光学相干断层成像判断冠状动脉不稳定斑块

光学相干断层成像是近年出现的一项光学成像技术,其原理是基于光学干涉现象。该项技术与血管内超声相比具有更高的分辨率,本文根据光学相干断层成像在心血管疾病领域的研究进展,总结了该项技术对冠状动脉不稳定斑块方面的研究现状。     

光学相干断层成像判断冠状动脉不稳定斑块

光学相干断层成像是近年出现的一项光学成像技术,其原理是基于光学干涉现象.该项技术与血管内超声相比具有更高的分辨率,本文根据光学相干断层成像在心血管疾病领域的研究进展,总结了该项技术对冠状动脉不稳定斑块方面的研究现状.     

OCT-IVUS一体成像的多模态血管腔内成像技术的应用与进展

作为冠状动脉介入诊疗中最主要的两种血管腔内影像学技术,光学相干断层成像(OCT)和血管内超声(IVUS)已在临床应用数十年。OCT具有更高的分辨率,能更好地对比斑块成分,IVUS能够穿透血液,具有更深的成像深度,两种影像学技术已成为心血管介入医生不可或缺的辅助手段。但两种影像学技术也各有不足,OCT成像穿透深度有限,IVUS的空间分辨率较弱。单一的OCT或IVUS很难完全提供血管及斑块内部完整的解剖学信息。利用二者的互补性,将OCT与IVUS成像导管集成到同一成像导管中,实现二者的多模态血管内成像,则可以为介入医生提供更加理想的斑块与血管壁的组织学和形态学信息。     

血管内超声和光学相干断层成像在冠状动脉介入治疗中的应用对比

血管内超声（IVUS）和光学相干断层成像（optical coherence tomography,OCT）作为成熟的冠状动脉血管内成像技术,已成为冠状动脉造影的重要补充手段。IVUS的优势在于透射深度大,在管腔结构之外可获取血管壁结构;而OCT则空间分辨率高,与组织学结果高度相关。随着无需球囊阻断血流的频域光学相干断层成像（FD-OCT）的不断推广,OCT临床实用性增强。本文就最新研究进展中IVUS与FD-OCT的成像方式、对病变血管的评估效用及对介入治疗的指引作用进行对比,以探讨冠状动脉介入治疗影像学未来的发展方向。     

光学相干断层成像在冠状动脉非阻塞性心肌梗死中的应用

冠状动脉非阻塞性心肌梗死(MINOCA)的病因复杂多样,临床诊断往往存在较多困难。光学相干断层成像作为新兴的腔内影像学技术,可提供高分辨率的血管内成像,在MINOCA的诊治中具有重要意义。现就光学相干断层成像在MINOCA中的研究进展做一综述。     

光学相干断层成像与冠状动脉粥样硬化

光学相干断层成像（optical coherence tomography,OCT）是应用1300 nm波长的近红外线来对血管进行横断成像的血管内成像技术。     

光学相干断层成像在冠心病研究中的应用

光学相干断层成像是近年来出现的血管内成像新技术，具有分辨率高、穿透力强的特点，对于不稳定斑块的识别具有很重要的意义，现着重描述其在冠心病研究中的应用。     

光学相干断层成像指导钙化病变介入治疗策略

冠状动脉钙化病变的存在,尤其是严重内膜钙化病变和钙化结节,明显增加了介入治疗的难度和风险。钙化病变普遍存在于目前的冠状动脉介入治疗中,中重度钙化病变约占30%,其中约5%为重度钙化病变。因此,准确地识别、评估钙化病变,选择恰当的技术,对严重钙化病变进行充分的预处理,对于提高手术成功率、减少手术相关并发症、改善患者近期/远期预后具有重要意义。目前常用的评估冠状动脉钙化的手段包括:冠状动脉CT血管造影、冠状动脉造影、血管内超声、光学相干断层成像等。血管内超声和光学相干断层成像是目前最常用的评估钙化病变的腔内影像学检查方法。与血管内超声相比,光学相干断层成像可评估钙化病变的厚度,能更准确地量化钙化病变的容积。因此,本文将综述光学相干断层成像在指导钙化病变介入治疗中的作用。     

