Two-dimensional echocardiography (2DE) is limited for the accurate measurement of chamber volumes and their function by image plane positioning errors and geometric assumptions that become invalid in patients with abnormally shaped chambers. Among the various three-dimensional (3D) echocardiographic (3DE) techniques for image acquisition and quantification of left ventricular volumes, real-time 3DE was developed approximately a decade ago. Currently, 3DE is a noninvasive tool to obtain 3D information on the chamber cavity with high spatial and temporal resolution. A number of previous studies have demonstrated the accuracy of 3DE for the assessment of left ventricular volume and mass as well as the 3D geometry of the heart structure, including the left atrium and right ventricle. Further, recent improvements in computer technology have introduced 3DE software that allows automated delineation of the left ventricular surface during a cardiac cycle. Such improvements in 3DE systems and software would support the notion of bringing 3DE into the mainstream for diagnosis and management of patients with cardiac diseases in clinical settings.

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Speckle tracking echocardiography has allowed us to evaluate novel cardiac functions including left ventricular torsion, longitudinal function, and dyssynchrony in addition to left ventricular ejection fraction. Commercially available 3-dimensional speckle tracking echocardiography was recently introduced, and it has provided various knowledge that could not be assessed by 2-dimensional speckle tracking echocardiography. For example, novel myocardial deformation parameters, i.e., area change ratio and 3D-strain, which may be more sensitive to myocardial deformation as compared to standard strain parameters, were proposed for 3-dimensional speckle tracking echocardiography. In the area of clinical research, imaging for propagation of cardiac contraction has been attempted, and it may contribute to prediction of responses for cardiac resynchronization therapy, assessment of arrhythmic pathophysiology, risk stratification of life-limiting arrhythmia, and detecting myocardial ischemia. In addition, 3-dimensional speckle tracking echocardiography has been applied in assessing right ventricular segmental function, and future developments are expected. In contrast, 3-dimensional speckle tracking echocardiography has limitations in terms of spatio-temporal resolutions that require more complex computations compared to 2-dimensional speckle tracking echocardiography. However, improvements in spatio-temporal resolutions have been swift thanks to technological innovations. In the near future, general use of 3-dimensional speckle tracking echocardiography in a clinical setting is expected as well as its application in clinical research.

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The surgeon's view by three-dimensional (3D) transesophageal echocardiography is widely accepted as a useful way of imaging in clinical settings. It allows us to easily understand the anatomy of the mitral valve in real time. Another useful way of imaging in 3D echocardiography is the multiplanar reconstruction (MPR) method, which enables us to crop the acquired 3D data and have optimal images that are difficult to visualize in two-dimensional echocardiography. Vena contracta area can be measured using MPR from the color Doppler 3D volume dataset to evaluate the severity of mitral regurgitation. Stich artifact is one of the limitations of 3D echocardiography, but minimizing the area of interest allows one-beat acquisition of high-quality volume data even in patients with atrial fibrillation. Transthoracic one-beat acquisition of the mitral orifice allows precise measurement of the orifice area with cropping of the true orifice by MPR. To visualize the submitral apparatus, including the papillary muscle and chordae tendineae, the transgastric approach in transesophageal echocardiography should be performed as an adjunct to the conventional mid-esophageal approach. 3D quantification, such as tenting volume or leaflet surface area, is one of the big advantages of 3D echocardiography. However, it does not easily lend itself to clinical settings, because it is labor-intensive and time-consuming. An automated approach for quantification that minimizes inter-operator variability needs to be developed not only for transesophageal but also for transthoracic images.

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Accurate assessment of aortic root geometry is increasingly important in the era of transcatheter aortic valve replacement (TAVR) in symptomatic patients with severe aortic stenosis (AS) and high surgical risk. Although contrast-enhanced multidetector computed tomography (MDCT) has become an integral part of evaluating aortic root morphology in AS patients, not all patients who would be candidates for TAVR can undergo MDCT due to renal impairment and radiation exposure. Except for accurate determination of left ventricular volumes, which has the potential for reliable determination of functional aortic valve area, three-dimensional (3D) transthoracic echocardiography has limited utility due to lower spatial and temporal resolution and large 3D transducer. In contrast, 3D transesophageal echocardiography (3DTEE) provides a superb view of the aortic root in every patient and is another potential modality for the assessment of aortic root geometry. This article will describe the current clinical utility of 3D echocardiography for assessment of the aortic root, and its advantage and limitations compared to other imaging modalities.

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Imaging of prosthetic devices has several technical limitations, especially in cases with acoustic shadowing or reverberation when valve dysfunction is suspected. Three-dimensional (3D) transesophageal echocardiography (3D-TEE) images provide appropriate visualization of valvular anatomy and proper quantification of valvular heart disease with superior spatial and temporal resolution compared with transthoracic echocardiography (TTE). 3D-TEE has improved visualization and assessment of complications in prosthetic valves, such as endocarditis or paravalvular regurgitation. Deep anatomic structures can be well displayed by manipulation and cropping wide-angled, full-volume datasets. Moreover, 3D-TEE images provide valvular visualization from any angle, which has been limited in 2D planar views. We can see the mitral mechanical and bioprosthetic valve rings, leaflets, and struts clearly by using 3D-TEE. Paravalvular regurgitation can also be identified. Quantification of the dehisced area using multiplanar imaging can be confirmed by the use of 3D color flow. It clearly demonstrates the location and size of mitral paravalvular leaks, describing the number of sites of dehiscence and its configuration. For the imaging of prosthetic valves, ‘3D zoom’ and ‘live’ modes are the most frequently used, giving priority to frame rate and imaging resolution. Orientating a structure from the axial direction of the beam allows new perspectives of the valvular structures on its face view (surgeon's view) and on its ventricular view. These allow us to understand the morphology and spatial relation among the intracardiac structures, resulting in diagnostic confidence and better communication among the heart team, at the time of clinical decision-making for surgery, for selecting patients for percutaneous interventions, and during the effective performance of these procedures.

