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Identification of imaging features that determine quality and repeatability of retinal capillary plexus density measurements in OCT angiography
  1. Beau J Fenner1,
  2. Gavin SW Tan1,2,
  3. Anna CS Tan1,2,
  4. Ian YS Yeo1,3,
  5. Tien Yin Wong1,2,3,4,
  6. Gemmy CM Cheung1,2
  1. 1Vitreo-Retinal Service, Singapore National Eye Centre, Singapore
  2. 2Retina Research Group, Singapore Eye Research Institute, Singapore
  3. 3Ophthalmology and Visual Sciences Academic Clinical Research Program, Duke-NUS Medical School, National University of Singapore, Singapore
  4. 4Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
  1. Correspondence to Dr Gemmy CM Cheung, Singapore National Eye Centre, 11 Third Hospital Ave, 168751 Singapore; gemmy.cheung.c.m{at}singhealth.com.sg

Abstract

Purpose Optical coherence tomography angiography (OCT-A) potentially allows for rapid and non-invasive quantification of retinal capillary plexus density in various disease states. This study aims to identify the key features that influenced the repeatability of OCT-A measurements.

Methods We obtained OCT-A images on two separate visits in 44 healthy eyes from 44 subjects, each imaged with using the Topcon DRI OCT Triton imaging system. The parafoveal vessel density within a 1.5 mm radius centred over the fovea was obtained with the built-in tool for the superficial and deep retinal plexuses. Repeatability of vessel density was determined by intraclass correlation (ICC) and mean variation. We evaluated several image parameters to determine their influence on the repeatability of vessel density measurement in each of the two capillary plexuses.

Results The mean age of the subjects was 70.2±9.2 years, with 64% males. Mean parafoveal vessel density measurements for the first and second visits were 53.3±11.1 and 53.3±10.3 for the superficial plexus and 27.3±8.59 and 27.0±8.78 for the deep plexus. ICC analyses demonstrated that high fine vessel visibility, the absence of motion artefact and software-derived image quality score of 60 or above were necessary to obtain a good (ICC>0.6) or excellent (ICC>0.75) repeatability.

Conclusions Our study identified the imaging parameters that determined the repeatability of quantitative retinal vessel density measurements. These findings have implications in determining if OCT-A images can be used to accurately evaluate serial changes in retinal vessel density.

  • Retina
  • Macula

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Footnotes

  • Contributors BJF and GCMC were responsible for the original concept, data collection and analysis and manuscript writing. Drafting and critical revision were done by GSWT, ACST, IYSY and TYW.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval SingHealth Centralized Institutional Review Board.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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