Role of Live/Real Time Three-Dimensional Transthoracic Echocardiography in Pericardial Disease

Despite the high sensitivity of two-dimensional transthoracic echocardiography (2DTTE) in diagnosing pericardial effusion, it has limitations in assessing its size and extent and in evaluating other pericardial pathologies. There are only limited reports so far, but live/real time three-dimensional transthoracic Echocardiography (3DTTE) has shown promise and potential advantages over 2DTTE in certain clinical situations. With its ability to crop and view cardiac structures from any desired angulation it offers incremental value in assessing the anatomy of the pericardium including echo densities within the effusion, fibrinous bands, and loculated effusions. It offers significant supplemental information over 2DTTE in clinical scenarios like post cardiac surgery follow up of hemopericardium, quantification of the effusion, evaluation of pericardial masses including granuloma, differentiating pericardial effusion from ascites and pleural effusion and in studying the extent of the disease in constrictive pericarditis. However, comprehensive studies are needed to further define its role in daily clinical practice. (Echocardiography 2012;29:98-102)     

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。     

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.     

Live three-dimensional echocardiography: imaging principles and clinical application

Live three-dimensional echocardiography (L3DE) is an important breakthrough in the field of medical ultrasound. It will provide a great potential tool for clinical diagnosis and treatment. In this article, the authors first review the bottlenecks in 3D cardiac imaging and the technical principles of L3DE that have been used to overcome some of these problems. We then discuss the scanning methods, clinical usefulness, and the future of L3DE, drawing on our experiences in examining 124 human patients and in conducting animal verification studies with a live 3D ultrasound system.     

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。     

Live/real time three-dimensional transthoracic echocardiographic assessment of left ventricular volumes, ejection fraction, and mass compared with magnetic resonance imaging

Due to reliance upon geometric assumptions and foreshortening issues, the traditionally utilized transthoracic two-dimensional echocardiography (2DTTE) has shown limitations in assessing left ventricular (LV) volume, mass, and function. Cardiac magnetic resonance imaging (MRI) has shown potential in accurately defining these LV characteristics. Recently, the emergence of live/real time three-dimensional (3D) TTE has demonstrated incremental value over 2DTTE and comparable value with MRI in assessing LV parameters. Here we report 58 consecutive patients with diverse cardiac disorders and clinical characteristics, referred for clinical MRI studies, who were evaluated by cardiac MRI and 3DTTE. Our results show good correlation between the two modalities.     

The value of live three-dimensional echocardiography in an adult patient with aortico-left ventricular tunnel

Aortico-left ventricular tunnel (ALVT) is a rare cardiac abnormality. This article presents an adult case of ALVT with aortic ostium lying above the left-noncommissure which was diagnosed with live three-dimensional echocardiography (3DE). Live 3DE has shown its value in providing more detailed information. (Echocardiography 2012;29:E10-E12))     

Is It Time to Move on from Two-Dimensional Transesophageal to Three-Dimensional Transthoracic Echocardiography for Assessment of Left Atrial Appendage? Review of Existing Literature

Left atrial appendage (LAA) has unique anatomical and physiological properties, which make it a common site for thrombus formation in many cardiovascular and systemic diseases. Assessment of LAA for thrombus thus becomes important in many clinical situations and two-dimensional transesophageal echocardiography (2D TEE), which allows excellent quality images of LAA because of its close proximity to esophagus is routinely used for this purpose. However, it is a semiinvasive procedure, requires more time and involves some degree of patient discomfort. With some training and experience, two-dimensional transthoracic echocardiography (2D TTE) can visualize LAA in most patients with good acoustic windows. A disadvantage of both 2D TTE and 2D TEE is that they provide only a thin slice or section of cardiac structures at any given time limiting their utility in comprehensively assessing the LAA for thrombus. On the other hand, live/real time three-dimensional (3D) TTE overcomes this limitation of both 2D TTE and 2D TEE because of its ability to encompass whole of the LAA in three-dimensions in the acquired data set, which can then be cropped and sectioned systematically at any desired angulation to more definitively look for clot. 3D TTE is also useful in differentiating a clot from pectinate muscles in the LAA, which can mimic a thrombus resulting in patient mismanagement. In addition, 3D TTE is helpful in sectioning a clot for lysis, which has implications in clot resolution. We reviewed the existing literature comparing the relative advantages and disadvantages of 3D TTE versus 2D TEE and found that in patients with good acoustic windows 3D TTE had similar efficacy for detecting LAA thrombus. (Echocardiography 2012;29:112-116)     

三维超声心动图在心功能评价中的应用现状

心功能的准确评价对心脏病患者的治疗、预后具有重要意义。三维超声心动图(3 dimensional echocardiography,3DE)能准确测量心功能而无需依赖几何形状的假设,是超声领域的重大突破。     

