Optical coherence tomography angiography.

PURPOSE

To compare the quality of four OCT-angiography(OCT-A) modules.

METHOD

The retina of nineteen healthy volunteers were scanned with four OCT-devices (Topcon DRI-OCT Triton Swept-source OCT, Optovue RTVue-XR, a prototype Spectralis OCT2, Heidelberg-Engineering and Zeiss Cirrus 5000-HD-OCT). The device-software generated en-face OCT-A images of the superficial (SCP) and deep capillary plexuses (DCP) were evaluated and scored by 3 independent retinal imaging experts. The SCP vessel density was assessed using Angiotool-software. After the inter-grader reliability assessment, a consensus grading was performed and the modules were ranked based on their scoring.

RESULTS

There was no significant difference in the vessel density among the modules (Zeiss 48.7±4%, Optovue 47.9±3%, Topcon 48.3±2%, Heidelberg 46.5±4%, p = 0.2). The numbers of discernible vessel-bifurcations differed significantly on each module (Zeiss 2±0.9 bifurcations, Optovue 2.5±1.2, Topcon 1.3±0.7 and Heidelberg 0.5±0.6, p≤0.001). The ranking of each module differed depending on the evaluated parameter. In the overall ranking, the Zeiss module was superior and in 90% better than the median (Bonferroni corrected p-value = 0.04). Optovue was better than the median in 60%, Topcon in 40% and Heidelberg module in 10%, however these differences were not statistically significant.

CONCLUSION

Each of the four evaluated OCT-A modules had particular strengths, which differentiated it from their competitors.

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OCT-angiography: A qualitative and quantitative comparison of 4 OCT-A devices.

Early microvascular damage in diabetes (eg capillary nonperfusion and ischemia) can now be assessed and quantified with optical coherence tomography-angiography (OCT-A) The morphology of vascular tissue is indeed affected by different factors; however, there is a paucity of data examining whether OCT-A metrics are influenced by ocular, systemic and demographic variables in subjects with diabetes We conducted an observational cross-sectional study and included 434 eyes from 286 patients with diabetes Foveal avascular zone (FAZ) area, FAZ circularity, total and parafoveal vessel density (VD), fractal dimension (FD), and vessel diameter index (VDI) from the superficial capillary plexus OCT-angiogram were measured by a customized automated image analysis program We found that diabetic retinopathy (DR) severity was associated with increased FAZ area, decreased FAZ circularity, lower VD, lower FD, and increased VDI Enlarged FAZ area was correlated with shorter axial length and thinner central subfield macular thickness Decreased FAZ circularity was correlated with a reduction in visual function Decreased VD was correlated with thinner macular ganglion-cell inner plexiform layer Increased VDI was correlated with higher fasting glucose level We concluded that the effects of ocular and systemic factors in diabetics should be taken into consideration when assessing microvascular alterations via OCT-A

/pdf/determinants-of-quantitative-optical-coherence-tomography-4amg7cqs5e.pdf

Determinants of Quantitative Optical Coherence Tomography Angiography Metrics in Patients with Diabetes.

Imaging Protocols in Clinical Studies in Advanced Age-Related Macular Degeneration: Recommendations from Classification of Atrophy Consensus Meetings.

Background Glaucoma is the leading cause of irreversible blindness worldwide. Several techniques exist for the diagnosis and follow-up of patients. Optical coherence tomography (OCT) angiography (OCTA) is a recently developed technique that provides a quantitative assessment of the microcirculation of the retina and choroid in a fast, noninvasive way. Despite it being a novel technique, several publications have already been done in the glaucoma field. However, a summary of findings is currently lacking. Aims To perform a literature review to assess the role of OCTA in glaucoma diagnosis and follow-up. Methods A database search was carried out using MEDLINE, Embase, and Web of Science, including all original works registered until July 23, 2017. Results OCTA (1) has a high repeatability and reproducibility, (2) has good discriminatory power to differentiate normal eyes from glaucoma eyes, (3) is more strongly correlated with visual function than conventional OCT, (4) has good discriminatory power to differentiate early-glaucoma eyes from normal eyes (i.e., at least equal to that of OCT), (5) reaches a floor effect at a more advanced disease stage than OCT, and (6) is able to detect progression in glaucoma eyes. Conclusion OCTA shows potential to become a part of everyday glaucoma management.

/pdf/optical-coherence-tomography-angiography-in-glaucoma-a-2o8mh1kziy.pdf

Optical Coherence Tomography Angiography in Glaucoma: A Review.

Optical coherence tomography (OCT) angiography (OCTA) is a novel, noninvasive, three-dimensional imaging technique that allows for the visualization of intravascular flow in the microvasculature. Swept-source OCT technology utilizes longer-wavelength infrared light than conventional spectral-domain OCT. This enables improved penetration into tissue and imaging through optical opacities and is invisible to the subject. Topcon has recently developed an innovative OCTA algorithm, OCTARA (OCTA Ratio Analysis), which benefits from being paired with swept-source OCT. OCTARA aims to provide improved detection sensitivity of low blood flow and reduced motion artifacts without compromising axial resolution. In this chapter, we describe the implementation of OCTARA with swept-source OCT technology, the technical specifications of acquisition (e.g. the number of scans, area of examination field, etc.) along with the algorithm's function and principles for analysis of B-scan data to achieve angiographic visualization. Examples of OCTA scans performed using the OCTARA algorithm and a comparison of these scans with images obtained using other technologies are also presented.

Swept-Source Optical Coherence Tomography Angio™ (Topcon Corp, Japan): Technology Review.

Purpose: To describe the optical coherence tomography (OCT) angiography (OCTA) features of diabetic retinopathy. Methods: Re

New Findings in Diabetic Maculopathy and Proliferative Disease by Swept-Source Optical Coherence Tomography Angiography

Purpose: To describe the optical coherence tomography (OCT) angiography (OCTA) features of paediatric macular pathologies. Methods: Retrospective serial case reports of patients who underwent routine clinical examination and OCTA of the posterior pole using both a DRI OCT Atlantis prototype and Triton Swept-Source OCT. When considered necessary, imaging was performed using Optos wide-field imaging or another non-invasive imaging system. The findings were compared with the current literature. Results: Three cases with X-linked retinoschisis, 2 with epiretinal membrane, 1 with Best disease and 2 with Coats disease are fully illustrated. Conclusion: OCTA is an effective, non-invasive imaging technique that can offer additional information regarding the morphologies and vascular characteristics of macular lesions in paediatric ophthalmology. Because of the rarity and characteristics of many paediatric macular pathologies, further multi-centric research is required with regard to the utilisation and features of OCTA imaging.

Tim Cole

Papers

Swept-Source Optical Coherence Tomography Angio™ (Topcon Corp, Japan): Technology Review.

New Findings in Diabetic Maculopathy and Proliferative Disease by Swept-Source Optical Coherence Tomography Angiography

Swept-Source Optical Coherence Tomography Angiography of Paediatric Macular Diseases

Ultra-wide field swept-source optical coherence tomography angiography (uwf ss oct-a) in diabetic retinopathy