背景：目前已有研究报道了一种MATLAB的定制算法，用于Triton光学相干断层扫描血管成像(optical coherence tomography angiography，OCTA)图像的中心凹无血管区(fovea avascular zone，FAZ)的自动测量。由于这种算法非开源，且难以获取，因而大大限制了其在临床实践和科学研究中的应用。本研究提出一种用于Triton OCTA图像的FAZ自动分割的开源算法，即Smooth Level Sets macro(SLSM)算法，并将其测量结果与MATL AB和人工方法相比较，评估该算法分割的准确性和可靠性。方法：纳入35位健康受试者的35只健眼，选用Triton OCTA机器中的3 mm×3 mm扫描模式，对其黄斑区进行连续4次扫描。分别用人工和自动方法(包括MATL AB和SLSM)，测量浅层毛细血管图像中FAZ的面积、周长和圆度。分析各种自动算法的准确性、重复性，以及与人工方法结果的一致性。结果：SLSM算法的准确性仅低于人工方法，而高于MATLAB算法(Dice系数：人工方法，0.9568；SLSM，0.9506；MATL AB，0.9483)。SLSM和MATL AB测量FAZ面积的重复性均很高[组内相关系数(intraclass correlation coefficient，ICC)：SLSM，0.987；MATLAB，0.983]。SLSM、MATLAB测量FAZ面积的结果均与人工方法呈很高的一致性(ICC：SLSM，0.973；MATL AB，0.968)。结论：SLSM在Triton OCTA图像的FAZ自动分割中的准确性高于MATL AB，其测量结果与人工测量结果很相近。作为免费和开源的资源，SLSM有望成为Triton OCTA图像中有效可靠的FAZ自动分割和测量方法。
Background: Previous studies have proposed an automated customized program named MATLAB used in the foveal avascular zone (FAZ) measurements in Triton optical coherence tomography angiography (OCTA) images. But it is not open-source and not easy to obtain, which will largely restrict its application in clinical practice and medical research. In this study, we aimed to investigate the feasibility of the Smooth Level Sets macro (SLSM), a free and open-source program, and compared with the manual measurements and MATLAB in the FAZ quantification in Triton OCTA. Methods: Thirty-five eyes of 35 healthy subjects were scanned four times continuously using Triton OCTA. Manual and automated methods including the SLSM and MATLAB were used in the FAZ metrics (area, perimeter, and circularity) of the superficial capillary plexus. The accuracy, repeatability of all methods, and agreement between automated and manual methods were analyzed. Results: The SLSM presented higher accuracy with a higher average Dice coefficient (0.9506) than MATLAB (0.9483), which was just second to the manual method (0.9568). Both the SLSM [intraclass correlation coefficient (ICC) =0.987; coefficient of variation (CoV) =3.935%] and MATLAB (ICC =0.983; CoV =4.165%) showed excellent repeatability for the FAZ area. They also had excellent agreement with manual measurement (SLSM, ICC =0.973; MATLAB, ICC =0.968). Conclusion: The SLSM exhibits better accuracy than MATLAB in the automated FAZ measurement in Triton OCTA, the results of which were comparable to those obtained by manual measurement. This free and open-source program may be an accessible and feasible option for automated FAZ segmentation on Triton OCTA images.
视网膜微循环与脑小血管具有相似的特征。视网膜被认为是可检测到的“窗口”，以检测在神经退行性疾病中发生的微血管损伤。光学相干断层扫描血管造影(optical coherence tomography angiography，OCTA)是一种非侵入性成像方式，可提供视网膜、脉络膜和视神经中血流的深度分辨图像。现总结有关OCTA在与眼科相关的阿尔茨海默病、帕金森病、多发性硬化症及视神经退行性疾病等神经系统疾病中的应用，并讨论其可否作为早期诊断和监测神经退行性疾病的重要工具。
Retinal microcirculation shares similar features with cerebral small blood vessels. Thus, the retina may be considered as an accessible ‘window’ to detect the microvascular damage occurred during the development and progression of neurodegenerative disorders. Optical coherence tomography angiography (OCTA) is a non-invasive imaging modality providing in-depth and high-resolved images of blood flow in the retina, choroid,and optic nerve. In this review, we summarize the current advances in the application of OCT-A in neurological diseases associated with ophthalmology such as Alzheimer’s disease, Parkinson’s disease, multiple sclerosis and optic nerve degenerative diseases. Future directions for evaluating whether OCTA can be used as an important tool to early diagnose and monitor the neurodegenerative disorders are also discussed.
