Intravascular photoacoustic and optical coherence tomography imaging dual-mode system for detecting spontaneous coronary artery dissection: A feasibility study

In this work,we present an intravascular dual-mode endoscopic system capable of both intravascular photoacoustic imaging(IVPAI)and intravascular optical coherence tomography(IVOCT)for recognizing spontaneous coronary artery dissection(SCAD)phantoms.IVPAI provides high-resolution and high-penetration images of intramural hematoma(IMH)at different depths,so it is especially useful for imaging deep blood clots associated with imaging phantoms.IVOCT can readily visualize the double-lumen morphology of blood vessel walls to identify intimal tears.We also demonstrate the capability of this dual-mode endoscopic system using mimicking phantoms and biological samples of blood clots in ex vivo porcine arteries.The results of the experiments indicate that the combined IVPAI and IVOCT technique has the potential to provide a more accurate SCAD assessment method for clinical applications.

Vascular Stress Analysis Based on in vivo Intravascular Optical Coherence Tomography Image Segmentation

Identification of carotid artery atherosclerosis is crucial for the diagnosis of the cerebral apoplexy and other vascular diseases.Intravascular optical tomography(IVOCT)has been employed to clinical coronary imaging for several years.Vessel morphological information on IVOCT images together with blood flow information on Doppler OCT(DOCT)images could provide a more accurate internal environment of arteries.Images integrated with fluid-structure interaction(FSI)could obtain the accurate mechanical responses and the quantitative material characters.A porcine carotid artery was imaged with an intravascular system(C7-XR,St.Jude Medical Inc.St.Paul,Minnesota,USA)in vivo,during which 120 images of one section and 600 images of a 5 mm/s pull back were captured within 6 s.Those images were then overlapped with Doppler phase changes to imply the changes in flow profiles.Segmentation and quantification of vessel structure was done in the software(MATLAB 2014b),including specifically the segmentation of lumen,imaging catheter,vessel wall and the guide wire.Appropriate interpolation functions are selected in the coordinate transformation algorithm to have smooth boundaries from images.A set of flow algorithms include image segmentation,three-dimensional/two-dimensional model reconstruction,inversion of material parameters,fitting of experimental velocity data and theoretical derivation based on simulation results is proposed.All steps are programmed to provide a theoretical basis for the future simplified process control.3D-reconstruction FSI model was built in SOLIDWORKS by lofting operation based on the segmentation results.Commercial finite element software(COMSOL 5.3,Sweden)numerically analyzed the entity model to obtain vessel stress/strain and flow shear stress data.Boundary conditions are from the OCT detection.Material of the artery was set to be the modified Mooney-Rivlin constitutive model and the parameters used were adjusted in an algorithm to match an ex vivo experiment.Wall shear stresses(WSS)and vessel deformations were chosen to measure the conditions of the artery and would serve as a target variables for future prediction.Thus,the geometric information together with the data of materials and other mechanical properties are possible to obtain during the imaging process.Segmentation process provided anatomically correct models of a two-layered artery.Numerical simulation permits reliable stress distribution in which the position of catheter and the artery curvature have a neglectable disturbance.Shear stress of the fluid is quite small compared with that of the wall at the same interface,which shows good agreement with the former studies.Moreover,a high flushing speed of 0.1 mps have little impact on the stress distributions and magnitudes,which denotes that the OCT imaging process brings little harm to the vessel.It is the first attempt to combine the OCT imaging and Doppler OCT within a full algorithm and a structural analysis.This study is helpful for the biomechanical property studies of carotid arteries and the development of medical imaging technology.

Pencil-beam scanning catheter for intracoronary optical coherence tomography

Current gradient-index(GRIN)lens based proximal-driven intracoronary optical coherence tomography(ICOCT)probes consist of a spacer and a GRIN lens with large gradient constant.This design provides great flexibility to control beam profiles,but the spacer length should be well controlled to obtain desired beam profiles and thus it sets an obstacle in mass catheter fabrication.Besides,although GRIN lens with large gradient constant can provide tight focus spot,it has short depth of focus and fast-expanded beam which leads to poor lateral resolution for deep tissue.In this paper,a type of spacer-removed probe is demonstrated with a small gradient constant GRIN lens.This design simplifies the fabrica-tion process and is suitable for mass production.The output beam of the catheter is a narrow nearly collimated light beam,referred to as pencil beam here.The full width at half maximum beam size varies from 35.1μm to 75.3μm in air over 3-mm range.Probe design principles are elaborated with probe/catheter fabrication and performance test.The in vivo imaging of the catheter was verified by a clinical ICOCT system.Those results prove that this novel pencil-beam scanning catheter is potentially a good choice for ICOCT systems.

