Repeatability and Reproducibility of Foveal Avascular Zone Area Measurement on Normal Eyes by Different Optical Coherence Tomography Angiography Instruments

Pilotto, Elisabetta; Frizziero, Luisa; Crepaldi, Anna; Dora, Enrico Della; Deganello, Davide; Longhin, Evelyn; Convento, Enrica; Parrozzani, Raffaele; Midena, Edoardo

doi:10.1159/000485463

Cited by 33 publications

(26 citation statements)

References 16 publications

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“…There are several published reports on repeatability of FAZ size measurement using OCTA in normal eyes with variable findings depending on how FAZ size is measured and what machine is used. [5][6][7][8][9][10] Most studies measured FAZ by segmenting the superficial and/or deep retinal capillary layers separately and showed good repeatability using the same instrument (intra-instrument) but some variability using machines made by different vendors (interinstrument). Repeatability of the FAZ measurement using OCTA in eyes with fundus pathology would be more clinically relevant but has not been studied in detail.…”

Section: Introductionmentioning

confidence: 99%

<p>Factors Affecting Repeatability of Foveal Avascular Zone Measurement Using Optical Coherence Tomography Angiography in Pathologic Eyes</p>

Buffolino¹,

Vu²,

Amin³

et al. 2020

OPTH

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Purpose: To determine factors that may affect the repeatability of the foveal avascular zone (FAZ) measurement obtained using optical coherence tomography angiography (OCTA) including instrument type, image segmentation, image quality, and fundus pathology. Patients and Methods: This prospective single-center study enrolled 43 subjects (85 eyes) with retinal vasculopathy, macular edema, optic pathology or normal contralateral eye. The macula was imaged twice using Optovue Angiovue and once using Cirrus Angioplex to obtain 3x3mm OCTA images centered on the fovea. Images were generated by the same operator within 30 mins. The FAZ size for the entire retinal thickness ("overall FAZ") was measured automatically using the OCTA software. The FAZ size of the superficial and deep retinal vascular plexus layers was measured manually using the enface OCTA images of the segmented layers and Image J analysis. Intraclass correlations coefficient (ICC) was calculated to determine repeatability. Results: For the overall FAZ measurement, repeatability was excellent (ICC 0.953 right eye, 0.938, left eye) using the same machine (intra-instrument) and somewhat lower but still good to excellent (ICC 0.803 right eye, 0.917 left eye) using machines made by different vendors (inter-instrument). For the segmented layers, intra-instrument repeatability of FAZ measurement was excellent (ICC > 0.95) for both plexus layers. Inter-instrument repeatability was good for the superficial plexus layer (ICC 0.86 right eye, 0.88 left eye) but reduced for the deep plexus layer (ICC 0.63 right eye, 0.57 left eye). Suboptimal image quality and presence of retinal vasculopathy and macular edema tended to reduce FAZ repeatability but to a lesser degree. Conclusion: Inter-and intra-instrument repeatability of the overall FAZ measurement was high using commercial OCTA instruments and only mildly reduced by suboptimal image quality and fundus pathology. For segmented layers, intra-instrument repeatability remained high but inter-instrument repeatability was reduced for the deep plexus layer.

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Section: Introductionmentioning

confidence: 99%

<p>Factors Affecting Repeatability of Foveal Avascular Zone Measurement Using Optical Coherence Tomography Angiography in Pathologic Eyes</p>

Buffolino¹,

Vu²,

Amin³

et al. 2020

OPTH

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show abstract

“…Due to its high axial resolution, OCTA can visualize multiple layers of micro-retinal vasculature that cannot be analyzed using fluorescein angiography [8]. In addition, OCTA allows detection and measurement of foveal avascular zone (FAZ) area, which can be affected by several retinal diseases [9]. Since the FAZ is surrounded by interconnected capillaries, it is affected by changes in the retinal microvasculature of the macula, which is one of the most important parameters in central retinal circulation [10].…”

mentioning

confidence: 99%

Repeatability of Manual Measurement of Foveal Avascular Zone Area in Optical Coherence Tomography Angiography Images in High Myopia