光学相干断层扫描血管成像(optical coherence tomography angiography，OCTA)是一种非接触、无创的、快速的血管造影技术，它通过检测红细胞在血管内的光学相干断层扫描(optical coherence tomography，OCT)信号的变化来提供血管影像。由于这项技术不需要注射血管造影剂，使得它比传统的眼科血管造影技术更安全。在前节疾病的检查中，OCTA不仅能够量化前节血管的范围和密度，还显示出良好的成像质量，为临床监测疾病的病程和对治疗的反应提供客观的评价。
Optical coherence tomography angiography (OCTA) is a noncontact, noninvasive, and rapid angiography technique. It provides vascular images by detecting changes in the optical coherence tomography (OCT) signal of red blood cells in the blood vessel. Since this technique does not require injection of angiography, it is safer than traditional ophthalmic angiography. In the examination of anterior segment diseases, OCTA can not only quantify the range and density of anterior segment blood vessels, but also shows good imaging quality, providing an objective evaluation for clinical monitoring of the disease course and response to treatment.
光学相干断层扫描血管成像术(optical coherence tomography angiography，OCTA)作为一项新兴的检查手段，现已被广泛应用于眼科临床及科研工作中。鉴于OCTA在血管成像方面的独特优势，近年来关于其在眼前段的临床应用和研究也愈发得到关注。关于OCTA对结膜、巩膜、角膜以及虹膜的血管和相关眼表疾病的研究日益增多，其在眼前段应用潜力巨大。
As a new examination method, optical coherence tomography angiography (OCTA) has been increasingly used in ophthalmology clinical work and scientific research. In view of the unique advantages of OCTA in angiography,the clinical application and research of OCTA in the anterior segment have attracted more and more attention in recent years. Studies of OCTA in vessels of conjunctiva, sclera, cornea, iris, and related ocular surface diseases have shown great potential for its application in the anterior segment.
目的：应用Cirrus HD-OCT 5000对正常眼黄斑及视盘血流参数进行血管成像测量，评估其可重复性及再现性。方法：纳入40只正常眼进行前瞻性研究。操作者A于一周内3天的同一时段(T1，T2，T3)对正常受试者的同一眼黄斑及视盘进行3次血管成像扫描，扫描过程中均开启FastTracTM图像跟踪功能，操作者B在T 2时间点再次对受试者同一眼进行相同程序扫描，使用Angio PlexMetrixTM量化软件(版本10.0)自动测量黄斑和视盘的血管长度密度(vessel length density，VD)和血管灌注密度(vascular perfusion density，PD)。应用单因素方差分析或非参数检验比较3次扫描的VD、PD是否有差异。采用组内相关系数(intraclass correlation coefficient，ICC)、变异系数(coefficient of variation，CV)评价操作者A的可重复性，采用一致性相关系数(consistent correlation coefficient，CCC)、重复性系数(repeatability coefficient，CR)、C V评价操作者间的再现性。结果：操作者A对黄斑及视盘各区域3次扫描的V D、P D之间差异无统计学意义(P >0.05)。操作者A对黄斑和视盘V D、PD 3次扫描的ICC值分别为0.260~0.517、0.362~0.898，黄斑及视盘各区域V D、P D的C V值均<8.1%。黄斑和视盘V D、P D的操作者间CCC值分别为0.3130~0.5665、0.5149~0.7801；黄斑VD和PD的CR值分别为3.2212~4.6399、0.0574~0.0832；视盘VD和PD的CR值分别为2.0675~4.0630、0.0447~0.0730。黄斑CV值均<9.0%，视盘CV值均<6.9%。结论：非同日的同一时段视盘浅层血流参数具有较好的重复性及再现性，黄斑浅层血流参数的重复性及再现性相对较差。
Objective: To evaluate the repeatability and reproducibility of quantification of macular and peri-papillary superficial capillaries in normal eyes using Cirrus HD-OCT 5000 angiography. Methods: Forty normal eyes were included in this prospective study. Angiography 3 mm × 3 mm scan protocol centered on the disc or macula of the same eye was repeated 3 times by operator A in the same period on 3 days (T1, T2, T3) within 1 week,and the FastTracTM image tracking function was turned on during the scan. Operator B repeated the same scan independently at T2 after operator A. Angio Plex MetrixTM quantification software (version 10.0) was used to automatically measure the vessel length density (VD) and vascular perfusion density (PD) of macular and peri-papillary superficial capillaries. One-way analysis of variance or nonparametric test was used