基于光学相干层析的视网膜图像分割

利用光学相干层析（optical coherence tomography,OCT）技术可以得到清晰的视网膜层状结构,实现视网膜层状结构自动分割功能是解决OCT技术应用于视网膜疾病诊断的一项基础问题。本文通过图像平滑、峰值探测、Snake模型、贪婪算法和样条插值等综合技术,对OCT视网膜图像进行分割,自动提取层状结构轮廓并获取视网膜厚度分布图。将以上算法应用于24例正常人眼底图像,并与专家手动标记轮廓提取的厚度相比,结果证实上述视网膜自动测量算法与专家人工标记取得较好一致性。本文提出的测量算法有望应用于视网膜变异性评估。     

光学相干层析成像技术与医学应用

光学相干层析成像(optical coherence tomography,OCT)是近年来发展较快的一种新型成像技术,能对生物组织内部的微观结构进行高分辨率的横断面层析成像,具有快速、非侵入及高分辨率等特点,对在体生物组织的微观结构分析和疾病诊断等方面具有重要的应用价值。我们简要介绍了光学相干层析成像工作原理,及在生物组织测量及医学等方面的应用。     

早期糖尿病患者黄斑区光学相干断层扫描的分析

目的 利用光学相干断层扫描(OCT)测量并分析早期糖尿病(DM)患者的黄斑区视网膜厚度.方法 正常对照组30例60只眼,其中男性15例,女性15例;年龄38～71岁,平均年龄51岁.DM组60例120只眼,其中男性30例,女性30例;年龄32～73岁,平均年龄54.5岁.患有DM但不伴或伴有轻微视网膜病变的患者被纳入研...     

定量血管内光学相干层析成像的研究进展

血管内光学相干层析成像(IVOCT)是目前分辨率最高的血管内成像技术,可对冠状动脉血管腔及管壁内膜下病变进行快速、清晰的成像。仅根据组织结构的层析图像无法精确识别粥样硬化斑块成分(如钙化、纤维化、脂质和混合斑块),需要形态结构之外的生理信息的对比机制,获得具有临床诊断价值的组织参数,即定量IVOCT(qIVOCT)。本文针对根据IVOCT原始背向散射信号和灰阶图像定量测量血管壁组织的光学特性参数、弹性参数和血流动力学参数的研究现状进行归纳和总结,分析目前存在的问题,展望可能的发展方向。     

体外构建3D人工皮肤

BACKGROUND: Epidermis is unable to differentiate into stratum corneum and other parts in the previous artificial skin constructed using three-dimensional printing. OBJECTIVE: To optimize the method of artificial skin construction to obtain more feasible artificial skin. METHODS: Type I collagen extracted from rat-tail and bovine tail was purified. Primary dermal fibroblasts and keratinocytes were isolated from children’s foreskin, and then embedded in bovine or rat tail collage to construct the dermis; keratinocytes were seeded on the dermis for 7 days, followed by 7-day air liquid interface, and the artificial skin was finally achieved. The contraction and hydrophobicity by water contact angle were detected, as well as the morphology was observed by hematoxylin-eosin staining, sirius red staining and immunofluorescence analysis. RESULTS AND CONCLUSION: Seven days after fibroblasts embedded in collagen, the area of bovine collagen was reduced by 21%, while that of rat tail collagen decreased about a half. The water contact angle of the skin constructed by bovine tail collagen was similar to that of human skin, which was much higher than that of the skin constructed by rat tail collagen. Sirius red staining found that the skin constructed by bovine tail collagen had stronger refractivity, more intact structure and thicker fibers than those of the skin constructed by rat tail collagen. Moreover, more multilayer keratinocytes appeared in the skin constructed by bovine tail collagen through hematoxylin-eosin staining. In conclusion, bovine tail collagen is more available for the artificial skin construction. 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

血管内光学相干层析成像技术在冠状动脉粥样硬化斑块检测方面的应用

血管内光学相干层析成像(IVOCT)技术近年来在冠状动脉粥样硬化斑块检测方面发展非常迅速,可实现血管内病变组织高分辨率、无辐射、实时在体成像,在临床诊断方面发挥了重要的作用.本文简要介绍了IVOCT的成像原理、生物组织光学特征参数以及色散系数的计算方法,并对动脉粥样硬化斑块的机器学习算法进行了概述,为构建斑块的智能识别...     

