Controlling for Artifacts in Widefield Optical Coherence Tomography Angiography Measurements of Non-Perfusion Area

• Published in: Scientific reports Vol. 9; no. 1; pp. 9096 - 15
• Main Authors: De Pretto, Lucas R., Moult, Eric M., Alibhai, A. Yasin, Carrasco-Zevallos, Oscar M., Chen, Siyu, Lee, ByungKun, Witkin, Andre J., Baumal, Caroline R., Reichel, Elias, de Freitas, Anderson Zanardi, Duker, Jay S., Waheed, Nadia K., Fujimoto, James G.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 24.06.2019; Nature Publishing Group
• Subjects: 639/624/1107/510; 692/699/3161/3175; Angiography; Diabetes mellitus; Diabetic retinopathy; Humanities and Social Sciences; Humans; Image Processing, Computer-Assisted; Medical imaging; multidisciplinary; Perfusion; Quantitative analysis; Retina; Retinopathy; Science; Science (multidisciplinary); Segmentation; Signal-To-Noise Ratio; Tomography; Tomography, Optical Coherence
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-019-43958-1

The recent clinical adoption of optical coherence tomography (OCT) angiography (OCTA) has enabled non-invasive, volumetric visualization of ocular vasculature at micron-scale resolutions. Initially limited to 3 mm × 3 mm and 6 mm × 6 mm fields-of-view (FOV), commercial OCTA systems now offer 12 mm × 12 mm, or larger, imaging fields. While larger FOVs promise a more complete visualization of retinal disease, they also introduce new challenges to the accurate and reliable interpretation of OCTA data. In particular, because of vignetting, wide-field imaging increases occurrence of low-OCT-signal artifacts, which leads to thresholding and/or segmentation artifacts, complicating OCTA analysis. This study presents theoretical and case-based descriptions of the causes and effects of low-OCT-signal artifacts. Through these descriptions, we demonstrate that OCTA data interpretation can be ambiguous if performed without consulting corresponding OCT data. Furthermore, using wide-field non-perfusion analysis in diabetic retinopathy as a model widefield OCTA usage-case, we show how qualitative and quantitative analysis can be confounded by low-OCT-signal artifacts. Based on these results, we suggest methods and best-practices for preventing and managing low-OCT-signal artifacts, thereby reducing errors in OCTA quantitative analysis of non-perfusion and improving reproducibility. These methods promise to be especially important for longitudinal studies detecting progression and response to therapy.