to compare the VD and PD measurements of the 3 scans. The intraclass correlation coefficient (ICC) and coefficient of variation (CV)were calculated to evaluate the intra-operator repeatability. Consistent correlation coefficient (CCC), repeatability coefficient (CR), and CV were calculated to evaluate the inter-operator reproducibility. Results: There was no statistically significant difference in the measurements of VD and PD between the 3 scans of the macular and peri-papillary superficial capillaries by operator A (P>0.05). The ICC values for the 3 scans of VD and PD of the macular and peri-papillary superficial capillaries by operator A were 0.260–0.517 and 0.362~0.898, respectively.The CV values of the VD and PD of the macular and peri-papillary superficial capillaries were all <8.1%. The inter-operator CCC values of the macular and peri-papillary superficial capillaries were 0.3130–0.5665 and 0.5149~0.7801,respectively; the CR values of the VD and PD of macula were 3.2212–4.6399 and 0.0574–0.0832, respectively; the CR values of the VD and PD of optic disc were 2.0675–4.0630 and 0.0447–0.0730, respectively. The CV values of macular were all <9.0%, and the CV values of optic disc were all <6.9%. Conclusion:The macular and peri-papillary superficial capillaries parameters in the same period on different days have a good repeatability and reproducibility,while the superficial macular blood flow parameters have relatively poor repeatability and reproducibility.
目的：探讨光学相干断层扫描血管成像(optical coherence tomography angiography，OCTA)扫描信号强度对视盘周围血管密度的影响。方法：本研究为单中心横断面研究，所有受试者分别接受了身高、体重、血压、眼压、眼轴及视盘OCTA检查，利用广义估计方程分析OCTA扫描信号强度对视盘周围血管密度的影响。结果：共186人359眼纳入本研究，年龄为(47.86±17.86)岁，视盘周围血管密度为(17.75±1.99)mm?1 。单因素分析显示视盘周围血管密度与眼轴呈负相关(β=?0.5120，P<0.001)，与扫描信号强度呈正相关(β=1.0240，P<0.001)。在校正了年龄、性别、视盘面积及眼轴后的多因素分析中，OCTA扫描信号强度依然与视盘周围血管密度显著正相关(β=0.9721，P<0.001)。结论：视盘周围血管密度不仅与眼轴和视盘面积显著负相关，而且与OCTA扫描信号强度显著正相关，在临床应用或研究中，需要考虑其影响。
Objective: To explore the effect of scanning signal intensity on the peripapillary vessel density measured by optical coherence tomography angiography (OCTA). Methods: This study was a single-center cross-sectional study. All the participants received comprehensive examinations including height, weight, blood pressure,intraocular pressure, axial length, and OCTA scan of the optic disc. The effect of OCTA scanning signal intensity on the peripapillary vessel density was analyzed using the generalized estimation equation. Results: A total of 186 participants with 359 eyes were included in this study. The mean age of all the participants was (47.86±17.86)years old, and the average peripapillary vessel density was (17.75±1.99)mm?1. In a univariate analysis,peripapillary vessel density was associated with the axial length (β=?0.5120, P<0.001) and the scanning signal intensity (β=1.0240, P<0.001). After adjusting for age, gender, axial length, and optic disc area in the multivariate analysis, the OCTA scanning signal intensity was still significantly associated with the peripapillary vessel density (β=0.9721, P<0.001). Conclusion: The peripapillary vessel density is significantly negatively associated with the axial length and optic disc area, significantly positively associated with the scanning signal intensity. In clinical practice, the influence needs to be considered.
