Impact of scanning density on spectral domain optical coherence tomography assessments in neovascular age-related macular degeneration

Authors

  • Anne E. Barañano,

    1. Doheny Image Reading Center, Doheny Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
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  • Pearse A. Keane,

    1. Doheny Image Reading Center, Doheny Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
    2. NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
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  • Humberto Ruiz-Garcia,

    1. Doheny Image Reading Center, Doheny Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
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  • Alexander C. Walsh,

    1. Doheny Image Reading Center, Doheny Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
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  • Srinivas R. Sadda

    1. Doheny Image Reading Center, Doheny Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
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  • A.E. Barañano and P.A. Keane contributed equally to the submission.

Srinivas R. Sadda, MD
Doheny Eye Institute-DEI 3623
1450 San Pablo Street
Los Angeles
California 90033
USA
Tel: + 1 323 442 6503
Fax: + 1 323 442 6460
Email: ssadda@doheny.org

Abstract.

Purpose:  To determine the effect of optical coherence tomography (OCT) B-scan density on the qualitative assessment of neovascular age-related macular degeneration (AMD).

Methods:  Data were collected from 59 patients imaged with Topcon 3D OCT-1000 (128 B-scans × 512 A-scans). Custom software was used to generate less dense subsets of scans: 1/16 (eight B-scans), 1/8 (16 B-scans), 1/4 (32 B-scans) and 1/2 (64 B-scans). At each B-scan density, scans were assessed for cystoid spaces, subretinal fluid (SRF), subretinal tissue (SRT) and pigment epithelium detachment (PED). For each sampling density, sensitivity, specificity and predictive values were calculated using the full volume scan (128 B-scans) as the reference standard.

Results:  For cystoid spaces, the detection sensitivity was 76.3% at 1/16 density; this rose to 89.5% with a 1/4 density. For SRF, the detection sensitivity was 75.0% at a 1/16 density; this increased to 91.1% with 1/4 density. For PED, even at the lowest sampling density (1/16) the detection sensitivity was 86.4%; this rose to 94.9% at 1/4 density. For SRT, detection sensitivity at a 1/16 density was 64.7% and only rose above 90% with the densest sampling subset (1/2).

Conclusions:  Use of scanning protocols with reduced sampling densities resulted in decreased detection of key features of neovascular AMD; despite this, a sampling density reduced to 1/4 appeared to allow accurate assessment for most features. Current management of neovascular AMD is dependent on qualitative assessment of OCT images; with the recent proliferation of OCT systems, optimization and standardization of scanning protocols may be of value.

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