光学相干断层成像对支架内再狭窄诊断的应用

支架内再狭窄是冠心病患者经皮冠脉介入术后的主要并发症,目前对术后支架内再狭窄的评价成为医学关注的焦点。光学相干断层成像技术具有分辨率高,组织相关性良好等特点,可以提供更多的临床信息,现就光学相干断层成像在支架内再狭窄诊断的应用做一综述。     

光学相干断层成像在冠心病研究中的应用

光学相干断层成像（Optical coherence tomography,OCT）是将光学技术与超灵敏探测器合为一体,应用计算机进行图像处理的断层成像诊断技术。它采用低相干的近红外光线从组织反射回来的不同光学特征进行组织分析成像,成像速度快,其分辨率接近组织学水平,是目前分辨率最高的血管腔内成像技术。目前关于OCT在冠心病的研究领域主要集中在动脉粥样硬化斑块易损性,急性冠脉综合症病理生理形态变化及支架置入后组织覆盖方面的评价。现就OCT在冠心病研究中的应用状况做一综述。     

The Role of Intracoronary Plaque Imaging with Intravascular Ultrasound,Optical Coherence Tomography,and Near-Infrared Spectroscopy in Patients with Coronary Artery Disease

The development of multiple diagnostic intracoronary imaging modalities has increased our understanding of coronary atherosclerotic disease. These imaging modalities, intravascular ultrasound (IVUS), optical coherence tomography (OCT), and near-infrared spectroscopy (NIRS), have provided a method to study plaques and introduced the concept of plaque vulnerability. They are being increasingly used for percutaneous coronary intervention (PCI) optimization and are invaluable tools in research studying the pathophysiology of acute coronary syndrome (ACS), in-stent thrombosis and in-stent restenosis. IVUS has the ability to visualize the intracoronary lumen and the vessel wall and can be used to detect early atherosclerotic disease even in the setting of positive arterial remodeling. Studies supporting the use of IVUS to optimize stent deployment and apposition have shown a significant reduction in cardiovascular events. OCT provides even higher resolution imaging and near microscopic detail of plaques, restenoses, and thromboses; thus, it can identify the etiology of ACS. Ongoing trials are evaluating the role of OCT in PCI and using OCT to study stent endothelialization and neointimal proliferation. NIRS is a modality capable of localizing and quantifying lipid core burden. It is usually combined with IVUS and is used to characterize plaque composition. The benefits of NIRS in the setting of ACS have been limited to case reports and series. The utilization of all these intracoronary imaging modalities will continue to expand as their indications for clinical use and research grow. Studies to support their use for PCI optimization resulting in improved outcomes with potential to prevent downstream events are ongoing.     

Assessment of coronary plaque with optical coherence tomography and high-frequency ultrasound

This study compares the ability of intravascular optical coherence tomography (OCT) and high-frequency intravascular ultrasound (IVUS) to image highly stenotic human coronary arteries in vitro. Current imaging modalities have insufficient resolution to perform risk stratification based on coronary plaque morphology. OCT is a new technology capable of imaging at a resolution of 5 to 20 microm, which has demonstrated the potential for coronary arterial imaging in prior experiments. Human postmortem coronary arteries with severely stenotic segments were imaged with catheter-based OCT and IVUS. The OCT system had an axial resolution of 20 microm and a transverse resolution of 30 microm. OCT was able to penetrate and image near-occlusive coronary plaques. Compared with IVUS, these OCT images demonstrated superior delineation of vessel layers and lack of ring-down artifact, leading to clearer visualization of the vessel plaque and intima. Histology confirmed the accuracy and high contrast of vessel layer boundaries seen on OCT images. Thus, catheter-based OCT systems are able to image near-occlusive coronary plaques with higher resolution than that of IVUS.     