基于Transformer的结构强化IVOCT导丝伪影去除方法

为去除导丝伪影以提高血管内光学相干断层扫描(IVOCT)的图像质量,辅助医师更加准确地诊断心血管疾病,降低误诊及漏诊的概率,针对IVOCT图像结构信息复杂且伪影区域占比大的难点,提出一种采用生成对抗网络(GAN)架构的基于Transformer的结构强化网络(SETN)。首先,GAN的生成器在提取纹理特征的原始图像(ORI)主干生成网络的基础上,并联了RTV(Relative Total Variation)图像强化生成网络用于获取图像的结构信息;其次,在ORI/RTV图像的伪影区域重建过程中,引入了分别关注时/空间域信息的Transformer编码器,用于捕获IVOCT图像序列的上下文信息以及纹理/结构特征之间的关联性;最后,利用结构特征融合模块将不同层次的结构特征融入ORI主干生成网络的解码阶段,配合判别器完成导丝伪影区域的图像重建。实验结果表明,SETN的导丝伪影去除结果在纹理和结构的重建上均十分优秀。此外,导丝伪影去除后IVOCT图像质量的提高,对于IVOCT图像的易损斑块分割及管腔轮廓线提取任务均具有积极意义。

支架术后即刻冠状动脉光学相干断层扫描结果的临床影响

冠状动脉光学相干断层扫描的分辨率为10μm,它可为术者提供支架贴壁不良、组织脱垂、支架内血栓和支架边缘夹层等支架术后即刻结果,但其对临床预后的影响一直存在争议。现总结既往研究,并就支架术后即刻冠状动脉光学相干断层扫描结果的研究进展及临床影响进行综述。

基于影像的冠状动脉生理学功能评估研究进展

血流储备分数(FFR)已经成为评估冠状动脉狭窄程度、指导血运重建策略以及选择治疗方案的冠状动脉生理学“金标准”。然而,由于FFR评估过程中存在压力导丝侵入性操作、充血药物的使用等诸多因素,其在临床实践中的应用受到限制。随着冠状动脉虚拟生理学的应用,基于冠状动脉影像衍生FFR的技术得以研发,如冠状动脉造影衍生FFR、光学相干断层成像(OCT)衍生的FFR以及血管内超声(IVUS)衍生的FFR。同时这些功能学评估手段的诊断效能不断被大量临床研究证实。本文旨在对基于冠状动脉造影、IVUS和OCT衍生的FFR的诊断效能、临床运用等方面进行综述。

光学相干断层成像技术在经皮冠状动脉血管内冲击波能量钙化碎裂术治疗冠状动脉钙化斑块中应用的研究进展

冠状动脉钙化病变会增加介入手术的难度和并发症发生率,导致患者预后不良,在支架置入前对钙化斑块进行充分预处理将有效减少不良结局发生。经皮冠状动脉血管内冲击波能量钙化碎裂术(IVL)能有效破坏钙化斑块,从而有利于支架输送和促进支架膨胀完全。光学相干断层成像(OCT)可准确识别钙化病变,评估钙化斑块经IVL预处理效果,指导介入手术策略制定。本文将综合近年来此领域研究进展,总结OCT在IVL治疗冠状动脉钙化病变中的作用。

血管腔内超声在下肢动脉疾病中的应用现状与进展

下肢动脉粥样硬化性疾病是临床上较常见的一种周围动脉疾病。目前临床常用的影像学诊断方法主要有超声、计算机断层扫描和动脉造影术等,但这些手段仅能观察到下肢动脉形态学改变,对于动脉腔内病变的评估(如粥样斑块的性质)具有一定的局限性。随着血管腔内超声(Intravascular Ultrasound,IVUS)技术的逐渐成熟以及对下肢动脉粥样硬化性疾病发病机制研究的不断深入,IVUS为临床诊疗方法的选择提供了更好的帮助。本文对IVUS在辅助诊断下肢动脉粥样硬化性疾病中的最新应用进展进行综述,以期促进IVUS技术在临床的应用。

