一种基于淘汰粒子群优化聚类算法的心肌超声造影分析系统

背景:心肌超声造影已成为评价心肌微灌注有效的影像学方法之一,但目前心肌超声造影图像的分析判断多采用目测法或手动描记感兴趣区域,很大程度上依赖观察者的经验,缺乏客观定量分析方法.目的:探讨新型心肌超声造影图像定量分析系统评价心肌灌注的可行性.方法;采集家兔心肌超声造影图像,应用基于淘汰粒子群优化聚类(EPSO)算法的计算机图像定量分析系统对造影图像进行自动处理,获得心肌灌注定量参数.结果与结论:①图像识别软件自动识别心内膜与心外膜,确定心肌区域.②自动将心肌区域分割为相等的6个区.③自动标记各节段心肌的标化对比剂密度值.④以标化对比剂密度值为依据行彩色编码,获得彩色编码面积百分比.⑤自动生成心肌节段灌注分布直方图.基于淘汰粒子群优化聚类算法的心肌超声图像分析软件,在定量评价心肌微灌注和识别灌注异常方面具有较好的可行性和较高的应用价值.     

人工智能在心肌声学造影中的应用现状及发展趋势

心肌声学造影(MCE)作为一种检测心肌缺血的便捷检查方式,近年在临床逐渐推广应用,但MCE专业性强,学习时间成本高,无法在所有医院广泛开展。若能将人工智能应用于MCE,简化操作步骤,甚至实现自动化诊断,将大大降低学习成本,缩短学习时间,减少超声医师工作负荷。本文就人工智能在MCE心肌轮廓描记中的应用现状及其发展趋势进行综述。     

本期图片精选

图1，2经皮消融阻断荷瘤血管前超声造影和彩色多普勒超声声像图。图1示超声造影动脉期肿瘤呈团状增强（箭头所示为肿瘤部位）；图2为彩色多普勒血流成像示肿瘤周边及内部血管走行（箭头所示为荷瘤血管及进入肿瘤部位）图3应用描记计。量软件计算造影增强区及灌注缺失区面积图4根据超声造影结果指导消融肿瘤活性区域及周边区域（箭头所示）     

超声造影心肌灌注显像的研究热点

近年来超声造影心肌灌注显像的研究有了重大进展．为临床医生了解冠状动脉的血流分布心肌灌注情况提供了一种全新的方法。静脉注射超声造影剂和心肌灌注定量测定将使该技术更广泛地应用于临床。     

心肌超声造影和冠状动脉造影对比研究初析

目的 探讨心肌超声造影定量分析对冠心病的诊断价值。方法：10例临床诊断冠心病的患者行MCE，从时间-强度曲线中获得造影荆再灌注强度峰值（Slpeak），再灌注时间（Rt），再灌注率（b）和心肌血流量（SI＊b）。同一检查对象不同心肌节段的4个参数（Slpeak、Rt、b和SI＊b）均有统计学上的差异（P〈0．05），对照组和观察组Slpeak具有统计学上的差异，Slpeak预测冠心病的ROC曲线下面积（AUC）为0．782，最佳临界值为64，4，以Slpeak≤64．4来预测冠心病，敏感性83．3%，特异性69．0%。利用超声造影匹配成像技术能够较满意地显示心肌灌注状态，初步研究表明通过MCE及Qontrast多参数定量分析软件可以评价心肌梗死区和缺血区的血流灌注。     

白细胞靶向超声造影显像无创评价犬心肌缺血再灌注损伤

目的 用白细胞靶向超声造影剂无创评价犬心肌缺血再灌注（ischemia-reperfusion，I-R）损伤的范围及严重程度。 方法 将自制“表活显”（self-made surfactant fluorocarbon-filled microbubbles，SFCMB）与磷脂酰丝氨酸（phosphatidylserine，PS）结合，制备成白细胞靶向超声造影剂（SFCMB-PS），在实时心脏超声造影（myocardial contrast echocardiography，MCE）条件下，用SFCMB-PS对9只犬心肌I-R模型进行延迟心肌显像。实验结束后，在心肌I-R损伤处取组织块立即进行髓过氧化物酶（myeloperoxidase，MPO）活性测定。 结果 延迟心肌显像可见缺血心肌部位有明显充盈缺损，而再灌注后心肌的造影剂回声明显增强。定量分析结果表明I-R损伤心肌部位声像图的灰阶强度与MPO活性有明显的相关关系（r=0．776，P〈0．05）。 结论 用白细胞靶向超声造影剂评价心肌I-R损伤有明显的临床价值。     

