实时三维超声心动图评价左心室功能新进展

近年发展起来的实时三维超声心动图技术是超声成像领域内的一项重大的技术突破,它使临床医师能够采用无创的方法,方便的、立体的、准确的观察心脏的解剖和功能。本文回顾了实时三维超声心动图技术评价左心室形状、左心室质量、左心室局部功能、左心室整体功能及左心室非同步性分析等方面的临床应用。     

实时三维超声心动图评估左心室功能

自从左心室射血功能作为预测生存期的重要指标以来，非侵人性方法准确估价左心室功能对患者的治疗成为必须。虽然，二维超声心动图常规地用于临床获得了一些左室功能的重要指标，如左室壁厚度及其活动度；但是，这项技术在评估左心室功能的测量上严重地受到几何形态的限制。为了避免几何形态的限制，在过去的30年中采用了多种方法来完成左心室的三维重建。     

实时三维超声心动图评价冠心病的研究进展

传统的三维超声心动图因获取图像费时而限制了其临床应用。实时三维超声心动图是近年出现的一项新的三维成像技术。其快速成像这一特点使三维成像应用于临床成为可能。本文对实时三维超声心动图在评价冠心病方面的进展加以综述     

实时三维超声心动图与临床

实时三维超声成像是心脏超声发展的重大飞跃,可为心血管疾病的准确诊断提供更多的有用信息。实时三维超声无论在定性和定量两个方面都对临床诊断具有重要作用。现就实时三维超声心动图在心脏瓣膜、先天性心脏病、心脏占位、心肌病、主动脉夹层、左室室壁瘤、Bental术后人造血管吻合口漏、左心功能评价等方面的临床价值做一综述。     

实时三维超声心动图技术及其临床应用

传统的二维超声心动图(2D)在心脏疾病的诊断中已被广泛应用。但由于它的二维特性使得它难于提供精确的定量信息,显示了其局限性,实时三维超声可为心血管疾病的准确诊断及治疗提供更多的有用信息。     

实时三维超声心动图的临床应用及研究进展

实时三维超声心动图技术是超声成像领域内一项重大的技术性突破。它不仅能够精确、可靠的评价心功能的定性及定量参数,而且对于瓣膜结构、先天性心脏病各种畸形提供新的图像视角。可使临床医师方便、立体、准确、实时的观察心脏的解剖结构和功能。实时三维超声心动图必定在各类心脏疾病的诊断、治疗及预后评估方面起到越来越重要的作用。现就三维超声成像原理、临床应用、研究进展予以综述。     

实时三维超声心动图在冠心病中的应用

实时三维超声心动图是超声医学领域内新近发展起来的一项新技术,它将在心血管疾病的诊断和治疗中发挥巨大作用。现将就其在冠心病中临床应用及其发展前景等问题进行探讨。     

实时三维超声心动图优化CRT心室起搏

目的探讨利用实时三维超声心动图(RT3DE)评价左心功能和室壁运动同步性在双心室优化起搏过程中即刻的变化,以指导心脏再同步化治疗患者VV间期优化起搏。方法选择接受CRT治疗的心力衰竭患者32例,术前采用RT3DE检测左室16个心肌节段达收缩末最小容积时间的差值(Tmsv16-Dif)和心率标化后的标准差(Tmsv16-SD/R-R)作为同步性参数,与即刻的主动脉速度时间积分(VTIAV)进行比较,同时测量左室舒张末及收缩末容积(LVEDV,LVESV)和射血分数(LVEF)作为左心功能参数,与常规二维超声Simpson双平面法及M型超声Teich法测量左室射血分数(LVEF)评价左心功能比较,1月后行VV间期优化,优化前及每个VV间期均采集术前相同数据,每调整一次双室起搏顺序后10min后同术前相同采集图像。对上述三维及常规参数定量分析比较。结果优化VV间期后与优化前比较,RT3DE所测室壁运动同步化指标包括Tmsv16-Dif,Tmsv16-SD%(R-R)有明显改善,与VTIAV成负相关。结论 RT3DE能更精确、更方便地评价左室收缩同步性和收缩功能,且能即刻反映相关变化趋势,在双心室优化起搏治疗重度充血性心力衰竭中发挥其应有的作用。     

实时三维超声心动图在冠心病中的应用

实时三维超声心动图是超声医学领域内新近发展起来的一项新技术,它将在心血管疾病的诊断和治疗中发挥巨大作用。现就其在冠心病中临床应用及其发展前景等问题进行探讨。     

实时三维超声心动图的临床应用现状及进展

自20世纪60年代初Baun和GreeWood提出三维超声成像以来,受到众多学者的关注,迄今已经历了静态三维、动态三维,直至目前正在使用的实时三维超声心动图(real-time three-dimensional echocardiography, RT-3DE).ORT-3DE的问世是超声发展史上一个令人瞩目的技术突破[1],现就RT-3DE临床应用现状及进展等综述如下.     