基于深度学习的冠状动脉IVOCT图像中易损斑块识别算法研究进展

介绍了冠状动脉血管内光学相干断层成像(intravascular optical coherence tomography,IVOCT)图像中易损斑块的智能识别算法的研究现状,分析了传统机器学习算法在易损斑块识别领域的不足及深度学习算法的优势。从斑块分类、检测、分割3个方面阐述了基于深度学习的斑块识别网络的结构特征及针对性的结构改进方法,指出了现有基于深度学习的识别算法的局限性,提出了提升识别精度、理解易损斑块破裂机理是该领域的未来发展方向。

Multimodal intravascular imaging technology for characterization of atherosclerosis

Early detection of vulnerable plaques is the critical step in the prevention of acute coronary events.Morphology,composition,and mechanical property of a coronary artery have been demonstrated to be the key characteristics for the identification of vulnerable plaques.Several intravascular multimodal imaging technologies providing co-registered simultaneous images have been developed and applied in clinical studies to improve the characterization of atherosclerosis.In this paper,the authors review the present system and probe designs of representative intra-vascular multimodal techniques.In addition,the scientific innovations,potential limitations,and future directions of these technologies are also discussed.

腔内影像技术指导下的PCI精准治疗策略研究进展

腔内影像学作为三维成像,较二维的冠状动脉造影更能准确地反映血管腔内结构及识别病变斑块的性质,因此有助于介入术前支架或球囊类型和置入部位的选择,指导不同类型病变合理的预处理方式,并证实可以优化左主干及慢性完全性闭塞病变介入治疗的策略,最终减少并发症及不良事件的发生。本综述从国内外循证医学证据和指南的角度,介绍了冠脉介入治疗腔内影像学研究在优化经皮冠状动脉介入治疗中的最新进展。

自发性冠状动脉夹层的临床特点及腔内影像分析

目的探讨自发性冠状动脉夹层(SCAD)的临床表现,夹层不同分型在腔内影像中的表现及治疗策略选择。方法纳入2021年8月至2022年8月以急性冠状动脉综合征收住于兰州大学第一医院心内科,经冠状动脉造影联合腔内影像检查[血管内超声(IVUS)或光学相干断层成像(OCT)]明确诊断SCAD的患者20例,收集相关临床资料,术后1~6个月通过门诊及电话随访,术后6个月复查冠状动脉造影联合腔内影像检查(IVUS或OCT),观察夹层及血肿吸收情况,有无新发病变出现及病变延展。结果SCADⅠ型5例(5/20),SCADⅡ型9例(9/20),SCADⅢ型4例(4/20),SCADⅣ型2例(2/20)。药物保护治疗13例(13/20,SCADⅡ型、Ⅲ型),行经皮冠状动脉介入治疗(PCI)7例(7/20,SCADⅠ型、Ⅳ型)。血肿入口和出口均出现明显夹层,血肿内可见斑块破裂,或有机化血栓形成,或SCADⅠ型、Ⅳ型,多采用PCI;血肿入口无夹层,血肿出口也无夹层的病变,管腔内未见斑块,血肿内部呈低回声,可采用药物保守治疗。患者平均随访6个月,药物保守治疗患者中再发急性心肌梗死1例(1/20)。结论SCAD通过腔内影像评估后确定夹层性质,选择适合的治疗策略,可以提高患者整体预后。

光学相干断层成像指导血管内冲击波钙化碎裂术治疗冠状动脉重度钙化病变的有效性和安全性

目的探讨在光学相干断层成像(optical coherence tomography,OCT)指导下,冲击波钙化碎裂术(intravascular lithotripsy,IVL)治疗冠状动脉重度钙化病变的有效性和安全性。方法选择2022年8月至2023年3月江南大学附属医院收治的20例冠状动脉重度钙化患者,在OCT指导下应用冠状动脉内冲击波导管对钙化病变进行预处理,随后植入药物洗脱支架(drug-eluting stent,DES)。比较IVL治疗前、IVL治疗后、支架植入后OCT相关参数,包括钙化病变的长度、角度和厚度,最小管腔面积、最小管腔直径、支架膨胀系数、钙化断裂数、支架膨胀率、斑块光衰指数(index of plaque attenuation,IPA)、虚拟血流储备分数(virtual fractional flow reserve,VFR)等。记录患者围手术期发生的主要不良心血管事件(major adverse cardiovascular events,MACEs)。结果20例患者中,男性12例、女性8例;平均年龄(65.3±9.69)岁。与IVL前相比,最严重钙化病变处的最小管腔直径在IVL后显著扩大[(2.45±0.37)mm vs(2.64±0.33)mm,P<0.05],最小管腔面积在IVL后显著增加[(3.78±0.81)mm^(2)vs(5.22±1.45)mm^(2),P<0.05];钙化角度在IVL后显著减小[(324.5±94.2)°vs(284.3±79.4)°,P<0.001],钙化厚度和长度无明显变化。100%的病变发生钙化断裂,85%的病变发生≥2个钙化断裂;支架植入成功率100%,支架膨胀率(97.10±5.28)%。最严重钙化处支架植入后IPA<110,VFR>0.8。所有患者围手术期未发生MACEs。结论OCT指导下,采用IVL预处理重度冠状动脉钙化病变并植入支架是安全有效的。

