal imaging, including confocal fundus photography (CFP), SD-OCT, High-Res SD-OCT and OCTA, and volume-averaged SS-OCTA. The volume renderings of High-Res OCTA and averaged SS-OCTA were used to analyze capillary abnormalities and inflow or outflow connectivity pathways. MAIN OUTCOME MEASURES The primary outcomes were the characteristics of capillary abnormalities (number, size, shape, reflectivity, and location) and inflow or outflow connectivity pathways. The secondary outcomes were nearby changes in CFP and structural OCT (hyperreflective foci [HRF], outer retinal atrophy, and retinal pigment epithelium [RPE] atrophy). RESULTS From 8 eyes of 8 patients, 2 subtypes of DRAMA were identified: small-diameter perifoveal capillary dilations with hyperreflective walls within the inner nuclear layer (type 1, n = 4) and vascular outpouchings, typically multiple, extending posteriorly into the Henle fiber layer, with reflectivity similar to adjacent normal retinal capillaries (type 2, n = 10). Four eyes had both subtypes of DRAMA. The 3-dimensional visualization of OCTA data demonstrated DRAMA corresponding to the dilations of DCP capillaries without direct inflow or outflow connections to the superficial plexus. Fundus photographs showed circular red dots in 3 eyes, all corresponding to type 1 DRAMA. In all the cases, DRAMA colocalized with HRF. No lesions were found anterior to the areas of the RPE or outer retina atrophy. Asymptomatic intraretinal exudation varied through a follow-up duration of up to 6 years, with no lesions progressing to type 3 MNV. CONCLUSIONS In eyes with non-neovascular AMD, DRAMA include 2 types of capillary dilations occurring without the remodeling of the surrounding vascular network. Deep retinal age-related microvascular anomalies can resemble microvascular changes due to other causes and can masquerade as type 3 MNV. Mild intraretinal exudation can vary during follow-up, without progression to type 3 MNV.
Collapse
Affiliation(s)
- Diogo Cabral
- Vitreous Retina Macula Consultants of New York, New York, New York; Nova Medical School Research, Nova Medical School, Universidade Nova de Lisboa, Lisbon, Portugal; Department of Ophthalmology, New York University Grossman School of Medicine, New York, New York
| | - Prithvi Ramtohul
- Vitreous Retina Macula Consultants of New York, New York, New York; Department of Ophthalmology, New York University Grossman School of Medicine, New York, New York
| | - Ana C Fradinho
- Nova Medical School Research, Nova Medical School, Universidade Nova de Lisboa, Lisbon, Portugal
| | - K Bailey Freund
- Vitreous Retina Macula Consultants of New York, New York, New York; Department of Ophthalmology, New York University Grossman School of Medicine, New York, New York.
| |
Collapse
|
7
|
The Role of Optical Coherence Tomography Angiography in Optic Nerve Head Edema: A Narrative Review. J Ophthalmol 2022; 2022:5823345. [PMID: 36505507 PMCID: PMC9729054 DOI: 10.1155/2022/5823345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 10/21/2022] [Accepted: 11/16/2022] [Indexed: 12/03/2022] Open
Abstract
Optic nerve head (ONH) edema is a clinical manifestation of many ocular and systemic disorders. Ocular and central nervous system imaging has been used to differentiate the underlying cause of ONH edema and monitor the disease course. ONH vessel abnormalities are among the earliest signs of impaired axonal transportation. Optical coherence tomography angiography (OCTA) is a noninvasive method for imaging ONH and peripapillary vessels and has been used extensively for studying vascular changes in ONH disorders, including ONH edema. In this narrative review, we describe OCTA findings of the most common causes of ONH edema and its differential diagnoses including ONH drusen.