目的：探讨光学相干断层扫描血管成像(optical coherence tomography angiography，OCTA)在糖尿病性视网膜病变中的应用。方法：选取2021年中山大学附属第七医院眼科63例糖尿病患者为研究对象，分为无糖尿病性视网膜病变(T0，21眼)、轻度非增殖期(T1，21眼)、中重度非增殖期(T2，14眼)及增殖期(T3，7眼)。收集各组生化指标，包括空腹血糖、糖化血红蛋白、谷丙转氨酶、谷草转氨酶、碱性磷酸酶、血清尿素氮、肌酐、尿素氮肌酐比值，及OCTA数据，即中心视网膜厚度、Angiography3×3及Angiography6×6血管线性密度及血管灌注密度等。采用单因素方差分析比较各组间差异。结果：T2组、T3组与T0组相比，T3组与T1组相比，糖尿病病程延长；T3组与其他各组相比，尿素氮升高；T1组、T2组、T3组与T0组相比，T3组与T1组相比，6 mm ×6 mm外层血流线性密度减少；与T0组相比，T1组、T2组及T3组6 mm ×6 mm完整血流线性密度减少；与T0相比，T2组、T3组6 mm ×6 mm外层血流灌注密度减少；与T0组相比，T3组6 mm ×6 mm完整血流灌注密度减少；T2组、T3组与T0组相比，T3与T1相比，3 mm ×3 mm内层血流线性密度明显减少；T3组与T0组及T1组相比，3 mm ×3 mm完整血流线性密度减少。结论：随着糖尿病性视网膜病变的进展，患者的尿素氮及肌酐逐渐升高，OCTA的血流线性密度及血流灌注密度逐渐减少。与血流灌注密度相比，血流线性密度对于早期糖尿病性视网膜病变筛查可能更为敏感。而利用Angiography6×6模式可能可以更早地发现糖尿病性视网膜病变的视网膜血流变化。
Objective: To explore the applications of optical coherence tomography angiography (OCTA) in diabetic retinopathy. Methods: A total of 63 diabetic patients in the Department of Ophthalmology, Seventh Affiliated Hospital of Sun Yat-sen University in 2021 were divided into 4 groups: the patients without diabetic retinopathy (T0, n=21), mild non-proliferative diabetic retinopathy (T1, n=21), moderate-to-severe non-proliferative diabetic retinopathy (T2, n=14) and proliferative diabetic retinopathy (T3, n=7). Biochemical Indicators were collected in all patients, such as fasting plasma glucose (FPG), glycated hemoglobin A1c (HbA1c), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), the blood urea nitrogen (BUN), creatinine (CRE) and the ratio of blood urea nitrogen and creatinine (BUN/CRE). The Macular Cube 521×128, Angiography3×3, and Angiography6×6 models of OCTA were used to obtain central retinal thickness (CRT), vascular density (VD) and perfusion density (PD) of each group. The data of all subjects was applied to do one-way ANOVA. Results: Prolonged duration of diabetes in T2 and T3 compared to T0 and in T3 compared to T1. Elevated BUN in T3 compared to all other groups. When T1, T2 and T3 were compared to T0, and T3 was compared to T1, the VD of the 6 mm ×6 mm outer layer decreased. Reduced VD of intact 6 mm ×6 mm region in T1, T2 and T3 compared to T0. Declining PD of the 6 mm ×6 mm outer layer in T2 and T3 compared to T0. Diminished PD of whole 6 mm ×6 mm area at T3 compared to T0. The VD of 3 mm ×3 mm inner layer was significantly reduced in T3 compared to T0 and T1. The VD of 3 mm ×3 mm intact area gradually dwindled in T3 compared with T0 and T1 (P<0.05). Conclusion: With the progression of diabetic retinopathy, the levels of BUN and CRE gradually increased, and the OCTA-derived vascular density and perfusion density gradually decrease. Vascular density may be more sensitive for early diabetic retinopathy screening than perfusion density.The use of the Angiography6×6 model may result in an earlier detection of changes in retinal blood flow in diabetic retinopathy.