Neointimal coverage of sirolimus-eluting stents 6 months and 12 months after implantation： evaluation by optical coherence tomography

Optical coherence tomography （OCT） is a new imaging modality with resolution of approximately 10 pm and can be employed to visualize intracoronary characteristics. Sirolimus-eluting stents （SES） are susceptible to late thrombosis due to delayed reendothelialization over the stent struts, which may result in acute myocardial infarction or death. This study was designed to evaluate the re-endothelialization and neointimal coverage of SES with OCT 6 months and 12 months after implantation.Methods A total of 36 patients enrolled in the study underwent OCT examination 6 months （17 patients） and 12 months （19 patients） after SES implantation, The strut apposition to the vessel wall and neointimal coverage on SES struts were evaluated by OCT, Results Forty-six SES and 6561 struts were analyzed, At 6 months, 3041 struts （98.7%） were well-apposed and 39 struts （1,3%） were malapposed, At 12 months, 3434 struts （98,6%） were well-apposed and 47 struts （1,4%） were malapposed, Furthermore, only 4 SES at 6 months （18,2%） and 10 SES at 12 months （41,7%） were fully covered by neointimal growth, The average neointimal thicknesses covering the analyzed struts at 6 months and 12 months were （42±28） μm and （88±32） μm, respectively, There were 1989 struts at 6 months （72,1%） and 1461 struts at 12 months （45,6%） with neointimal thickness 〈100 μm, Conclusions OCT was able to visualize the strut apposition to the vessel wall and neointimal coverage on SES struts, At 6-month and 12-month follow-up examinations most struts were covered with thin neointima, but few of the entire SES showed full coverage. To prevent late-stent thrombosis in the presence of uncovered stent struts, longer dual antiplatelet drugs therapy should be recommended,

基于IVOCT的动脉粥样硬化斑块识别与风险评估

动脉粥样硬化引起的易损斑块破裂已经严重危害到人类的健康,而血管内光学相干断层成像(IVOCT)凭借其高分辨率已经成为识别冠脉易损斑块的主要工具,但图像判读费时费力,通常还依赖于医生的经验。目前已有基于传统机器学习的研究实现了对单帧图像的分类,但这些信息不足以辅助医生确定治疗方案,仍然需要医生二次判读。基于Faster R-CNN(R-CNN,区域卷积神经网络),针对IVOCT图像中易损斑块的特点,在数据增强、预测框(BBox)编码、网络结构等方面进行了改进和优化,实现了对易损斑块的自动识别,并选取易损斑块的病变累积角度、纤维帽厚度、巨噬细胞浸润情况、浅表微钙化情况和血管狭窄程度作为指标,对易损斑块的破裂风险进行多方面评估。在公开数据集CCCV2017 IVOCT中进行训练,测试后取得了较好结果,该方法可推广应用于同类图像。

一例梅毒感染合并家族性高胆固醇血症的早发心肌梗死

梅毒感染可以引起心血管系统受累,但冠状动脉受累是较为少见的临床表现。家族性高胆固醇血症(FH)是一种因低密度脂蛋白胆固醇(LDL-C)清除障碍导致LDL-C水平显著升高,造成早发严重动脉粥样硬化的常染色体显性遗传疾病。本文报道一例梅毒感染合并FH的青年男性患者,临床表现为急性心肌梗死、高LDL-C血症,冠脉造影及腔内影像检查可见冠状动脉多发瘤样扩张和狭窄,经反复冠状动脉药物球囊扩张后短期内再狭窄,最终植入支架治疗。

