正确认识OCT血管成像技术的临床应用价值

OCT血管成像(OCTA)是一项无创、快捷的血流检测技术,目前主要用于视网膜脉络膜的血流成像.与传统的荧光素眼底血管造影(FFA)和吲哚青绿血管造影(ICGA)技术不同,OCTA无需静脉注射造影剂就能够对血流信号进行探测和量化分析,并且能够分层观察和判断视网膜脉络膜的血流改变情况,因此OCTA比传统的眼底血管造影技术提供的血流信息更多、更准确.OCTA作为一项具有革命性突破的新技术,在眼科血管性疾病的诊断及血流改变有关眼病的发病机制探讨方面具有划时代的意义.但是,任何新技术的临床应用都有其限制性和局限性,如OCTA观察的眼底范围并不如FFA和ICGA大,且检查和读图过程中也受到一些因素的影响.充分了解OCTA的成像原理和成像特点有助于眼科医师更好地了解视网膜脉络膜疾病、青光眼和神经眼科疾病的血流改变,并加深对这些疾病发病机制的认识,同时利用该技术对相关眼病进行有效监测和随访.     

增强成像技术光学相干断层扫描在在体脉络膜结构研究中的应用

增强成像技术光学相干断层扫描(optical coherence tomography,OCT)是一种较新的眼科检查手段,它是在传统OCT的基础上,增加光源的聚焦深度,实现在体的脉络膜成像,对在体脉络膜进行定量测量.这一技术有助于临床医师认识、诊断和治疗脉络膜视网膜疾病.本文就近年来增强成像技术OCT在眼科研究中的应用加以总结.     

肥厚型脉络膜谱系疾病影像特征研究进展

肥厚型脉络膜谱系疾病(PSD)是近年来被定义的一组具有相似脉络膜解剖学特点及相同病理过程的一组疾病,包括中心性浆液性脉络膜视网膜病变(CSC)、息肉样脉络膜血管病变(PCV)等。其主要特征是脉络膜各血管层厚度改变和血管通透性增强。随着以光学相干断层扫描血流成像(OCTA)为代表的现代眼科影像技术不断发展,使这类疾病脉络膜各血管层的变化得以更直观地呈现,从而对该谱系疾病发病机制研究有了新的认识。本文对健康人及PSD的共同临床特点进行归纳,对各种PSD的最新影像学发现进行综述。从遗传背景及解剖学结构等不同角度,讨论各型PSD是同一疾病不同阶段的表型还是类似特征的不同疾病。以期为该类疾病的发病机制、早期临床诊断及防治提供参考。     

超高分辨率OCT在眼科临床诊疗和基础研究中的应用

光学相干断层扫描(OCT)技术是一种非侵入性、无接触的活体内部形态成像技术,已广泛应用于眼科临床,特别是视网膜疾病领域。近年来出现的超高分辨率OCT通过对黄斑疾病、糖尿病视网膜病变和中心性浆液性脉络膜视网膜病变患者视网膜结构细微变化的测量,能对患者视网膜神经纤维层做出精确分析,可用于探究疾病的病理机制。本文就超高分辨率OCT的技术原理以及在眼科临床诊疗和基础研究中的应用进行综述。     

值得关注的肥厚型脉络膜病变

近年来,随着眼科学影像技术的不断发展,人们对于脉络膜的特征及其在眼底疾病发生发展中的作用的了解不断加深,提出了"肥厚型脉络膜病变"的概念,拓宽了视野。然而目前仍有很多问题需要明晰和探索,如肥厚脉络膜和肥厚血管的概念、多种影像检查时疾病的表现特征、此类疾病之间的关系和转归以及对治疗的反应等。关注这些问题,将有助于提高对此类疾病的临床诊疗水平。     

光学相干断层扫描血管成像在眼科的应用进展

光学相干断层扫描血管成像(OCTA)是近年逐渐兴起的一种眼科非入侵式影像学检查方法,它是在光学相干断层扫描(OCT)的基础上逐渐发展起来并逐步应用于临床。OCTA通过扫描血管内流动的红细胞显示出眼底血流密度与眼底组织结构形态,在眼科相关疾病(尤其是眼底病变)的诊治及疗效评估方面具有很高的价值。OCTA具有高分辨率、易操作、快速扫描、三维成像等优势,现已被应用于眼科疾病(脉络膜新生血管、糖尿病视网膜病变、角膜和虹膜相关疾病、弱视、青光眼等)的评估和诊断。本文就OCTA技术在眼科疾病中的应用进行综述。     