基于光学相干断层成像量化评估平滑面早期牙釉质龋的研究进展

背景：平滑面早期牙釉质龋虽然已发生脱矿改变但无肉眼可见的龋洞形成,目前临床采用的常规检测方法难以对其准确诊断。 目的：应用光学相干断层成像技术对平滑面早期牙釉质龋的量化研究进展进行综述。 方法：由第一作者检索CNKI和EBSCO HOST数据库中1979/2011发表的关于光学相干断层成像技术定量研究平滑面早期龋的相关文献,以“光学相干断层成像,早期龋,平滑面,量化评估”和“optical coherence tomography, early caries, smooth surface,quantitative assessment”为检索词进行检索。纳入31篇进行综述。 结果与结论：新兴的光学相干断层成像技术能够检测龋变牙釉质的背向散射信号使脱矿牙釉质成像,并应用深度、反射率、衰减系数等定量指标对平滑面早期牙釉质龋进行量化评估,为牙釉质早期龋的诊断提供了新的方法。     

人工皮肤的研究进展

利用组织工程原理研究人工皮肤是近年来皮肤缺损修复临床研究中一个重要课题,为临床上从根本上解决皮肤缺损的修复提供了良好的前景。本文从人工皮片、真皮和复合皮肤等方面对该领域的最新研究现状进行综述,分析了人工皮肤目前存在的问题及未来发展方向。     

3D-SC人工皮肤材料对新西兰兔损伤皮肤的修复实验研究

目的观察3D—SC人工皮肤材料对损伤皮肤的修复作用。方法建立皮肤损伤动物模型，分别用3D-SC人工皮肤材料、动物自体皮肤和油纱覆盖创面，测定动物手术前后的体温，分阶段观察创面的愈合情况和创面的一般特征、动物的生长情况，取材作组织学检查，观察创面的组织学反应。结果3组动物手术前后体温变化不明显，动物的生长情况一致，材料组和动物自体皮肤组的抗感染能力、防止创面出血的作用优于对照组。实验组创面未见红肿、坏死。3组创面的愈合时间无统计学意义。组织学观察显示3D-SC人工皮肤材料促进皮肤结构再生能力强于对照组。结论3D-SC人工皮肤材料质地柔软，有良好的抗撕拉能力，便于剪切，覆盖在创面上与创面结合紧密，黏附性较好；对动物无刺激性；能吸收创面渗出液，防止创面积液；对诱导皮肤组织再生有促进作用。     

利用光学相干断层图像平均灰度值定量研究牛恒牙早期人工脱矿

目的 研究经酸蚀脱矿后牛恒牙光学相干断层图像平均灰度值的变化,探讨平均灰度值作为一个参数指标定量检测牛恒牙早期脱矿的可行性.方法 以正常离体牛恒牙为样本,采用凝胶酸蚀法制备人工脱矿模型;用光学相干断层摄影术对人工脱矿模型扫描成像,利用Matlab软件计算不同酸蚀时间脱矿区牙体层110 μm范围内的平均灰度值.将测得图像灰度和归一化后图像灰度,分别进行单因素方差分析.结果 牙体表层110 μm范围内不同时间酸蚀脱矿区的平均灰度值从大到小依次为30 min酸蚀脱矿区、1O min酸蚀脱矿区、0 min酸蚀脱矿区,图像灰度归一化后做单因素方差分析,P＜0.05.结论 牙体表层110 μm范围内不同酸蚀时间脱矿区平均灰度值差异有统计学意义,并随脱矿时间增加而增大,即平均灰度值可以用于光学相干断层摄影术定量检测牙齿的早期脱矿.光学相干断层图像灰度归一化使得不同酸蚀脱矿区的平均灰度值更有可比性,减小了由于样本之间差异引起的误差,提高了平均灰度值作为参数指标定量检测牙齿早期脱矿的可靠性.     

