Approaches to quantify optical coherence tomography angiography metrics

Abstract

Optical coherence tomography (OCT) has revolutionized the field ofophthalmology in the last three decades. As an OCT extension, OCTangiography (OCTA) utilizes a fast OCT system to detect motion contrastin ocular tissue and provides a three-dimensional representation of theocular vasculature in a non-invasive, dye-free manner. The first OCTmachine equipped with OCTA function was approved by U.S. Food and DrugAdministration in 2016 and now it is widely applied in clinics. To date,numerous methods have been developed to aid OCTA interpretation andquantification. In this review, we focused on the workflow of OCTA-basedinterpretation, beginning from the generation of the OCTA images usingsignal decorrelation, which we divided into intensity-based, phase-basedand phasor-based methods. We further discussed methods used to addressimage artifacts that are commonly observed in clinical settings, to thealgorithms for image enhancement, binarization, and OCTA metricsextraction. We believe a better grasp of these technical aspects of OCTAwill enhance the understanding of the technology and its potentialapplication in disease diagnosis and management. Moreover, futurestudies will also explore the use of ocular OCTA as a window to linkocular vasculature to the function of other organs such as the kidneyand brain.