光学多普勒层析成像技术及其在医学上的应用

<正>光学多普勒层析成像(ODT)是近年来发展起来的一种高分辨无损生物医学成像方法,它通过将光学多普勒原理与传统的光学相干层析技术(OCT)相结合,能同时得到组织形态结构和血管流速信息。ODT技术最早在时域OCT系统上     

鲜红斑痣光学测评技术的研究进展

鲜红斑痣（PWS）在病理学上主要表现为先天性的真皮浅层毛细血管网的扩张畸形。血管靶向光动力疗法（V-PDT）是治疗PWS的一种有效方法,在临床应用中,为了不断提高疗效,需要准确判定PWS患者病变靶组织特性（如病变血管深度、管径和血流等）,以便为不同患者制定个体化V-PDT治疗方案。近年来,大量研究组致力于开发用于评估PWS病变靶组织结构和功能特性的无创光学测评技术,笔者将在文中综述目前仍处于基础研究阶段以及已经应用于临床评估PWS的光学测评技术,主要包括：光学相干层析成像技术、光声成像技术、反射式共聚焦显微镜、激光多普勒血流成像技术、激光散斑成像技术和空间频域成像技术。     

光学相干层析成像术在皮肤科的应用

1991年美国麻省理工学院的Huang和哈佛医学院的Schuman等[1]首次报道了光学相干层析成像技术(optical co-herence tomography,OCT)。近10年来OCT已经成为一种可靠的活体组织成像方法。OCT成像是非接触式、非侵入性断层成像,其二维成像轴向分辨率可达10μm。OCT最早应用于眼睛这     

皮肤光学相干成像技术

光学相干断层扫描成像或光学相干成像(optical coherence tomography,OCT)是基于光线的反射延迟和干涉成像原理进行组织内部结构成像。OCT技术在皮肤科的应用有一定优势。近年来,随着OCT技术的发展,皮肤组织和皮肤疾病的OCT成像也有多方面的进展。本文将对皮肤OCT检查的技术发展和一些代表性进展做一介绍。     

生物医学光学(诊断与治疗)新技术的研究

通过对生物医学光学中理论基础和技术重点的学习和研究,清晰生物医学光学具体范畴及相互交叉学科相互关联和应用、发展方向。更好地解决从宏观到微观多层面上对研究生物体特别是人体的结构、功能和生命现象、疾病探测、诊断和治疗提供理论依据,寻找热点问题与发展趋势。生物医疗光学是光学与生命科学互相交叉的学科,包括生物光子学和医学光子学两部分。医学光子学的基础和技术,包括组织光学、医学光谱技术、医学成像术的研究。生物光子学是以研究生物体辐射的光子特性来研究生物体自身的功能和特性的学科。生物光子学在临床诊断、农作物遗传性诊断及环境检测等领域有重要的应用,主要包括生物系统的诱导发光、激光扫描共焦显微技术、光学相干断层扫描(Optical coherence tomography,OCT)、光学光钳等技术的研究。现代医学正由传统的基于症状治疗模式向以信息为依据的治疗模式转变,生物医学光学为医学诊断与治疗提供了更多、更有效的手段。生物光子学在医学治疗方面的技术应用广泛,主要应用包括:光动力疗法(photodynamic therapy,PDT)、激光在牙科、美容、眼科应用及其他应用。生物医学光学是新兴的学科,为揭示生命活动的基本规律、临床医学诊断与治疗提供了新的技术手段和方法。随着生物医学光学研究的进一步深入,也展现了一些亟待解决的问题。光学层析成像及光谱学技术的理论与模型、生物组织的光学成像和用于生物监测的光谱学技术、生物医学和临床的相干域光学方法、生物光谱学和显微术、激光与生物组织的相互作用,这些方面的问题成为研究热点问题与发展趋势,都需要加强研究。     

光学相干断层成像技术判断心肌缺血损伤程度和范围在体研究的进展

外科手术对心肌缺血的血运重建是目前治疗心肌缺血性疾病的重要手段之一。术中准确判断心肌缺血范围及程度和严密监测心脏停跳后心肌细胞损伤是否加重，对于血运重建的准确性，更好地实施心肌保护及对手术疗效的评估和术后处理方案的拟定有着重要意义。因此，如何在术中判断心肌缺血的损伤程度和范围具有极为重要的实验研究意义与临床现实意义。光学相干层析成像作为一种新颖的成像技术，能对活体组织内部微小结构进行实时、在体、高分辨率断层成像。     

光学相干断层成像技术在颈部及颅内血管检查和介入治疗中应用研讨

光学相干断层成像技术(OCT)是将光学相干技术与激光扫描共焦技术相结合起来的一种新型断层成像技术,自1995年诞生以来广泛应用于全身各器官及肿瘤的检查、治疗中;其分辨率、灵敏度高,被称为"光学活检"。本文就OCT的临床应用作综合回顾,并探讨其应用于颈部及颅内血管检查及介入治疗中的可行性。     

