In routine echocardiography, the views to be examined and the structures and blood flow to be elucidated in each view are fixed for the most part with only slight variations between institutions. Once examiners master the echocardiographic technique and experience a series of abnormal findings, too much focus on recording routine views may lead us to perform echocardiographic examinations without considering the spatial relationships between the cardiovascular and surrounding organs. In this case, when finding unexpected structures or blood flows, it may be difficult to distinguish them from normal findings. This review outlines normal structures (findings) as well as the normal variants in healthy subjects that are easily overlooked in routine echocardiographic examinations.

As ultrasound (US) is simple and minimally invasive, it is widely used for mass screening. However, since conventional US screening focused on mass lesions and indirect findings such as the dilated extrahepatic bile duct and main pancreatic duct, the detection rate of pancreatic cancer was low, and most detected lesions were advanced. Although there is still no definition of early-stage pancreatic cancer, Stage 0 and Stage 1A pancreatic cancers less than 10 mm are considered pancreatic cancers with good prognosis. To detect these lesions, it is useful to perform detailed examinations and regular follow-up for high-risk individuals who have multiple risk factors for pancreatic cancer. It is also the role of US to identify high-risk individuals who show a dilated main pancreatic duct or cystic lesion. The pancreas is sometimes difficult to visualize not only because of its complicated anatomical location but also because of its susceptibility to obesity and gastrointestinal gas. Although the pancreatic head is a common site of pancreatic cancers with good prognosis, it is important to pay attention to lesions in the groove region and uncinate process, which are often not accompanied by indirect findings. To minimize poorly visualized areas, positional changes such as right and left decubitus, sitting and standing positions, and the liquid-filled stomach method should be applied. Furthermore, employing magnified observation with high-frequency transducers for the detailed examination and follow-up of high-risk individuals could detect smaller mass lesions and abnormalities of the pancreatic ducts.

The Liver Imaging Reporting and Data System (LI-RADS), endorsed by the American College of Radiology (ACR), includes four algorithms: ultrasound (US) LI-RADS for hepatocellular carcinoma (HCC) screening and surveillance, contrast-enhanced US (CEUS) LI-RADS and computed tomography/magnetic resonance imaging (CT/MRI) LI-RADS for HCC diagnosis, and CT/MRI LI-RADS treatment response algorithm. Recently, LI-RADS has been adopted in clinical practice throughout the United States, and the standardization and consensus regarding the imaging diagnosis of HCC have been improved. LI-RADS achieved consistency with and integration into the American Association for the Study of Liver Diseases HCC clinical practice guidance in 2018. LI-RADS has been gaining international attention, with CT/MRI LI-RADS and CEUS LI-RADS translations now available in 11 and nine languages, respectively. Meanwhile, two US clinical guidelines, supported by the Japan Society of Ultrasonics in Medicine, the manual for abdominal US in cancer screening and health checkups and the ultrasound diagnostic criteria for hepatic tumors, have been adopted in clinical practice in Japan. Sonazoid is available clinically in Japan but not in the United States; therefore, the use of Sonazoid is not supported by CEUS LI-RADS. At present, US LI-RADS and CEUS LI-RADS are not commonly used in Japan. However, CEUS LI-RADS has the potential to become a global standard in the event of the additional inclusion of Sonazoid. We have to keep our eyes on future developments in the area of CEUS LI-RADS.

Introduction: Advances and widespread use of various diagnostic imaging modalities have dramatically improved our ability to visualize and diagnose pancreatic diseases. In particular, ultrasonography in pancreatic diseases plays an important role from screening to diagnosis as a simple and safe examination method. Methods: The basic scanning method of transabdominal pancreatic ultrasonography, characterization, and differential diagnosis by ultrasonography including contrast-enhanced ultrasonography (CEUS) for solid pancreatic tumors are reviewed with reference to various papers. Results: In recent years, the ability to visualize and diagnose pancreatic mass lesions has been dramatically improved with advances in ultrasound equipment. In particular, CEUS using an ultrasound contrast agent has made it possible to evaluate hemodynamics in organs or lesions as well as in the flow signal of arterial blood vessels, and it has played an important role not only in diagnosis of the presence of a lesion but also in the qualitative diagnosis. The enhancement behavior and pattern with CEUS of pancreatic solid tumors is shown in text and Fig. 9. Moreover, the flow chart for diagnosing pancreatic solid tumors with CEUS classifying the enhancement behavior and pattern for pancreatic solid tumors on CEUS is shown (Fig. 10). In meta-analyses, the pooled sensitivity in the differential diagnosis of pancreatic adenocarcinomas and other pancreatic focal masses with CEUS was 86-90%, and the pooled specificity was 75-88%. Conclusion: CEUS is a minimally invasive and useful diagnostic method that can be used to make a simple and quick qualitative diagnosis of pancreatic diseases. CEUS provides a lot of information important for diagnosis, and has led to changes in the conventional diagnostic systems in pancreatic diseases.