血管内超声——诊断和指导冠状动脉粥样硬化及其介入治疗的“金标准”

随着微型导管超声换能器和声学成像技术的飞速进步,血管内超声检查已由实验研究阶段逐步发展成为冠心病临床诊断和介入治疗中具有重要价值的新方法。血管内超声利用安装在心导管顶端的微型超声换能器,在血管内发射和接收高频超声信号,实时显示血管的切面图像,能清晰显示管壁结构的厚度、管腔大小和形态等,甚至可以辨认钙化、纤维化和脂质池等病变。现就血管内超声的发展历程、应用现状和发展前景作一简略论述。     

Utility of optical coherence tomography and intravascular ultrasound for the evaluation of coronary lesions

Optical coherence tomography (OCT) and intravascular ultrasound (IVUS) are imaging methods used in the diagnosis of coronary lesions. IVUS is widely used in interventional cardiology laboratories, but OCT is now increasingly used. Conventional coronary angiography can identify different types of coronary lesions but sometimes is unable to diagnose them correctly. Both intravascular imaging methods are useful for better interpretation of these lesions, and can accurately diagnose ruptured plaques, thrombosis, stent restenosis and hazy images. However, the resolution of OCT is ten times higher than IVUS, and so an accurate diagnosis cannot always be achieved with ultrasound imaging. We present three cases in which IVUS was unable to identify the lesion causing the condition and OCT was required to obtain clearer images that helped to confirm the diagnosis. The advantages and disadvantages of each method are then discussed.     

Intravascular Imaging to Guide Lithotripsy in Concentric and Eccentric Calcific Coronary Lesions

BackgroundCalcified coronary lesions still represent a challenge for coronary angioplasty, with sub-optimal acute PCI results causing more frequent late stent failure.PurposeThe study aimed at the evaluation of the immediate procedural outcome in a real-world consecutive population of a selective use of lithotripsy based on the intravascular imaging assessment with IVUS or OCT.Methods and resultsThirty-one calcified stenoses (28 patients) out of a total of 455 lesions (370 patients) treated between November 2018 and May 2019 received IVL under intravascular imaging guidance. The majority of the IVL lesions had angiographically severe calcifications and were selected after intravascular imaging. A smaller group was identified by poor expansion after high-pressure balloon dilatation, in one case despite preliminary small burr Rotablation. After IVL, when OCT was performed calcium fractures were observed in 71% of cases. After OCT/IVUS guided stent optimization a satisfactory lumen enlargement (minimal stent area 7.09 ± 2.77 mm²) was observed with good stent expansion (residual area stenosis<20% in 29 lesions, 93.5%) Peri-procedural complications were limited to one dissection at the distal edge requiring an additional stent and 3 peri-procedural myocardial infarctions. There were no periprocedural coronary perforations or pericardial effusions, and no in-hospital or 30 days stent thrombosis.When patients were divided into two subgroups according to a calcium arc ≤180° (Group A: 10 lesions, calcium arc 140 ± 24°; Group B: 21 lesions, calcium arc 289 ± 53°), at OCT Group B presented also a higher number of calcium fractures post IVL than group A (group A: 38% vs group B: 92%, p = 0.03). The in-stent minimum lumen diameter (MSD), the in stent minimal lumen area (MSA) and the acute gain, however, were similar between the two groups (acute gain group A: 1.22 ± 0.29 mm; group B: 1.31 ± 0.52 mm, p = 0.63).ConclusionsA standardized algorithm applying intravascular imaging guidance of IVL facilitated second generation DES expansion delivers excellent immediate lumen expansion and patient outcome, both in concentric and eccentric calcifications.     

