A practical guide to optical coherence tomography angiography interpretation

Abstract

Background Optical coherence tomography angiography (OCTA) can image the retinal vasculature in vivo, without the need for contrast dye. This technology has been commercially available since 2014, however, much of its use has been limited to the research setting. Over time, more clinical practices have adopted OCTA imaging. While countless publications detail OCTA’s use for the study of retinal microvasculature, few studies outline OCTA’s clinical utility. Body This review provides an overview of OCTA imaging and details tips for successful interpretation. The review begins with a summary of OCTA technology and artifacts that arise from image acquisition. New methods and best practices to prevent image artifacts are discussed. OCTA has the unique ability among retinovascular imaging modalities to individually visualize each retinal plexus. Slabs offered in standard OCTA devices are reviewed, and clinical uses for each slab are outlined. Lastly, the use of OCTA for the clinical interpretation of retinal pathology, such as diabetic retinopathy and age-related macular degeneration, is discussed. Conclusion OCTA is evolving from a scientific tool to a clinical imaging device. This review provides a toolkit for successful image interpretation in a clinical setting.

In vivo human retinal swept source optical coherence tomography and angiography at 830 nm with a CMOS compatible photonic integrated circuit

“…The angiogram in Fig. 6 a shows vessels in the foveal region and no signal in the macula as expected 18 .…”

Macular Vessel Density in Diabetic Retinopathy Patients: How Can We Accurately Measure and What Can It Tell Us?

“…In chronic diabetic macular edema (DME), for example, turbid fluid may shadow, obscuring vessels and result in artifactually reduced vessel density. 44 , 52 Similarly, motion artifacts as a result of patient movement during scan acquisition can alter vessel density measurements. These artifacts present as white horizontal lines on the en face OCTA image.…”

“…It is important that good acquisition technique, as well as tools such as eye tracking and software-based motion correction are utilized in order to reduce the effects of these artifacts on vessel density measurements. 44 , 52 , 53 Additionally, sometimes the only way to correct for these artifacts is by looking at the images and removing areas of motion artifact from the analysis. 54 Vignetting artifacts, occurring at the margins of the image as a result of large OCT beam size, small pupil and axial misalignment can lead to falsely decreased vessel density measurements.…”

Standardization of Optical Coherence Tomography Angiography Imaging Biomarkers in Diabetic Retinal Disease

“…Image quality control mechanisms are also necessary for the effective use of OCT-A in DR evaluation and multicenter clinical trials [105]. Greig, Duker, and Waheed [106] offered a guide for a more effective OCT-A image analysis by assessing the (1) en face OCT-A image, (2) corresponding B-scans with vessel flow overlay, and (3) structural en face image for each retinal slab using a step-by-step method. As consensus on the elements of quality assurance and interpretation is still lacking, the utility of OCT-A for clinical trials and subsequent centralized reading center image analysis are also limited at present.…”