Agreement and reproducibility of retinal pigment epithelial detachment volumetric measurements through optical coherence tomography.

PURPOSE: To assess the agreement and reproducibility of retinal pigment epithelial detachment (RPED) volumetric measurements using a commercially available optical coherence tomography software available for the Zeiss Cirrus HD-OCT.
METHODS: Twelve eyes of 10 patients with a diagnosis of neovascular age-related macular degeneration with RPED, seen at the New England Eye Center between October 2012 and December 2012, were enrolled in the study. Three separate scans per affected eye were obtained using the "Macular Cube 512 × 128" protocol. "Retinal pigment epithelial (RPE) elevation analysis" software was used to measure RPED volumes in the central 3-mm and 5-mm circles by calculating the volume between the "RPE fit" and "true RPE" lines. All 128 raster scans for each eye were exported into the AMIRA software for manual segmentation of RPED volumes in the central 3-mm and 5-mm circles. Interscan reproducibility and manual-to-automated agreement were assessed by intraclass correlation coefficient. Incidence of automated segmentation line error for both RPE fit and true RPE lines in the central 1 mm region was calculated.
RESULTS: Average RPED volumes through automated segmentation software were 0.14 mm3 and 0.21 mm3 in the central 3-mm and 5-mm circles, respectively. Manual segmentation yielded average RPED volumes of 0.50 mm3 in the 3-mm circles and 0.92 mm3 in the 5-mm circles. Manual segmentation yielded significantly greater RPED volumes compared with automated measurements (P < 0.05). Intraclass correlation coefficients across the 3 automated measurements were 0.954 and 0.983 for volume in the 3-mm and 5-mm circles, respectively. Intraclass correlation coefficients between the manual and automatic volumes were 0.296 and 0.337 for the 3-mm and 5-mm circles, respectively. In the central 1 mm region, 11 of the 12 scans had breakdown in RPE fit line, whereas 8 of the 12 scans showed true RPE line breakdown.
CONCLUSION: Automated "RPED elevation" software demonstrated high interscan reproducibility. However, it showed low agreement with manual measurements from high rates of segmentation line breakdown, especially at the level of the RPE fit line (91.7%). Manual measurements resulted in greater volumes compared with automated measurements.