Assessment of a Novel Semi-Automated Algorithm for the Quantification of the Parafoveal Capillary Network
Zoi Kapsala,1 Aristofanis Pallikaris,1,2 Miltiadis K Tsilimbaris1,2 1Department of Neurology and Sensory Organs, Medical School, University of Crete, Heraklion, Greece; 2Vardinoyiannion Eye Institute of Crete, Medical School, University of Crete, Heraklion, GreeceCorrespondence: Zoi Kapsala, Departm...
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| Format: | Article |
| Language: | English |
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Dove Medical Press
2023-06-01
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| Series: | Clinical Ophthalmology |
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| Online Access: | https://www.dovepress.com/assessment-of-a-novel-semi-automated-algorithm-for-the-quantification--peer-reviewed-fulltext-article-OPTH |
| _version_ | 1827910362180091904 |
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| author | Kapsala Z Pallikaris A Tsilimbaris MK |
| author_facet | Kapsala Z Pallikaris A Tsilimbaris MK |
| author_sort | Kapsala Z |
| collection | DOAJ |
| description | Zoi Kapsala,1 Aristofanis Pallikaris,1,2 Miltiadis K Tsilimbaris1,2 1Department of Neurology and Sensory Organs, Medical School, University of Crete, Heraklion, Greece; 2Vardinoyiannion Eye Institute of Crete, Medical School, University of Crete, Heraklion, GreeceCorrespondence: Zoi Kapsala, Department of Neurology and Sensory Organs, Medical School, University of Crete, P.O. Box 2208, Heraklion, 71003, Greece, Email z.kapsala@med.uoc.grIntroduction: We present a novel semi-automated computerized method for the detection and quantification of parafoveal capillary network (PCN) in fluorescein angiography (FA) images.Material and Methods: An algorithm detecting the superficial parafoveal capillary bed in high-resolution grayscale FA images and creating a one-pixel-wide PCN skeleton was developed using MatLab software. In addition to PCN detection, capillary density and branch point density in two circular areas centered on the center of the foveal avascular zone of 500μm and 750μm radius was calculated by the algorithm. Three consecutive FA images with distinguishable PCN from 56 eyes from 56 subjects were used for analysis. Both manual and semi-automated detection of the PCN and branch points was performed and compared. Three different intensity thresholds were used for the PCN detection to optimize the method defined as mean(I)+0.05*SD(I), mean(I) and mean(I)-0.05*SD(I), where I is the grayscale intensity of each image and SD the standard deviation. Limits of agreement (LoA), intraclass correlation coefficient (ICC) and Pearson’s correlation coefficient (r) were calculated.Results: Using mean(I)-0.05*SD(I) as threshold the average difference in PCN density between semi-automated and manual method was 0.197 (0.316) deg− 1 at 500μm radius and 0.409 (0.562) deg− 1 at 750μm radius. The LoA were − 0.421 to 0.817 and − 0.693 to 1.510 deg− 1, respectively. The average difference of branch point density between semi-automated and manual method was zero for both areas; LoA were − 0.001 to 0.002 and − 0.001 to 0.001 branch points/degrees2, respectively. The other two intensity thresholds provided wider LoA for both metrics. The semi-automated algorithm showed great repeatability (ICC> 0.91 in the 500μm radius and ICC> 0.84 in the 750μm radius) for both metrics.Conclusion: This semi-automated algorithm seems to provide readings in agreement with those of manual capillary tracing in FA. Larger prospective studies are needed to confirm the utility of the algorithm in clinical practice.Keywords: detection, fluorescein angiography, parafoveal capillary network, quantification, semi-automated algorithm |
| first_indexed | 2024-03-13T01:49:44Z |
| format | Article |
| id | doaj.art-92eb8d43845d49a1b1c144623791897f |
| institution | Directory Open Access Journal |
| issn | 1177-5483 |
| language | English |
| last_indexed | 2024-03-13T01:49:44Z |
| publishDate | 2023-06-01 |
| publisher | Dove Medical Press |
| record_format | Article |
| series | Clinical Ophthalmology |