光学相干层析系统对人体皮肤的成像

目的 验证光纤型光学相干层析(OCT)成像系统对人体正常皮肤的成像结果.方法 采用光栅相位延迟线搭建了光纤型时域光学相干层析成像仪,针对鲜红斑痣病变的组织病理学特点对OCT的穿透深度和分辨率等参数进行了优化设计,系统的成像速率为4f/s,信噪比为108 dB,在皮肤组织中的分辨率为10 μm,穿透深度为2mm.结果 OCT仪能清楚地显示正常皮肤结构图像,可提取皮肤表皮层厚度,有助于更精确地确定激光照光剂量.结论 OCT可成为鲜红斑痣病变类型诊断的有利工具,为光动力学疗法治疗鲜红斑痣激光参数提供客观的选择依据.     

光学相干CT成像及应用

光学相干ＣＴ(简称ＯＣＴ)是基于迈可尔逊干涉仪的新型光学成像技术。它测量的是生物样品背向散射光。利用光源的相干长度来获得达微米量级的分辨率 ,具有无损、无创的特点以及易于集成 ,能够作为一种方便、常规的临床检测手段 ,显示出极大的发展潜力 ,是一种新兴的医学成像系统。本文通俗形象地介绍了ＯＣＴ技术的原理 ,并且给出了该技术在脑部成像中的应用 ,并对其结果进行了初步的分析。此外 ,还给出了眼和血管成像方面例子。光学相干CT成像及应用@王磊$清华大学现代应用物理系原子分子测控教育部重点实验室!北京市100084 @张新峰$清…     

光学相干断层成像(OCT)新技术及其在临床诊断中的应用

光学相干断层成像术（OCT）是一种能对生物组织浅表微结构进行断层成像的新技术，笔者总结了OCT新技术的研究进展及其发展趋势，介绍了几种功能OCT；概述了OCT在生物医学领域的应用情况及其在光动力学疗法（PDT）疗效检测中的应用前景，最后讨论了OCT技术的应用局限。     

Dental optical coherence tomography: a comparison of two in vitro systems

OBJECTIVE: To compare the imaging results obtained with two different in vitro prototype dental optical coherence tomography (OCT) systems. METHODS: Two prototypes were evaluated: an 850 nm wavelength, 700 microW OCT system with a relatively low numerical aperture (0.03) and a 1310 nm wavelength, 140 microW system with a higher numerical aperture (0.20). RESULTS: Using the 850 nm system a characteristic scattering signal was observed that correlated with the depth of a periodontal probe. There was, however, insufficient light penetration to create images with adequate resolution. Improved image quality was achieved with the 1310 nm OCT system; these images had sufficient resolution to allow identification of anatomical structures important for the diagnostic assessment of oral structures. CONCLUSIONS: These results illustrate the improvement in imaging dental structures that can be obtained with a prototype 1310 nm OCT system. The feasibility of OCT as a dental imaging technique is verified.     

基于深度学习的OCT医学图像研究进展

近年来,深度学习的研究和应用价值在学术领域和工业领域中扮演着越来越重要的角色,并且在生物医学领域也开始崭露头角。光学相干断层扫描成像(Optical Coherence Tomography,OCT)技术具有无损和分辨率高的特点,在临床诊疗与科学研究中得到了广泛的应用。本文首先介绍了深度学习和OCT技术,然后阐释了深度学习的卷积神经网络和OCT成像的基本机制,最后概述了基于深度学习技术的OCT医学图像研究,主要包括卷积神经网络在眼科、泌尿科、心血管科和肿瘤科等相关医学研究中的应用。     

Review of the Ability of Optical Coherence Tomography to Characterize Plaque, Including a Comparison with Intravascular Ultrasound

Over the last 50 years the introduction of several imaging technologies have been pivotal in reducing mortality associated with coronary artery disease. However coronary disease continues to be the leading cause of mortality in the industrialized world. Optical coherence tomography (OCT) has recently been introduced for micron scale intravascular imaging. It is analogous to ultrasound, measuring the intensity of back-reflected infrared light instead of sound. Some of the advantages of OCT include its resolution, which is higher than any currently available imaging technology and acquisition rates are near video speed. Unlike ultrasound, OCT catheters consist of simple fiber optics and contain no transducers within their frame, thereby making imaging catheters both inexpensive and small. Currently, the smallest catheters have a cross-sectional diameter of 0.014. OCT systems are compact and portable and can be combined with a range of spectroscopic techniques. We review the application of OCT to intracoronary imaging.     

