实时心肌声学造影结合多巴酚丁胺负荷试验检测存活心肌的临床研究

目的评价实时小剂量多巴酚丁胺(LD-DSE)(10μg·kg~(-1)·min~(-1))负荷心肌声学造影(RT-MCE)试验检测存活心肌的临床价值。方法 22例经彩超检查存在左心室壁节段运动障碍冠心病患者,进行LD-DSE负荷RT-MCE试验、冠状动脉造影(CAG)及介入治疗(PCI),所有狭窄病变行完全血运重建。按美国超声心动图学会16节段划分法获得各运动异常节段显影,图像用目测半定量法分析。术后1、3、6个月时复查心脏超声,以冠脉血运重建后室壁节段收缩功能改善为判断存活心肌的金标准。结果普通RT-MCE目测半定量法检测存活心肌的灵敏度、特异度及准确度分别是75.7%、84.2%、78.8%;LD-DSE负荷RT-MCE目测半定量法检测存活心肌的灵敏度、特异度和准确度分别是89.3%、89.5%、89.4%;应用LD-DSE负荷RT-MCE目测半定量法对存活心肌检测的灵敏度有所提高(89.3%比75.7%,P<0.05)。结论 RT-MCE目测半定量法检测存活心肌具有较高的临床价值,LD-DSE负荷RT-MCE可提高其检测价值。     

超声心肌声学造影对存活心肌的评价及临床意义

超声心肌声学造影为一种诊断心肌组织水平灌注的新型超声技术,可从微循环完整性的角度评价存活心肌。存活心肌的识别对冠状动脉粥样硬化性心脏病患者选择积极、合理的治疗方案、评估疗效及预后有重要临床价值。本文就该技术对存活心肌的评价及临床意义作一综述。     

实时心肌声学造影对冠心病患者心肌灌注的定量评价

目的探讨实时心肌声学造影(RTMCE)定量分析冠心病患者心肌血流量的临床应用价值。方法对20例冠脉造影左前降支冠脉狭窄>75%以上的冠心病患者(观察组)和20例健康体检者(对照组)行静息状态下RTMCE检查,同时应用超声心动图检测造影剂峰值密度(A)、心肌血流速率(β)、心肌血流量(MBF,MBF=A×β)、左室舒张末期内径(LVEDD)、左室收缩末期内径(LVESD)、射血分数(EF)、舒张早期峰值血流速度(Emax)、舒张晚期峰值血流速度(Amax)。比较两组相应节段的心肌灌注情况和心脏功能。结果观察组β及MFB均显著低于对照组(P均<0.01),LVEDD、LVSED、EF、Emax、Amax、Emax/Amax、Dt等两组比较无明显差异。结论冠心病患者心肌血流速度减慢,存在心肌微循环损伤;RIMCE可定量评价缺血心肌的血流灌注状况。     

实时心肌超声造影与心脏磁共振成像心肌灌注延迟显像评价急性心肌梗死微循环的对比分析

目的 研究实时心肌超声造影(real-time myocardial contrast echocardiography,RT-MCE)与心脏磁共振成像心肌灌注延迟显像(delayed enhancement-magnetic resonance imaging,DE-MRI)在急性心肌梗死(acute myo-car...     

心肌声学造影定量心肌血流判断存活心肌的实验研究

目的　评价经静脉心肌声学造影 (MCE)判断存活心肌的可行性。方法　建立急性心肌梗死犬模型 ,经外周静脉持续滴注微泡造影剂 ,通过计算A·β值测定心肌相对血流量。以放射性微球法测定的心肌血流量 (MBF)为标准 ,了解A·β值测定MBF的准确性。通过A·β值估测心肌存活与否 ,病理检查验证其可靠性。结果　放射性微球法所测的正常区、缺血区、坏死区的MBF分别为 ( 1 5± 0 3)、( 0 7± 0 3)、( 0 3± 0 2 )ml·min-1·g-1;MCE测得的A·β值分别为 5 2 46± 15 0 9、2 4 36±3 89、3 74± 3 80 ;正常区、缺血区、坏死区的MBF和A·β值“标化”后分别为 1 0± 0 0、0 44± 0 17、0 17± 0 11和 1 0± 0 0、0 48± 0 0 9、0 0 7± 0 0 8,二者的相关性良好 (r=0 81,P =0 0 0 1)。MCE对坏死心肌的判定结果与病理结果吻合。结论　心肌声学造影可用于活体状态下评价存活心肌 ,“标化”后的A·β值 <0 2 3提示心肌坏死。     

