Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Jun 30;18(6):e0287783.
doi: 10.1371/journal.pone.0287783. eCollection 2023.

Retinal capillary and choriocapillaris assessment using a beam modifier optical coherence tomography angiography module to increase lateral optical resolution

Sophie Bonnin  1   2 , Sophie Kubach  3 , Pierre Négrier  1 , Warren Lewis  3 , Luis de Sisternes  3 , Aude Couturier  1 , Ali Erginay  1 , Marco Nassisi  4   5 , Stephanie Magazzeni  3 , Carlo Lavia  6 , Ramin Tadayoni  1   2
Affiliations

Retinal capillary and choriocapillaris assessment using a beam modifier optical coherence tomography angiography module to increase lateral optical resolution

Sophie Bonnin et al. PLoS One. .

Abstract

Purpose: To assess a new optical coherence tomography angiography (OCTA) technology and its contribution to retinal vascularization and choriocapillaris (CC) exploration.

Methods: A new module, named "Beam expander" (BE), which increases the lateral resolution of OCTA, was used in combination with a prototype software in the PLEX® Elite 9000 Swept-Source OCT instrument (ZEISS, Dublin, CA). This prospective study involved 22 healthy subjects imaged with and without BE. Qualitative analysis of superficial capillary plexus (SCP), deep capillary complex (DCC) retinal and CC angiograms were performed. Perfusion density (PD), vessel density (VD), and foveal avascular zone (FAZ) measurements were also compared.

Results: Qualitative analysis of single SCP and DCC retinal angiograms acquired with BE showed significantly better vessel sharpness (respectively, p = 0.0002, and p<0.0001), and greater peripheral image quality (p = 0.028 and p = 0.007) compared to standard OCTA images. Mean VD of whole retina single scans was significantly higher for BE angiograms compared to classic angiograms (28.16 ±1.29 mm-1 and 23.36 ±0.92 mm-1, respectively, p<0.0001). Repeatability of VD, PD and FAZ raw size were found to be similar between the two methods (intraclass correlation coefficient: 0.671, 0.604 and 0.994 with BE versus 0.764, 0.638 and 0.990 without BE). CC image quality was found to be significantly superior with BE, and flow deficits were more visible in all BE scans compared to standard scans.

Conclusions: An increase in lateral resolution of the OCT beam resulted in higher quality of retinal and choriocapillaris OCTA images in healthy subjects. These results provide significant insights into the future OCTA imaging enhancements.

PubMed Disclaimer

Conflict of interest statement

I have read the journal’s policy and the authors of this manuscript have the following competing interests: Warren Lewis and Luis de Sisternes are employeed of Zeiss. Sophie Kubach was employeed of Zeiss. Dr. Négrier, Dr Erginay, Dr Nassisi and Dr Lavia have nothing to disclose. Dr. Bonnin reports personal fees from Allergan, outside the submitted work. Dr. Couturier reports personal fees from Allergan, Bayer and Novartis, outside the submitted work. Prof. Tadayoni reports personal fees from Novartis, Bayer, Roche, Genentech, Allergan, Zeiss, Alcon and Oculis, outside the submitted work. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Figures