重视自发荧光检测技术在眼底疾病诊断中的应用

目前检查眼底疾病的方法较多,包括荧光素眼底血管造影(FFA),吲哚氰绿脉络膜血管造影(ICGA)及相干光断层扫描(OCT)等,这些检查技术均已在国内外眼底疾病的诊断中被广泛应用.近十年来,国外对眼底自发荧光检测技术在眼底疾病诊断中的价值十分关注,但在我国尚未引起重视,其原因可能与对自发荧光产生的机制和临床意义认识不足有关.为了使国内眼科医师充分认识自发荧光检测技术在眼底疾病中的诊断价值,笔者在阐明自发荧光产生机制的基础上,着重指出自发荧光是一种非侵入性、有发展潜力的眼底成像检测技术,其对多种眼底疾病的早期诊断、病情监控及预后评估等均具有较高的临床应用价值,因而需引起我国眼科医师的高度重视并逐步推广和普及.     

相干光断层扫描血管成像技术临床应用前景

相干光断层扫描(OCT)是眼科发展最迅速的检查之一,而OCT血管成像是近年来OCT发展的新兴领域,是目前唯一无创、无需造影剂的眼底血管成像技术,逐渐被应用于眼底病的临床诊断与鉴别诊断及随诊等方面,在眼科疾病的诊治中有着广阔的应用前景。     

眼前节相干光断层扫描技术的临床应用进展

近年来,相干光断层扫描(OCT)技术在眼前节疾病诊治中的应用飞速发展.由于OCT的分辨率更高、成像效果更好且为无创的非接触测量,所以它在前房参数测量、角膜地形测量及房角测量等方面具有明显的优势.高速、高分辨率的傅立叶OCT技术与传统的时域OCT技术相辅相成,推动和发展OCT在眼科临床中的应用.本文介绍了眼前节OCT的成像原理,结合相应的临床应用展示了OCT在眼前节疾病发病机制研究及诊疗中的价值与局限,并对OCT技术未来的发展进行展望.     

超高分辨率OCT评价外层视网膜微结构

光学相干断层扫描（optical coherence tomography,OCT）是一种光学断层成像技术,具有高分辨力、断层扫描和实时测量的特点,广泛应用于眼科诊断中.随着OCT技术的发展,设备的扫描速度及轴向分辨率大幅度提高,称之为超高分辨率OCT.超高分辨率OCT可以将视网膜外层结构分辨为不同的条带.近些年来,许多研究关注于这些条带在视网膜疾病中的变化,进一步增加了对外层视网膜微结构的认识.此外,通过增强成像技术（enhanced depth imaging-technique,EDI）,脉络膜中的各血管层也可在OCT中呈现清晰完整的像.本文就超高分辨率OCT对于外层视网膜高反射条带所对应的微结构及脉络膜成像的研究进展及临床应用进行综述.     

脉络膜成像技术的进展及其在青光眼临床研究中的应用

脉络膜与青光眼关系的研究一直受限于研究方法而难以深入开展。近年,基于OCT技术的脉络膜成像技术例如增强深部成像OCT（EDI-OCT）和扫频光源OCT（SS-OCT）进入临床应用,青光眼领域借此观察了不同类型青光眼的脉络膜厚度及其有关影响因素,推进了脉络膜厚度与各种青光眼间关系的了解和认识。     

脉络膜血管指数的临床运用研究进展

光学相干断层扫描(optical coherence tomography,OCT)是目前发展迅猛的新型层析成像技术,在眼科应用广泛。目前通过扫频OCT(swept source optical coherence tomography,SS-OCT)增强深度成像光学相干断层扫描(enhanced-depth imaging optical coherence tomography,EDI-OCT)模式可以活体观察视网膜脉络膜横断面。视网膜脉络膜相关疾病的发生发展与脉络膜的结构和功能密切相关,尤其与脉络膜厚度(choroidal thickness,CT)变化有关。因为CT受年龄、眼轴、屈光等多因素影响,所以单纯观察CT不能客观反映上述疾病的病理发生发展过程。近年来运用二值化处理技术对EDI-OCT获取的图像进行量化分析处理后,可得到测量区域脉络膜总面积、管腔面积、基质区面积、脉络膜血管指数(choroidal vascularity index,CVI)等数据。SS-OCT以及衍生的图像处理技术无疑对分析相关疾病的发病机制、疾病的预防及治疗具有重要意义。本文将对运用二值化处理SS-O...     

