共查询到20条相似文献,搜索用时 0 毫秒
1.
Schaefer AW Reynolds JJ Marks DL Boppart SA 《IEEE transactions on bio-medical engineering》2004,51(1):186-190
We present the development and use of a real-time digital signal processing (DSP)-based optical coherence tomography (OCT) and Doppler OCT system. Images of microstructure and transient fluid-flow profiles are acquired using the DSP architecture for real-time processing of computationally intensive calculations. This acquisition system is readily configurable for a wide range of real-time signal processing and image processing applications in OCT. 相似文献
2.
3.
Zhu H Crabb DP Schlottmann PG Wollstein G Garway-Heath DF 《IEEE transactions on medical imaging》2011,30(6):1228-1238
Optical coherence tomography (OCT) is widely used in the assessment of retinal nerve fibre layer thickness (RNFLT) in glaucoma. Images are typically acquired with a circular scan around the optic nerve head. Accurate registration of OCT scans is essential for measurement reproducibility and longitudinal examination. This study developed and evaluated a special image registration algorithm to align the location of the OCT scan circles to the vessel features in the retina using probabilistic modelling that was optimised by an expectation-maximization algorithm. Evaluation of the method on 18 patients undergoing large number of scans indicated improved data acquisition and better reproducibility of measured RNFLT when scanning circles were closely matched. The proposed method enables clinicians to consider the RNFLT measurement and its scan circle location on the retina in tandem, reducing RNFLT measurement variability and assisting detection of real change of RNFLT in the longitudinal assessment of glaucoma. 相似文献
5.
6.
Yazdanpanah A Hamarneh G Smith BR Sarunic MV 《IEEE transactions on medical imaging》2011,30(2):484-496
Optical coherence tomography (OCT) is a noninvasive, depth-resolved imaging modality that has become a prominent ophthalmic diagnostic technique. We present a semi-automated segmentation algorithm to detect intra-retinal layers in OCT images acquired from rodent models of retinal degeneration. We adapt Chan-Vese's energy-minimizing active contours without edges for the OCT images, which suffer from low contrast and are highly corrupted by noise. A multiphase framework with a circular shape prior is adopted in order to model the boundaries of retinal layers and estimate the shape parameters using least squares. We use a contextual scheme to balance the weight of different terms in the energy functional. The results from various synthetic experiments and segmentation results on OCT images of rats are presented, demonstrating the strength of our method to detect the desired retinal layers with sufficient accuracy even in the presence of intensity inhomogeneity resulting from blood vessels. Our algorithm achieved an average Dice similarity coefficient of 0.84 over all segmented retinal layers, and of 0.94 for the combined nerve fiber layer, ganglion cell layer, and inner plexiform layer which are the critical layers for glaucomatous degeneration. 相似文献
7.
A linear shift invariant system model describing coherent light-specimen interactions in optical coherence tomography is presented. Based on this model, an iterative deconvolution algorithm is demonstrated for enhancing the sharpness of optical coherence tomographic images of biological structures 相似文献
8.
Full-field optical coherence tomography(FFOCT)was used for imaging the interior part of an object.Firstly,the mathematical modeling and performance analysis of the FFOCT system mounted was provided.Secondly,images of several different human tissues were obtained by FFOCT system,including esophagus,uterus,etc.The images of different depths of the same tissue were shown and compared.It was the first time in China that FFOCT was used for generating depth images on human esophagus and uterus;high-resolution images had been obtained for different depths without cutting the tissue sample,in which intercellular substance and myofibril structure could be clearly identified.As the in-depth structure could be imaged without the process needed for frozen and paraffin sectioning methods,the technology could been highly valuable for early cancer diagnosis and pathological analysis in tumor research. 相似文献
9.
Intraretinal layer segmentation of macular optical coherence tomography images using optimal 3-D graph search 总被引:2,自引:0,他引:2
Garvin MK Abramoff MD Kardon R Russell SR Wu X Sonka M 《IEEE transactions on medical imaging》2008,27(10):1495-1505
10.
11.
生物组织样品的光学特性可以由光学相干层析成像系统探测到的后向散射功率确定,文中建立了入射光线在样品介质内的一阶散射数学模型,揭示了样品的衰减系数和后向散射系数与系统探测结果之间的关系。 相似文献
12.
Optical coherence tomography (OCT) is a widely used optical imaging modality for three-dimensional structural and functional imaging. The prevalent OCT systems use an invisible light laser source beyond 800 nm and up to 1 500 nm to allow deep image penetration in biological tissues. Recently, visible light OCT (vis-OCT) using a short wavelength range between 400 nm to 700 nm has gained significant progress and attracted interest in its unique capability of high resolution imaging and spatially-resolved spectroscopy. In this article, we will briefly review the recent advance of vis-OCT imaging and its potential biomedical applications. 相似文献
13.