Fig 1
Fig 1. Retinal image quality criteria (3x3-mm angiograms) in the superficial capillary plexus (SCP) and deep capillary complex (DCC).
A.B. Vessel sharpness, SCP (A: 0 = poor; B: 2 = good); C.D. FAZ visibility, SCP (C: 0 = poor; D: 2 = good); E.F. Artery-vein distinction, SCP (E: 0 = poor; F: 2 = good); G.H. Vortex visibility, DCC (G: poor; H: 2 = good); I.J. Peripheral image quality, SCP (I: poor; J: 2 = good); K.L. Segmentation errors, DCC (K: poor; L: 2 = good); M.N. Background noise, SCP (M: poor; N: 2 = good); O.P. Motion artifacts, SCP (G: poor; H: 2 = good). The orange arrow on image O is showing the discontinuity of vessel course (motion artifact).
Fig 2
Fig 2. Choriocapillaris image quality assessment (3x3-mm angiograms).
The overall image quality seems greater in B compared to A with higher uniformity and capillary sharpness, and fewer artifacts (for example, one projection artifact is showed by the white circle) (A: medium overall image quality; B: good overall image quality). The visualization of flow voids is enhanced in D compared to C with a better contrast in flow and no-flow areas (C: medium visualization of flow voids; D: good visualization of flow voids).
Fig 3
Fig 3
Comparison of quantitative measurements in 3x3-mm angiograms (A, B, C, D) and 2.25x2.25-mm angiograms (D, F, G, H). A and E: Superficial capillary plexus angiograms. B and F: Perfusion trace allowing measuring perfusion density, and showing the inner ring used to compare the measurements. This inner ring is delimited by a 2-mm diameter circle, and a 1-mm diameter circle (in red). C and G: Vessel trace allowing measuring perfusion density. D and H: The foveal avascular zone is delineated in red.
Fig 4
Fig 4
Comparison between 3x3-mm standard angiograms (A, D), the same 3x3 mm angiograms cropped to a 2.25x2.25 mm field of view (B, E) and 2.25x2.25-mm angiograms (C, F) acquired with the Beam Expander (BE). A, B and C: Superficial capillary plexus; D, E and F: Deep capillary complex (DCC). The vessels are more continuous (as circled on the images A, B and C) in the BE scans, resulting in a higher uniformity of image quality. Some vessels are more visible (white arrow), contributing to improve the visualization of the foveal avascular zone. The radial organization of the vortex in the DCC is better defined in F than in E (white asterisk).
Fig 5
Fig 5. Comparison of choriocapillaris images from the same healthy subject.
A. 3x3-mm standard angiogram. B. Same 3x3-mm angiogram cropped to match the scan area of the corresponding 2.25x2.25-mm angiogram. C. 2.25x2.25-mm angiogram acquired with the Beam Expander and registered using the superficial slab of the to the 3x3 mm angiogram for comparison. The flow voids are more distinct in C and the capillary structures are better defined.
Fig 6
Fig 6
Comparison between single (A, C, E) and average (B, D, E) 2.25x2.25-mm angiograms (performed with Beam Expander). A and B: Superficial capillary plexus (SCP); C and D: Deep capillary complex; E and F: Choriocapillaris.
See this image and copyright information in PMC

References

    1. Spaide RF, Fujimoto JG, Waheed NK, Sadda SR, Staurenghi G. Optical coherence tomography angiography. Prog Retin Eye Res. 2018;64: 1–55. doi: 10.1016/j.preteyeres.2017.11.003 - DOI - PMC - PubMed
    1. Spaide RF, Klancnik JM, Cooney MJ. Retinal Vascular Layers Imaged by Fluorescein Angiography and Optical Coherence Tomography Angiography. JAMA Ophthalmology. 2015;133: 45. doi: 10.1001/jamaophthalmol.2014.3616 - DOI - PubMed
    1. Kashani AH, Chen C-L, Gahm JK, Zheng F, Richter GM, Rosenfeld PJ, et al.. Optical coherence tomography angiography: A comprehensive review of current methods and clinical applications. Prog Retin Eye Res. 2017;60: 66–100. doi: 10.1016/j.preteyeres.2017.07.002 - DOI - PMC - PubMed
    1. Wang RK. Optical Microangiography: A Label Free 3D Imaging Technology to Visualize and Quantify Blood Circulations within Tissue Beds in vivo. IEEE J Sel Top Quantum Electron. 2010;16: 545–554. doi: 10.1109/JSTQE.2009.2033609 - DOI - PMC - PubMed
    1. Bonnin S, Mané V, Couturier A, Julien M, Paques M, Tadayoni R, et al.. NEW INSIGHT INTO THE MACULAR DEEP VASCULAR PLEXUS IMAGED BY OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY. Retina (Philadelphia, Pa). 2015;35: 2347–2352. doi: 10.1097/IAE.0000000000000839 - DOI - PubMed