Dynamic Three-Dimensional Reconstruction of Abnormal Intracardiac Blood Flow

Dynamic three-dimensional (3-D) echocardiography has so far focused on reconstruction of cardiac structures. In this preliminary study, abnormal intracardiac blood flow has been reconstructed in 3-D from multiplane transesophageal and transthoracic two-dimensional (2-D) echocardiograms using modified omniplane probes with 3.7- or 5.0-MHz transducers. The study group included patients with native (40) and prosthetic (11) mitral regurgitant jets, aortic regurgitant jets (8), and shunt flow in atrial septal defect (20), ventricular septal defect (19), tetralogy of Fallot (14), and ruptured sinus of Valsalva aneurysm (6). For dynamic 3-D intracardiac flow imaging the gain of 2-D images of cardiac structures was lowered slightly and color Doppler flow signals were transformed into gray scale flow signals, which were then collected in the TomTec 3-D Echo Scan System. Dynamic 3-D cardiac flow images were displayed with volume rendering. The results indicated that dynamic 3-D cardiac flow imaging facilitates display of the stereo shape, spatial orientation, profiles and volume of regurgitant jets, and the intracardiac shunting blood flow. It allows differentiation of prosthetic transvalvular from paravalvular regurgitant jets. Limitations include nonvelocity and nonECG synchronized display.     

Echocardiographic Assessment of Right Ventricular Volume and Function

Echocardiographic evaluation of right ventricular volume and function has become a subject of growing interest with the increasing awareness of the important role of the right ventricle in the entire circulation. However, the anatomically complex and load-dependent shaped right ventricle shape is difficult to describe by a simple geometric figure and its volume and function are, therefore, difficult to assess in a simple manner. A number of echocardiographic methods for evaluating right ventricular volume and function have emerged; to date, however, their quantification remains a clinical challenge. The major goal is to develop a reproducible method that will allow for quantitative comparisons between patients or serially within a given patient. This discussion examines the available methods with specific attention to their reliability and limitations. Visual inspection or measurement of single plane indices is limited by their lack of standardization and failure to describe the entire right ventricle. Simpson's rule requires computer calculations and assumes an elliptic symmetry present in the left, but not the right ventricle. Application of the area-length method to the subcostal outflow tract and apical four-chamber views is a particularly practical current approach. Three-dimensional echo reconstruction, which eliminates the need for geometric assumptions and individual standardized views, although only in its infancy, promises to be the most accurate method for right ventricular volume calculation and in the future should emerge as the standard for research and many clinical applications.     

Valvular heart disease. The value of 3-dimensional echocardiography

Significant advances in 3-dimensional echocardiography (3DE) technology have ushered its use into clinical practice. The recent advent of real-time 3DE using matrix array transthoracic and transesophageal transducers has resulted in improved image spatial resolution, and therefore, enhanced visualization of the pathomorphological features of the cardiac valves compared with previously used sparse array transducers. It has enabled an unparalleled real-time visualization of valves and subvalvular anatomic features from a single volume acquisition without the need for offline reconstruction. On-cart or offline post-processing using commercially available and custom 3-dimensional analysis software allows the quantification of multiple parameters, such as orifice area, prolapse height and volume in mitral valve disease, area of the left ventricular outflow tract, and tricuspid annular geometry. In this review, we discuss the incremental role of 3DE in evaluating valvular anatomic features, volumetric quantification, pre-surgical planning, intraprocedural guidance, and post-procedural assessment of valvular heart disease.     

Volumetric Holography of Cardiac Defects in Humans: Initial Clinical Experience Using Tomographic Echocardiographic Data

We have previously described a method to develop holograms that does not entail the presence of laser light source in the clinical environment. Although we have demonstrated the feasibility of holography from cardiac ultrasound data to depict normal and abnormal cardiac anatomy in experimental studies, the ability of holography from ultrasound data to image structural cardiac anomalies in patients is not known. In this exploratory study, we addressed the question of whether it was possible to image cardiac pathology by holography in patients with mitral valve disease, atrial septal defects, and ventricular aneurysms. Parallel, tomographic echocardiographic data obtained during transesophageal echocardiography were used to generate holograms of cardiac disorders. Holographic three-dimensional (3-D) reproduction contains up to 1024 by 1024 pixels and full gray scale in each of the individual slices. Holograms of cardiac defects depicted their true spatial location, which not only enhanced the anatomic appreciation of the defect itself, but also revealed the depth and the relationship of the structures in proximity of the defect. Thus, 3-D imaging of cardiac anomalies by volumetric multiplexed holography is feasible.     

