The purpose of performing an ultrasound examination in the early stage of pregnancy is to confirm the gestational weeks of pregnancy, expected delivery date, diagnoses for abnormal pregnancies such as miscarriages, ectopic pregnancy, hydatidiform moles, etc., the presence of relatively large fetal morphological abnormalities, chorionicity diagnoses in the case of multiple pregnancies, and searching for the presence of gynecologic diseases complicating the pregnancy such as uterine myoma, ovarian tumors, etc. In recent years, the evaluation risk for fetal chromosomal abnormalities including the anechoic area of the posterior region of the neck (nuchal translucency, hereinafter referred to as NT) has been added to the abovementioned items. Investigations other than NT do not have any particular ethical issues and the doctor making the diagnosis is required to provide patients with the investigation results; however, NT is regarded as a so-called prenatal diagnosis, meaning there is a great impact on the investigation results. Furthermore, a consistent technique is required for the measurement of NT. Accordingly, a tester carrying out the investigation must be skilled in this technique and, along with the evaluation results, it is desirable to counsel pregnant women in advance regarding the nature of the investigation with regard to the potential that some things may be found and others not found upon undergoing this investigation; therefore, it should be carried out only for those who are interested in self-determination. In this paper, an overview is provided regarding the procedures and method of performing an ultrasound examination in the early stage of pregnancy, along with the safety of ultrasound examinations in the early stage of pregnancy.

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The liver is fed by two vessels, an artery and the portal vein. The portal vein is very important because of the nutritionally rich blood flow compared with the artery. However, the blood flow of the portal vein is easily influenced by liver diseases since the blood pressure of this important vessel is very low. To gain a better understanding, the authors evaluated changes in the micro-circulation within the liver parenchyma and the behavior of the portal vein blood flow using arrival-time parametric imaging, perfusion parametric imaging, and arterialization ratio obtained by contrast-enhanced ultrasound. We found that contrast-enhanced ultrasonographical analysis of the liver parenchymal micro-circulation and of the portal vein blood flow may be of great help for understanding what is happening within the liver parenchyma in patients with liver disease.

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This article mainly provides a guideline for contrast-enhanced ultrasound diagnosis of hepatic tumors in Japan. Liver tumor diagnostic criteria were first published in 1988 by Japan Society of Ultrasonics in Medicine. With recent advances in ultrasound equipment and changes in the concept of liver tumors, various issues have emerged that cannot be handled by the previous guideline. Currently, Sonazoid^® (Daiichi-Sankyo, Tokyo, Japan), a lipid stabilized suspension of perfluorobutane gas microbubbles, has been licensed in Japan. In the present revision, typical findings necessary for differentiation of 6 major diseases (hepatocellular carcinoma, intrahepatic cholangiocarcinoma [cholangiocellular carcinoma], metastatic liver tumor, hepatocellular adenoma, hepatic hemangioma, and focal nodular hyperplasia [FNH]) are described. Ultrasound findings were divided into B-mode findings, Doppler findings, and contrast-enhanced findings. B-mode findings are based on the tumor shape, border and contour, tumor margin, intra-tumor, posterior echo, and additional findings. Doppler findings are based on the degree of blood flow, vascularity, blood flow characteristics (pulsatile wave and steady wave), and additional findings. The phases of contrast-enhanced ultrasound are classified into the vascular phase and post-vascular phase. The vascular phase is further divided into the arterial [predominant] phase and the portal [predominant] phase. The characterization of liver tumors is made by the findings of three phases. The vascular phase is used for characterization, and the post-vascular phase is used for detection. The post-vascular image is also called the “Kupffer image” and is closely correlated with the presence or absence of Kupffer cells in the tumor. However, this term is controversial and requires further consideration.

