title: Evaluation of segmentation procedures using spectral domain optical coherence tomography in exudative age-related macular degeneration.
abstract: OBJECTIVE
  The purpose of this study was to evaluate standardized automated segmentation procedures of spectral domain optical coherence tomography (SD-OCT) in imaging of age-related macular degeneration.
  
  
  METHODS
  Twenty-nine eyes of 29 patients with neovascular age-related macular degeneration were included. Three groups were assigned, according to the predominant localization of extravasated fluid in the intra-, subretinal, and subretinal pigment epithelium (RPE) compartment. Automated segmentation procedures were evaluated in B scans of 512 × 128 × 1024 and 200 × 200 × 1024 scan patterns using SD-OCT (Cirrus). Alignment errors at the internal limiting membrane, actual RPE, and extrapolation of the physiologic RPE (RPE fit) were graded using a standardized classification system.
  
  
  RESULTS
  The rate of severe alignment failures was 56% and 41% for the 512 × 128 and the 200 × 200 raster pattern, respectively. Internal limiting membrane and actual RPE boundaries were most correctly delineated in the 200 × 200 raster pattern. Retinal pigment epithelium fit alignment was generally poor in 50% of scans. Retinal thickness values defined by internal limiting membrane and actual RPE segmentation were 90% accurate and not compromised by RPE fit misalignment. Subretinal fluid was demarcated most reliably. Alignment errors may occur together with a large spectrum of morphologic alterations.
  
  
  CONCLUSIONS
  Automated algorithms of SD-OCT demonstrate a substantial rate of alignment failures in the assessment of exudative age-related macular degeneration pathologies, which are usually associated with misinterpretation of boundaries at the (sub) RPE level.
authors.affiliation: Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Malamos
authors.forename: Christian
authors.initials: C
authors.lastname: Ahlers
authors.forename: Giorgos
authors.initials: G
authors.lastname: Mylonas
authors.forename: Christopher
authors.initials: C
authors.lastname: Schütze
authors.forename: Gabor
authors.initials: G
authors.lastname: Deak
authors.forename: Markus
authors.initials: M
authors.lastname: Ritter
authors.forename: Stefan
authors.initials: S
authors.lastname: Sacu
authors.forename: Ursula
authors.initials: U
authors.lastname: Schmidt-Erfurth
mesh_terms: D000368:Aged; D000465:Algorithms; D001485:Basement Membrane / Q000473:pathology; D005122:Exudates and Transudates; D005260:Female; D006801:Humans; D008297:Male; D012160:Retina / Q000473:pathology; D055213:Retinal Pigment Epithelium / Q000473:pathology; D041623:Tomography, Optical Coherence / Q000295:instrumentation* / Q000379:methods; D014792:Visual Acuity; D057135:Wet Macular Degeneration / Q000175:diagnosis*