Three-dimensional echocardiographic determination of cardiac output at rest and under dobutamine stress: comparison with thermodilution measurements in the ischemic pig model

Determination of cardiac output is a potentially important clinical application of three-dimensional (3-D) echocardiography since it could replace invasive measurements with the Swan-Ganz-catheter. To date, there are no studies available to determine whether cardiac output measured by thermodilution can be predicted reliably under changing hemodynamic conditions. Fifteen pigs with ischemic myocardium were examined under four hemodynamic conditions at rest and under pharmacological stress with 5, 10, and 20 microg/kg/min dobutamine. The 3-D datasets were recorded by means of transesophageal echocardiography. The endocardial definition was enhanced by administering the contrast agent FS069 (Optison). Cardiac output was calculated as the product of stroke volume (end-diastolic - end-systolic volume) and heart rate. The invasive measurements were performed with a continuous thermodilution system. In general, there was moderate correlation between 3-D echocardiography and thermodilution(r = 0.72, P < 0.001). At rest, the 3-D echocardiographic measurements were slightly but significantly lower than the invasive measurements (mean difference 0.6 +/- 0.5L/min,P < 0.001). Under stress with 5, 10, and 20 microg/kg/min dobutamine, there was a marked increase in the deviation (1.3 +/- 0.5L/min,P < 0.001; 1.6 +/- 0.7 L/min,P < 0.001; and 2.1 +/- 1.1L/min,P < 0.001, respectively). The deviation was based on two factors: (1). Under stress, the decreasing number of frames per cardiac cycle acquired with 3-D echocardiography led to imprecise recording of end-diastolic and end-systolic volumes, and thus to an underestimation of cardiac output. At least 30 frames per cardiac cycle are needed to eliminate this effect. (2). There is a systematic difference between 3-D echocardiographic and invasive measurements, which is independent of the imaging rate. This is based on an overestimation of the true values by thermodilution. In conclusion, cardiac output can be determined correctly by 3-D echocardiography for normal heart rates at rest. At elevated heart rates, the temporal resolution of 3-D systems currently available is not adequate for reliable determination. In performing and evaluating future clinical comparative studies, the systematic difference between 3-D echocardiography and thermodilution, based on overestimation by thermodilution, must be taken into account.     

Clinical Determinations of Volumes of Normal and Aneurysmatic Left Ventricles by Three-Dimensional Transesophageal Echocardiography

Biplane methods of determining left ventricular volumes are inaccurate in the presence of aneurysmal distortions. Multiplane transesophageal echocardiography, which provides multiple, unobstructed cross-sectional views of the heart from a single, stable position, has the potential for more accurate determinations of volumes of irregular cavity forms than the biplane methods. The aim of the study was to determine the feasibility of three-dimensional measurements of ventricular volumes in patients with normal and aneurysmatic left ventricles by using multiplane transesophageal echocardiography. With the echotransducer in the mid-esophageal (transesophageal) position, nine echo cross-sectional images of the left ventricle in approximately 20 degrees angular increments were obtained from each of 29 patients with coronary artery disease who had undergone biplane ventriculography during diagnostic cardiac catheterization. In 17 of these 29 patients, echo cross-sectional images of the left ventricle with the echotransducer in transgastric position were also obtained. End-diastolic volume, end-systolic volume, and ejection fraction were determined from multiplane transesophageal echocardiographic images and biplane ventriculographic images by the disc-summation method and compared with each other. In another ten patients with indwelling pulmonary artery catheters, stroke volumes calculated from multiplane transesophageal echocardiographic images were compared with those derived from thermodilution cardiac output measurements. Correlations between biplane ventriculographic and multiplane transesophageal echocardiographic measurements were higher in the ten patients with normal ventricular shape [for end-diastolic volumes, r = 0.91, SEE = 19 ml; for end-systolic volumes, r = 0.98, SEE = 9.3 ml; for ejection fractions (EFs), r = 0.91, SEE = 5.4%] than in the 19 patients with ventricular aneurysms (for end-diastolic volumes, r = 0.61, SEE = 31.5 ml; for end-systolic volumes, r = 0.66, SEE = 32.5 ml; for EFs, r = 0.79, SEE = 8%). Correlations between echocardiographic volumes from the transesophageal and transgastric transducer positions were high independent of left ventricular geometry (for end-diastolic volumes, r = 0.84, SEE = 13.1 ml; for end-systolic volumes, r = 0.98, SEE = 9.6 ml; for EFs, r = 0.97, SEE = 3.4%). In 12 observations (4 normal and 8 aneurysmal) from the ten patients with indwelling pulmonary artery catheters, correlation between stroke volumes determined from thermodilution cardiac output measurements and those derived from multiplane transesophageal echocardiographic images was high (r = 0.91, SEE = 6 ml). The results indicate that three-dimensional measurements of volumes of irregular and distorted left ventricles are feasible with multiplane transesophageal echocardiography. This method may be more accurate than biplane methods, especially in the presence of left ventricular aneurysms.     

