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F.D. Verbraak, M.E. J. Velthoven van, K. Vos de, C.W. Pool, M.D. De Smet; Software assisted overlay of OCT C–scans and conventional angiography. . Invest. Ophthalmol. Vis. Sci. 2004;45(13):2380.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose:Recently a new modality in OCT imaging has been introduced using a system combining OCT and confocal ophthalmoscopy. This OCT Ophthalmoscope (OTI, Toronto, Canada) produces en–face OCT and confocal images, so called C–scans. The confocal images have a very high transversal resolution (∼20µm), and can be used to make a precise overlay with angiographic images (FAG, ICG) using the vasculature of the retina as reference. Given the pixel–to–pixel correspondence of the confocal image with the OCT image the same transformed angiographic image can be applied to the OCT C–scan, enabling direct correlation of the angiographic images with the transversal OCT images.We have studied the potential use of making such overlay images in patients with Central Serous Retinopathy Methods:Patients with a diagnosis of Central Serous Retinopathy seen in the Department of Ophthalmology of the Academic Medical Center and examined with both FAG and OCT–Ophthalomoscope were analysed. Custom software was used to find a spatial transformation of the angiogram to the confocal image. Using the retinal vasculature, four to six pairs of reference points were manually chosen, and used to compute a least squares linear transformation. For convenient visualization the spatially transformed angiogram was then combined in an RGB image together with the confocal and the OCT image, using the green channel for the angiogram and the other channels for the C–scan images Results: In some patients with chronic CSR the difference between window defects, staining and leakage on the fluorescein angiogram was difficult to make. In these patients the overlay of the transversal OCT– , and the angiographic images was able to show that a number of small hyperfluorescent areas were correlated to small epithelial detachments in the OCT image Conclusions:Making the overlay between the OCT C–scans and the angiograms in patients with chronic CSR helped to improve the interpretation of the angiogram. It seems worthwhile to use this overlay technique in analysing patients with complex central macular pathology.
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