OCTA: What Can it Tell Me and How to Use It

Optical coherence tomography angiography (OCTA) compares the decorrelation signal (differences in the backscattered OCT light signal amplitude) between sequential OCT B-scans taken at a single cross section(motion contrast). Since only blood flow would be expected to create movement and differences in sequential images, the motion contrast allows for the creation of a map of vascular structures. The map registers focal regions of flow, but does not allow for quantification of flow volume. Because in ophthalmology, eye movements produce artifact for long interscan times, only 2-4 scans per location are done.