June 2023
Volume 64, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2023
Normalized Blood Flow Analysis in OCT Angiography
Author Affiliations & Notes
  • Albert Kofi Dadzie
    Department of Biomedical Engineering, University of Illinois Chicago, Chicago, Illinois, United States
  • David Le
    Department of Biomedical Engineering, University of Illinois Chicago, Chicago, Illinois, United States
  • Mansour Abtahi
    Department of Biomedical Engineering, University of Illinois Chicago, Chicago, Illinois, United States
  • Behrouz Ebrahimi
    Department of Biomedical Engineering, University of Illinois Chicago, Chicago, Illinois, United States
  • Taeyoon Son
    Department of Biomedical Engineering, University of Illinois Chicago, Chicago, Illinois, United States
  • Jennifer I Lim
    Department of Ophthalmology and Visual Sciences, University of Illinois Chicago College of Medicine, Chicago, Illinois, United States
  • Xincheng Yao
    Department of Biomedical Engineering, University of Illinois Chicago, Chicago, Illinois, United States
    Department of Ophthalmology and Visual Sciences, University of Illinois Chicago College of Medicine, Chicago, Illinois, United States
  • Footnotes
    Commercial Relationships   Albert Dadzie None; David Le None; Mansour Abtahi None; Behrouz Ebrahimi None; Taeyoon Son None; Jennifer Lim Allergan, Aura, Cognition, Eyenuk, Iveric Bio, JAMA Ophthalmology Editorial Board, Luxa, Novartis Pharma AG, Opthea, Quark, Regeneron, Roche/Genentech, Inc., Santen, Unity, Viridian, Code C (Consultant/Contractor), Adverum, Aldeyra, Chengdu Kanghong, Graybug, Janssen, NGM Bio, Ocugen, RegenexBio, Roche/Genentech, Inc., Spring Vision, Stealth, Code F (Financial Support), CRC Press/Taylor and Francis, Code P (Patent), Alimera, Genentech/ Roche , Code R (Recipient); Xincheng Yao None
  • Footnotes
    Support  National Eye Institute (R01 EY023522, R01 EY029673, R01 EY030101, R01 EY030842, P30EY001792); Research to Prevent Blindness; Richard and Loan Hill Endowment.
Investigative Ophthalmology & Visual Science June 2023, Vol.64, 2535. doi:
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    • Get Citation

      Albert Kofi Dadzie, David Le, Mansour Abtahi, Behrouz Ebrahimi, Taeyoon Son, Jennifer I Lim, Xincheng Yao; Normalized Blood Flow Analysis in OCT Angiography. Invest. Ophthalmol. Vis. Sci. 2023;64(8):2535.

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

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Abstract

Purpose : The purpose of this study is to establish normalized blood flow index (NBFI) in OCT angiography (OCTA) and to test if the NBFI analysis can be a sensitive marker of early diabetic retinopathy (DR).

Methods : OCTA images of 30 eyes from 20 healthy controls, 21 eyes from 15 diabetic patients with no DR (NoDR), and 26 eyes from 22 patients with mild non-proliferative DR (NPDR) were analyzed in this study. All OCTA images were centered on the fovea and covered a 6 mm x 6 mm area. Enface projections of the superficial vascular plexus (SVP) and the deep capillary plexus (DCP) were obtained for the quantitative OCTA feature analysis. Alterations to blood flow in DR was assessed quantitatively by calculating blood flow index (BFI) and NBFI. Normalization of BFI (NBFI) was performed to compensate for the inherent noise and variabilities such as pigmentation level, eye condition and illumination irradiance present in the OCTA images that may affect the quantification of BFI. A thresholding algorithm was used to remove the noise from the OCTA images. The BFI of these noiseless images were calculated and normalized by dividing it by the standard deviation of the noise removed. Each feature was calculated from both the SVP and DCP and their sensitivities to distinguish the three cohorts of the study were evaluated.

Results : The only quantitative feature that was capable of distinguishing between all three cohorts was NBFI in the DCP image. Comparative study revealed that BFF in the DCP and NBFI in the SVP were able to distinguish the controls and NoDR from mild NPDR. However, neither BFF in the DCP nor NBFI in the SVP was sensitive enough to separate NoDR from the healthy controls.

Conclusions : The NBFI has been demonstrated as a sensitive biomarker of early DR, revealing retinal blood flow abnormality better than traditional BFF. The NBFI in the DCP was verified as the most sensitive biomarker, supporting that diabetes affects the DCP earlier than SVP in DR.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

 

Image processing steps in the quantification of OCTA features. (A) Representative OCTA image. (B) Vessel map. (C) OCTA image with the noise removed. (D) Background noise removed from the OCTA image.

Image processing steps in the quantification of OCTA features. (A) Representative OCTA image. (B) Vessel map. (C) OCTA image with the noise removed. (D) Background noise removed from the OCTA image.

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