Patel NA Zoeller J Stamper DL Fujimoto JG Brezinski ME 《IEEE transactions on medical imaging》2005,24(2):155-159
OBJECTIVE: A need exists for an animal model to assess therapeutics for osteoarthritis (OA) without sacrificing the animal. Our goal is to assess the progression of experimentally induced osteoarthritis in the rat knee joint by monitoring articular cartilage thickness, surface abnormalities, and collagen organization using a new technology known as optical coherence tomography (OCT). DESIGN: OA was generated in Wistar Hanover rats via injection of sodium iodoacetate into the left articular joint of the knee while normal saline was injected as a control in the contralateral right knee. Rats were sacrificed at 1-, 2-, 3-, 4-, and 8-week intervals and the knee joints were subsequently harvested and imaged using normal and polarization sensitive OCT (PS-OCT). Treated knees were compared to normal counterparts in the contralateral leg. Following imaging, knees underwent both routine histological processing and picrosirus staining for organized collagen. RESULTS: OCT images indicate that injection of sodium iodoacetate resulted in a progressive decrease in cartilage thickness and loss of the bone-cartilage interface which correlated with histology. In addition, PS-OCT was able to detect collagen disorganization, an early indicator of OA. CONCLUSIONS: The use of OCT in combination with the induction of OA in rats is a promising new animal model for assessing articular changes with the goal of monitoring therapeutics longitudinally. Future work will extend the model to in vivo assessments. 相似文献
14.
Fiber-optic probes are a key component in a range of emerging clinical applications of optical coherence tomography (OCT). These miniaturized probes offer new possibilities to image diseased tissue deep within the body. This paper presents an overview of the design and use of fiber-optic probes for OCT. Three different deployment scenarios are identified: endoscopic, intravascular and needle-based probes, and specific case studies are presented for both endoscopic and intravascular probes. 相似文献
15.
16.
介绍了一种基于谱域光学相干层析成像的光学测量技术,对其基本原理进行了分析,并通过平面镜位移实验对该理论进行了验证。实验结果表明,该方法测得的数值与理论值基本一致,表明谱域光学相干层析成像技术的测量结果真实可靠,可以为高散射物体的表面轮廓测量和低散射物体的内部结构成像提供技术支撑。 相似文献
17.
根据光学相干层析成像(OCT)的基本原理,通过在系统中添加一个作为参考的光纤迈克尔逊干涉仪,替代了全场OCT系统中通常采用的扫描参考光路、设计了一种可以有效地保障系统长期稳定的技术方案,并在实验室中获得了良好的试验效果. 相似文献
18.
Optical coherence tomography (OCT) uses retroreflected light to provide micrometer-resolution, cross-sectional scans of biological tissues. OCT's first application was in ophthalmic imaging where it has proven particularly useful in diagnosing, monitoring, and studying glaucoma. Diagnosing glaucoma is difficult and it often goes undetected until significant damage to the subject's visual field has occurred. As glaucoma progresses, neural tissue dies, the nerve fiber layer thins, and the cup-to-disk ratio increases. Unfortunately, most current measurement techniques are subjective and inherently unreliable, making it difficult to monitor small changes in the nervehead geometry. To our knowledge, this paper presents the first published results on optic nervehead segmentation and geometric characterization from OCT data. We develop complete, autonomous algorithms based on a parabolic model of cup geometry and an extension of the Markov model introduced by Koozekanani, et al. to segment the retinal-nervehead surface, identify the choroid-nervehead boundary, and identify the extent of the optic cup. We present thorough experimental results from both normal and pathological eyes, and compare our results against those of an experienced, expert ophthalmologist, reporting a correlation coefficient for cup diameter above 0.8 and above 0.9 for the disk diameter. 相似文献
19.
为了对薄膜厚度进行测量,采用白光谱域光学相干层析成像的测量方法,进行了理论分析和实验验证,对以玻璃为基片的单层和多层薄膜样品进行了层析成像实验,获得了样品的2维层析图像。结果表明,该系统不仅能显示薄膜样品内部的微观结构,而且能从2维层析图像中得到单层和多层薄膜的厚度(分别为68μm和30μm),测量值与理论值相吻合,从而验证了测量理论正确性。该系统具有较高分辨率,可实现快速成像,满足实际工业测量需要。 相似文献
20.
Current gradient-index (GRIN) lens based proximal-driven intracoronary optical coherence tomography (ICOCT) probes consist of a spacer and a GRIN lens with larg... 相似文献