实时三维斑点追踪成像结合实时心肌声学造影预测心肌梗死后患者心肌存活性的临床研究

摘要 目的 探讨实时三维斑点追踪成像技术（RT-3D-STI）结合实时心肌声学造影（RT-MCE）技术评价心肌梗死后患者心肌存活性的临床应用价值。方法 选取 25 例根据心电图、心肌酶学及冠脉造影确诊,且成功进行冠状动脉血运重建术的心肌梗死患者。所有患者于术前 1 周内行 RT-MCE 检查,对心肌灌注结果进行半定量评价;分别于术前及术后 6 个月行二维超声分析左室各节段心肌进行室壁运动,根据术后室壁运动是否改善将室壁运动异常的心肌节段分为两组：存活心肌组和非存活心肌组;同时行 RT-3D-STI 技术测得左室心肌整体及各节段三维峰值长轴应变 (3D-LPS) 、环向应变 (3D-CPS) 、面积应变 (3D-APS) 及径向应变 (3D-RPS) 参数指标。结果 血运重建术前,存活心肌组 3D-PLS、3D-PAS、3D-PCS、3D-PRS 明显高于无存活心肌组（P <0.05）;单参数 ROC 曲线分析结果显示,静息状态下,以术前 3D-PAS ≤ -16.5% 作为截断值判断心肌梗死后存活心肌的 AUC 为 0.944,敏感性为 91.3%,特异性为 93.8%,明显高于其它应变值;多参数联合分析结果显示,三维应变参数联合判断心肌梗死后存活心肌的 AUC 为 0.969,灵敏度及特异度分别为 95.7%、 90.6%。血运重建术前,RT-MCE 评价存活心肌的敏感度及特异度分别为 93.1％、 68.8％,一致性分析得出 Kappa 值为0.645。结论 在静息状态下, RT-3D-STI 技术预测心肌梗死后心肌的存活性地价值高于 RT-MCE 技术,其中三维应变参数以 3D-PAS ≤ -16.5% 作为截断值判断心肌梗死后心肌存活性的价值最高,且两种技术联合应用能更好地评价心肌存活性。     

存活心肌的磁共振研究

心肌梗死后存活心肌的诊断可以预测功能受损心肌在血运重建后的功能恢复。存活心肌检测方法很多,磁共振成像提供了不同的方法观察存活心肌。本文综述了磁共振延迟增强成像及舒张末期室壁厚度和小剂量多巴酚丁胺负荷磁共振成像在诊断存活心肌方面的进展。     

超声心动图诊断存活心肌新进展

近年来人们认为缺血除引起心肌坏死外 ,仍有部分心肌可能存活 ,是心肌为免受坏死的一种保护反应。准确地判断心肌存活性对缺血性心脏病治疗方案的选择、危险程度分级、正确估价再灌注治疗的疗效以及对预后的估测均具有重要的临床意义。近年来超声心动图在诊断存活心肌方面取得长足进展 ,本文将对这些新方法和新技术作一综述。1　药物负荷超声心动图二维超声是目前观察节段室壁运动异常较可靠的方法 ,利用药物负荷超声心动图是评价心肌存活性较实用的方法 ,常用的药物有多巴酚丁胺及硝酸酯等。1.1　小剂量多巴酚丁胺 :兴奋 β1及β2 、α1受…     

实时心肌声学造影检测高血压心肌微血管功能

目的:通过实时心肌声学造影(MCE),检测有心绞痛症状而冠状动脉造影(CAG)正常的高血压患者心肌微血管功能. 方法:入选有心绞痛症状而CAG正常的患者12例(高血压组),心绞痛症状不典型而CAG正常的非高血压患者8例(对照组),采用声学造影剂声诺维进行实时MCE检查,分别测定静息状态和腺苷负荷后造影剂微泡达到峰值的平台期强度(A),再充盈平均速度(β)及A·β,并测定A比值、β比值和冠状动脉血流储备(CFR)值.结果:高血压组静息时反映局部心肌血容量的A值、反映局部心肌血流量的A·β值与对照组差异无统计学意义(P>0.05),而反应局部心肌血流速度的β值小于对照组(P<0.05),反应心肌血容量储备的A比值、反应心肌血流速度储备的β比值较对照组低(P<0.05),高血压组CFR低于对照组(P<0.01).结论:有心绞痛症状而CAG正常的高血压患者心肌缺血与心肌微血管密度下降、CFR减退有关,实时MCE可定量检测心肌微血管功能.     

