July 2018
Volume 59, Issue 9
Open Access
ARVO Annual Meeting Abstract  |   July 2018
Evaluation of Automatically Quantified Foveal Avascular Zone Metrics in Diabetic Retinopathy Using OCTA
Author Affiliations & Notes
  • Joseph Michael Simonett
    Ophthalmology , Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
  • Yansha Lu
    Ophthalmology , Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
    Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, Institute of Biomedical Sciences, School of Physics and Electronics, Shandong Normal University, Jinan, China
  • JIE WANG
    Ophthalmology , Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
  • Miao Zhang
    Ophthalmology , Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
    Optovue, Fremont, California, United States
  • Ahmed M Hagag
    Ophthalmology , Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
  • David Huang
    Ophthalmology , Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
  • Thomas S Hwang
    Ophthalmology , Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
  • Yali Jia
    Ophthalmology , Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
  • Footnotes
    Commercial Relationships   Joseph Simonett, None; Yansha Lu, None; JIE WANG, None; Miao Zhang, Optovue (E); Ahmed Hagag, None; David Huang, Optovue, Inc (I), Optovue, Inc (F), Optovue, Inc (P); Thomas Hwang, None; Yali Jia, Optovue, Inc (I), Optovue, Inc (F)
  • Footnotes
    Support   R01 EY027833, DP3 DK104397, R01 EY024544, R01 EY010145, P30 EY010572 from the National Institutes of Health (Bethesda,MD), and an unrestricted departmental funding grant and William & Mary Greve Special Scholar Award from Research to Prevent Blindness (New York, NY)
Investigative Ophthalmology & Visual Science July 2018, Vol.59, 3921. doi:
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    • Get Citation

      Joseph Michael Simonett, Yansha Lu, JIE WANG, Miao Zhang, Ahmed M Hagag, David Huang, Thomas S Hwang, Yali Jia; Evaluation of Automatically Quantified Foveal Avascular Zone Metrics in Diabetic Retinopathy Using OCTA. Invest. Ophthalmol. Vis. Sci. 2018;59(9):3921.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : To test an automated algorithm to identify the foveal avascular zone (FAZ) in eyes with diabetic retinopathy (DR), and to compare the performance of novel FAZ metrics to that of conventional FAZ metrics and extrafoveal avascular area (EAA) for the diagnosis of DR.

Methods : A generalized gradient vector flow (GGVF) model based algorithm detected the FAZ in 3×3-mm macular OCTA scans from diabetic and healthy subjects. Automated FAZ detection was compared to manual delineation and within-visit repeatability was tested. The correlations of two novel FAZ metrics (STD4 and NR300, Fig. 1), two conventional FAZ metrics (FAZ area and acircularity index), and EAA with ETDRS DR severity and BCVA were assessed.

Results : Eighty eyes from 66 diabetic patients and 33 control eyes from 19 healthy subjects were included. The agreement between automated and manual FAZ delineation had a Jaccard index > 0.82, and the repeatability of FAZ detection was excellent at all DR grades. Novel FAZ metrics that incorporated both FAZ size and irregularity, and partially controlled for physiologic FAZ variation, had stronger correlations with DR grade and BCVA than conventional FAZ metrics (Fig. 2). Of all tested OCTA metrics, EAA had the greatest sensitivity in differentiating diabetic from healthy eyes at all DR severity when specificity was held at 95%.

Conclusions : The GGVF algorithm tested in this study allows for rapid FAZ delineation and performs well on the more complicated FAZ borders present in advanced DR, where traditional semi-automated algorithms are more likely to fail. FAZ metrics that partially control for physiologic variation in FAZ by utilizing a maximum inscribed circle, such as STD4 and NR300, show stronger correlations with DR grade and BCVA than conventional FAZ metrics. While FAZ metrics can provide clinically useful information regarding macular ischemia, EAA measurements may be a better biomarker for the presence and severity of DR.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.

 

Quantitative FAZ metrics. (A) FAZ area, (B) acircularity index defined as the ratio of perimeter of the FAZ to the perimeter of a circle of equal area, (C) STD4 defined as the standard deviation of the areas of 4 sectors of the FAZ after excluding the maximum inscribed circle, (D) NR300 defined as the area of intersection of the FAZ and R300 annulus divided by the area of R300 annulus.

Quantitative FAZ metrics. (A) FAZ area, (B) acircularity index defined as the ratio of perimeter of the FAZ to the perimeter of a circle of equal area, (C) STD4 defined as the standard deviation of the areas of 4 sectors of the FAZ after excluding the maximum inscribed circle, (D) NR300 defined as the area of intersection of the FAZ and R300 annulus divided by the area of R300 annulus.

 

OCTA metrics by DR grade and corresponding correlation coefficient. *=P-value<0.05

OCTA metrics by DR grade and corresponding correlation coefficient. *=P-value<0.05

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