超声心动描记术在冠心病诊断中的应用

1　引　言心肌缺血和心肌坏死是冠心病两种特征性的病理改变。从影像学诊断的水平来看,主要表现为不同程度的心肌血流灌注异常和由灌注异常导致的心室整体及心肌局部舒缩和增厚功能的改变。超声心动描记术(UCG)作为一种无创的方法在心肌缺血和心肌坏死的诊断上得到广泛的应用[1]。近年发展的心肌声学造影和血管内超声技术使直接观察心肌血流灌注和冠状动脉病变成为可能。2　心肌缺血的诊断正常冠状动脉循环有很大的储备能力,在各种应激情况下,冠状动脉血流量从安静时的300mL/min增加到2000mL/min。冠心病病人的心肌缺血主要表现为冠状动脉…     

心肌造影超声心动图定量分析的影响因素

心肌造影超声心动图定量分析的影响因素邵波钱蕴秋心肌造影超声心动图（ｍｙｏｃａｒｄｉａｌｃｏｎｔｒａｓｔｅ－ｃｈｏｃａｒｄｉｏｇｒａｐｈｙ，ＭＣＥ）作为一项活体研究局部心肌血流灌注和功能的新方法，近十年来受到广泛关注。实验研究证实ＭＣＥ能确定冠状动脉及...     

携抗P-selectin靶向超声造影剂犬体内超声分子成像

目的 制备携抗P-selectin靶向超声造影剂,探讨其评价心肌缺血再灌注损伤的超声分子成像效果。方法 采用“生物素-亲和素”桥接法制备携抗P-selectin靶向超声造影剂,建立犬心肌缺血再灌注模型,分别注入携抗P-selectin靶向超声造影剂（MBp）和空白超声造影剂（MBc）,行心肌声学造影检查,采图、存盘。应用DFY型超声图像定量分析诊断仪中的彩色编码技术对存储的图像进行脱机处理,观察MBp体内超声分子成像效果。结果 成功制备携抗P-selectin靶向超声造影剂及建立犬心肌缺血再灌注模型。彩色编码图像示MBp行心肌声学造影可见缺血再灌注区心肌显著增强;MBc于缺血再灌注区心肌造影无明显增强。结论 应用携抗P-selectin靶向超声造影剂行心肌声学造影检查能准确检测再灌注治疗后犬心肌缺血再灌注损伤。     

造影超声心动图的临床应用现状

随着临床诊断要求的不断提高,常规超声心动图已经不能满足对某些心血管疾病精确完善的诊断需求.造影超声心动图的出现是超声心动图发展史上的又一座里程碑,为医学超声诊断的发展带来了一次新的革命,其在临床上得到了迅速而广泛的应用.目前,造影超声心动图主要包括心腔超声造影和心肌灌注超声造影两个方面.     

冠心病的心肌超声造影

目的 探索心肌超声造影（MCE）在可疑冠心病及冠心病中的应用.方法 43例患者进行了超声心动图检查,并在静息状态下行心肌声学造影.造影图像采用ACQ软件对微泡再充盈曲线进行定性及定量分析.结果 43例患者中有60个节段显示灌注异常,冠脉造影正常者中有4个节段灌注减弱,定性分析和定量分析基本一致.结论 心肌超声造影有望成为可疑冠心病及冠心病的常规检查方法.     

Assessment of resting perfusion defects in patients with acute myocardial infarction: comparison of myocardial contrast echocardiography, combined first-pass/delayed contrast-enhanced magnetic resonance imaging and 99mTC-sestamibi SPECT

Background Information on the accuracy of both magnetic resonance imaging (MRI) and myocardial contrast echocardiography (MCE) for the identification of perfusion defects in patients with acute myocardial infarction is limited. We evaluated the accuracy of MRI and MCE, using Single Photon Emission Computed Tomography (SPECT) imaging as reference technique.Methods Fourteen consecutive patients underwent MCE, MRI and ^99mTc-MIBI SPECT after acute myocardial infarction to assess myocardial perfusion. MCE was performed by Harmonic Power Angio Mode, with end-systolic triggering 1:4, using i.v. injection of Levovist^®. First-pass and delayed enhancement MRI was obtained after i.v administration of Gadolinium-DTPA. At MCE, homogeneous perfusion was considered as normal and absent or “patchy” perfusion as abnormal. At MRI, homogenous contrast enhancement was defined as normal whereas hypoenhancement at first-pass followed by hyperenhancement or persisting hypoenhancement in delayed images was defined as abnormal.Results At MCE 153 (68%) of segments were suitable for analysis compared to 220 (98%) segments at MRI (p<0.001). Sensitivity, specificity and accuracy of MCE for segmental perfusion defects in these 153 segments were 83, 73 and 77%, respectively. Sensitivity, specificity and accuracy of MRI were 63, 82, and 77%, respectively. MCE and MRI showed a moderate agreement with SPECT (k: 0.52 and 0.46, respectively). The agreement between MCE and MRI was better (k: 0.67) that the one of each technique with SPECT.Conclusion MCE and MRI may be clinically useful in the assessment of perfusion defects in patients with acute myocardial infarction, even thought MCE imaging may be difficult to obtain in a considerable proportion of segments when the Intermittent Harmonic Angio Mode is used.     