Collapse
|
8
|
The OCT angular sign of Henle fiber layer (HFL) hyperreflectivity (ASHH) and the pathoanatomy of the HFL in macular disease. Prog Retin Eye Res 2022:101135. [DOI: 10.1016/j.preteyeres.2022.101135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/08/2022] [Accepted: 10/12/2022] [Indexed: 11/11/2022]
|
9
|
Abtahi M, Le D, Lim JI, Yao X. MF-AV-Net: an open-source deep learning network with multimodal fusion options for artery-vein segmentation in OCT angiography. BIOMEDICAL OPTICS EXPRESS 2022; 13:4870-4888. [PMID: 36187235 PMCID: PMC9484445 DOI: 10.1364/boe.468483] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/12/2022] [Accepted: 08/12/2022] [Indexed: 06/16/2023]
Abstract
This study is to demonstrate the effect of multimodal fusion on the performance of deep learning artery-vein (AV) segmentation in optical coherence tomography (OCT) and OCT angiography (OCTA); and to explore OCT/OCTA characteristics used in the deep learning AV segmentation. We quantitatively evaluated multimodal architectures with early and late OCT-OCTA fusions, compared to the unimodal architectures with OCT-only and OCTA-only inputs. The OCTA-only architecture, early OCT-OCTA fusion architecture, and late OCT-OCTA fusion architecture yielded competitive performances. For the 6 mm×6 mm and 3 mm×3 mm datasets, the late fusion architecture achieved an overall accuracy of 96.02% and 94.00%, slightly better than the OCTA-only architecture which achieved an overall accuracy of 95.76% and 93.79%. 6 mm×6 mm OCTA images show AV information at pre-capillary level structure, while 3 mm×3 mm OCTA images reveal AV information at capillary level detail. In order to interpret the deep learning performance, saliency maps were produced to identify OCT/OCTA image characteristics for AV segmentation. Comparative OCT and OCTA saliency maps support the capillary-free zone as one of the possible features for AV segmentation in OCTA. The deep learning network MF-AV-Net used in this study is available on GitHub for open access.
Collapse
Affiliation(s)
- Mansour Abtahi
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA
- These authors contributed equally to this work
| | - David Le
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA
- These authors contributed equally to this work
| | - Jennifer I. Lim
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Xincheng Yao
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| |
Collapse
|
10
|
Gao M, Guo Y, Hormel TT, Tsuboi K, Pacheco G, Poole D, Bailey ST, Flaxel CJ, Huang D, Hwang TS, Jia Y. A Deep Learning Network for Classifying Arteries and Veins in Montaged Widefield OCT Angiograms. OPHTHALMOLOGY SCIENCE 2022; 2:100149. [PMID: 36278031 PMCID: PMC9562370 DOI: 10.1016/j.xops.2022.100149] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 03/16/2022] [Accepted: 03/28/2022] [Indexed: 01/18/2023]
|
11
|
Berlin A, Cabral D, Chen L, Messinger JD, Balaratnasingam C, Mendis R, Ferrara D, Freund KB, Curcio CA. Correlation of Optical Coherence Tomography Angiography of Type 3 Macular Neovascularization With Corresponding Histology. JAMA Ophthalmol 2022; 140:628-633. [PMID: 35446357 PMCID: PMC9204546 DOI: 10.1001/jamaophthalmol.2022.0890] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 03/02/2022] [Indexed: 01/10/2023]
Abstract
Importance By validating optical coherence tomography angiography (OCTA) in the analysis of type 3 macular neovascularization secondary to age-related macular degeneration, the overall value of clinical OCTA for disease observation, diagnosis, and staging is increased. Objective To assess the association of in vivo OCTA of type 3 macular neovascularization secondary to age-related macular degeneration with corresponding ex vivo histology. Design, Setting, and Participants This study included clinical imaging, laboratory microscopy, and eye-tracked clinicopathologic correlation of a single case from a community-based practice evaluated at a university-based research laboratory from 2014 to 2019. Exposures Infrared reflectance and eye-tracked spectral-domain OCTA clinical imaging was correlated with ex vivo high-resolution histologic images of the preserved donor eye. Eye tracking, applied to the donor eye, enabled identification of histologic features corresponding with clinical OCTA signatures. Projection artifact removal based on 2-dimensional vessel-shape estimation and a Gaussian blur filter demonstrated a robust preservation of neovascular flow signal. Main Outcomes and Measures Histology findings associated with clinical OCTA signatures. Three-dimensional view of neovascularization via video. Results A White woman in her 90s with type 3 neovascularization secondary to age-related macular degeneration was treated with 37 intravitreal injections of ranibizumab and aflibercept in the right eye. The index lesion displayed a drusenoid pigment epithelium detachment, characteristic of type 3 neovascularization. OCTA decorrelation signal in the index lesion corresponded in histology to a collagen-ensheathed vascular complex contacting basal laminar deposit that outlasted the retinal pigment epithelium. The subretinal pigment epithelium-basal laminar space contained calcified material and glial processes. No connection between the choriocapillaris and this space was observed. Video showed a columnar tangle of flow signal in the outer nuclear layer, with inflow and outflow vessels connecting to the superficial artery and vein. Conclusions and Relevance While this study presents only 1 case in which a vascular connection between subretinal pigment epithelium-basal laminar space and choriocapillaris was undetected, these results support the potential value of OCTA for diagnosis. OCTA decorrelation signal of type 3 neovascularization corresponded with intraretinal neovessels on histology. Projection artifact removal based on 2-dimensional vessel-shape estimation and Gaussian blur filter demonstrated their potential value for further use in OCTA decorrelation signal processing.