Three-Dimensional Myocardial Perfusion Maps by Contrast Echocardiography

We evaluated the clinical applicability of a system for three-dimensional (3-D) display of a perfusion map following myocardial contrast echocardiography (MCE). The system was used in 12 patients (9 males and 3 females, mean age 52 ± 10 years) undergoing interventional treatment of chronic total coronary occlusion. In each patient three standard apical views were acquired at baseline with sonicated Iopamidol^R injections into the left coronary artery (LCA) and into the right coronary artery (RCA). Following successful recanalization of the occluded artery MCE was repeated. The patients tolerated the procedure well. Acquisition of three standard apical views provided sufficient information for the reconstruction of 3-D perfusion maps containing the 16 standard left ventricular (LV) segments. Side-by-side display of the perfusion maps obtained following LCA and RCA echocontrast injections allowed us to classify the myocardial segments (192) into three groups: (1) those supplied by one major artery (124); (2) those supplied by collaterals from contralateral or both major arteries (58); and (3) segments supplied by none of the major arteries (10). Decreased opacification was observed in 50 segments of group 2. Following successful intervention we were able to visualize the redistribution of blood flow delivered to the LV myocardium by each major coronary artery in 3-D format. We conclude that this 3-D approach, which can easily be performed with currently available ultrasound equipment, allows an estimate of the contribution of each major coronary artery to LV perfusion before and after coronary angioplasty.     

Bulls-Eye Display and Quantitation of Myocardial Perfusion Defects Using Three-Dimensional Contrast Echocardiography

Three-dimensional (3-D) myocardial contrast echocardiography (MCE) is able to derive parallel cutting planes of the left ventricle (LV). However, assessment of the site and extent of myocardial perfusion abnormalities has to rely on the reader's 3-D mental reconstruction from the tomograms, and a manual approach has to be employed for quantitative analysis. The objective of this study was to explore the display and quantitative capability of a bulls-eye format from contrast 3-D MCE in the assessment of perfusion abnormalities derived from a canine model of acute myocardial infarction (MI). Three-dimensional MCE data were acquired sequentially in a rotational scanning format during triggered harmonic imaging with an intravenous contrast agent. Reconstructed short-axis views of the LV were aligned in a bulls-eye format with the apex as the inner most ring. The total LV was divided into 120 sectors. The number of sectors with lack of contrast enhancement was used to derive the percent of the LV (%LV) with perfusion defect and was compared with the extent of MI calculated from postmortem triphenyl tetrazolium chloride (TTC) staining. The perfusion defect regions shown on bulls-eye images corresponded correctly with the territories of the occluded coronary arteries. Three-dimensional MCE perfusion defect mass (19.2 +/- 6.0 %LV) correlated well with anatomic MI mass (19.3 +/- 5.6 %LV; r = 0.92, SEE = 2.3%, mean differential = 0.1 +/- 2.4%). We conclude that bulls-eye display of contrast 3-D MCE demonstrates the site and extent of perfusion abnormalities in an easily appreciable manner. It also allows fast and accurate assessment of endangered myocardium.     

Live/Real Time Three-Dimensional Transesophageal Echocardiography

Since the advent of matrix array transducer, three-dimensional transesophageal echocardiography has come to frequent clinical use. It has significantly enhanced the communication between the operators and cardiac imagers in the operating room as well as in the cardiac interventional labs. This article reviews the history, technological aspects, and the protocol for acquisition and processing of the data sets. It also discusses its advantages in various clinical scenarios, both in diagnostic and therapeutic situations. It highlights its limitations in the current form and prospects of future development. (Echocardiography 2012;29:103-111)     

Three-Dimensional Echocardiography of Right Heart Pathology

Three-dimensional (3-D) echocardiography uses sequentially acquired tomography echocardiographic data, which is gated to the cardiac cycle, to reconstruct 3-D views of the heart. So far, this technique has been used primarily to evaluate left-sided heart structures. This report focuses on congenital and acquired right-sided heart pathologies that have been visualized by 3-D echocardiography. In addition to reviewing the literature, several representative figures are included illustrating the unique ability of 3-D echo to elucidate complex right heart anatomy. After a brief introduction to the technical aspects of 3-D echocardiography, the discussion centers on evaluation of congenital heart disease and right-sided masses, determination of right ventricular mass and volume, and evaluation of right-sided valvular heart disease. Congenital heart diseases that are reviewed include atrial septal defect (location, size, efficacy of repair), ventricular septal defect, and congenital heart disease in the fetus being evaluated in utero. Evaluation of right-sided masses, including tumors, vegetations, and thrombi, is reviewed. Methods of determining right ventricular volume and mass using 3-D echo are discussed. Evaluation of valvular heart disease, including Doppler analysis of regurgitant flow, is examined. Finally, special attention is given to the perioperative and intraoperative use of 3-D echocardiography for patients with these conditions. The conclusion summarizes the current and potential future uses of 3-D echocardiography.     

