ID-OCTA:OCT angiography based on inverse SNR and decorrelation features

Optical coherence tomography angiography(OCTA)takes the flowing red blood cells(RBCs)as intrinsic contrast agents,enabling fast and three-dimensional visualization of vasculature per-fusion down to capillary level,without a requirement of exogenous fluorescent injection.Various motion-contrast OCTA algorithms have been proposed to effectively extract dynamic blood flow from static tissues utilizing the different components of OCT signals(including amplitude,phase and complex)with various operations(such as differential,variance and decorrelation).Those algorithms promote the application of OCTA in both clinical diagnosis and scientific research.The purpose of this paper is to provide a systematical review of OCTA based on the inverse SNR and decorrelation features(ID-OCTA),mainly including the OCTA contrast origins,ID-OCTA imaging,quantification and applications.

Advances in swept-source optical coherence tomography and optical coherence tomography angiography

Background:The fast development of swept-source optical coherence tomography(SS-OCT)and swept-source optical coherence tomography angiography(SS-OCTA)enables both anterior and posterior imaging of the eye.These techniques have evolved from a research tool to an essential clinical imaging modality.Main text:The longer wavelength and faster speed of SS-OCT and SS-OCTA facilitate better visualization of structure and vasculature below pigmented tissue with a larger field of view of the posterior segment and 360-degree visualization of the anterior segment.In the past 10 years,algorithms dealing with OCT and OCTA data also vastly improved the image quality and enabled the automated quantification of OCT-and OCTA-derived metrics.This technology has enriched our current understanding of healthy and diseased eyes.Even though the high cost of the systems currently limited the widespread use of SS-OCT and SS-OCTA at the first beginning,the gap between research and clinic practice got obviously shortened in the past few years.Conclusions:SS-OCT and SS-OCTA will continue to evolve rapidly,contributing to a paradigm shift toward more widespread adoption of new imaging technology in clinical practice.

Digital subtraction angiographic characteristics of progression of moyamoya disease 6 months prior to surgical revascularisation

background Evidence on the natural angiographic course of moyamoya disease(MMD)is lacking.It takes about 6 months for waiting for revascularisation surgery.The issue of when to perform subtraction angiography(DSA)for follow-up remains unclear.We investigated the natural course of MMD by DSA and attempted to determine the best interval to perform the follow-up DSA.Methods This is a single-centre cohort study of Chinese MMD inpatients treated from 1 January 2015 to 31 August 2019.Their angiographic findings were evaluated on Suzuki stage and collateral circulation between two follow-ups of the same hemisphere.results A total of 110 patients who met the criteria were enrolled in this study.After a median 6 months follow-up,five patients(4.5%)had progression,four females and one male.Time interval of progression ranged from 4 to 137 months with a mean of 61.4 months.Of five patients with progression,four had unilateral lesion(two ipsilateral and two contralateral)and one had bilateral lesions.Collateral circulation was changed in three of five patients.Conclusions The angiographic evidence of progression in MMD was rare in the short-term follow-up,and most patients with progression had initial unilateral involvement.DSA re-examination may be not needed in patients with bilateral MMD,but needed in unilateral MMD.