Collapse
Affiliation(s)
- Andreas Berlin
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham
- University Hospital Würzburg, Würzburg, Germany
| | - Diogo Cabral
- Vitreous Retina Macula Consultants of New York, New York
- CEDOC-NOVA Medical School, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Ling Chen
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham
- The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, and Chongqing Eye Institute, Chongqing, China
| | - Jeffrey D. Messinger
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham
| | - Chandrakumar Balaratnasingam
- Centre for Ophthalmology and Visual Science, University of Western Australia, Perth, Western Australia, Australia
- Lions Eye Institute, Nedlands, Western Australia, Australia
- Department of Ophthalmology, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | | | | | - K. Bailey Freund
- Vitreous Retina Macula Consultants of New York, New York
- Department of Ophthalmology, New York University Grossman School of Medicine, New York
| | - Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham
| |
Collapse
|
12
|
Cabral D, Fradinho AC, Pereira T, Ramakrishnan MS, Bacci T, An D, Tenreiro S, Seabra MC, Balaratnasingam C, Freund KB. Macular Vascular Imaging and Connectivity Analysis Using High-Resolution Optical Coherence Tomography. Transl Vis Sci Technol 2022; 11:2. [PMID: 35648637 PMCID: PMC9172017 DOI: 10.1167/tvst.11.6.2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 05/06/2022] [Indexed: 11/24/2022] Open
Abstract
Purpose To characterize macular blood flow connectivity in vivo using high-resolution optical coherence tomography (HighRes OCT). Methods Cross-sectional, observational study. Dense (6-µm interscan distance) perifoveal HighRes OCT raster scans were performed on healthy participants. To mitigate the limitations of projection-resolved OCT-angiography, flow and structural data were used to observe the vascular structures of the superficial vascular complex (SVC) and the deep vascular complex. Vascular segmentation and rendering were performed using Imaris 9.5 software. Inflow and outflow patterns were classified according to vascular diameter and branching order from superficial arteries and veins, respectively. Results Eight eyes from eight participants were included in this analysis, from which 422 inflow and 459 outflow connections were characterized. Arteries had direct arteriolar connections to the SVC (78%) and to the intermediate capillary plexus (ICP, 22%). Deep capillary plexus (DCP) inflow derived from small-diameter vessels succeeding ICP arterioles. The most prevalent outflow pathways coursed through superficial draining venules (74%). DCP draining venules ordinarily merged with ICP draining venules and drained independently of superficial venules in 21% of cases. The morphology of DCP draining venules in structural HighRes OCT is distinct from other vessels crossing the inner nuclear layer and can be used to identify superficial veins. Conclusions Vascular connectivity analysis supports a hybrid circuitry of blood flow within the human parafoveal macula. Translational Relevance Characterization of parafoveal macular blood flow connectivity in vivo using a precise segmentation of HighRes OCT is consistent with ground-truth microscopy studies and shows a hybrid circuitry.
