EVALUATION OF SEGMENTATION PROCEDURES USING SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY IN EXUDATIVE AGE-RELATED MACULAR DEGENERATION

Purpose: 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 X 128 X 1024 and 200 X 200 X 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 X 128 and the 200 X 200 raster pattern, respectively. Internal limiting membrane and actual RPE boundaries were most correctly delineated in the 200 X 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. Conclusion: 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. RETINA 31: 453-463, 2011