Frequency-Domain Intravascular Optical Coherence Tomography of the Femoropopliteal Artery

Purpose  

Optical coherence tomography (OCT) is a catheter-based imaging method that employs near-infrared light to produce high-resolution intravascular images. The authors report the safety and feasibility and illustrate common imaging findings of frequency-domain OCT (FD-OCT) imaging of the femoropopliteal artery in a series of 20 patients who underwent infrainguinal angioplasty.     

High resolution imaging of transitional cell carcinoma with optical coherence tomography: feasibility for the evaluation of bladder pathology

Significant challenges regarding patient morbidity and mortality remain in the management of transitional cell carcinoma (TCC). Among the most important of these challenges is the inability to identify early neoplastic changes and to assess the degree of tumour invasion into the bladder wall in vivo. Optical coherence tomography (OCT) has been recently developed to provide in situ, high resolution, catheter/endoscope based imaging. This study explored the feasibility of OCT for the evaluation of bladder pathology. Both in vitro and in vivo studies were performed. In vitro imaging of pathological human bladder was performed and compared with normal specimens and histopathology. In vivo imaging of normal rabbit bladder was also performed with our current catheter/endoscope based systems. In the in vitro studies, OCT was able to delineate normal microstructure of the bladder, such as the mucosa, submucosa and muscularis layers. This was in contrast to specimens of invasive carcinoma, where a disruption of the normal bladder wall architecture was seen. The in vivo experiment demonstrated current limitations of the catheter/endoscope based systems and provided valuable information for developing an improved system for bladder imaging. The ability of OCT to delineate microstructure of the bladder wall suggests feasibility for endoscopic based imaging. In particular, there is a potential role envisioned for OCT in the management of TCC, identifying pre-malignant states and the depth of tumour invasion.     

Optical coherence tomography

A review is presented of different scanning, acquisition and processing techniques used to obtain depth-resolved information in optical-coherence tomography (OCT). The principles and performances of different OCT techniques are discussed and images from different types of tissue are presented. Special attention is devoted to the progress in using the time-domain flying spot OCT technique and combination of the en face OCT imaging with confocal microscopy. Although OCT is based on white light interferometry, which is a well established and an old technology, the quest for higher resolution and faster acquisition of in vivo images has ensured OCT a rapid evolution in the last decade. Highly adventurous avenues to expand the OCT capabilities and trends are presented at the end of the review.     

Characterization of radiofrequency ablated myocardium with optical coherence tomography

Certain types of cardiac arrhythmias are best treated with radiofrequency (RF) ablation, in which an electrode is inserted into the targeted area of the myocardium and then RF electrical current is applied to heat and destroy surrounding tissue. The resulting ablation lesion usually consists of a coagulative necrotic core surrounded by a rim region of mixed viable and non-viable cells. The characterization of the RF ablated lesion is of potential clinical importance. Here we aim to elaborate optical coherence tomography (OCT) imaging for the characterization of RF-ablated myocardial tissue. In particular, the underlying principles of OCT and its polarization-sensitive counterpart (PS-OCT) are presented, followed by the knowledge needed to interpret their optical images. Studies focused on real-time monitoring of RF lesion formation in the myocardium using OCT systems are summarized. The design and development of various hybrid probes incorporating both OCT guidance and RF ablation catheters are also discussed. Finally, the challenges related to the transmission of OCT imaging systems to cardiac clinics for real-time monitoring of RF lesions are outlined.     

Optical coherence tomography in forensic sciences: a review of the literature

Optical coherence tomography (OCT) is an interferometric imaging technique that has revolutionized clinical ophthalmology since the first half of the 1990’s. Despite this approach being successfully employed in ophthalmology and having great potential in forensic cases, its use in different forensic fields appears to be quite limited. In this review we reviewed the scientific literature regarding the application of OCT in forensic science and legal medicine from 1995 to 2019. Our research showed the usefulness of this approach for the study of coronary injuries, postmortem ocular changes, forensic entomology, and several other applications of specific forensic interest (the study of blood stains, fingerprints, and hair bulbs for personal identification, as well as the study of materials found in the crime scene for comparation, or anti-fraud investigation). The creation of specific ‘ad hoc’ devices and a better knowledge of this type of technology by pathologists will be a fundamental step to continue to develop the use of OCT forensic fields.     

Management of COPD: Is there a role for quantitative imaging?

While the recent development of quantitative imaging methods have led to their increased use in the diagnosis and management of many chronic diseases, medical imaging still plays a limited role in the management of chronic obstructive pulmonary disease (COPD). In this review we highlight three pulmonary imaging modalities: computed tomography (CT), magnetic resonance imaging (MRI) and optical coherence tomography (OCT) imaging and the COPD biomarkers that may be helpful for managing COPD patients. We discussed the current role imaging plays in COPD management as well as the potential role quantitative imaging will play by identifying imaging phenotypes to enable more effective COPD management and improved outcomes.