Collapse
Affiliation(s)
- Diogo Cabral
- Vitreous Retina Macula Consultants of New York, NY, USA
- CEDOC, NOVA Medical School I Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Ana C. Fradinho
- CEDOC, NOVA Medical School I Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Telmo Pereira
- CEDOC, NOVA Medical School I Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisbon, Portugal
| | | | - Tommaso Bacci
- Vitreous Retina Macula Consultants of New York, NY, USA
| | - Dong An
- Centre for Ophthalmology and Visual Science, University of Western Australia, Nedlands, Western Australia, Australia
- Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Sandra Tenreiro
- CEDOC, NOVA Medical School I Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Miguel C. Seabra
- CEDOC, NOVA Medical School I Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisbon, Portugal
- UCL Institute of Ophthalmology, London, UK
| | - Chandrakumar Balaratnasingam
- Centre for Ophthalmology and Visual Science, University of Western Australia, Nedlands, Western Australia, Australia
- Lions Eye Institute, Nedlands, Western Australia, Australia
| | - K. Bailey Freund
- Vitreous Retina Macula Consultants of New York, NY, USA
- Department of Ophthalmology, NYU Grossman School of Medicine, New York, NY, USA
| |
Collapse
|
13
|
Adejumo T, Kim TH, Le D, Son T, Ma G, Yao X. Depth-resolved vascular profile features for artery-vein classification in OCT and OCT angiography of human retina. BIOMEDICAL OPTICS EXPRESS 2022; 13:1121-1130. [PMID: 35284164 PMCID: PMC8884205 DOI: 10.1364/boe.450913] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 01/22/2022] [Accepted: 01/23/2022] [Indexed: 05/11/2023]
Abstract
This study is to characterize reflectance profiles of retinal blood vessels in optical coherence tomography (OCT), and to test the potential of using these vascular features to guide artery-vein classification in OCT angiography (OCTA) of the human retina. Depth-resolved OCT reveals unique features of retinal arteries and veins. Retinal arteries show hyper-reflective boundaries at both upper (inner side towards the vitreous) and lower (outer side towards the choroid) walls. In contrast, retinal veins reveal hyper-reflectivity at the upper boundary only. Uniform lumen intensity was observed in both small and large arteries. However, the venous lumen intensity was dependent on the vessel size. Small veins exhibit a hyper-reflective zone at the bottom half of the lumen, while large veins show a hypo-reflective zone at the bottom half of the lumen.
Collapse
Affiliation(s)
- Tobiloba Adejumo
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA
- These authors contributed equally to this work
| | - Tae-Hoon Kim
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA
- These authors contributed equally to this work
| | - David Le
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Taeyoon Son
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Guangying Ma
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Xincheng Yao
- Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| |
Collapse
|
14
|
Lu BW, Chao GJ, Wu GP, Xie LK. In depth understanding of retinitis pigmentosa pathogenesis through optical coherence tomography angiography analysis: a narrative review. Int J Ophthalmol 2021; 14:1979-1985. [PMID: 34926217 DOI: 10.18240/ijo.2021.12.25] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 09/13/2021] [Indexed: 12/11/2022] Open
Abstract
Retinitis pigmentosa (RP) is the most recognized inherited retinal disorder involving progressive photoreceptors degeneration which eventually causes blindness. However, the pathogenesis of RP is still unclear, making it difficult to establish satisfying treatments. Evidence have been found to support the theory that vascular dysfunction is associated with the progression of RP. Optical coherence tomography angiography (OCTA) is a newly developed technology that enables visualization as well as quantitative assessment of retinal and choroidal vasculature non-invasively. Advances in OCTA have opened a window for in-depth understanding of RP pathogenesis. Here, we propose a hypothesis of RP pathogenesis based on the current OCTA findings in RP, which includes four stages and two important key factors, vascular dysfunction and microglia activation. Further, we discuss the future animal experiments needed and how advanced OCTA technology can help to further verity the hypothesis. The final goal is to explore potential treatment options with enhanced understanding of RP pathogenesis.
Collapse
Affiliation(s)
- Bing-Wen Lu
- Department of Ophthalmology, Ophthalmology Hospital of China Academy of Traditional Chinese Medicine, Beijing 100040, China
| | - Guo-Jun Chao
- Department of Ophthalmology, Ophthalmology Hospital of China Academy of Traditional Chinese Medicine, Beijing 100040, China
| | - Gai-Ping Wu
- Department of Ophthalmology, Ophthalmology Hospital of China Academy of Traditional Chinese Medicine, Beijing 100040, China
| | - Li-Ke Xie
- Department of Ophthalmology, Ophthalmology Hospital of China Academy of Traditional Chinese Medicine, Beijing 100040, China
| |
Collapse
|
15
|
Alam MN, Le D, Yao X. Differential artery-vein analysis in quantitative retinal imaging: a review. Quant Imaging Med Surg 2021; 11:1102-1119. [PMID: 33654680 PMCID: PMC7829162 DOI: 10.21037/qims-20-557] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 06/19/2020] [Indexed: 11/06/2022]
Abstract
Quantitative retinal imaging is essential for eye disease detection, staging classification, and treatment assessment. It is known that different eye diseases or severity stages can affect the artery and vein systems in different ways. Therefore, differential artery-vein (AV) analysis can improve the performance of quantitative retinal imaging. In this article, we provide a brief summary of technical rationales and clinical applications of differential AV analysis in fundus photography, optical coherence tomography (OCT), and OCT angiography (OCTA).