The incidence and mortality rates of pancreatic cancer, which has a poor prognosis, are rising rapidly. Endoscopic ultrasonography (EUS) provides superior spatial resolution compared with other imaging modalities such as transabdominal ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI), and it is considered among the most reliable and efficient diagnostic modalities for pancreatic diseases. In this review, we show that EUS is useful for detection of pancreatic solid lesions and staging of pancreatic cancer. EUS also plays an important role in screening patients with high-risk factors for pancreatic cancer. Although EUS is useful for detection of small pancreatic lesions, pancreatic lesions are difficult to characterize using this modality, because most pancreatic solid lesions appear hypoechoic on EUS. From this point of view, contrast-enhanced harmonic EUS (CH-EUS) plays an important role in the differential diagnosis of pancreatic lesions. EUS and CH-EUS are also useful for staging pancreatic cancer. Moreover, EUS-guided fine-needle aspiration (EUS-FNA) is superior to other modalities in terms of cytopathological diagnosis. Although EUS-FNA has a high diagnostic ability for pancreatic cancer, the combination of EUS-FNA and CH-EUS improves the diagnostic ability by decreasing the number of false-negative cases. Thus, conventional EUS, EUS-FNA, and CH-EUS are essential in clinical practice for the diagnosis of pancreatic solid lesions.

Pancreatic cystic lesions (PCLs) are incidental findings that are being increasingly identified because of recent advancements in abdominal imaging technologies. PCLs include different entities, with each of them having a peculiar biological behavior, and they range from benign to premalignant or malignant neoplasms. Therefore, accurate diagnosis is important to determine the best treatment strategy. As transabdominal ultrasonography (US) is noninvasive, inexpensive, and widely available, it is considered to be the most appropriate imaging modality for the initial evaluation of abdominal diseases, including PCLs, and for follow-up assessment. We present a review of the possibilities and limits of US in the diagnosis of PCLs, the technical development of US, and the ultrasonographic characteristics of PCLs.

Endoscopic ultrasonography (EUS) is a modality with high spatial resolution that enables comprehensive observation of the entire pancreas and plays an important role in the diagnosis of pancreatic lesions. Recent advances in diagnostic imaging methods such as ultrasound, computed tomography, and magnetic resonance imaging have increased the incidental detection of pancreatic cystic lesions (PCLs). EUS has been recognized as an essential diagnostic method for the detection and evaluation of PCLs. EUS has two important roles: as a detailed (high-resolution) imaging diagnostic method and as an approach for collecting cyst fluid content by EUS-guided fine needle aspiration for pathological diagnosis or biomarker evaluation. Furthermore, in recent years, the usefulness of contrast-enhanced EUS for the differential diagnosis of PCLs or evaluation of grade of malignancy, and a novel imaging technique called needle-based confocal laser endomicroscopy to observe intraductal structures through a needle, has been reported. An understanding of the morphological characteristics of PCLs depicted by ultrasound imaging and of the benefits and limitations of EUS diagnosis in daily practice is needed.