| spelling | doaj.art-92eb8d43845d49a1b1c144623791897f2023-07-02T19:49:18ZengDove Medical PressClinical Ophthalmology1177-54832023-06-01Volume 171661167484327Assessment of a Novel Semi-Automated Algorithm for the Quantification of the Parafoveal Capillary NetworkKapsala ZPallikaris ATsilimbaris MKZoi Kapsala,1 Aristofanis Pallikaris,1,2 Miltiadis K Tsilimbaris1,2 1Department of Neurology and Sensory Organs, Medical School, University of Crete, Heraklion, Greece; 2Vardinoyiannion Eye Institute of Crete, Medical School, University of Crete, Heraklion, GreeceCorrespondence: Zoi Kapsala, Department of Neurology and Sensory Organs, Medical School, University of Crete, P.O. Box 2208, Heraklion, 71003, Greece, Email z.kapsala@med.uoc.grIntroduction: We present a novel semi-automated computerized method for the detection and quantification of parafoveal capillary network (PCN) in fluorescein angiography (FA) images.Material and Methods: An algorithm detecting the superficial parafoveal capillary bed in high-resolution grayscale FA images and creating a one-pixel-wide PCN skeleton was developed using MatLab software. In addition to PCN detection, capillary density and branch point density in two circular areas centered on the center of the foveal avascular zone of 500μm and 750μm radius was calculated by the algorithm. Three consecutive FA images with distinguishable PCN from 56 eyes from 56 subjects were used for analysis. Both manual and semi-automated detection of the PCN and branch points was performed and compared. Three different intensity thresholds were used for the PCN detection to optimize the method defined as mean(I)+0.05*SD(I), mean(I) and mean(I)-0.05*SD(I), where I is the grayscale intensity of each image and SD the standard deviation. Limits of agreement (LoA), intraclass correlation coefficient (ICC) and Pearson’s correlation coefficient (r) were calculated.Results: Using mean(I)-0.05*SD(I) as threshold the average difference in PCN density between semi-automated and manual method was 0.197 (0.316) deg− 1 at 500μm radius and 0.409 (0.562) deg− 1 at 750μm radius. The LoA were − 0.421 to 0.817 and − 0.693 to 1.510 deg− 1, respectively. The average difference of branch point density between semi-automated and manual method was zero for both areas; LoA were − 0.001 to 0.002 and − 0.001 to 0.001 branch points/degrees2, respectively. The other two intensity thresholds provided wider LoA for both metrics. The semi-automated algorithm showed great repeatability (ICC> 0.91 in the 500μm radius and ICC> 0.84 in the 750μm radius) for both metrics.Conclusion: This semi-automated algorithm seems to provide readings in agreement with those of manual capillary tracing in FA. Larger prospective studies are needed to confirm the utility of the algorithm in clinical practice.Keywords: detection, fluorescein angiography, parafoveal capillary network, quantification, semi-automated algorithmhttps://www.dovepress.com/assessment-of-a-novel-semi-automated-algorithm-for-the-quantification--peer-reviewed-fulltext-article-OPTHdetectionfluorescein angiographyparafoveal capillary networkquantificationsemi-automated algorithm. |
| spellingShingle | Kapsala Z Pallikaris A Tsilimbaris MK Assessment of a Novel Semi-Automated Algorithm for the Quantification of the Parafoveal Capillary Network Clinical Ophthalmology detection fluorescein angiography parafoveal capillary network quantification semi-automated algorithm. |
| title | Assessment of a Novel Semi-Automated Algorithm for the Quantification of the Parafoveal Capillary Network |
| title_full | Assessment of a Novel Semi-Automated Algorithm for the Quantification of the Parafoveal Capillary Network |
| title_fullStr | Assessment of a Novel Semi-Automated Algorithm for the Quantification of the Parafoveal Capillary Network |
| title_full_unstemmed | Assessment of a Novel Semi-Automated Algorithm for the Quantification of the Parafoveal Capillary Network |
| title_short | Assessment of a Novel Semi-Automated Algorithm for the Quantification of the Parafoveal Capillary Network |
| title_sort | assessment of a novel semi automated algorithm for the quantification of the parafoveal capillary network |
| topic | detection fluorescein angiography parafoveal capillary network quantification semi-automated algorithm. |
| url | https://www.dovepress.com/assessment-of-a-novel-semi-automated-algorithm-for-the-quantification--peer-reviewed-fulltext-article-OPTH |
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