Morphologic analysis of macular neovascularizations by OCT angiography—Technical limitations in the comparison of 3×3mm and 6×6mm images

BACKGROUND: The aim of this study was to ascertain whether there are relevant differences between the vascular morphology of macular neovascularizations (MNV) in 3×3mm and 6×6mm images, produced by optical coherence tomography angiography (OCTA). METHODS: MNV of 49 patients were automated quantitative analysed, measuring area, flow, the fractal dimension, average vessel length, vascular density, and average vessel caliber. These parameters were compared between the 3×3mm and the 6×6mm images. RESULTS: A strong linear association was found between the 3×3mm and the 6×6mm images. While area, flow, and FD of the MNV were very similar, the 3×3mm images showed significantly lower average total vessel length, greater vascular density, and lower average vessel caliber. CONCLUSION: In quantitative analysis of the morphologic parameters of MNV in 3×3mm and 6×6mm images, the structures are not directly equivalent in the two sizes of scan. The images must be evaluated on an individual basis.