June 2020
Volume 61, Issue 7
Open Access
ARVO Annual Meeting Abstract  |   June 2020
Attenuation correction assisted automated choroidal vessel visualization and quantification in eyes with atrophy
Author Affiliations & Notes
  • Hao Zhou
    University of Washington, Seattle, Washington, United States
  • Yingying Shi
    Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States
  • Qinqin Zhang
    University of Washington, Seattle, Washington, United States
  • Zhongdi Chu
    University of Washington, Seattle, Washington, United States
  • Yuxuan Cheng
    University of Washington, Seattle, Washington, United States
  • Yining Dai
    University of Washington, Seattle, Washington, United States
  • Giovanni Gregori
    Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States
  • Philip J Rosenfeld
    Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States
  • Ruikang K Wang
    University of Washington, Seattle, Washington, United States
  • Footnotes
    Commercial Relationships   Hao Zhou, None; Yingying Shi, None; Qinqin Zhang, None; Zhongdi Chu, None; Yuxuan Cheng, None; Yining Dai, None; Giovanni Gregori, Carl Zeiss Meditec, Inc. (F), Carl Zeiss Meditec, Inc. (P); Philip Rosenfeld, Apellis (C), Boehringer-Ingelheim (F), Boehringer- Ingelheim (C), Carl Zeiss Meditec (C), Carl Zeiss Meditec, Inc. (F), Chengdu Kanghong Biotech (C), F. Hoffmann- La Roche Ltd. (C), Hemera Biosciences (C), Isarna Pharmaceuticals (C), Lin Bioscience (C), Ocudyne (C), Ocunexus (C), Stealth (F), Unity Biotechnology (C); Ruikang Wang, Carl Zeiss Meditec, Inc (F), Carl Zeiss Meditec, Inc (P), Carl Zeiss Meditec Inc (C), Insight Photonic Solutions, Kowa (C), Tasso Inc (F)
  • Footnotes
    Support  Grants from the National Eye Institute (R01EY024158, R01EY028753), Carl Zeiss Meditec, the Salah Foundation, an unrestricted grant from the Research to Prevent Blindness, Inc., New York, NY, and the National Eye Institute Center Core Grant (P30EY014801) to the Department of Ophthalmology, University of Miami Miller School of Medicine.
Investigative Ophthalmology & Visual Science June 2020, Vol.61, 3236. doi:
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      Hao Zhou, Yingying Shi, Qinqin Zhang, Zhongdi Chu, Yuxuan Cheng, Yining Dai, Giovanni Gregori, Philip J Rosenfeld, Ruikang K Wang; Attenuation correction assisted automated choroidal vessel visualization and quantification in eyes with atrophy. Invest. Ophthalmol. Vis. Sci. 2020;61(7):3236.

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

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Abstract

Purpose : To develop automated visualization and quantification of choroidal vessels in the entire scanning volume of eyes with geographic atrophy using SS-OCT, with improved attenuation correction to overcome the issues of choroidal hypertransmission.

Methods : Subjects with geographic atrophy (GA) were imaged using a SS-OCT (PLEX® Elite 9000; ZEISS, Dublin, CA; central wavelength: 1050 nm, scanning rate: 100 kHz). 6x6 mm macular scans were obtained and processed by the improved attenuation correction algorithm. Choroid slab was segmented automatically from Bruch’s membrane to the outer boundary of choroidal vessels. Choroidal vessels were further segmented using Otsu’s thresholding method and volumetric choroidal vascularity index (CVI) was calculated. The en face CVI mapping calculates the ratio of vessel pixels to the full depth of choroid in each A-scan. CVIs were compared on eyes under and outside atrophy with and without attenuation correction as well as between GA patients and age-matched normals.

Results : 30 patients with GA were recruited in the study. Histogram of OCT signals demonstrated that choroidal hypertransmission caused uneven illumination of choroid structure under and outside atrophy. This resulted in shadows of atrophy in en face vasculature map when extracting dark lumens that correspond to choroidal vessels, leading to failure of Otsu’s method to segment vessels (Fig 1. A-E). With attenuation correction, we observed identical pixel intensity distributions under and outside atrophy both in B-scans and in 3D choroid slabs. En face choroidal vasculature showed continuous vessels across GA region, meeting the requirement of Otsu’s method to segment choroid vessels (Fig 1. F-J). Statistical analysis showed significantly reduced CVI in eyes with atrophy compared with age-matched normals.

Conclusions : The improved attenuation correction approach can be used to better visualize and quantify choroidal vessels in eyes with atrophy. This technique overcomes the issues with hypertransmittion and provides reliable CVI quantifications. It may be useful to provide better understanding of the role that choroid plays in atrophy-related pathologies.

This is a 2020 ARVO Annual Meeting abstract.

 

Figure 1. Choroidal vessels visualization and quantification with and without attenuation correction.

Figure 1. Choroidal vessels visualization and quantification with and without attenuation correction.

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