TY - JOUR
T1 - Visualization of radial peripapillary capillaries using optical coherence tomography angiography
T2 - The effect of image averaging
AU - Mo, Shelley
AU - Phillips, Erika
AU - Krawitz, Brian D.
AU - Garg, Reena
AU - Salim, Sarwat
AU - Geyman, Lawrence S.
AU - Efstathiadis, Eleni
AU - Carroll, Joseph
AU - Rosen, Richard B.
AU - Chui, Toco Y.P.
N1 - Funding Information:
This work was funded by the Marrus Family Foundation (RBR), Bendheim-Lowenstein Family Foundation (RBR), Wise Family Foundation (RBR), New York Eye and Ear Chairman's Research Fund (RBR), Violett Fund (RBR), and Milbank Foundation (RBR). Research reported in this publication was supported by the Eye Institute of the National Institutes of Health under award numbers P30EY001931 (JC) and R01EY024969 (JC). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Publisher Copyright:
© 2017 Mo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
PY - 2017/1
Y1 - 2017/1
N2 - Objectives: To assess the effect of image registration and averaging on the visualization and quantification of the radial peripapillary capillary (RPC) network on optical coherence tomography angiography (OCTA). Methods: Twenty-two healthy controls were imaged with a commercial OCTA system (AngioVue, Optovue, Inc.). Ten 10×10° scans of the optic disc were obtained, and the most superficial layer (50-μm slab extending from the inner limiting membrane) was extracted for analysis. Rigid registration was achieved using ImageJ, and averaging of each 2 to 10 frames was performed in five ∼2×2° regions of interest (ROI) located 1° from the optic disc margin. The ROI were automatically skeletonized. Signal-to-noise ratio (SNR), number of endpoints and mean capillary length from the skeleton, capillary density, and mean intercapillary distance (ICD) were measured for the reference and each averaged ROI. Repeated measures analysis of variance was used to assess statistical significance. Three patients with primary open angle glaucoma were also imaged to compare RPC density to controls. Results: Qualitatively, vessels appeared smoother and closer to histologic descriptions with increasing number of averaged frames. Quantitatively, number of endpoints decreased by 51%, and SNR, mean capillary length, capillary density, and ICD increased by 44%, 91%, 11%, and 4.5% from single frame to 10-frame averaged, respectively. The 10-frame averaged images from the glaucomatous eyes revealed decreased density correlating to visual field defects and retinal nerve fiber layer thinning. Conclusions: OCTA image registration and averaging is a viable and accessible method to enhance the visualization of RPCs, with significant improvements in image quality and RPC quantitative parameters. With this technique, we will be able to non-invasively and reliably study RPC involvement in diseases such as glaucoma.
AB - Objectives: To assess the effect of image registration and averaging on the visualization and quantification of the radial peripapillary capillary (RPC) network on optical coherence tomography angiography (OCTA). Methods: Twenty-two healthy controls were imaged with a commercial OCTA system (AngioVue, Optovue, Inc.). Ten 10×10° scans of the optic disc were obtained, and the most superficial layer (50-μm slab extending from the inner limiting membrane) was extracted for analysis. Rigid registration was achieved using ImageJ, and averaging of each 2 to 10 frames was performed in five ∼2×2° regions of interest (ROI) located 1° from the optic disc margin. The ROI were automatically skeletonized. Signal-to-noise ratio (SNR), number of endpoints and mean capillary length from the skeleton, capillary density, and mean intercapillary distance (ICD) were measured for the reference and each averaged ROI. Repeated measures analysis of variance was used to assess statistical significance. Three patients with primary open angle glaucoma were also imaged to compare RPC density to controls. Results: Qualitatively, vessels appeared smoother and closer to histologic descriptions with increasing number of averaged frames. Quantitatively, number of endpoints decreased by 51%, and SNR, mean capillary length, capillary density, and ICD increased by 44%, 91%, 11%, and 4.5% from single frame to 10-frame averaged, respectively. The 10-frame averaged images from the glaucomatous eyes revealed decreased density correlating to visual field defects and retinal nerve fiber layer thinning. Conclusions: OCTA image registration and averaging is a viable and accessible method to enhance the visualization of RPCs, with significant improvements in image quality and RPC quantitative parameters. With this technique, we will be able to non-invasively and reliably study RPC involvement in diseases such as glaucoma.
UR - http://www.scopus.com/inward/record.url?scp=85009107972&partnerID=8YFLogxK
U2 - 10.1371/journal.pone.0169385
DO - 10.1371/journal.pone.0169385
M3 - Article
C2 - 28068370
AN - SCOPUS:85009107972
SN - 1932-6203
VL - 12
JO - PLoS ONE
JF - PLoS ONE
IS - 1
M1 - e0169385
ER -