Qualitative and quantitative real time myocardial contrast echocardiography for detecting hibernating myocardium

Background: Real time myocardial contrast echocardiography (RTMCE) is an emerging imaging modality for assessing myocardial perfusion that allows for noninvasive quantification of regional myocardial blood flow (MBF). Aim: We sought to assess the value of qualitative analysis of myocardial perfusion and quantitative assessment of myocardial blood flow (MBF) by RTMCE for predicting regional function recovery in patients with ischemic heart disease who underwent coronary artery bypass grafting (CABG). Methods: Twenty‐four patients with coronary disease and left ventricular systolic dysfunction (ejection fraction <45%) underwent RTMCE before and 3 months after CABG. RTMCE was performed using continuous intravenous infusion of commercially available contrast agent with low mechanical index power modulation imaging. Viability was defined by qualitative assessment of myocardial perfusion as homogenous opacification at rest in ≥2 segments of anterior or ≥1 segment of posterior territory. Viability by quantitative assessment of MBF was determined by receiver‐operating characteristics curve analysis. Results: Regional function recovery was observed in 74% of territories considered viable by qualitative analysis of myocardial perfusion and 40% of nonviable (P = 0.03). Sensitivity, specificity, positive and negative predictive values of qualitative RTMCE for detecting regional function recovery were 74%, 60%, 77%, and 56%, respectively. Cutoff value of MBF for predicting regional function recovery was 1.76 (AUC = 0.77; 95% CI = 0.62–0.92). MBF obtained by RTMCE had sensitivity of 91%, specificity of 50%, positive predictive value of 75%, and negative predictive value of 78%. Conclusion: Qualitative and quantitative RTMCE provide good accuracy for predicting regional function recovery after CABG. Determination of MBF increases the sensitivity for detecting hibernating myocardium. (Echocardiography 2011;28:342‐349)     

Identification of viable myocardium by perfusion imaging with intravenous contrast echocardiography after acute myocardial infarction

Myocardial perfusion contrast echocardiography is evolving into an effective method for the evaluation of myocardial blood flow after acute coronary events. The direct injection of ultrasound contrast agents into the aortic and coronary circulation has been shown to accurately identify areas of viable myocardial tissue. Recently, intravenous ultrasound contrast has been found to be useful in detecting microvascular blood flow after the restoration of blood flow in patients with myocardial infarction. We present the case of a patient in whom intravenous ultrasound contrast assisted in the detection of viable myocardial tissue after an acute ischemic syndrome.     

Assessment of myocardial viability with myocardial contrast echocardiography

The application of noninvasive imaging techniques to assess myocardial viability has become an important part of routine management of patients with acute myocardial infarction and chronic coronary artery disease. Information regarding the presence and extent of viability may help identify patients likely to benefit from revascularization or therapy directed at attenuating left ventricular remodeling. Myocardial contrast echocardiography (MCE) is capable of defining the presence and extent of viability by providing an accurate assessment of microvascular integrity needed to maintain myocellular viability. It is especially suited for the spatial assessment of perfusion, even when myocardial blood flow is reduced substantially in the presence of severe epicardial stenoses or in a bed dependent on collateral perfusion. The routine use of MCE to evaluate viability in patients with acute and chronic coronary artery disease is now feasible with the advent of new imaging technologies and microbubble agents capable of myocardial opacification from venous injections. The utility of this technique for determining treatment strategies has not been established but is forthcoming.     

Intravenous myocardial contrast echocardiography during angioplasty

Myocardial contrast echocardiography (MCE) using power Doppler harmonic imaging (PDHI) has been reported to document regional myocardial perfusion. Two case reports demonstrate the potential of intravenous myocardial contrast echocardiography during angioplasty.     

Assessment of myocardial viability: comparison of echocardiography versus cardiac magnetic resonance imaging in the current era

Detecting viable myocardium, whether hibernating or stunned, is of clinical significance in patients with coronary artery disease and left ventricular dysfunction. Echocardiographic assessments of myocardial thickening and endocardial excursion during dobutamine infusion provide a highly specific marker for myocardial viability, but with relatively less sensitivity. The additional modalities of myocardial contrast echocardiography and tissue Doppler have recently been proposed to provide further, quantitative measures of myocardial viability assessment. Cardiac magnetic resonance (CMR) has become popular for the assessment of myocardial viability as it can assess cardiac function, volumes, myocardial scar, and perfusion with high-spatial resolution. Both 'delayed enhancement' CMR and dobutamine stress CMR have important roles in the assessment of patients with ischaemic cardiomyopathy. This article reviews the recent advances in both echocardiography and CMR for the clinical assessment of myocardial viability. It attempts to provide a pragmatic approach toward the patient-specific assessment of this important clinical problem.     