生物磁光声联合成像的研究现状

超声(US)成像、光学相干断层(OCT)成像和磁共振成像(MRI)是临床常用的医学成像手段。此外,光声层析(PAT)和磁声(MA)成像是近年来新兴的多物理场耦合功能成像手段。将两种或者两种以上的成像手段结合起来形成多模态联合成像,可以使各成像模态的优点得到充分展现,对目标进行高精度和高分辨率的成像,精确识别病变组织,并对其功能成分进行定性和定量的分析。对US-PAT、US-OCT、PAT-OCT、US-PAT-OCT、磁光以及磁光声(MPA)联合成像,特别是对血管内联合成像的研究进展和临床应用前景进行综述,总结目前存在的问题,并展望未来可能的发展方向。     

Mechanical Analysis of Atherosclerotic Plaques Based on Optical Coherence Tomography

Finite element analysis is a powerful tool for investigating the biomechanics of atherosclerosis and has thereby provided an improved understanding of acute myocardial infarction. Structural analysis of arterial walls is traditionally performed using geometry contours derived from histology. In this paper we demonstrate the first use of a new imaging technique, optical coherence tomography (OCT), as a basis for finite element analysis. There are two primary benefits of OCT relative to histology: 1) imaging is performed without excessive tissue handling, providing a more realistic geometry than histology and avoiding structural artifacts common to histologic processing, and 2) OCT imaging can be performed in vivo, making it possible to study disease progression and the effect of therapeutic treatments in animal models and living patients. Patterns of mechanical stress and strain distributions computed from finite element analysis based on OCT were compared with those from modeling based on "gold standard" histology. Our results indicate that vascular structure and composition determined by OCT provides an adequate basis for investigating the biomechanical factors relevant to atherosclerosis and acute myocardial infarction.     

Quantification of Stiffness Change in Degenerated Articular Cartilage Using Optical Coherence Tomography-Based Air-Jet Indentation

Articular cartilage is a thin complex tissue that covers the bony ends of joints. Changes in the composition and structure of articular cartilage will cause degeneration, which may further lead to osteoarthritis. Decreased stiffness is one of the earliest symptoms of cartilage degeneration and also represents the imperfect quality of repaired cartilage. An optical coherence tomography (OCT)-based air-jet indentation system was recently developed in our group to measure the mechanical properties of soft tissues. In this study, this system was applied to quantify the change of mechanical properties of articular cartilage after degeneration induced by enzymatic digestions. Forty osteochondral disks (n = 20 × 2) were prepared from bovine patellae and treated with collagenase and trypsin digestions, respectively. The apparent stiffness of the cartilage was measured by the OCT-based air-jet indentation system before and after the degeneration. The results were also compared with those from a rigid contact mechanical indentation and an ultrasound water-jet indentation. Through the air-jet indentation, it was found that the articular cartilage stiffness dropped significantly by 84% (p < 0.001) and 63% (p < 0.001) on average after collagenase and trypsin digestions, respectively. The stiffness measured by the air-jet indentation system was highly correlated (R > 0.8, p < 0.001) with that from the other two indentation methods. This study demonstrated that the OCT-based air-jet indentation can be a useful tool to quantitatively assess the mechanical properties of articular cartilage, and this encourages us to further develop a miniaturized probe suitable for arthroscopic applications.     

