Improving visualization and quantitative assessment of choriocapillaris with swept source OCTA through registration and averaging applicable to clinical systems

PurposeTo compare anterior segment optical coherence tomography angiography (AS-OCTA) systems in delineating normal iris vessels and iris neovascularisation (NVI) in eyes with pigmented irides.MethodsProspective study from January 2019 to June 2019 of 10 consecutive patients with normal pigmented iris, had AS-OCTA scans with a described illumination technique, before using the same protocol in five eyes with NVI (clinical stages 1–3). All scans were sequentially performed using a spectral-domain OCTA (SD-OCTA), and a swept-source OCTA (SS-OCTA, Plex Elite 9000). Images were graded by two masked observers for visibility, artefacts and NVI characteristics. The main outcome measure was iris vessel density measurements comparing SS-OCTA and SD-OCTA systems.ResultsThe median age of subjects was 28 (20–35) years, and 50% were female. The paired mean difference of iris vessel density measurements was 11.7 (95% CI 14.7 to 8.1; p=0.002), SS-OCTA detecting more vessels than SD-OCTA. The inter-rater reliability for artefact score (κ=0.799, p<0.001) and visibility score (κ=0.722; p<0.001) were substantial. Both AS-OCTA systems were able to detect NVI vessels with a fair agreement (κ=0.588), with clearer NVI characteristics in stage 1/2 compared to stage 3 NVI (mean difference NVI score: 2.7±0.4, p=0.009).ConclusionThe SS-OCTA was better able to delineate iris vessels in normal pigmented irides compared to SD-OCTA. Both AS-OCTA systems identified NVI characteristics based on its atypical configuration or location, but further improvements are needed to allow for more accurate objective, serial quantification for clinical use.

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Effect of vessel enhancement filters on the repeatability of measurements obtained from widefield swept-source optical coherence tomography angiography

Scientific Reports ◽

10.1038/s41598-020-79281-3 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Jimmy Hong ◽

Mengyuan Ke ◽

Bingyao Tan ◽

Amanda Lau ◽

Damon Wong ◽

...

Keyword(s):

Peripheral Region ◽

Swept Source ◽

Capillary Plexus ◽

Flow Void ◽

Vessel Enhancement ◽

Good Repeatability ◽

Perfusion Density ◽

Superficial Capillary Plexus ◽

Large Vessels ◽

Swept Source Octa

AbstractWe assessed the inter-visit repeatability of 15 × 9-mm2 swept-source OCTA (SS-OCTA; PLEX Elite 9000, Carl Zeiss Meditec) metrics in 14 healthy participants. We analysed the perfusion density (PD) of large vessels, superficial capillary plexus (SCP), and deep capillary plexus (DCP) as well as choriocapillaris flow voids in 2 different regions: the macular region and peripheral region. Also, retinal plexus metrics were processed further using different filters (Hessian, Gabor and Bayesian) while choriocapillaris flow voids were calculated with 1 and 1.25 standard deviation (SD) thresholding algorithms. We found excellent repeatability in the perfusion densities of large vessels (ICC > 0.96). Perfusion densities varied with different filters in the macular region (SCP: 24.12–38.57% and DCP: 25.16–38.50%) and peripheral (SCP: 30.52–39.84% and DCP: 34.19–41.60%) regions. The ICCs were lower in the macular region compared to the peripheral region and lower for DCP than for SCP. For choriocapillaris flow voids, the 1.25 SD threshold resulted in fewer flow voids, while a good ICC (ICC > 0.81) was achieved using either threshold settings for flow void features in both regions. Our results suggest good repeatability of widefield SS-OCTA for the measurements of retinal perfusion density and choriocapillaris flow voids, but measurements from different filters should not be interchanged.

