The Utility of Frame Averaging for Automated Algorithms in Analyzing Retinal Vascular Biomarkers in AngioVue OCTA

This study proposes an optical coherence tomography angiography (OCTA) frame-averaging method and investigates the effects of the number of frames acquired and averaged on metrics quantifying the foveal avascular zone (FAZ), vessel morphology, and parafoveal intercapillary area (PICA). Ten OCTA fram...

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Bibliographic Details
Published in:Translational vision science & technology Vol. 8; no. 1; p. 10
Main Authors: Schmidt, Taly Gilat, Linderman, Rachel E., Strampe, Margaret R., Chui, Toco Y. P., Rosen, Richard B., Carroll, Joseph
Format: Journal Article
Language:English
Published: United States The Association for Research in Vision and Ophthalmology 01.01.2019
Subjects:
foveal avascular zone
imaging
optical coherence tomography angiography
averaging
ISSN:2164-2591, 2164-2591
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Summary:This study proposes an optical coherence tomography angiography (OCTA) frame-averaging method and investigates the effects of the number of frames acquired and averaged on metrics quantifying the foveal avascular zone (FAZ), vessel morphology, and parafoveal intercapillary area (PICA). Ten OCTA frames were acquired for each of the 19 subjects without known retinal disease using the AngioVue OCTA system. For each subject, acquired frames were ranked by an image quality metric. A subset of frames was then registered and averaged. The effects of the number of frames acquired and averaged on FAZ segmentation and metrics of FAZ geometry, vessel morphology, and PICA were analyzed. Frame averaging increased the accuracy of the automatically segmented FAZ region; for example, the absolute error in FAZ area decreased from 0.026 mm (1 frame) to 0.005 mm (5 frames). Averaging multiple frames exponentially decreased the estimated number of vessel endpoints and increased the average vessel length with a 32% decrease in number of endpoints and 14% increase in average vessel length when averaging five frames compared with one. Frame averaging also improved the precision of PICA estimates. Averaging multiple OCTA frames using the Optovue AngioVue system reduced error in FAZ segmentation and improved the robustness of OCTA vessel morphology and perfusion metrics. The study demonstrated limited benefit in acquiring and averaging more than five frames. Averaging multiple OCTA frames improved the robustness of OCTA foveal biomarkers with limited benefit when averaging more than five frames.
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Taly Gilat Schmidt and Rachel E. Linderman contributed equally to this work.
ISSN:2164-2591
2164-2591
DOI:10.1167/tvst.8.1.10