Assessment of myocardial perfusion by power contrast imaging using a new echo contrast agent

In a patient with previously documented myocardial infarction, we assessed myocardial perfusion by using power contrast imaging and a newer intravenous echo contrast agent. The images were captured and stored digitally, and various image processing algorithms were used to assess myocardial perfusion. An apical perfusion defect was clearly visualized, and it correlated with radionuclide findings.     

Prolapsing left atrial myxoma: preoperative diagnosis using a multimodal imaging approach with magnetic resonance imaging and real-time three-dimensional echocardiography

Real-time three-dimensional echocardiography (RT3DE) is a newpromising technique for the evaluation of intracardiac masses.We present the diagnostic work-up using a multimodal-imagingapproach in a 74-year-old patient with a prolapsing tumour inthe left atrium suggestive of a myxoma, causing severe congestiveheart failure attributable to dynamic left ventricular inflowobstruction, and mimicking severe mitral valve stenosis. Real-timethree-dimensional echocardiography allowed to accurately imagethe entire volume of the myxoma, and to analyse the dynamicleft ventricular inflow obstruction. The size of the lobulatedmass as assessed by RT3DE was 65 x 25 x 22 mm. The mass was surgically removed, histology was diagnostic formyxoma, and the patient had an uneventful recovery. Real-time three-dimensional echocardiography images the entirevolume of a mass allowing for accurate measurements in multipleplanes, and allowing for real-time evaluation of obstructiveeffects on ventricular in- or outflow. This case shows how RT3DEand other non-invasive imaging modalities may be used as complementarytechniques for evaluation of intracardiac masses.     

Triggered replenishment imaging reduces variability of quantitative myocardial contrast echocardiography and allows assessment of myocardial blood flow reserve

Assessment of replenishment kinetics (RK) following ultrasound-induced destruction of contrast microbubbles allows quantification of myocardial blood flow reserve (MBFR) applying the model f (t) = A (1 - e(-betat)), with parameter beta describing mean flow velocity and parameter A representing blood volume. However, few data on the variability and reproducibility of RK in a clinical setting are available. Therefore, we examined 30 patients in a rest-adenosine protocol in one center. Off-line quantification of real-time perfusion imaging (RTPI) and triggered replenishment imaging (TRI) was performed at two sites and compared with coronary angiography and flow reserve measurements. Parameter A was found to be robust in all investigated segments (coefficient of variation (CV) < 7.2%+/- 5.1). Variability was lowest for parameter beta using TRI in apical segments (CV 6.5%+/- 5.2, P < 0.01). Highest CV was found with RTPI in lateral segments (CV : 39.8%+/- 40.6). Concerning day-to-day reproducibility both methods revealed similar results within range of heterogeneity of myocardial blood flow. Both sites obtained significantly lower MBFR in patients with flow-limiting CAD, compared to subjects without (P < 0.01). Correlation of both sites showed close relationship (y = 0.88x + 0.45, r = 0.83, P < 0.0001), without systematic bias. TRI significantly reduces variability of RK in quantitative MCE. Assessment of MBFR allows investigator-independent evaluation of CAD.     

Abnormal myocardial flow reserve in sickle cell disease: a myocardial contrast echocardiography study

Background: Sickle cell disease (SCD) is characterized by obstruction of microvessels leading to ischemia and necrosis. We have aimed to demonstrate whether myocardial contrast echocardiography (MCE) is able to detect myocardial perfusion abnormalities in SCD patients and to assess their relationship with left ventricle ( LV) perfusion and systolic function. Methods: A group of 25 patients with SCD and a control group of 19 normal individuals were studied. Using MCE, myocardial perfusion reserve indices (A, β, and A×β) were obtained, before and after hyperemia with dypiridamole. LV function was also analyzed: ejection fraction (EF), index of myocardial performance (IMP), the ratio of transmitral early-diastolic flow velocity E and the pulsed tissue Doppler mitral annular early diastolic velocity Ea (E/Ea) (E/Ea), tissue Doppler mitral annular peak systolic velocity (Sa), and peak systolic strain (S) were obtained. Results: Myocardial velocity (β) and myocardial blood flow (A×β) reserves were lower in the patients than in controls (1.7 ± 0.4 vs. 3.3 ± 0.2, P = 0.000 and 2.1 ± 0.6 vs. 4.1 ± 0.2, P = 0.000, respectively). In SCD patients, a correlation was found between β reserve and EF, IMP, Sa, E/Ea, and S% and between A×β reserve and Sa. Conclusions: MCE detected abnormal perfusion reserve in patients with SCD, which correlated with systolic function indices. This suggests that perfusion plays a role in SCD ventricular dysfunction.