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Longitudinal study of serpiginous choroiditis and serpiginous like choroiditis using wide field OCT angiography

European Journal of Ophthalmology ◽

10.1177/11206721211028529 ◽

2021 ◽

pp. 112067212110285

Author(s):

Manpreet Brar ◽

Mansi Sharma ◽

SPS Grewal ◽

Dilraj Grewal ◽

Mangat Ram Dogra

Keyword(s):

Fundus Autofluorescence ◽

Case Series ◽

Response To Treatment ◽

Wide Field ◽

Swept Source ◽

Morphological Variations ◽

Serpiginous Choroiditis ◽

Flow Void ◽

Swept Source Octa

Purpose: To assess the ability of wide field Swept Source OCTA (SS-OCTA) imaging to detect morphological variations in Serpiginous Choroiditis (SC) and Serpiginous Like Choroiditis (SLC) in response to treatment and also analyze these findings quantitatively using Image J software. Methods: Retrospective observational case series of nine eyes with clinical diagnosis of active SC and SLC, who underwent SS-OCTA and fundus autofluorescence (FAF) imaging at baseline and each follow up visit till 6 months. Morphological analysis was done by two independent graders and quantitative analysis to measure the size and intensity of lesion was done using publicly available Image J software at baseline and each follow up visit. Design: Retrospective observational case series. Results: Using SS-OCTA, all the active lesions followed a characteristic healing pattern. Active lesions appear well defined hypo flow void patches and as healing progressed, lesion became more ill-defined and iso-hyper- intense. Significant increase in mean intensity of the lesion could be apparent after 1 and 6 month of treatment. There was reduction in the size of lesions during follow up however this difference was not statistically significant. Conclusion: SS-OCTA could be a useful noninvasive tool to study the treatment response in SC/SLC both morphologically as well as quantitatively. Quantitative parameters need to be designed in further research studies to aid in uniform management and follow up of uveitis cases.

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Swept-Source OCTA Imaging of a Presumed Solitary Circumscribed Retinal Astrocytic Proliferation

Ophthalmic Surgery Lasers and Imaging Retina ◽

10.3928/23258160-20210330-08 ◽

2021 ◽

Vol 52 (4) ◽

pp. 232-235

Author(s):

Meryem Filali Ansary ◽

Francesca Amoroso ◽

Raimondo Forte ◽

Salomon Y. Cohen ◽

Alexandra Miere ◽

...

Keyword(s):

Swept Source ◽

Swept Source Octa

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Swept-source OCT angiography imaging of the macular capillary network in glaucoma

British Journal of Ophthalmology ◽

10.1136/bjophthalmol-2016-309816 ◽

2017 ◽

Vol 102 (4) ◽

pp. 515-519 ◽

Cited By ~ 15

Author(s):

Handan Akil ◽

Vikas Chopra ◽

Mayss Al-Sheikh ◽

Khalil Ghasemi Falavarjani ◽

Alex S Huang ◽

...

Keyword(s):

Layer Thickness ◽

Open Angle Glaucoma ◽

Retinal Nerve Fibre Layer ◽

Capillary Network ◽

Mean Deviation ◽

Inner Plexiform Layer ◽

Swept Source ◽

Normal Individuals ◽

The Mean ◽

Swept Source Octa

PurposeTo evaluate the macular capillary network density of superficial and deep retinal layers (SRL/DRL) by swept-source optical coherence tomography angiography (OCTA) in patients with primary open angle glaucoma (POAG) and to compare the results with those of normal subjects.MethodIn this prospective study, 24 eyes of 24 normal individuals and 24 eyes of 24 patients with mild to moderate POAG underwent fovea centred 6×6 mm cube macular OCTA imaging by a swept-source OCTA device (Triton, Topcon, Tokyo, Japan). Quantitative analysis of the retinal vasculature was performed by assessing vessel density (VD) as the ratio of the retinal area occupied by vessels at the SRL and DRL.ResultsThe mean VD (ratio) at the SRL and DRL was statistically significantly lower in patients with POAG (SRL, p<0.001; DRL, p<0.001). In the SRL, the mean±SD VD ratio was 0.34±0.05 in patients with POAG and 0.40±0.02 in normal individuals (p<0.001). In the DRL, the mean (SD) ratio was 0.37±0.05 in patients with POAG and 0.43±0.02 in normal individuals (p<0.001). The mean VD at the SRL was significantly correlated with ganglion cell inner plexiform layer thickness (r=0.42, p=0.04) but not with visual field mean deviation (r=0.4, p=0.06) and retinal nerve fibre layer thickness (r=0.5, p=0.06). The mean VD at the DRL did not show significant correlation with any other glaucoma parameter (p>0.05).ConclusionThe assessment of macular VD by swept-source OCTA may offer additional information for detection of glaucoma.

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