Retinal applications of swept source optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA)

The advent of optical coherence tomography (OCT) revolutionized both clinical assessment and research of vitreoretinal conditions. Since then, extraordinary advances have been made in this imaging technology, including the relatively recent development of swept-source OCT (SS-OCT). SS-OCT enables a fast scan rate and utilizes a tunable swept laser, thus enabling the incorporation of longer wavelengths than conventional spectral-domain devices. These features enable imaging of larger areas with reduced motion artifact, and a better visualization of the choroidal vasculature, respectively. Building on the principles of OCT, swept-source OCT has also been applied to OCT angiography (SS-OCTA), thus enabling a non-invasive in depth-resolved imaging of the retinal and choroidal microvasculature. Despite their advantages, the widespread use of SS-OCT and SS-OCTA remains relatively limited.In this review, we summarize the technical details, advantages and limitations of SS-OCT and SS-OCTA, with a particular emphasis on their relevance for the study of retinal conditions. Additionally, we comprehensively review relevant studies performed to date to the study of retinal health and disease, and highlight current gaps in knowledge and opportunities to take advantage of swept source technology to improve our current understanding of many medical and surgical chorioretinal conditions. We anticipate that SS-OCT and SS-OCTA will continue to evolve rapidly, contributing to a paradigm shift to more widespread adoption of new imaging technology to clinical practice.     

Serous retinal detachment as a sign of leukemic choroidopathy: A systematic review

Leukemia is a rare disease associated with a high mortality rate. The presence of unilateral or bilateral serous retinal detachment (SRD) as a sign of choroidal infiltration can be one of the manifestations of acute leukemia, both as a primary sign or in a relapse. We consolidated the literature on SRD as a sign of leukemic choroidopathy regarding its epidemiology, clinical manifestations, and main imaging diagnostic tools. Well-documented cases regarding acute lymphoblastic leukemia (ALL), acute myelogenous leukemia (AML), relapsed ALL and relapsed AML published until September, 2020, in peer reviewed journals were included. The literature shows an interesting range of choroidal infiltration cases assessed by modern imaging techniques, such as optical coherence tomography (OCT) with and without enhanced depth imaging (EDI) and fluorescein angiography (FA). These tools allow choroidal assessment and better understanding and characterization of this rare condition. Complete ophthalmological workup should be performed in these patients using both FA and EDI-OCT to assess the choroidal anatomy and integrity. An increase in choroidal thickness measured with EDI-OCT can reveal active disease and potentially diagnose a leukemic relapse promptly.     

