Visualization and Quantization of 3D Retinal Vessels in OCTA Images

Optical coherence tomography angiography (OCTA) has been increasingly used in the analysis of ophthalmic diseases in recent years. Automatic vessel segmentation in 2D OCTA projection images is commonly used in clinical practice. However, OCTA provides a 3D volume of the retinal blood vessels with rich spatial distribution information, and it is incomplete to segment retinal vessels only in 2D projection images. Here, considering that it is difficult to manually label 3D vessels, we introduce a 3D vessel segmentation and reconstruction method for OCTA images with only 2D vessel labels. We implemented 3D vessel segmentation in the OCTA volume using a specially trained 2D vessel segmentation model. The 3D vessel segmentation results are further used to calculate 3D vessel parameters and perform 3D reconstruction. The experimental results on the public dataset OCTA-500 demonstrate that 3D vessel parameters have higher sensitivity to vascular alteration than 2D vessel parameters, which makes it meaningful for clinical analysis. The 3D vessel reconstruction provides vascular visualization in different retinal layers that can be used to monitor the development of retinal diseases. Finally, we also illustrate the use of 3D reconstruction results to determine the relationship between the location of arteries and veins.