Session Title: Imaging I
Session Date/Time: Thursday 26/09/2013 | 08:30-10:30
Paper Time: 08:38
Venue: Hall 3 (Level 0)
First Author: R.Sayegh AUSTRIA
Co Author(s): C. Kiss C. Simader S. Sacu C. Hitzenberger
Fundus autofluorescence (FAF), used since the early nineties, filled a GAP in geographic atrophy progression (GAP) imaging. In this millennium of scientific breakthroughs, OCT imaging is dominating monitoring of patients with “wet” AMD and recently also research in the dry phenotype. The aim of this project is a comparison of these two imaging modalities in GA.
The Clinical Study Center (CSC) enrolled 100 patients with either uni-or bilateral GA with follow-up visits every 3 months for 5 years.
Study procedures included best-corrected-visual-acuity (BCVA), microperimetry and fixation testing (MP1, Nidek), OCT [(Stratus/Cirrus, Carl-Zeiss Meditec), (Spectralis, Heidelberg-Engineering), infrared imaging and FAF (Spectralis). The OCT-tool-kit, a novel software designed by the Vienna Reading Center (VRC), enabled to delineate the lesion area in SD-OCT volume scans and to compare the dataset to FAF. Automatically GA delineating software algorithms based on OCT and FAF were compared. An updated version of the tool-kit allowed an exact correlation of OCT and microperimetry. SD-OCT gradings and epidemiological data gathered were combined and served as an SD-OCT based epidemiological approach to GAP. In respect to new therapeutic targeted studies we analyzed which imaging modality is most accurate in foveal diagnostics, a probable endpoint parameter in future pharmacologic strategies. Finally, polarization-sensitive(PS)-OCT an enhanced OCT system was compared to conventional imaging.
In GA subgroups we found OCT and FAF delineated lesions comparable. Regression analysis was significant for choroidal signal enhancement (R2 = 0.93) with a progression of 2,34 mm2/year. Neurosensory layers (OPL thinning and ELM loss) were closely related to GAP (R2 = 0.93/0.89) and retinal function (-1,3 dB when ELM was lost). Epidemiological criteria and adequate retinal imaging is crucial for new insight in GA management. Foveal status was more precise using Spectralis instead of FAF and IR imaging. BCVA and fixation served as impartial criterions in this question (p < 0.001). Furthermore PS-OCT proved its sensitivity for foveal sparing (mean BCVA = 20/43).
FAF filled a GAP when GA imaging and pathophysiology were initially analyzed. Imaging GA will presumably diverge to screening larger populations with OCT as a state of the art method. PS-OCT could build the future bridge between metabolic en face imaging and high-end OCT technology.