Lee

Baek

et al. 2020

Korean J Ophthalmol

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This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses /by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 113 Original ArticleHigh myopia is one of the most common causes of visual loss and is especially common in Asia. The prevalence of myopia is as high as 80% in Asia and 25% in other regions [1][2][3]. Severe myopia can increase the risk of glaucoma, retinal detachment, chorioretinal atrophy, and lacquer cracks. Therefore, high myopia patients, even those without other ophthalmic diseases, should not be overlooked [4]. In myopia, the sclera and chorioretina are enlarged to reduce the thickness of the macular choroid, which may result in delayed choroidal circulation to induce an ischemic state of Purpose: To analyze the repeatability of manual measurement of foveal avascular zone (FAZ) area in an optical coherence tomography angiography (OCTA) image in high myopia. Methods: This study comprised patients with high myopia and controls. Two consecutive FAZ areas of the superficial and deep capillary plexus were obtained using OCTA. The intraclass correlation coefficient (ICC) and coefficient of variation (CV) were assessed, and univariate and multivariate generalized linear mixed models were conducted to identify factors related to repeatability. Results: Thirty eyes with high myopia and 34 eyes of healthy subjects were included in the study. The mean age in high myopia and control subjects was 55.5 and 60.8 years, respectively, the mean spherical equivalent was -9.98 and -0.55 diopters, and the mean axial length was 28.0 and 23.9 mm. The ICCs of FAZ area of the superficial capillary plexus (SCP) were 0.891 and 0.919, while the CVs were 8.8% and 8.5%. In measurement of the deep capillary plexus, the ICCs were 0.788 and 0.907, while the CVs were 11.2% and 11.0%, which were acceptable but exhibited lower repeatability than those of SCP. Multivariate analyses showed that older age (p = 0.030) and greater axial length (p = 0.005) were significantly associated with lower repeatability of SCP FAZ area measurements. In addition, greater axial length (p = 0.044) was a significant factor for lower repeatability of deep capillary plexus FAZ area measurements. Conclusions: Manual measurement of FAZ area using OCTA exhibited relatively good repeatability for high myopia. Age and axial length affected repeatability and should be considered when analyzing FAZ areas in high myopia patients.

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“…The change of the FAZ is critical in many pathological conditions [15][16][17], and the reproducibility of FAZ measurements in the evaluation of the FAZ is important. Previous studies [12,18,19] evaluated the reproducibility of FAZ measurements obtained by different OCTA devices and reported excellent reproducibility and repeatability. However, these results were based on the 3 × 3 mm scan protocols, as few studies have assessed the reproducibility of FAZ measurements obtained by the 6 × 6 mm protocol [7].…”

Section: Discussionmentioning

confidence: 99%

“…Since OCTA is still a relatively new imaging technique, the reproducibility of quantitative metrics obtained by OCTA must be assessed before these data can be confidently interpreted in clinical research and practice. The reproducibility of the FAZ area and macular retinal vasculature measured by different types of OCTA devices have been conducted in some studies [11][12][13]. Corvi et al [10] compared 7 different OCTA devices and found that it was nearly impossible to compare these instruments and that the set of measurements produced by various instruments were not interchangeable.…”

Section: Introductionmentioning

confidence: 99%

Reproducibility of Foveal Avascular Zone and Superficial Macular Retinal Vasculature Measurements in Healthy Eyes Determined by Two Different Scanning Protocols of Optical Coherence Tomography Angiography

et al. 2019

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Purpose: To assess the reproducibility of quantitative measurements of the foveal avascular zone (FAZ) and retinal vasculature determined by different scanning protocols of optical coherence tomography angiography (OCTA) in healthy volunteers. Method: All participants were scanned by two trained operators using an AngioPlex OCTA. Both angiography protocols (6 × 6 mm and 3 × 3 mm) were performed three times on the same eye by operator A and one additional time by operator B. The FAZ area and perimeter, retinal vessel length density (VLD) and perfusion density (PD) of different regions were analysed. Results: Fifty-two eyes from 52 subjects were recruited for this study. The repeated measurements of FAZ, VLD, and PD parameters obtained by the same operator, as well as by different operators, were not significantly different when the same protocol was used (p > 0.05). The intra-and inter-operator intraclass correlation coefficients (ICCs) of the FAZ and central VLD and PD parameters (range, 0.99-0.95) were better than the intra-and inter-operator ICCs of VLD and PD in the inner and outer rings (range, 0.86-0.90). The FAZ area, perimeter, and VLDs obtained by the 3 × 3 mm protocol were larger than those obtained by the 6 × 6 mm protocol (p < 0.01), but the PDs obtained by the 3 × 3 mm protocol were smaller than those obtained by the 6 × 6 mm protocol (p < 0.001). All of the corresponding parameters obtained by the two protocols were positively correlated (r = 0.64-0.99, p < 0.001). Conclusion: Both the 6 × 6 and 3 × 3 mm protocols of the AngioPlex OCTA provide good reproducibility for assessing the FAZ and superficial retinal vasculature. However, the values obtained by these different protocols cannot be compared directly.

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Repeatability and Reproducibility of Foveal Avascular Zone Area Measurement on Normal Eyes by Different Optical Coherence Tomography Angiography Instruments

Cited by 33 publications

References 16 publications

<p>Factors Affecting Repeatability of Foveal Avascular Zone Measurement Using Optical Coherence Tomography Angiography in Pathologic Eyes</p>

<p>Factors Affecting Repeatability of Foveal Avascular Zone Measurement Using Optical Coherence Tomography Angiography in Pathologic Eyes</p>

Repeatability of Manual Measurement of Foveal Avascular Zone Area in Optical Coherence Tomography Angiography Images in High Myopia

Reproducibility of Foveal Avascular Zone and Superficial Macular Retinal Vasculature Measurements in Healthy Eyes Determined by Two Different Scanning Protocols of Optical Coherence Tomography Angiography

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