title: Quantifying disrupted outer retinal-subretinal layer in SD-OCT images in choroidal neovascularization.
abstract: OBJECTIVE
  We reported a fully automated method to identify and quantify the thickness of the outer retinal-subretinal (ORSR) layer from clinical spectral-domain optical coherence tomography (SD-OCT) scans of choroidal neovascularization (CNV) due to exudative age-related macular degeneration (eAMD).
  
  
  METHODS
  A total of 23 subjects with CNV met eligibility. Volumetric SD-OCT scans of 23 eyes were obtained (Zeiss Cirrus, 200 × 200 × 1024 voxels). In a subset of eyes, scans were repeated. The OCT volumes were analyzed using our standard parameters and using a 3-dimensional (3D) graph-search approach with an adaptive cost function. A retinal specialist graded the segmentation as generally accurate, local segmentation inaccuracies, or failure. Reproducibility on repeat scans was analyzed using root mean square coefficient of variation (RMS CV) of the average ORSR thickness.
  
  
  RESULTS
  Using a standard segmentation approach, 1/23 OCT segmentations was graded generally accurate and 22/23 were failure(s). With the adaptive method 21/23 segmentations were graded generally accurate; 2/23 were local segmentation inaccuracies and none was a failure. The intermethod quality of segmentation was significantly different (P << 0.001). The average ORSR thickness measured on CNV patients (78.0 μm; 95% confidence interval [CI], 72.5-83.4 μm) is significantly larger (P << 0.001) than normal average ORSR layer thickness (51.5 ± 3.3 μm). The RMS CV was 8.1%.
  
  
  CONCLUSIONS
  We have developed a fully automated 3D method for segmenting the ORSR layer in SD-OCT of patients with CNV from eAMD. Our method can quantify the ORSR layer thickness in the presence of fluid, which has the potential to augment management accuracy and efficiency of anti-VEGF treatment.
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.forename: Milan
authors.initials: M
authors.lastname: Sonka
authors.forename: James C
authors.initials: JC
authors.lastname: Folk
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Russell
authors.forename: Michael D
authors.initials: MD
authors.lastname: Abràmoff
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D020256:Choroidal Neovascularization / Q000150:complications / Q000175:diagnosis*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008268:Macular Degeneration / Q000175:diagnosis* / Q000209:etiology; D008297:Male; D015203:Reproducibility of Results; D055214:Retinal Photoreceptor Cell Outer Segment / Q000473:pathology*; D041623:Tomography, Optical Coherence / Q000379:methods*
keywords: AMD; OCT; choroidal neovascularization; imaging; retina