自发性右冠状动脉夹层1例

本文回顾1例年轻女性严重自发性右冠状动脉夹层病例,对近年自发性冠状动脉夹层(SCAD)相关文献进行复习,探讨SCAD的病理机制、临床特征及诊疗经验,为今后的临床工作提供诊治经验、减少漏诊及误诊率、改善患者预后。本例患者入院后予双联抗血小板聚集、控制心率、改善心室重构等治疗,发病1个月后复查冠状动脉造影(CAG)显示病变已自行愈合。SCAD可通过CAG、血管内超声及光学相干断层扫描确诊,药物治疗为首选方案。

光学相关断层摄影技术观察壁冠状动脉的可行性研究

目的 讨论光学相关断层摄影技术观察壁冠状动脉的可行性。方法 选择36名心肌桥（myocardial bridging,MB）患者（即冠脉造影可见“挤奶现象”的患者）行光学相干断层摄影检查（optical coherence tomography,OCT）及血管内超声检查（intravascular ultrasound,IVUS）,并进一步用猪的心脏作为动物模型以确认与OCT图像相对应的组织学结构。结果 所有患者OCT检测均发现MB节段内一紧邻动脉管壁外的边界清晰、不均质的、低信号梭形区域;且在舒张期更易观察到这一特征性的图像表现。该梭形区域的最大弧度为176.3°±53.1°（106°~287.5°）,最大厚度为（0.41±0.12）mm（0.25~0.69 mm）。所有患者均在且只在肌桥节段外近段血管内检出动脉粥样硬化改变,仅1例患者在肌桥节段内发现了管壁内膜增厚。OCT所发现的梭形区域不同于IVUS图像中代表MB肌束的半月形无回声区域。另外,线性相关分析发现梭形区域弧度与管腔受压迫程度呈负相关（r=-0.403,P=0.004）。进一步的动物模型的组织学检查结果发现这一梭形、低信号区域是位于肌肉与动脉血管之间的结缔组织。结论 在造影和IVUS确诊的MB患者中,OCT检查可在肌桥节段发现一紧邻动脉管壁外的边界清晰、不均质的、低信号梭形区域,进一步组织学检查结果发现这一区域为动脉周围结缔组织,而非IVUS中代表肌束的半月形无回声区域。

血管内光学相干成像技术检测易损斑块研究进展

动脉粥样硬化斑块破裂引发血栓形成是临床急性冠脉综合征的根本原因。易损斑块的早期识别与及时处理是避免临床心血管事件的关键。目前已经有很多影像学方法应用于冠脉内易损斑块的检测,但易损斑块的形态学及其破裂导致血栓形成的机制仍是临床医生关注的重点。血管内光学相干成像技术(OCT)是一种基于心脏导管的检查方法,它利用近红外光,可获取高达10μm分辨率的影像,从而在细胞水平实现体内血管壁微结构成像。随着新一代频域OCT(FD-OCT)的发展,这一技术在易损斑块研究中发挥积极作用。现将OCT在易损斑块相关研究中的进展作一综述。

应用血管内超声/光学相干断层成像杂交技术研究冠状动脉钙化与斑块回缩的关系

目的:冠状动脉钙化是否与斑块回缩相关尚不清楚。本研究的目的是结合光学相干断层扫描(OCT)和血管内超声(IVUS)评估冠状动脉钙化和斑块回缩(PS)之间的关系。方法:15例患者,16支血管纳入本研究,术后即刻和术后5年联合应用OCT和IVUS评估钙化斑块面积变化和斑块回缩,及二者之间的关系。IVUS检测管腔面积(LA)、血管面积(VA)和斑块/中膜面积(PA)。将斑块/中层回缩(PS)定义为PA相对减少>5%。OCT检测钙化面积、钙化弧度和钙化长度。结果:术后即刻和5年随访时,共有72个OCT和IVUS完全匹配的横断面(共432个图)纳入该研究。72个横截面中,35个横截面在5年随访时显示为PS,37个横截面为非PS。斑块面积的变化分别与OCT测量的钙化面积变化呈负相关(r=-0.29,P=0.004),与OCT钙化弧度变化(r=-0.42,P<0.001),OCT钙化长度变化(r=-0.5,P<0.001)呈负相关,与IVUS测量的钙化弧度变化呈负相关(r=-0.31,P=0.024),而与管腔面积变化呈正相关(r=0.24,P=0.044)。结论:冠状动脉钙化斑块进展使得斑块回缩和管腔扩大。应用IVUS/OCT杂交技术能更好的评估钙化斑块进展和斑块回缩之间的相关性。