Optical coherence tomography angiography: A comprehensive review of current methods and clinical applications

Abstract

OCT has revolutionized the practice of ophthalmology over the past 10 to 20 years. Advances in OCT technology have allowed for the creation of novel OCT-based methods. OCT-Angiography (OCTA) is one such method that has rapidly gained clinical acceptance since it was approved by the FDA in late 2016. OCTA images are based on the variable backscattering of light from the vascular and neurosensory tissue in the retina. Since the intensity and phase of backscattered light from retinal tissue varies based on the intrinsic movement of the tissue (e.g. red blood cells are moving, but neurosensory tissue is static), OCTA images are essentially motion-contrast images. This motion-contrast imaging provides reliable, high resolution, and non-invasive images of the retinal vasculature in an efficient manner. In many cases, these images are approaching histology level resolution. This unprecedented resolution coupled with the simple, fast and non-invasive imaging platform have allowed a host of basic and clinical research applications. OCTA has been shown to demonstrate many important clinical findings including areas of macular telangiectasia, impaired perfusion, microaneurysms, capillary remodeling, some types of intraretinal fluid, and neovascularization among many others. More importantly, OCTA provides depth-resolved information that has never before been available. Correspondingly, OCTA has been used to evaluate a spectrum of retinal vascular diseases including diabetic retinopathy (DR), retinal venous occlusion (RVO), uveitis, retinal arterial occlusion, and age-related macular degeneration among others. In this review, we will discuss the methods used to create OCTA images, the practical applications of OCTA in light of invasive dye-imaging studies (e.g. fluorescein angiography) and review clinical studies demonstrating the utility of OCTA for research and clinical practice.

Optical coherence tomography angiography monitors human cutaneous wound healing over time

“…One such method whose high sensitivity has already been shown to be successful in the visualization of functional vasculatures in small animal models and human tissues, such as skin and eye (43)(44)(45) is optical microangiography (OMAG) (39,(46)(47)(48). The recent development of OMAG for imaging dynamic blood perfusion within tissue beds was heralded as one of the most significant extensions of conventional OCT, and has been successfully translated to clinical ophthalmic imaging (45,(49)(50)(51). Here, we present a clinical prototype OMAG system that was specially designed for dermatological applications for high resolution monitoring of the microcirculatory and structural features underlying the processes of wound healing in otherwise healthy skin.…”

Looking into the eye of patients with chronic obstructive pulmonary disease: an opportunity for better microvascular profiling of these complex patients

“…In addition to OCT, recently OCT angiography (OCTA) has been introduced with a superior view to look at the microvasculature (Kashani et al. ; Tan et al. ).…”

“…The technique allows detailed study of flow within vascular structures of the eye and has the potential to improve diagnosis and monitoring of various retinal vascular abnormalities (Kashani et al. ; Tan et al. ).…”

A noninvasive imaging and measurement using optical coherence tomography angiography for the assessment of gingiva: An in vivo study

“…From its initial success in eye imaging, OCTA has demonstrated its ability to separate dynamic and static signals, colloquially known as vascular and nonvascular signals. OCT and OCTA are most successfully used in ophthalmology . Its unique capability to provide high‐resolution three‐dimensional (3D) visualization of microcirculation networks has also gained significant interests in neuroimaging and dermatology applications .…”