Abstract
Purpose: :
To evaluate the correlation between optical reflectivity of classic choroidal neovascularization (CNV) in Spectral-Domain Optical Coherence Tomography (SD-OCT) images and leakage at fluorescein angiography (FA)
Methods: :
Retrospective analysis of images from 14 patients with fibrotic classic CNV (no leakage at FA), and 12 patients with active classic CNV (leakage at FA) examinated with simultaneous SD-OCT and FA using Heidelberg Spectralis HRA+OCT. Optical reflectivity at SD-OCT was measured placing a square selection (20x20 pixels) on the CNV area in B-scan images and calculating grey scale mean value. The measurement was repeated on three different images from the same patient. To eliminate the influence of different brightness on grey scale measurements, due for example to cataract or vitreous opacities, retinal pigmented epithelium (RPE) reflectivity under healthy portion of retina was measured in every images, to obtain a ratio between CNV and RPE reflectivity. RPE reflectivity was measured placing a 5x5 pixels square in the RPE layer in healthy areas on the same B-scans used to calculate CNV reflectivity, and measuring grey scale mean values
Results: :
Optical reflectivity of fibrotic CNV is significantly higher compared to CNV with leakage at FA (ANOVA p=0.00012). Measurements on the three images from the same patients did not vary significantly, considering both absolute values and ratio values (ANOVA p>0.05)
Conclusions: :
Optical reflectivity of CNV, measured on SD-OCT images, seems to be inversely correlated to the presence of leakage at FA. This could be explained with 1)minor fibrous component in the vascular net in active membranes 2)presence of peri and intralesional inflammatory material that organizes with the fibrotic evolution of the lesions 3)presence of fluid component around active lesions
Keywords: imaging/image analysis: clinical • neovascularization • retina