能量多普勒造影技术在经静脉心肌声学造影研究中的临床初步应用

目的：观察能量多普勒造影技术（ＰＣＩ）行静脉心肌声学造影（ＭＣＥ）的效果。方法：利用ＰＣＩ技术观察６例非特异性胸痛患者及３例陈旧性心肌梗塞患者的经静脉心肌声学造影效果。其中,心肌梗塞患者在ＭＣＥ后一周内行核素检查。结果：６例非特异性胸痛患者均未见节段室壁运动异常,在声学造影剂注射后见全部心肌组织均匀显影 ３例陈旧性心肌梗塞患者则见梗塞相应部位室壁运动异常,且声学造影检查发现该部位多普勒能量信号缺失     

Real-Time Myocardial Contrast Echocardiography in Rat: Infusion Versus Bolus Administration

To compare the feasibility of real-time myocardial contrast echocardiography (MCE) in rats with infusion and bolus administration of a second-generation ultrasound contrast agent BR1. B-mode real-time MCE was performed in 12 Sprague Dawley rats following the BR1 infusion or bolus injection. The myocardium signal intensity (SI) was plotted against time and was fitted to exponential functions. The plateau SI (A) and rate of SI increase (β) for the infusion study and peak signal intensity (PSI) for the bolus study were obtained. ^99mTc-Sestamibi and Evans blue were used to assess myocardial blood perfusion and to calculate the myocardium perfusion defect area ex vivo. High-quality real-time MCE images were successfully obtained using each method. At baseline, all LV segments showed even contrast distribution. Following left anterior descending coronary artery (LAD) ligation, significant perfusion defect was observed in LAD beds with a significantly decreased A* β and PSI values compared with LCx beds (Infusion: A*β _LAD: 5.42 ± 1.57dB, A*β _LCx: 46.52 ± 5.32dB, p < 0.05; Bolus: PSI _LAD: 2.11 ± 0.67dB, PSI _LCx: 20.68 ± 0.72 dB, p < 0.05), which was consistent with ^99mTc-Sestamibi distribution findings. Myocardial perfusion defect areas, assessed by both methods, showed no differences and showed good correlation with Evans blue staining. ED frames were more favorable for imaging analysis. Both infusion and bolus administration of the contrast agent combined with real-time MCE technique can provide a reliable and noninvasive approach for myocardial perfusion assessment in rats and the infusion method was more suitable for quantitative analysis of myocardial blood flow. (E-mail: suhaili@fmmu.edu.cn)     

心肌声学造影无创评价犬急性冠状动脉闭塞缺血心肌及侧支循环的状态

目的：探讨经静脉心肌志学造影在动态评价犬急性冠状动脉闭塞时缺血、坏死心肌，及侧支循环逐步建立开放中的价值。方法：7只健康杂种犬，分别于基础状态，左冠前降支（LAD）结扎即刻、结扎后3h行经静脉心肌声学造影（MCE）。定量分析冠脉闭塞后心肌低灌注区视频密度峰值（VI），测量充盈缺损区面积，监测血流动力学变化。结果：1只犬于LAD结扎2min时因发生室颤死亡，统计分析时剔除，其余6只犬经静脉MCE未见血流动力学影响。LAD结扎3h的造影充盈缺损面积小于结扎即刻（P＜0．001）；LAD结扎3h的心肌低灌注区视频密度峰值较结扎即刻明显增加（P＜0．001）；心肌病理染色确定的坏死心肌部位在MCE的充盈缺损范围内。结论：MCE是反映心肌血流灌注的安全、有效方法，可准确评价冠脉急性闭塞时心肌血流灌注的变化及侧支循环状态。     