Collapse
Affiliation(s)
- Minhaj Nur Alam
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - David Le
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Xincheng Yao
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
| |
Collapse
|
16
|
Peripapillary and Macular Flow Changes in Nonarteritic Anterior Ischemic Optic Neuropathy (NAION) by Optical Coherence Tomography Angiography (OCT-A). J Ophthalmol 2021; 2020:3010631. [PMID: 33489325 PMCID: PMC7803121 DOI: 10.1155/2020/3010631] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 10/16/2020] [Accepted: 10/21/2020] [Indexed: 01/01/2023] Open
Abstract
Background To analyze the blood flow changes of radial peripapillary capillaries (RPCs) and macula with time procession in patients with nonarteritic anterior ischemic optic neuropathy (NAION) by optical coherence tomography angiography (OCT-A). Methods A total of 21 affected eyes and 19 unaffected eyes from 21 NAION patients were included. Assessments of BCVA, CFP, SD-OCT, and OCT-A were performed on NAION patients at enrollment and at 1-2 weeks, 1-2 months, and 3–6 months after enrollment. Measures of the thickness of the peripapillary retinal nerve fiber layer (wRNFL) and macular ganglion cell complex (wGCC) of the whole image in SD-OCT, vessel density of the RPC (wRPC) and superficial and deep vascular complexes (wSVD, wDVD) in the whole image of OCT-A, and their superior- and inferior-hemi values (s/iRNFL, s/iGCC, s/iRPC, and s/iSVD) were assessed. Results Compared to unaffected control eyes, wRPC (p ≤ 0.001) was significantly lower in affected eyes at baseline, and there was no significant difference in wSVD (p > 0.05). The wRPC and wSVD values of affected eyes were significantly decreased at follow-up time points of 1–2 and 3–6 months compared to baseline (p=0.001, p ≤ 0.001; p ≤ 0.001, p ≤ 0.001). The sRPC values were significantly lower than iRPC at 1-2/3–6 months (p=0.016, p=0.013), and sSVD values were lower than iSVD at 1-2 months (p=0.010). Statistically significant correlations were found between wRPC and wRNFL values at 3–6 months (r = 0.626, p=0.022), between wSVD and wGCC at 1-2 weeks and 1-2 months (r = 0.570, r = 0.436; p=0.007, p=0.048). Conclusion OCT-A revealed a sectorial reduction in vessel density in the RPC and macula with the disease progression of NAION from acute to atrophic stages, a classification associated with structural deficits.
Collapse
|
17
|
Cabral D, Pereira T, Ledesma-Gil G, Rodrigues C, Coscas F, Sarraf D, Freund KB. Volume Rendering of Dense B-Scan Optical Coherence Tomography Angiography to Evaluate the Connectivity of Macular Blood Flow. Invest Ophthalmol Vis Sci 2021; 61:44. [PMID: 32561927 PMCID: PMC7415320 DOI: 10.1167/iovs.61.6.44] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Purpose To characterize macular blood flow connectivity using volume rendering of dense B-scan (DB) optical coherence tomography angiography (OCTA) data. Methods This was a prospective, cross-sectional, observational study. DB OCTA perifoveal scans were performed on healthy subjects using the Spectralis HRA+OCT2. A volumetric projection artifact removal algorithm and customized filters were applied to raw OCTA voxel data. Volume rendering was performed using a workflow on Imaris 9.5 software. Vascular graphs were obtained from angiographic data using the algorithm threshold-loops. Superficial arteries and veins were identified from color fundus photographs and connections between adjacent arteries and veins displayed using the shortest path algorithm. Connective pathway locations were analyzed with cross-sectional OCT and OCTA to determine their course through the superficial vascular complex (SVC) and the deep vascular complex (DVC). Results Fourteen eyes from seven subjects (mean age: 28 ± 5 years; 3 women) were included in this analysis. One hundred and twenty-six vascular connections were analyzed. In all cases, the shortest path connections between superficial arteries and veins coursed through the DVC. We did not identify shortest path connections confined to the SVC. Conclusions Volumetric analysis of vascular connectivity supports a predominantly in-series arrangement of blood flow between the SVC and DVC within the human perifoveal macula.