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How can we utilize real-time three-dimensional (3D) echocardiography for diagnosis and treatment of congenital heart diseases? One of the most effective applications is to obtain critical information on complicated intracardiac 3D structures of the heart for planning of cardiac surgery, such as creation of an intracardiac route via a ventricular septal defect in patients with double outlet right ventricle, valvuloplasty for complicated atrioventricular valve regurgitation, or repair of intracardiac stenotic lesions. It is also useful for determining whether catheter intervention is indicated and for monitoring the procedure (while 3D echocardiography is only used for percutaneous atrial septal defect closure in Japan, it is also used for percutaneous ventricular septal defect closure in the US and Europe). Furthermore, transpericardial real-time 3D echocardiography is performed by placing the ultrasound probe directly onto the pericardium enables us to collect volume data with a high SN ratio and image resolution in pediatric patients for whom transesophageal echocardiography cannot be applied. This approach also enables both cardiovascular surgeons and cardiologists to share the ‘surgeon's view’ in the operating room. A new type to fetal echocardiography using the spatiotemporal image correlation (STIC) technique, which can reconstruct 3D fetal heart images by triggering the fetal cardiac motion, has been applied to fetal heart disease screening. Further investigations of 3D cardiac and valvular functions in congenital heart diseases are necessary to predict and improve the morbidity and the mortality of congenital heart diseases.

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Purpose: Coming up with a quantitative diagnosis method for liver fibrosis using ultrasound would be highly significant. To permit tissue characterization using the characteristics of the echo signal such as power spectrum, texture parameters, local attenuation, and statistical characteristics, the relation between complicated scatterer structures and the echo signal must be understood. Methods: In this study, we analyzed the property of the echo amplitude envelope using computer-simulated scatterer models. These models mimicked various liver conditions to evaluate our quantitative parametric imaging methods. Statistical echo characteristics changed with the density of the heterogeneous scatterer buried in a speckle. Results: The new analysis method for a medium in which some tissues are embedded was proposed in consideration of analysis results from computer simulations. In the new method, it is possible to eliminate the influence of a cyst or veins and to detect the existence of fibers more clearly than in previous methods.

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A 32-year-old woman complaining of stomach discomfort and high fever was referred to our hospital because of prolonged symptoms and the appearance of right upper quadrant abdominal pain. Ultrasonography visualized a 106mm iso-hypoechoic nodule with a clearly defined border in mainly hepatic segments 5 and 8. The hypoechoic lesion extended from the nodule to the right hepatic vein. The arterial phase of contrast-enhanced ultrasonography (CEUS) revealed a hypervascular, non-tortuous structure during the vascular image, and then showed a strong, inhomogeneous enhancement pattern during the perfusion image. In the portal phase, the strong enhancement pattern was slightly washed out. On Micro-Flow Imaging, an intense vessel structure was seen in the right hepatic vein that suggested a tumor thrombus. The poorly enhanced area indicated bleeding or a hemorrhage. The nodule was visualized as an enhancement defect in the post-vascular phase. Contrast-enhanced computed tomography showed an inhomogeneous, hyperenhanced pattern in the arterial phase. Contrast media washout was not seen in the delayed phase. MR T₁-weighted imaging showed homogeneous, low signal intensity, while T₂-weighted imaging showed heterogeneous, high signal intensity. The preoperative diagnosis was a malignant tumor such as a hepatocellular carcinoma, carcinosarcoma, or combined hepatocellular and cholangiocarcinoma. A histopathological examination revealed a proliferation of spindle cells in the background of myxoid stroma with arborizing blood vessels and small lymphocytic cells. The tumor was diagnosed as an inflammatory myofibroblastic tumor (IMT). IMT of the liver is rare and difficult to distinguish from malignant tumors. We report a case of IMT of the liver.

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We report a case of small intestinal diverticulitis diagnosed with abdominal ultrasonography. A 79-year-old man presented with right lower quadrant abdominal pain and fever. Because the physical examination showed tenderness and muscular guarding, we suspected local peritonitis due to acute appendicitis or diverticulitis of the ascending colon. However, ultrasonography and CT scan showed severer inflammatory change not in the ileocecal region. There was also no sign of local peritonitis caused by perforation of acute appendicitis. There was a mass lesion in the terminal ileum, 10 cm proximal to the ileocecal valve, which was found to be a mesenteric abscess secondary to perforation of the terminal ileum. The pathological diagnosis of this case was mesenteric abscess caused by a penetrated diverticulum of the terminal ileum. Ultrasonography was very useful in the preoperative diagnosis.

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