title: Validity of Automated Choroidal Segmentation in SS-OCT and SD-OCT.
abstract: OBJECTIVE
  To evaluate the validity of a novel fully automated three-dimensional (3D) method capable of segmenting the choroid from two different optical coherence tomography scanners: swept-source OCT (SS-OCT) and spectral-domain OCT (SD-OCT).
  
  
  METHODS
  One hundred eight subjects were imaged using SS-OCT and SD-OCT. A 3D method was used to segment the choroid and quantify the choroidal thickness along each A-scan. The segmented choroidal posterior boundary was evaluated by comparing to manual segmentation. Differences were assessed to test the agreement between segmentation results of the same subject. Choroidal thickness was defined as the Euclidian distance between Bruch's membrane and the choroidal posterior boundary, and reproducibility was analyzed using automatically and manually determined choroidal thicknesses.
  
  
  RESULTS
  For SS-OCT, the average choroidal thickness of the entire 6- by 6-mm2 macular region was 219.5 μm (95% confidence interval [CI], 204.9-234.2 μm), and for SD-OCT it was 209.5 μm (95% CI, 197.9-221.0 μm). The agreement between automated and manual segmentations was high: Average relative difference was less than 5 μm, and average absolute difference was less than 15 μm. Reproducibility of choroidal thickness between repeated SS-OCT scans was high (coefficient of variation [CV] of 3.3%, intraclass correlation coefficient [ICC] of 0.98), and differences between SS-OCT and SD-OCT results were small (CV of 11.0%, ICC of 0.73).
  
  
  CONCLUSIONS
  We have developed a fully automated 3D method for segmenting the choroid and quantifying choroidal thickness along each A-scan. The method yielded high validity. Our method can be used reliably to study local choroidal changes and may improve the diagnosis and management of patients with ocular diseases in which the choroid is affected.
authors.affiliation: Department of Electrical and Computer Engineering, University of Iowa, Iowa City, Iowa, United States.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands 3Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Gabriëlle H S
authors.initials: GH
authors.lastname: Buitendijk
authors.affiliation: Department of Electrical and Computer Engineering, University of Iowa, Iowa City, Iowa, United States.
authors.forename: Kyungmoo
authors.initials: K
authors.lastname: Lee
authors.affiliation: Department of Electrical and Computer Engineering, University of Iowa, Iowa City, Iowa, United States 4Department of Ophthalmology and Visual Sciences, University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States.
authors.forename: Milan
authors.initials: M
authors.lastname: Sonka
authors.affiliation: Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands 3Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Henriët
authors.initials: H
authors.lastname: Springelkamp
authors.affiliation: Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands 5Netherlands Consortium for Healthy Aging, Netherlands Genomics Initiative, The Hague, The Netherlands.
authors.forename: Albert
authors.initials: A
authors.lastname: Hofman
authors.affiliation: Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands 3Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Johannes R
authors.initials: JR
authors.lastname: Vingerling
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States 6Stephen Wynn Institute for Vision Research, University of Iowa, Iowa City, Iowa, United States.
authors.forename: Robert F
authors.initials: RF
authors.lastname: Mullins
authors.affiliation: Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands 3Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Caroline C W
authors.initials: CC
authors.lastname: Klaver
authors.affiliation: Department of Electrical and Computer Engineering, University of Iowa, Iowa City, Iowa, United States 4Department of Ophthalmology and Visual Sciences, University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States 6Stephen Wynn Institute for Vi.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Abràmoff
mesh_terms: D000328:Adult; D000368:Aged; D015862:Choroid Diseases / Q000175:diagnosis*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D011446:Prospective Studies; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence / Q000379:methods*