Collapse
|
18
|
Kim TH, Le D, Son T, Yao X. Vascular morphology and blood flow signatures for differential artery-vein analysis in optical coherence tomography of the retina. BIOMEDICAL OPTICS EXPRESS 2021; 12:367-379. [PMID: 33520388 PMCID: PMC7818960 DOI: 10.1364/boe.413149] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 12/07/2020] [Accepted: 12/09/2020] [Indexed: 05/09/2023]
Abstract
Differential artery-vein (AV) analysis is essential for retinal study, disease detection, and treatment assessment. This study is to characterize vascular reflectance profiles and blood flow patterns of retinal artery and vein systems in optical coherence tomography (OCT) and OCT angiography (OCTA), and establish them as robust signatures for objective AV classification. A custom designed OCT was employed for three-dimensional (3D) imaging of mouse retina, and corresponding OCTA was reconstructed. Radially resliced OCT B-scans revealed two, i.e. top and bottom, hyperreflective wall boundaries in retinal arteries, while these wall boundaries were absent in OCT of retinal veins. Additional OCTA analysis consistently displayed a layered speckle distribution in the vein, which may indicate the venous laminar flow. These OCT and OCTA differences offer unique signatures for objective AV classification in OCT and OCTA.
Collapse
Affiliation(s)
- Tae-Hoon Kim
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - David Le
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Taeyoon Son
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Xincheng Yao
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| |
Collapse
|
19
|
Borrelli E, Sacconi R, Querques L, Battista M, Bandello F, Querques G. Quantification of diabetic macular ischemia using novel three-dimensional optical coherence tomography angiography metrics. JOURNAL OF BIOPHOTONICS 2020; 13:e202000152. [PMID: 32526048 DOI: 10.1002/jbio.202000152] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/25/2020] [Accepted: 06/07/2020] [Indexed: 06/11/2023]
Abstract
We applied three-dimensional (3D) analysis to optical coherence tomography angiography (OCTA) to measure macular ischemia in eyes affected by non-proliferative diabetic retinopathy (DR). A previously validated algorithm was applied to OCTA data in order to obtain 3D visualization of the retinal vasculature. Successively, a global thresholding algorithm was applied and two novel quantitative metrics were introduced: 3D vascular volume and 3D perfusion density. Two-dimensional (2D) OCTA metrics were also obtained with different binarization thresholds for comparison. Of the 30 patients included, 15 were diagnosed with DR and 15 were controls. The 3D vascular volume and 3D perfusion density were reduced in DR eyes (P < .0001). The 2D variables also significantly differ between groups. The 3D perfusion density had the highest area under the receiver operating characteristic curve (0.964) among tested variables. Assessing quantitative perfusion using 3D analysis is reliable and promising, and with an elevated diagnostic efficacy in identifying DR eyes.
Collapse
Affiliation(s)
- Enrico Borrelli
- Department of Ophthalmology, University Vita-Salute, Milan, Italy
| | - Riccardo Sacconi
- Department of Ophthalmology, University Vita-Salute, Milan, Italy
| | - Lea Querques
- Department of Ophthalmology, University Vita-Salute, Milan, Italy
| | - Marco Battista
- Department of Ophthalmology, University Vita-Salute, Milan, Italy
| | | | | |
Collapse
|
20
|
Scharf J, Freund KB, Sadda S, Sarraf D. Paracentral acute middle maculopathy and the organization of the retinal capillary plexuses. Prog Retin Eye Res 2020; 81:100884. [PMID: 32783959 DOI: 10.1016/j.preteyeres.2020.100884] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 07/09/2020] [Accepted: 07/10/2020] [Indexed: 02/07/2023]
Abstract
The retinal capillary vasculature serves the formidable role of supplying the metabolically active inner and middle retina. In the parafoveal region, the retinal capillary plexuses (RCP) are organized in a system of three capillary layers of varying retinal depths: the superficial capillary plexus (SCP), intermediate capillary plexus (ICP) and deep capillary plexus (DCP). While the dynamic flow through these plexuses is complex and not completely understood, current research points to a hybrid model that includes both parallel and in series components in which blood flows in a predominantly serial direction between the superficial vascular complex (SVC) and deep vascular complex (DVC). Each capillary plexus autoregulates independently, so that under most conditions the retinal vasculature supplies adequate blood flow and oxygen saturation at varying depths despite diverse environmental stressors. When the flow in the deep vascular complex (i.e. ICP and DCP) fails, an ischemic lesion referred to as Paracentral Acute Middle Maculopathy (PAMM) can be identified. PAMM is an optical coherence tomography (OCT) finding defined by the presence of a hyperreflective band at the level of the inner nuclear layer (INL) that indicates INL infarction caused by globally impaired perfusion through the retinal capillary system leading to hypoperfusion of the DVC or specifically the DCP. Patients present with an acute onset paracentral scotoma and typically experience a permanent visual defect. Lesions can be caused by a diverse set of local retinal vascular diseases and systemic disorders. PAMM is a manifestation of the retinal ischemic cascade in which the mildest forms of ischemia develop at the venular end of the DCP, i.e. perivenular PAMM, while more severe forms progress horizontally to diffusely involve the INL, and the most severe forms progress vertically to infarct the inner retina. Management is targeted toward the identification and treatment of related vasculopathic and systemic risk factors.
