Automatic segmentation in three-dimensional analysis of fibrovascular pigmentepithelial detachment using high-definition optical coherence tomography.
OBJECTIVE
A limited number of scans compromise conventional optical coherence tomography (OCT) to track chorioretinal disease in its full extension. Failures in edge-detection algorithms falsify the results of retinal mapping even further. High-definition-OCT (HD-OCT) is based on raster scanning and was used to visualise the localisation and volume of intra- and sub-pigment-epithelial (RPE) changes in fibrovascular pigment epithelial detachments (fPED). Two different scanning patterns were evaluated.


METHODS
22 eyes with fPED were imaged using a frequency-domain, high-speed prototype of the Cirrus HD-OCT. The axial resolution was 6 mum, and the scanning speed was 25 kA scans/s. Two different scanning patterns covering an area of 6 x 6 mm in the macular retina were compared. Three-dimensional topographic reconstructions and volume calculations were performed using MATLAB-based automatic segmentation software.


RESULTS
Detailed information about layer-specific distribution of fluid accumulation and volumetric measurements can be obtained for retinal- and sub-RPE volumes. Both raster scans show a high correlation (p<0.01; R2>0.89) of measured values, that is PED volume/area, retinal volume and mean retinal thickness. Quality control of the automatic segmentation revealed reasonable results in over 90% of the examinations.


CONCLUSIONS
Automatic segmentation allows for detailed quantitative and topographic analysis of the RPE and the overlying retina. In fPED, the 128 x 512 scanning-pattern shows mild advantages when compared with the 256 x 256 scan. Together with the ability for automatic segmentation, HD-OCT clearly improves the clinical monitoring of chorioretinal disease by adding relevant new parameters. HD-OCT is likely capable of enhancing the understanding of pathophysiology and benefits of treatment for current anti-CNV strategies in future.
Ahlers
C
C
Klinik für Optometrie und Augenheilkunde, der medizinschen Universität Wien, Waehringer Guertel 18-20, 1090 Vienna, Austria. christian.ahlers@meduniwien.ac.at
Simader
C
C
Geitzenauer
W
W
Stock
G
G
Stetson
P
P
Dastmalchi
S
S
Schmidt-Erfurth
U
U
D000368:Aged; D000465:Algorithms; D020533:Angiogenesis Inhibitors / Q000627:therapeutic use; D020256:Choroidal Neovascularization / Q000150:complications / Q000188:drug therapy; D005240:Feasibility Studies; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008268:Macular Degeneration / Q000150:complications; D008875:Middle Aged; D010857:Pigment Epithelium of Eye / Q000473:pathology*; D011786:Quality Control; D012163:Retinal Detachment / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology; D012984:Software; D041623:Tomography, Optical Coherence / Q000379:methods; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors
D020533:Angiogenesis Inhibitors; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A