Pathophysiology of macular diseases--morphology and function

Ophthalmic fundus imaging plays an important role in the advances in the pathophysiology of retinal diseases. Using fundus imaging, we studied morphological changes in the choroid, subretinal pathophysiology and photoreceptor and retinal pigment epithelial (RPE) cell damage, and functional abnormalities of photoreceptor cells in macular diseases. To evaluate the choroidal changes, we performed enhanced depth imaging optical coherence tomography (EDI-OCT) for macular diseases. Choroidal thickness both in the affected eyes and in the fellow eyes with choroidal vascular hyperpermeability was thicker in patients with central serous chorioretinopathy (CSC). Photodynamic therapy (PDT) reduced the hyperpermeability and led to choroidal thinning in eyes with CSC, whereas laser photocoagulation did not result in any change in choroidal thickness, suggesting different mechanism of action for these two forms of treatment. PDT also decreased choroidal thickness in eyes with polypoidal choroidal vasculopathy. These findings will help to elucidate the pathophysiologic features of CSC as well as responses to treatment. Patients with acute Vogt-Koyanagi-Harada (VKH) disease have markedly thickened choroids. Both the choroidal thickness and the retinal detachment in these patients decreased quickly with corticosteroid treatment. EDI-OCT can be used to evaluate the choroidal involvement in VKH disease in acute stages and may prove useful in the diagnosis and management of this disease. Dome-shaped macula is the result of a localized thickening of the sclera under the macula in highly myopic patients, and it cannot be categorized into any known type of staphyloma. EDI-OCT is helpful in monitoring the proposed site of pathophysiologic changes in the choroid and the sclera, and provides noninvasively information not available by other means. To clarify the subretinal changes and the mechanism of cell damage in macular detachment, we studied the clinical characteristics of yellow deposits (multiple dot-like yellow precipitates and subretinal yellow material) seen in CSC using fundus autofluorescence and OCT. The yellow deposits had highly reflective tissue in the intraretinal and subretinal spaces seen on OCT and hyperfluorescence on short-wave autofluorescence (SW-AF) examinations during the follow-up period. These findings may indicate that formations of yellow deposits are associated with the accumulation of the photoreceptor outer segments and metabolism and phagocytosis by macrophages or RPE cells. SW-AF also demonstrated a hypofluorescence corresponding to the accumulated areas of yellow deposits during the long term followup period. Another study using infrared autofluorescence examination demonstrated that the yellow deposits induced a decrease in melanin and the functional decline of RPE cells in CSC. These may indicate that the existence of depositions in eyes with CSC is associated with photoreceptor and RPE cells damage. Similar yellow deposits can also be seen in eyes with macular detachment, e. g. branch retinal vein occlusion. We report a new method of retinal densitometry using SW-AF examination by scanning laser ophthalmoscope. We named the technique autofluorescence densitometry (AFD). This technique can evaluate photopigment density from serial SW-AF images during exposure to excitation light. This new technique can examine a much broader macular area and create a distribution map of optical density of the photopigments. It is also easy to compare the distribution of the photopigment densities with other retinal imaging devices such as OCT. To investigate functional abnormalities in eyes with CSC, we measured the optical density of the photopigments using AFD in both the acute and quiescent phase. The photopigment density decreased at the serous retinal detachment. The density remained decreased immediately after resolution and showed delayed recovery. The photopigments decreased even in eyes with a morphologic recovery of the outer retina. AFD could identify the functional impairment of the outer retina as characterized by changes in the photopigments.     

Enhanced Depth Imaging Optical Coherence Tomography in Age-related Macular Degeneration

Imaging of the choroidal layer has been limited with the conventional commercial SD-OCTs. Enhanced depth imaging optical coherence tomography (EDI-OCT) is a modification of the standard spectral-domain OCT (SD-OCT) technique that enables better non-invasive imaging of the choroid. This review contains an introduction of EDI imaging technique and principles and summarizes the findings of EDI-OCT imaging in age-related macular degeneration.     

OCT与mf-ERG在CSCR中的应用进展

中心性浆液性脉络膜视网膜病变(CSCR)为我国常见眼底疾病。近年来OCT在研究CSCR视网膜下渗出及分析视网膜结构改变等方面发挥着重要作用,同时脉络膜深层成像OCT(EDI-OCT)清晰地呈现了脉络膜形态学改变。此外,多焦视网膜电图(mf-ERG)证实了CSCR所引起的视网膜功能障碍,OCT和mf-ERG联合应用可以更好的理解CSCR结构和功能异常间的相关性。众多新技术的广泛应用,为CSCR的临床诊治、预后评估及随访提供了线索和依据。     

扫频光学相干断层扫描在眼科的应用进展

精准定性、定量评估眼前节及后节的影像学技术,不仅对多种眼病的准确诊断至关重要,同时也可为治疗方案、手术方式以及随访提供重要参考依据.作为一种分辨率高、非接触无创的成像技术,光学相干断层扫描(optical coherence tomography,OCT)已成为玻璃体视网膜相关疾病必不可少的辅助检查工具.近几年提出的扫频光学相干断层扫描成像(swept-source OCT,SS-OCT)技术,具备扫描速度提高及穿透深度加深的优点,同时运用不同成像系统可获得眼部不同层次结构精准的成像.新型的SS-OCT成像技术可用于评估眼前节结构,如角膜移植术后角膜瓣、前房参数等检查,也加深了对玻璃体视网膜相关疾病如糖尿病性黄斑病变、眼底新生血管的转归和黄斑毛细血管扩张等疾病病理形态改变的认识.同时,运用玻璃体增强成像(enhanced vitreous visualization,EVV)、分层扫描(En face SS-OCT)和SS-OCT血管造影等成像系统,可为眼底相关疾病,如玻璃体后脱离、视网膜前膜、视网膜脱离、糖尿病牵拉性视网膜脱离等手术适应证制定最佳的治疗方案并协助术后随访.此外,该技术还为多种眼部疾病如青光眼、眼肿瘤的病理形态学观察提供精准的微结构成像图.本文主要对SS-OCT的技术原理及临床应用进展等方面进行综述.