Pearls and Pitfalls of Optical Coherence Tomography Angiography Imaging: A Review

Optical coherence tomographic angiographic image of the macula of a healthy subject. The retinal vascularization at the macula includes four different plexuses: the superficial (SCP—second line from top), middle (MCP—third from top), and deep (DCP—second from bottom) retinal capillary plexuses, and choriocapillaris (CC—bottom). OCTA images are mainly displayed with en face visualization (images on the right) which is obtained by segmenting the volumetric OCTA scans at specific depths (indicated with white arrows). Using this strategy, the flow data within any slab, whose boundaries are red in the left images, are summed or projected into a two-dimensional en face image that can be viewed and studied. These boundaries follow predefined layers which can be differentiated on the basis of reflectivity, texture, or other attributes (top row). The layers are: (i) the inner limiting membrane (ILM), (ii) the inner border of the inner plexiform layer (IPL), (iii) the outer border of the outer plexiform layer (OPL), and (iv) Bruch’s membrane (BM