Role of Intravascular Imaging for the Diagnosis of Recanalized Coronary Thrombus

IntroductionRecanalized thrombus (RCT) of coronary arteries is frequently unrecognized in interventional cardiology practice. Intravascular imaging conclusively establishes its diagnosis, which otherwise is often misdiagnosed as fresh thrombus, spontaneous coronary artery dissection, or severe calcification based on angiography, alone. We hereby report our experience of 10 RCT patients, who had the intravascular imaging-guided diagnosis, followed by the successful percutaneous coronary intervention (PCI).MethodsIt was a retrospective analysis of 10 patients, who had angiographic haziness of the target lesion during PCI, which were found to be RCT on intravascular imaging. Either optical coherence tomography (OCT) or intravascular ultrasound (IVUS) was performed to characterize RCT in 9 and 1 patient, respectively.ResultsThe mean age was 53 ± 13.1 years, comprising 9 men and 1 woman. Six patients had acute coronary syndrome, while four had chronic stable angina. Coronary angiography revealed ≥ 70% angiographic stenosis, with intracoronary haziness/filling defects which were linear, spiral or braided in appearance. OCT findings in 9 patients include signal-rich, high backscattered septa dividing the lumen into multiple small cavities communicating with each other, giving a “Swiss cheese” or “honeycomb” appearance. Intravascular ultrasound (IVUS) findings in one patient showed multiple cavities filled with blood speckling consistent with recanalized thrombus. All patients underwent successful PCI with image-guided optimization.ConclusionWith the increasing use of intravascular imaging during PCI, RCT is frequently identified. OCT remains the investigation of choice to differentiate it from other similar entities on angiography.     

Imaging a spiral dissection of the superficial femoral artery in high resolution with optical coherence tomography—Seeing is believing

Optical coherence tomography (OCT) offers an alternative to intravascular ultrasound (IVUS) for endovascular imaging. Clinical and research applications for OCT have emerged in percutaneous coronary intervention (PCI), however, OCT has not found similar utility in peripheral arterial interventions. Early generation time‐domain OCT systems required arterial occlusion to create the blood free environment needed for image acquisition and could not reliably scan vessel diameters encountered in the peripheral circulation. However, the frequency‐domain OCT (FD‐OCT) system currently FDA approved for use in the United States does not require arterial occlusion to generate images and permits a greater scan diameter allowing for exploratory use in peripheral arteries. To our knowledge, this is the first report using non‐occlusive OCT imaging to serve as an adjunct to endovascular intervention for femoropopliteal disease. We illustrate the feasibility of acquiring high resolution images of a spiral dissection of the superficial femoral artery following balloon angioplasty that was not adequately visualized by angiography. © 2012 Wiley Periodicals, Inc.     

血管内超声与光学相干断层扫描在冠状动脉临界病变中的长期随访对比研究

目的:研究血管内超声(intravenous ultrasound,IVUS)与光学相干断层扫描(optical coher-ence tomography,OCT)在冠状动脉临界病变中的长期随访研究。方法:共入选经过冠状动脉造影(至少4体位造影)证实病变狭窄处于临界病变的患者90例。将入选者按照2∶1随机分为:血管内超声组(IVUS)60例,光学相干断层成像(OCT)组30例。通过血管内超声定量分析最小管腔直径、参考血管直径、最小管腔面积等参数指标;通过光学相干断层扫描分析最小管腔直径、最小管腔面积。同时依据两组检查方法不同特征确定斑块的性质进行定性亚组分析:纤维性斑块、钙化斑块及脂质斑块等,对于高危易损斑块进行冠状动脉介入治疗,术后规律服用药物,观察两组术后住院期间、30d、3个月、9个月、1年和2年的主要心血管事件。采用COX回归模型分析两组2年内免于心血管事件的差异。结果:IVUS和OCT进行亚组软斑块分析,两组测得最小管腔直径分别为[(1.84±0.06)vs.(1.84±0.13)mm,P=0.947]。另外,在最小管腔面积方面两组分别为[(4.7±0.98)vs.(4.8±1.17)mm2,P=0.853]。OCT组通过分析软斑块纤维帽厚度为(94±24.72)μm。通过COX回归模型显示,两组在免于心血管事件的差异无统计学意义(P=0.826)。结论:对于临界病变的患者,采用IVUS或OCT成像系统能够更好的分辨血管内斑块性质,尤其易识别易损斑块。对于临界病变的患者,采用介入影像学方法进行测量分析是安全的、可靠的,能更好指导临床治疗。     