实时心肌声学造影的仪器设置与显像效果的影响因素

目的：探讨实时心肌声学造影的仪器设置及显像效果的影响因素。方法：8只开胸充微量注射泵静脉滴注氟碳类造影剂全氟显（速度为5ml/min和10ml/min)进行实时心肌声学造影。调节仪器设置如增益,量程及深度等参数,于左室乳头肌水平短轴切面观察心肌显影的不同效果。结果：实时心肌声学造影可同时显示心肌血流灌注和室壁运动,除降低接受增益至50％,使用默认的仪器设置即可获得良好的造影效果,闪烁显像时最佳闪烁帧数为5个。结论：实时心肌声学造影易于掌握,影响因素较少,可同时观察心肌灌注和室壁运动,闪烁显像具有定量评价心肌血流灌注的潜力。     

Potential pitfalls of visualization of myocardial perfusion by myocardial contrast echocardiography with harmonic gray scale B-mode and power Doppler imaging

OBJECTIVE: The present study compared the regional variation of myocardial signal intensity in visualizing myocardial perfusion by myocardial contrast echocardiography (MCE) between harmonic gray scale and power Doppler imaging. METHODS: MCE was performed in 12 patients by electrocardiographic (ECG)-gated intermittent triggered MCE with harmonic gray scale and power Doppler imaging following slow intravenous injection of 0.5 ml contrast agent (Optison). The interval between the ECG triggers (pulsing interval) was increased from every heart beat (1:1) to every 2 (1:2), 4 (1:4), and 8 (1:8) cardiac cycles to allow incremental microbubble (contrast agent) replenishment. The MCE images were recorded when attenuation produced by the left ventricular cavity was minimal. The background-subtracted videointensity was measured in 7 segments in an apical 4-chamber view: 3 (apical, mid, and basal) septal segments, 3 (apical, mid, and basal) lateral segments, and 1 apex segment (apical cap). RESULTS: The background-subtracted videointensity for each segment was greater with the power Doppler than the gray scale imaging (p < 0.01). With the gray scale imaging, the background-subtracted videointensity in the basal septal segment demonstrated a negative value at all pulsing intervals, and the value (-9 +/- 13) was significantly lower than that (22 +/- 20) in the apical lateral segment at a pulsing interval of 1:8 (p < 0.01). With power Doppler imaging, the background-subtracted videointensity was high even in the basal septal segment (112 +/- 33), and no significant difference was observed among each segment. CONCLUSIONS: The findings indicate that quantitative assessment of myocardial perfusion based upon background-subtracted video-intensity may be difficult in the far field with harmonic gray scale imaging although the attenuation is not apparent by visual analysis. Harmonic power Doppler is more sensitive for detecting basilar perfusion in the far field compared with harmonic gray scale imaging.     

静脉输注国产声学造影剂定量心肌血流灌注的实验研究

目的：评价应用国产左心声学造影剂“全氟星”定量心肌血流灌注的可行性。方法：建立犬前降支缺血模型，经外周静脉持续匀速输注“全氟星”，存取不同触发间隔的造影图像，通过计算造影剂再充填曲线的平台声强度及微泡再充填速率估测心肌血流量。以正常区为参照、放射微球测定心肌血流量为“金标准”，判定应用国产左心声学造影剂定量心肌血流灌注的可行性。结果：放射微球测定心肌血流量与心肌声学造影定量结果相关良好（r=0.8913，P＜0．001）。结论：静脉均速输注“全氟显”可用于估测心肌血流量。     

心肌造影超声心动图与存活心肌的检测

研究表明,冠脉微血管的完整性是心肌存活的必备条件.由于心肌造影超声心动图在对心肌微循环灌注进行定性、定量评估的同时,还能检测局部室壁运动功能,因此,它在存活心肌的检测方面具有独到的应用价值.     

经静脉实时心肌声学造影评价犬急性心肌梗死的实验研究

目的 研究实时心肌声学造影检出犬急性心肌梗死的效果。方法 8只开胸犬结扎第一对角支起点以下冠脉左前降支主干,分别于结扎前、结扎后1h和3h静滴全氟显（5ml/min）进行实时心肌声学造影,左室乳头肌水平短轴切面观察造影效果和室壁运动,并与病理染色比较。结果 结扎后1h及3h,实时心肌声学造均能良好显示缺血区的造影剂充盈缺损,包括缺损大小、与形态,同时清楚显示缺血区室壁运动异常。与病理染色比较,充盈缺损区大于心梗区。闪烁显像很好反映出充盈缺损区周围心肌轿流再灌注减慢。结论 与病理染色比较,充盈缺损区大于心梗区。闪烁显像很好反映出充盈缺损区周围心肌血流再灌注减慢。结论 实时心肌声学造影可同时观察心肌灌注和室壁运动,闪烁显有定量评价心肌血流灌注的潜在价值,操作简便,具有良好的应用前景。