Three-Dimensional Echocardiography in Evaluation of Left Ventricular Indices

Accurate determination of left ventricular mass, volume, ejection fraction, and wall motion is important for clinical decision making. Currently, M-mode and two-dimensional echocardiography (2DE) have been routinely used for this purpose. Although these 1D or 2D modalities provide excellent diagnostic and prognostic information, they have a number of technical limitations including the time required to perform the procedure and operator-dependent image acquisitions. In addition, they are inherently limited by geometric assumption of three-dimensional (3D) left ventricular structures based on 2D slices. With the improvement in transducer technology and software development, 3D echocardiography (3DE) has become widely available. Left ventricular quantitation by 3DE has been demonstrated to be accurate by multiple studies that compared 3DE with reference techniques. In addition, 3DE measurements were found to be more reproducible and less variable than 2DE. Real time 3DE imaging has potential advantages in stress echocardiography including rapid acquisition, unlimited number of planes, avoidance of foreshortening, and precise segment matching. This is a major step forward in our diagnostic armamentarium for the evaluation of ischemia. In this review, we summarized the current evidence of 3DE for left ventricular evaluation. (Echocardiography 2012;29:66-75)     

Clinical Potential of Three-Dimensional Echocardiography in Endocarditis

All lesions associated with endocarditis are three dimensional (3-D). Transthoracic and trans-esophageal echocardiographic techniques, while highly useful in endocarditis, yield only two-dimensional (2-D) data. The newly evolving method of 3-D echocardiography that provides volume and surface rendered reconstructions could be helpful in endocarditis. The clinical feasibility of 3-D echocardiography and its ability to display valvular and other cardiac structures have been recently demonstrated. Early experience suggests that vegetations, damaged valves, and other abnormalities could be delineated well by this method in viewing projections unavailable by current clinical techniques. Ongoing refinements in data acquisition, image processing, and display are likely to make 3-D echocardiography a clinically valuable tool, aiding in enhanced diagnostic appraisal of disorders such as endocarditis, and in making therapeutic decisions.     

Three-Dimensional Echocardiography for Quantitative Analysis of Left-Ventricular Aneurysm

Background: Quantitative analysis of left-ventricular (LV) aneurysms after myocardial infarction is prognostically relevant and assists in planning surgery. Three-dimensional (3D) echocardiography facilitates clear visualization of cardiac anatomy and accurate assessment of functional parameters. The aim of the present study was to determine the ability of 3D echocardiography to quantify LV aneurysms. Methods: Ten patients with a known LV-aneurysm after myocardial infarction underwent 3D echocardiography and cardiac magnetic resonance (CMR) imaging at 1.5 Tesla within 3 days. For 3D echocardiography, a multiplanar transesophageal examination was performed with full LV coverage and the 3D dataset was analyzed offline. The LV-aneurysm was defined by a wall thickness <5 mm. The following quantitative parameters were determined: left ventricular end-diastolic and end-systolic volumes, LV myocardial mass (LV-mass) and mass of the LV-aneurysm. LV ejection fraction and percentage of aneurysm mass (%-aneurysm) were calculated. Results: LV volumes and ejection fraction showed a strong correlation between 3D echocardiography and CMR (r = 0.94–0.97; P < 0.01). Importantly, the mass and percentage of mass of the LV-aneurysm demonstrated a high correlation as well (r = 0.94 and r = 0.86, respectively; P < 0.01). For all parameters, the calculated bias between both methods was found to be minimal (0.8–7.6%). Conclusions: Three-dimensional echocardiography proved to be a reliable tool for quantitative analysis of LV volumes, ejection fraction and aneurysm size in patients with prior myocardial infarction. In addition, 3D visualization of the complex cardiac anatomy in patients with LV-aneurysm may assist surgical procedure planning. (Echocardiography 2010;27:64-68)     

Rapid Three-Dimensional Myocardial Contrast Echocardiography: Volumetric Quantitation of Nonperfused Myocardium After Intravenous Contrast Administration

Current acquisition methods for quantitative three-dimensional myocardial contrast echocardiography require long acquisition times and therefore require the invasive administration of deposit contrast agents administered intra-arterially or into the left atrium. This study addressed the feasibility of obtaining accurate and precise quantitative volumetric measurements of nonperfused myocardium after an intravenous bolus of echocardiographic contrast agent using a rapid three-dimensional myocardial contrast echocardiographic acquisition technique. An open-chest pig model of acute left anterior descending coronary artery (LAD) occlusion was used. After LAD ligature, an intravenous bolus of contrast agent was given and images were obtained over a 12-second period using a continuously rotating transducer placed at the apical position. There was no significant microbubble destruction during the rotational acquisition period as measured by differences in mean gray scale values of apical, mid, and basal myocardial regions between the first and last image frames of acquisition. Calculated volumes of nonperfused myocardium demonstrated significant agreement and correlation (mean difference ± SD =–0.30 ± 1.71 cm³; r = 0.89; P < 0.01; y = 1.06x – 1.08) with anatomic specimens. When expressed as percent of total LV volume being nonperfused, the mean difference ± SD was 2.1 ± 3.6%, r = 0.94, P < 0.01, and y = 1.33x – 4.08. We conclude that accurate and precise measurements of nonperfused myocardium after an acute LAD coronary artery occlusion can be obtained after the intravenous bolus administration of a contrast material when a rapid 12-second acquisition with a continuously rotating transducer is used.