Abstract
Purpose: :
Fluorescence angiography (FA) is used to define the lesion type and to evaluate exsudative changes in neovascular macular diseases. However, FA lacks the ability to visualize intra- and subretinal structures at their exact morphologic level.Manual segmentation of spectral domain (SD) OCT allows to assess and visualize volumes of subretinal fluid (SRFV), pigment epithelial detachment (PEDV) and intraretinal edema (RV) precisely.A study was performed to correlate the exact localization of different compartments identified in SD-OCT to FA in pretreatment and follow-up examinations.
Methods: :
14 eyes with neovascular age-related macular degeneration were imaged using a SD-OCT system (Cirrus prototype, Carl Zeiss Meditec) previous to monthly ranibizumab treatment. Further examinations were performed at month 3 following a standardized examination protocol including FA and SD-OCT. 25 k A-scans/second were recorded to examine a 6x6x2 mm3 retinal volume. Three different compartments, intra-, subretinal and subpigmentepithelial, were measured using a FDA approved manual segmentation software. FA was performed using the Heidelberg retina angiography system (HRA2, Heidelberg Engineering). FA and SD-OCT were correlated using overlay techniques.
Results: :
SRFV, PEDV and RV as identified in manual segmentation could be measured accurately in all cases examined by SD-OCT. Different compartments were visualized selectively using false colour illustrations and 3D-videos. Exact point-to-point correlation could be achieved for each dataset. Comparison of compartment analysis and FA revealed that FA failed to distinguish between SRF, RV at baseline and increasingly up to month 3.
Conclusions: :
Unlike FA, SD-OCT imaging of lesion compartments allows for a realistic evaluation of anatomy-related fluid pooling. With increasing presence of staining during follow-up FA, identification of discrete amounts of RV, SRFV and PEDV becomes increasingly challenging. Rasterscanning SD-OCT enables for direct comparison of scanned retinal areas to FA, enhancing the understanding of characteristic findings in both, FA and SD-OCT.
Clinical Trial: :
Retrospective study
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retinal neovascularization • imaging/image analysis: clinical