Automated segmentation and quantification of calcified drusen in 3D swept source OCT imaging

Jie Lu; Yuxuan Cheng; Jianqing Li; Ziyu Liu; Mengxi Shen; Qinqin Zhang; Jeremy Liu; Gissel Herrera; Farhan E Hiya; Rosalyn Morin; Joan Joseph; Giovanni Gregori; Philip J Rosenfeld; Ruikang K Wang

doi:10.1364/BOE.485999

Automated segmentation and quantification of calcified drusen in 3D swept source OCT imaging

Biomed Opt Express. 2023 Feb 28;14(3):1292-1306. doi: 10.1364/BOE.485999. eCollection 2023 Mar 1.

Authors

Jie Lu¹, Yuxuan Cheng¹, Jianqing Li², Ziyu Liu¹, Mengxi Shen², Qinqin Zhang^{1

3}, Jeremy Liu², Gissel Herrera², Farhan E Hiya², Rosalyn Morin², Joan Joseph², Giovanni Gregori², Philip J Rosenfeld², Ruikang K Wang^{1

4}

Affiliations

¹ Department of Bioengineering, University of Washington, Seattle, Washington, USA.
² Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA.
³ Research and Development, Carl Zeiss Meditec, Inc., Dublin, CA, USA.
⁴ Department of Ophthalmology, University of Washington, Seattle, Washington, USA.

Abstract

Qualitative and quantitative assessments of calcified drusen are clinically important for determining the risk of disease progression in age-related macular degeneration (AMD). This paper reports the development of an automated algorithm to segment and quantify calcified drusen on swept-source optical coherence tomography (SS-OCT) images. The algorithm leverages the higher scattering property of calcified drusen compared with soft drusen. Calcified drusen have a higher optical attenuation coefficient (OAC), which results in a choroidal hypotransmission defect (hypoTD) below the calcified drusen. We show that it is possible to automatically segment calcified drusen from 3D SS-OCT scans by combining the OAC within drusen and the hypoTDs under drusen. We also propose a correction method for the segmentation of the retina pigment epithelium (RPE) overlying calcified drusen by automatically correcting the RPE by an amount of the OAC peak width along each A-line, leading to more accurate segmentation and quantification of drusen in general, and the calcified drusen in particular. A total of 29 eyes with nonexudative AMD and calcified drusen imaged with SS-OCT using the 6 × 6 mm² scanning pattern were used in this study to test the performance of the proposed automated method. We demonstrated that the method achieved good agreement with the human expert graders in identifying the area of calcified drusen (Dice similarity coefficient: 68.27 ± 11.09%, correlation coefficient of the area measurements: r = 0.9422, the mean bias of the area measurements = 0.04781 mm²).