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Contrast-enhanced ultrasonography in the diagnosis of pancreatic disorders should be reviewed with regard to the development, varieties of contrast agents, and also ultrasound technologies. Contrast agents for ultrasonography are roughly divided into two categories: Those effective in the digestive tract and those in the vessels (arteries and veins). The former include the water-like material to bring proper acoustic windows between the US probe and pancreas. The latter are those including carbon dioxide microbubbles injected into the arteries (not used nowadays) and contrast agents effective after injection into peripheral veins (today's mainstream). As to the ultrasonographic technologies, color/power Doppler imaging and harmonic imaging have brought about a big change in the investigation of the hemodynamics of lesions. In addition, collaboration between novel US technologies and endosonoscopes with an electronic scanning probe has opened the door for far more accurate diagnosis evaluating hemodynamics in the diagnosis of pancreatic disorders. Here, we describe in this review the outline of a historical view and future perspective of contrast-enhanced US and EUS.

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Sonazoid^®, the only ultrasound contrast medium that can be used clinically in Japan, has been covered by insurance for focal breast lesions since August 2012. Contrast-enhanced ultrasound for focal breast lesions is not yet widespread, and a standard protocol and diagnostic criteria are not yet established. A consensus on a contrast-enhanced ultrasound method for breast lesion, phase, and observational points of contrast-enhanced findings will be needed. Based on our clinical experience and reports in the literature, the difference in contrast-enhanced ultrasound between the liver and breast and our opinions on contrast-enhanced methods and evaluation points of contrast-enhanced findings are discussed. Also, when presenting our clinical cases, we describe how contrast-enhanced ultrasound will be useful for the differential diagnosis of malignant and benign breast lesions, assessment of the spread of breast cancer, detection of lesions that cannot be detected by first ultrasonography examination, and assessment of response to chemotherapy.

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Purpose: Establishment of a method for the periodical measurement of bladder capacity by means of abdominal three-dimensional ultrasound. Materials and Methods: Simple devices to fix the three-dimensional ultrasound scanner on the lower abdomen stably were newly developed. The reliability of the method was examined in 18 subjects, while the possibility to apply the method for periodical measurement was tested in 4 subjects. Conclusion: Measured capacities were 18% lower on average than the actual values. When this deviation was corrected, however, the error fell within 12% in every case, which indicated a sufficient accuracy for practical use in physiology. Periodical measurement for overnight sessions was achieved successfully.

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Purpose: Echocardiography is a widely used modality for diagnosis of the heart. It enables observation of the shape of the heart and estimation of global heart function based on B-mode and M-mode imaging. Subsequently, methods for estimating myocardial strain and strain rate have been developed to evaluate regional heart function. Furthermore, it has recently been shown that measurements of transmural transition of myocardial contraction/relaxation and propagation of vibration caused by closure of a heart valve would be useful for evaluation of myocardial function and viscoelasticity. However, such measurements require a frame rate much higher than that achieved by conventional ultrasonic diagnostic equipment. In the present study, a method based on parallel receive beamforming was developed to achieve high-frame-rate (over 300 Hz) echocardiography. Methods: To increase the frame rate, the number of transmits was reduced to 15 with angular intervals of 6 degrees, and 16 receiving beams were created for each transmission to obtain the same number and density of scan lines as realized by conventional sector scanning. In addition, several transmits were compounded to obtain each scan line to reduce the differences in transmit-receive sensitivities among scan lines. The number of transmits for compounding was determined by considering the width of the transmit beam. For transmission, plane waves and diverging waves were investigated. Diverging waves showed better performance than plane waves because the widths of plane waves did not increase with the range distance from the ultrasonic probe, whereas lateral intervals of scan lines increased with range distance. Results: The spatial resolution of the proposed method was validated using fine nylon wires. Although the widths at half-maxima of the point spread functions obtained by diverging waves were slightly larger than those obtained by conventional beamforming and parallel beamforming with plane waves, point spread functions very similar to those obtained by conventional beamforming could be realized by parallel beamforming with diverging beams and compounding. However, there was an increase in the lateral sidelobe level in the case of parallel beamforming with plane and diverging waves. Furthermore, the heart of a 23-year-old healthy male was measured. Conclusion: Although the contrast of the B-mode image obtained by the proposed method was degraded due to the increased sidelobe level, a frame rate of 316 Hz, much higher than that realized by conventional sector scanning of several tens of Hertz, was realized with a full lateral field of view of 90 degrees.

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