Ultrasound elastography is a relatively new diagnostic technique for measuring tissue elasticity (hardness). This review describes the types and evaluation methods of elastographies used in diagnosing pancreatic tumors. It also evaluates the diagnostic ability of transabdominal (US) or endoscopic ultrasonography (EUS) elastography for pancreatic tumors, based on findings from a search of published articles. Twenty articles (2096 cases) were selected from the databases. The types of elastography used for the diagnosis of pancreatic tumors were strain elastography and shear wave elastography. The evaluation methods of elastography and their diagnostic abilities (sensitivity and specificity) were 0.78 (95% confidence interval 0.65-0.87) and 0.82 (0.63-0.94) for color pattern diagnosis (US), 0.82 (0.77-0.86) and 0.70 (0.64-0.76) for color pattern diagnosis (EUS), 0.94 (0.90-0.97) and 0.87 (0.81-0.92) for strain ratio (EUS), 0.92 (0.90-0.94) and 0.79 (0.75-0.82) for histogram analysis (EUS), and 0.90 (0.82-0.95) and 0.82 (0.57-0.72) for shear wave elastography. In conclusion, there are many types of elastographies and evaluation methods, and the diagnostic ability for pancreatic tumors is high for each evaluation method.

Purpose: The overlap between lifestyle-related diseases and visceral obesity is said to increase the risk of developing atherosclerosis. The assessment of visceral fat accumulation is commonly carried out by computed tomography scan (fat scan). However, due to radiation exposure and the cost of the test, it is difficult to perform this test on a large number of people. On the other hand, abdominal ultrasonography is a simple method without the problem of radiation exposure, and various reports on visceral fat accumulation have been published. In the present study, we focused on the perirenal fat (PRF) of the hepato-renal gap on abdominal ultrasonography. Subjects and Methods: The subjects were 478 patients (male: 333, female: 145, mean age: 58.3 ± 11.7 years, mean BMI: 24.6 ± 3.2) who underwent physical examination in 2018 and underwent abdominal ultrasonography and fat scan. PRF was measured from hepatic and renal images of abdominal ultrasound and compared with fat scan. The relationship between PRF and visceral fat accumulation was also investigated using a health questionnaire. Results and Discussion: The mean PRF of all subjects was 5 ± 5.5 mm, and the mean visceral fat area (VFA) on fat scan was 110 ± 51 cm². The correlation coefficient between PRF and VFA was 0.66 (p-value < 0.001), indicating a positive correlation. ROC analysis with PRF showed a threshold of 3 mm. The area under the curve was 0.855 (95% confidence interval: 0.821-0.889), the sensitivity was 81%, the specificity was 81%, the positive predictive value was 80%, and the negative predictive value was 82%.We considered that a fat layer of more than 3 mm in the hepato-renal gap on abdominal ultrasonography could estimate a visceral fat area of more than 100 cm². In addition, when the influence of medications (blood pressure, blood glucose, lipid) was examined based on the questionnaire, there was no difference in body mass index and abdominal circumference, and the fat scan and PRF showed a large amount of visceral fat (accumulation). Conclusion: Measurement of the hepato-renal gap using abdominal ultrasonography can help to estimate and diagnose visceral fat accumulation in physical examinations and screening tests.

Purpose: The aim of this study was to verify the validity of a shoulder ultrasonic training program in the clinical laboratory for human resource development. Methods: Three technicians were trained under this program for 1 year. We evaluated the sensitivity, specificity, and accuracy of shoulder ultrasound (SUS) findings in comparison with the intraoperative findings in 20 cases. SUS was performed in pairs during training, and SUS was performed by the technician alone at 1 year. At the end of the program, the diagnostic accuracy was of the instructor and the three technicians was evaluated using Fisher’s test. Results: There was no significant difference between the instructor and three technicians in terms of evaluation of the long head of biceps tendon (LHBT), subscapularis tendon, supraspinatus tendon, and infraspinatus tendon before surgery. At the start of this program, the accuracy of SUS findings for the LHBT was 69% (technicians 1: 70%, 2: 72%, and 3: 65%) and that for the subscapularis tendon was 53% (technicians 1: 50%, 2: 50%, and 3: 60%). After completion of the program, the accuracy of SUS findings for the LHBT improved to 80% (technicians 1: 85%, 2: 80%, and 3: 75%) and that for the subscapularis tendon improved to 71% (technicians 1: 65%, 2: 65%, and 3: 85%). Discussion: The education we provided using the shoulder ultrasonic training program was useful for learning SUS techniques regardless of whether or not the technician had experience with ultrasound examinations. Conclusion: It is conceivable that the shoulder ultrasonic training program is effective for technical guidance.