冠心病患者靶病变钙化特征的研究

目的观察冠心病患者靶病变钙化的特征,并比较不同临床类型之间的差异。方法连续入选2011年11月至2012年12月于东方医院心内科行冠状动脉造影和血管内超声检查的171例冠心病患者,其中稳定型心绞痛（SAP）30例（SAP组）,急性冠状动脉综合征（ACS）141例（ACS组）,分析靶病变的钙化类型、分布和长度。结果冠状动脉造影发现,钙化患者48例（28.1%）,而IVUS发现钙化患者为122例（71.3%）。按照造影来进行钙化程度的分组,使用IVUS测量的病变长度及斑块负荷,重度钙化组明显大于无或轻度钙化组,且有统计学意义[病变长度：（27.7±12.0）mm比（17.4±8.7）mm,P〈0.01;斑块负荷：（70.8±8.1）%比（67.2±7.0）%,P〈0.05],而重度钙化组和中度钙化组差异无统计学意义。三组间靶病变外弹力膜面积（EEM-CSA）及最小管腔面积（MLA）差异则无统计学意义。IVUS测定的钙化长度和最大钙化弧度,三组间差异有统计学意义,重度钙化组病变的钙化长度及最大钙化弧度大于其他两组（P〈0.05）。SAP组和ACS组之间,在EEM-CSA、MLA、斑块负荷及钙化的发生率方面,差异无统计学意义。但SAP组浅表性钙化与弥漫性钙化的发生率明显高于ACS组,而ACS组深部或混合钙化、点状钙化明显高于SAP组（P均〈0.05）。两组最大钙化弧度均值差异无统计学意义,但ACS组病变最大钙化弧度小于90°者高于SAP组（47.5%比26.1%,P〈0.05）;SAP组钙化弧度在90°以上者高于ACS组（73.9%比52.5%,P〈0.05）,以上结果ACS的不稳定斑块钙化程度尤其在横断面分布程度低于SAP的靶病变。ACS组IVUS检出存在斑块破裂的18例患者中,17例（94.4%）为点状钙化或混合钙化;ACS组未观察到斑块破裂且存在钙化的81例患者中,点状钙化的发生率仅为45例（55.6%）,两组差异具有统计学意义（P〈0.01）。结论 IVUS对检出钙化的敏感性远高于冠状动脉造影。与SAP相比,ACS患者靶病变钙化弧度小、深部多见,存在斑块破裂的病变以点状钙化为主。     

The role of optical coherence tomography in coronary intervention

Optical coherence tomography (OCT) is an optical analog of intravascular ultrasound (IVUS) that can be used to examine the coronary arteries and has 10-fold higher resolution than IVUS. Based on polarization properties, OCT can differentiate tissue characteristics (fibrous, calcified, or lipid-rich plaque) and identify thin-cap fibroatheroma. Because of the strong attenuation of light by blood, OCT systems required the removal of blood during OCT examinations. A recently developed frequency-domain OCT system has a faster frame rate and pullback speed, making the OCT procedure more user-friendly and not requiring proximal balloon occlusion. During percutaneous coronary intervention (PCI), OCT can provide detailed information (dissection, tissue prolapse, thrombi, and incomplete stent apposition [ISA]). At follow-up examinations after stent implantation, stent strut coverage and ISA can be assessed. Several OCT studies have demonstrated delayed neointimal coverage following drug-eluting stent (DES) implantation vs. bare metal stent (BMS) placement. While newer DESs promote more favorable vascular healing, the clinical implications remain unknown. Recent OCT studies have provided insights into restenotic tissue characteristics; DES restenotic morphologies differ from those with BMSs. OCT is a novel, promising imaging modality; with more in-depth assessments of its use, it may impact clinical outcomes in patients with symptomatic coronary artery disease.