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Angeli O, Hajdu D, Jeney A, Czifra B, Nagy BV, Balazs T, Nemoda DJ, Somfai GM, Nagy ZZ, Peto T, Schneider M. Qualitative and quantitative comparison of two semi-manual retinal vascular density analyzing methods on optical coherence tomography angiography images of healthy individuals. Sci Rep 2023; 13:16981. [PMID: 37813968 PMCID: PMC10562399 DOI: 10.1038/s41598-023-44234-z] [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: 03/01/2023] [Accepted: 10/05/2023] [Indexed: 10/11/2023] Open
Abstract
The aim of this study was to evaluate qualitative and quantitative differences in vascular density analysis of an established and a novel alternative for post-processing on optical coherence tomography angiography (OCTA) images in healthy individuals. OCTA examinations of 38 subjects were performed. After extracting the images, two semi-manual post-processing techniques, the already established Mexican hat filtering (MHF) and an alternative, the Shanbhag thresholding (ST) were applied. We assessed Vessel Density (VD), Skeleton Density (SkD) and Vessel Diameter Index (VDI). We analyzed the results in order to establish similarities or potentially relevant differences. Regarding SkD and VD, MHF generally gave higher values than ST. Simultaneously, mean values were also predominantly higher by MHF; however, standard deviations (SD) were higher by ST (range [mean ± SD]: 0.054 ± 0.038 to 0.134 ± 0.01 and 0.134 ± 0.095 to 0.362 ± 0.028 vs 0.012 ± 0.014 to 0.087 ± 0.03 and 0.039 ± 0.047 to 0.4 ± 0.095 for SkD and VD with MHF vs SkD and VD with ST, respectively). Values of VDI were considerably higher with ST than with MHF, while standard deviation was still significantly higher with ST (range [mean ± SD]: 2.459 ± 0.144 to 2.71 ± 0.084 and 2.983 ± 0.929 to 5.19 ± 1.064 for VDI with MHF and ST, respectively). The noise level reduction of the two methods were almost identical (noise levels: 65.8% with MHT and 65.24% with ST). Using MHF, the vascular network gets more fragmented by an average of 40% compared to ST. Both methods allow the segmentation of the vascular network and the examination of vascular density parameters, but they produce largely inconsistent results. To determine if these inconsistent results are clinically meaningful, and which method is more suitable for clinical use, our results provide further evidence that detailed understanding of the image analysis method is essential for reliable decision making for patients with retinal pathology. For longitudinal monitoring, use of the same image processing method is recommended.
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Affiliation(s)
- Orsolya Angeli
- Department of Ophthalmology, Semmelweis University, Budapest, Hungary
| | - Dorottya Hajdu
- Department of Ophthalmology, Semmelweis University, Budapest, Hungary
- Department of Ophthalmology and Optometry, Vienna Clinical Trial Center (VTC), Medical University of Vienna, Vienna, Austria
| | - Aniko Jeney
- Department of Ophthalmology, Flor Ferenc Hospital, Kistarcsa, Hungary
| | - Balint Czifra
- Department of Mechatronics, Optics and Mechanical Engineering, Budapest University of Technology and Economics, Budapest, Hungary
| | - Balazs Vince Nagy
- Department of Mechatronics, Optics and Mechanical Engineering, Budapest University of Technology and Economics, Budapest, Hungary
| | | | | | - Gabor Mark Somfai
- Department of Ophthalmology, Semmelweis University, Budapest, Hungary
- Department of Ophthalmology, Stadtspital Zurich, Zurich, Switzerland
- Spross Research Institute, Zurich, Switzerland
| | - Zoltan Z Nagy
- Department of Ophthalmology, Semmelweis University, Budapest, Hungary
| | - Tunde Peto
- Centre for Public Health, Queen's University Belfast, Belfast, UK
- Research Unit of Ophthalmology, Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Miklos Schneider
- Department of Ophthalmology, Semmelweis University, Budapest, Hungary.
- Department of Ophthalmology, Rigshospitalet Glostrup, Valdemar Hansens Vej 1-23, 2600, Glostrup, Denmark.
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Blanco-Hernández DMR, Somilleda-Ventura SA, Chávez-Herrera R, Colas-Calvere MG, Lima-Gómez V. Compensatory contribution of retinal larger vessels to perfusion density in diabetics without retinopathy. Sci Rep 2022; 12:329. [PMID: 35013324 PMCID: PMC8748763 DOI: 10.1038/s41598-021-02554-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 11/10/2021] [Indexed: 11/25/2022] Open
Abstract
Vessel and perfusion densities may decrease before diabetic retinopathy appears; it is unknown whether these changes affect the contribution of vessel density to perfusion density. This was a non-experimental, comparative, prospective, cross-sectional study in non-diabetic subjects (group 1) and diabetics without retinopathy (group 2). Vessel and perfusion densities in the superficial capillary plexus were compared between groups at the center, inner, and full regions and by field (superior, temporal, inferior, nasal) using optical coherence tomography angiography. Coefficients of determination (R2) between vessel and perfusion densities were calculated to find the contribution of larger retinal vessels to perfusion density. Percent differences were used to evaluate the contribution of these vessels to perfusion density in a regression model. There were 62 participants, 31 eyes by group; vessel and perfusion densities as well as the coefficients of determination between them were lower in group 2, especially in the nasal field (R2 0.85 vs. 0.71), which showed a higher contribution of larger retinal vessels to perfusion density. The regression model adjusted to a quadratic equation. In diabetics without retinopathy the contribution of vessel density to perfusion density may decrease; a low vessel density may increase the contribution of larger retinal vessels to perfusion density.
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Affiliation(s)
| | | | - Rebeca Chávez-Herrera
- Medicine School, Universidad Autonoma de Ciudad Juarez, 32315, Ciudad Juarez, Mexico
| | | | - Virgilio Lima-Gómez
- Ophthalmology Service, Hospital Juarez de Mexico, 07760, Mexico City, Mexico.
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