Optical coherence tomography angiography: an overview of the technology and an assessment of applications for clinical research

Abstract

In recent years, ophthalmology has experienced significant developments with respect to imaging modalities. Optical coherence tomography angiography is one such technology that seeks to improve diagnostics for retinal diseases. Using standard structural ocular coherence tomography hardware, optical coherence tomography angiography demonstrates the ability to non-invasively visualise the vasculature in the retina and the choroid with high resolution, allowing greater insight into retinal vascular pathologies. In addition, retinal and choroidal vessel density and blood flow can be quantified, offering potential to assist in the diagnosis of a variety of retinal diseases. To date, numerous retinal diseases, such as open-angle glaucoma, have been found to possess a vascular component. Specifically, ischaemia of the optic nerve head and lamina cribrosa has been theorised as a causative factor in ganglion cell death; however, confirmation of this mechanism has been prohibited by the limitations of currently existing imaging modalities. Optical coherence tomography angiography provides clear imaging of these regions and the possibility to elucidate further understanding of vascular factors that contribute to glaucoma development and progression. Furthermore, this imaging modality may provide insight to neural pathologies with vascular components such as Alzheimer's disease. Herein, the authors discuss the theory of operation for optical coherence tomography angiography and the current findings from pilot studies with a focus on open-angle glaucoma. In addition, speculation is offered for future applications of the technology to study other diseases with microvascular contributions.

Evaluation of optical coherence tomography angiographic findings in Alzheimer’s type dementia

“…Therefore, retinal blood flow rate results reported by the studies using retinal laser Doppler flowmetry in ATD are limited 6 13. In a review conducted by Koustenis et al 22 regarding OCTA, they argued that imaging with OCTA for retinal flow measurement could yield better results. Our study is the first in the literature also on this matter.…”

Integrated bioinformatics analysis of aberrantly-methylated differentially-expressed genes and pathways in age-related macular degeneration

“…Optical coherence tomography (OCT) is a noninvasive imaging modality that produces high-resolution, cross-sectional images of ocular tissues. Compared to time-domain OCT, spectral-domain OCT yields a higher degree of axial resolution and provides more detailed views of intraretinal structure [52]. Swept-source OCT can offer improved images of the choroid and pigmented lesions [53].…”

Optical coherence tomography angiography of the macular microvasculature changes in retinitis pigmentosa

“…Recent studies using OCTA have validated the concept that the deficits in retinal microvasculature have an important role in the pathophysiology of degeneration in the retina and optic nerve (Koustenis et al. ). A decrease in vessel density was observed in patients with glaucoma (Leveque et al.…”