Chalam K V, Sambhav Kumar
Department of Ophthalmology, University of Florida College of Medicine, Florida, USA.
J Ophthalmic Vis Res. 2016 Jan-Mar;11(1):84-92. doi: 10.4103/2008-322X.180709.
Optical coherence tomography angiography (OCTA) is a new, non-invasive imaging system that generates volumetric data of retinal and choroidal layers. It has the ability to show both structural and blood flow information. Split-spectrum amplitude-decorrelation angiography (SSADA) algorithm (a vital component of OCTA software) helps to decrease the signal to noise ratio of flow detection thus enhancing visualization of retinal vasculature using motion contrast. Published studies describe potential efficacy for OCTA in the evaluation of common ophthalmologic diseases such as diabetic retinopathy, age related macular degeneration (AMD), retinal vascular occlusions and sickle cell disease. OCTA provides a detailed view of the retinal vasculature, which allows accurate delineation of microvascular abnormalities in diabetic eyes and vascular occlusions. It helps quantify vascular compromise depending upon the severity of diabetic retinopathy. OCTA can also elucidate the presence of choroidal neovascularization (CNV) in wet AMD. In this paper, we review the knowledge, available in English language publications regarding OCTA, and compare it with the conventional angiographic standard, fluorescein angiography (FA). Finally, we summarize its potential applications to retinal vascular diseases. Its current limitations include a relatively small field of view, inability to show leakage, and tendency for image artifacts. Further larger studies will define OCTA's utility in clinical settings and establish if the technology may offer a non-invasive option of visualizing the retinal vasculature, enabling us to decrease morbidity through early detection and intervention in retinal diseases.
光学相干断层扫描血管造影（OCTA）是一种新型的非侵入性成像系统，可生成视网膜和脉络膜层的容积数据。它能够显示结构和血流信息。分裂频谱幅度去相关血管造影（SSADA）算法（OCTA软件的一个重要组成部分）有助于降低血流检测的信噪比，从而利用运动对比度增强视网膜血管系统的可视化。已发表的研究描述了OCTA在评估常见眼科疾病如糖尿病视网膜病变、年龄相关性黄斑变性（AMD）、视网膜血管阻塞和镰状细胞病方面的潜在疗效。OCTA提供了视网膜血管系统的详细视图，这使得能够准确描绘糖尿病性眼病中的微血管异常和血管阻塞情况。它有助于根据糖尿病视网膜病变的严重程度量化血管损伤。OCTA还可以阐明湿性AMD中脉络膜新生血管（CNV）的存在。在本文中，我们回顾了英文出版物中关于OCTA的知识，并将其与传统血管造影标准荧光素血管造影（FA）进行比较。最后，我们总结了其在视网膜血管疾病中的潜在应用。其目前的局限性包括视野相对较小、无法显示渗漏以及图像伪影的倾向。进一步的大型研究将确定OCTA在临床环境中的效用，并确定该技术是否可以提供一种可视化视网膜血管系统的非侵入性选择，使我们能够通过早期检测和干预视网膜疾病来降低发病率。