Three-dimensional and four-dimensional transesophageal echocardiographic imaging of the heart and aorta in humans using a computed tomographic imaging probe

We evaluated the clinical applicability of a prototype tomographic transesophageal echocardiographic (TEE) system, which not only provides conventional TEE images but also three-dimensional tissue reconstruction and four-dimensional display capabilities. The probe was used in 16 patients in the echocardiographic laboratory, intensive care unit, and the operating room. The instrument is a 5-MHz, 64-element, phased array unit mounted on a sliding carriage within a casing. After appropriate probe placement within the esophagus, the probe is straightened, a balloon surrounding the probe is inflated, and data acquisition begun with ECG and respiration gating. With computer controlled transducer movement at 1-mm increments, a complete cardiac cycle is recorded at each tomographic level. These are processed using a dedicated four-dimensional software, and displayed as a dynamic three-dimensional tissue image of the heart. We were able to see the dynamic motion of the ventricles and all the valves in the four-dimensional format. In addition to four-dimensional display, we were able to cut and visualize the heart in dynamic mode in any desired plane and also in multiple planes. Patients tolerated the procedure well. We conclude that this tomographic four-dimensional approach, which does not require tedious off-line processing, can easily be performed in patients and has a strong clinical potential.     

Two‐ and Three‐Dimensional Speckle Tracking Echocardiography: Clinical Applications and Future Directions

Two‐dimensional speckle tracking echocardiography (2D STE) is a novel technique of cardiac imaging for quantifying complex cardiac motion based on frame‐to‐frame tracking of ultrasonic speckles in gray scale 2D images. Two‐dimensional STE is a relatively angle independent technology that can measure global and regional strain, strain rate, displacement, and velocity in longitudinal, radial, and circumferential directions. It can also quantify rotational movements such as rotation, twist, and torsion of the myocardium. Two‐dimensional STE has been validated against hemodynamics, tissue Doppler, tagged magnetic resonance imaging, and sonomicrometry studies. Two‐dimensional STE has been found clinically useful in the assessment of cardiac systolic and diastolic function as well as providing new insights in deciphering cardiac physiology and mechanics in cardiomyopathies, and identifying early subclinical changes in various pathologies. A large number of studies have evaluated the role of 2D STE in predicting response to cardiac resynchronization therapy in patients with severe heart failure. However, the clinical utility of 2D STE in the above mentioned conditions remains controversial because of conflicting reports from different studies. Emerging areas of application include prediction of rejection in heart transplant patients, early detection of cardiotoxicity in patients receiving chemotherapy for cancer, and effect of intracoronary injection of bone marrow stem cells on left ventricular function in patients with acute myocardial infarction. The emerging technique of three‐dimensional STE may further extend its clinical usefulness.     

Two- and three-dimensional transthoracic echocardiographic assessment of hiatal hernia

Using two- (2DTTE) and three-dimensional transthoracic echocardiography (3DTTE) and an oral contrast agent (a carbonated beverage), a mass-like lesion behind the left ventricular posterior wall in an elderly female was definitively diagnosed as a hiatal hernia. A 3DTTE provided a more comprehensive evaluation of the hiatal hernia as compared to the 2DTTE in terms of its size and extent and thickness of the wall. The size of the hernia was underestimated by 2DTTE (3.3 × 3.2 cm) as compared to 3DTTE (at least 7 × 4.8 cm). The maximum thickness of the gastric wall was also found to be larger by 3DTTE (11 mm) as compared to 2DTTE (5 mm). Both the size of the hernia and thickness of the wall have important clinical implications. The size has been reported to be the strongest predictor of severity of esophagitis and gastric wall thickness of 10 mm or more has been associated with malignant or potentially malignant gastric lesions .     

Added value of three-dimensional transesophageal echocardiography in management of mitral paravalvular leaks

Prosthetic paravalvular leak (PVL) is a well-known serious complication following surgically as well as percutaneously implanted prosthetic valves. It usually happens due to incomplete sealing of the prosthetic ring to the native cardiac tissue whether immediately postoperative or considerably later as a complication of infective endocarditis, etc Surgery has been always the treatment of choice for clinically significant PVLs. However, percutaneous transcatheter closure therapy has become a successful alternative in carefully selected group of patients. Echocardiography is a cornerstone in the initial diagnosis, assessment of the severity and location of the PVL. Furthermore, it plays a crucial role in the assessment of the feasibility for percutaneous closure and during intra-procedural guidance. Transesophageal echocardiography (TEE) has the advantage over transthoracic echocardiography (TTE) of not being affected by the acoustic shadow of the mitral prosthesis that usually hides the regurgitation jets and makes TTE evaluation difficult. Three-dimensional (3D) TEE has been shown to provide better diagnostic accuracy compared to two-dimensional (2D) TEE as regard to evaluation of PVLs especially in patients with more than one PVL. This is due to better delineation of the location, shape, and size of the PVL and equally important during guiding the transcatheter percutaneous closure.