应用于生物组织的光学成像技术及国内可实施技术探讨

本文介绍了应用近红外或远红外光对高散射介质及生物组织中物体（肿瘤）进行光学成像的原理和目前主要采用的研究技术。对几种主要光学成像技术,时间分辨法、光学相干层析、应用光折变晶体的相干层析等技术的实验原理和设备进行分析比较,进一步探讨低成本可实施技术及可开展的有关研究。     

腔内影像学方法评价降脂治疗对冠状动脉粥样硬化斑块影响的研究进展

动脉粥样硬化斑块与动脉粥样硬化性心血管疾病(atherosclerotic cardiovascular diseases,ASCVD)的发生及发展密切相关.借助腔内影像学,如血管内超声(intravascular ultrasound,IVUS)、光学相干成像(optical coherence tomography...     

扫频光相干断层扫描对不同屈光度近视患者脉络膜厚度分析

目的 通过比较不同屈光度近视患者脉络膜厚度,初步探讨近视发生发展的可能机制。方法 收集2020年1月~8月在达州市中心医院眼科准分子激光中心行近视术前检查的患者共82例,根据等效球镜分别分为低度近视组（-0.50D~-3.00D）、中度近视组（-3.00D~-6.00D）,高度近视组（≥-6.00D）,使用视微影像超广角扫频相干光断层扫描（SS-OCTA）测量82例近视患者以黄斑中心凹为圆心直径分别为1、3、6、9、12 mm圆形的上方（S）颞侧（T）、下方（I）、鼻侧（N）脉络膜厚度（CT）,取右眼进行统计学分析。结果 随近视度数增加,低、中、高度近视患者CT变薄,差异有统计数意义（P＜0.05）;不同近视组鼻侧CT最薄,且三组进行比较,鼻侧CT最先出现改变,下方次之。三组进行两两比较,高度近视组CT与低度近视组、中度近视组比较,差异有统计学意义（P＜0.05）,而低度近视组与中度近视组比较,差异无统计学意义（P＞0.05）。结论 随着近视度数的增加CT变薄,近视患者CT变薄方位具有不一致性,与正常CT分布规律不同,与近视相关的一些列并发症可能与变薄的部位有一定联系,提示脉络膜的改变可能参与近视的发生发展。     

Mirau-based line-field confocal optical coherence tomography for three-dimensional high-resolution skin imaging

SignificanceLine-field confocal optical coherence tomography (LC-OCT) is a recently introduced high-resolution imaging modality based on a combination of low-coherence optical interferometry and reflectance confocal optical microscopy with line illumination and line detection. Capable of producing three-dimensional (3D) images of the skin with cellular resolution, in vivo, LC-OCT has been mainly applied in dermatology and dermo-cosmetology. The LC-OCT devices capable of acquiring 3D images reported so far are based on a Linnik interferometer using two identical microscope objectives. In this configuration, LC-OCT cannot be designed to be a very compact and light device, and the image acquisition speed is limited.AimThe objective of this work was to develop a more compact and lighter LC-OCT device that is capable of acquiring images faster without significant degradation of the resolution and with optimized detection sensitivity.ApproachWe developed an LC-OCT device based on a Mirau interferometer using a single objective. Dynamic adjustment of the camera frequency during the depth scan is implemented, using a faster camera and a more powerful light source. The reflectivity of the beam-splitter in the Mirau interferometer was optimized to maximize the detection sensitivity. A galvanometer scanner was incorporated into the device for scanning the illumination line laterally. A stack of adjacent B-scans, constituting a 3D image, can thus be acquired.ResultsThe device is able to acquire and display B-scans at 17 fps. 3D images with a quasi-isotropic resolution of ∼1.5μm (1.3, 1.9, and 1.1μm in the x,y, and z directions, respectively) over a field of 940μm×600μm×350μm (x×y×z) can be obtained. 3D imaging of human skin at cellular resolution, in vivo, is reported.ConclusionsThe acquisition rate of the B-scans, at 17 fps, is unprecedented in LC-OCT. Compared with the conventional LC-OCT devices based on a Linnik interferometer, the reported Mirau-based LC-OCT device can acquire B-scans ∼2 times faster. With potential advantages in terms of compactness and weight, a Mirau-based device could easily be integrated into a smaller and lighter handheld probe for use by dermatologists in their daily medical practice.