Collapse
Affiliation(s)
- Jackson Scharf
- Retina Disorders and Ophthalmic Genetics, Stein Eye Institute, University of California Los Angeles, Los Angeles, CA, United States; Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, United States
| | - K Bailey Freund
- Retina Department, Vitreous Retina Macula Consultants of New York, New York, NY, United States
| | - SriniVas Sadda
- Doheny Image Reading Center, Doheny Eye Institute, University of California Los Angeles (UCLA) Affiliated, Los Angeles, CA, United States; Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - David Sarraf
- Retina Disorders and Ophthalmic Genetics, Stein Eye Institute, University of California Los Angeles, Los Angeles, CA, United States; Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States; Greater Los Angeles VA Healthcare Center, Los Angeles, CA, United States.
| |
Collapse
|
21
|
Micevych PS, Soetikno BT, Fawzi AA. Perivenular Capillary Loss: An Early, Quantifiable Change in Macular Telangiectasia Type 2. Transl Vis Sci Technol 2020; 9:5. [PMID: 32818093 PMCID: PMC7396175 DOI: 10.1167/tvst.9.4.5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 11/08/2019] [Indexed: 01/18/2023] Open
Abstract
Purpose To evaluate differences in parafoveal vascular density surrounding arterioles and venules in type 2 macular telangiectasia (MacTel). Methods Thirty-seven eyes (20 subjects) diagnosed with MacTel and 16 healthy eyes (10 subjects) were imaged with optical coherence tomography angiography between March 2016 and June 2019 in this single-center, observational, cross-sectional study. Arterioles and venules were manually identified, and perivascular density was generated using a custom MATLAB code. The primary outcome measure was the ratio of periarteriolar to perivenular vascular density (arteriovenous [A/V] capillary ratio) in the superficial and deep capillary plexuses across MacTel stages. The main secondary outcome measures were overall parafoveal vascular density (VD), periarteriolar VD, and perivenular VD. Results In the superficial capillary plexus (SCP), the A/V capillary ratio was significantly higher in MacTel subjects than controls (0.914 vs. 0.892; P = 0.0044). The greatest differences occurred between controls and nonproliferative MacTel subjects without optical coherence tomography evidence of disease (P = 0.0055). A/V capillary ratios progressed in a nonlinear fashion with MacTel severity, increasing from nonproliferative disease (0.912) to intraretinal proliferative disease (0.931), then decreasing in subretinal proliferative disease (0.905). Parafoveal VD in the SCP was lower in MacTel subjects than controls only in subretinal proliferative disease (P = 0.0130). Conclusions The A/V capillary ratio of the SCP is a quantifiable metric of vascular pathology in MacTel that occurs earlier than decline in parafoveal VD. Elevated A/V capillary ratios in MacTel are consistent with an early, disproportionately perivenular disruption in the SCP. Translational Relevance Findings inform MacTel pathogenesis through revealing early perivenular capillary loss and offer a new quantitative metric for earliest stage MacTel.
Collapse
Affiliation(s)
- Paul S Micevych
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Brian T Soetikno
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Amani A Fawzi
- Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| |
Collapse
|