Echocardiography is essential in evaluating patients presenting various manifestations of coronary artery disease. No other imaging modality can readily provide such a wealth of information noninvasively and relatively inexpensively at the patient′s bedside. The role of echocardiography in coronary artery disease has evolved with changes in the management strategy of coronary artery disease. Transthoracic Doppler echocardiography enables us to diagnose coronary artery stenosis or occlusion based on coronary artery flow or coronary flow reserve (CFR). Stress echocardiography is useful for diagnosing myocardial ischemia and viability. Transthoracic echocardiography provides functional and hemodynamic information, as well as anatomic information, in the clinical setting.

View full abstract

In the past decade, remarkable progress has been made in the performance of diagnostic ultrasound equipment, and the basic policy regarding safety standards of acoustic output has also changed with the wave of globalization. Diagnostic equipment can now display TI and MI (thermal and mechanical indices) in real time, and operators of the equipment must determine the adequate acoustic output level by weighing the risks of adversely affecting tissue and making a diagnosis using an image of insufficient quality. The ALARA (as low as reasonably achievable) principle should be respected, with displayed TI and MI being used as a speedometer.

View full abstract

With the rapid improvement of ultrasound images, musculoskeletal ultrasonography has become an important imaging modality in addition to plain radiography, CT, and MRI. It is useful for the assessment of bone, cartilage, muscle, tendon, ligament, and peripheral nerve pathology. The utility of musculoskeletal ultrasound is not only suited for diagnosis in the clinic but also for preventive medicine in the field. As ultrasound technology rapidly advances, it opens new fields for the assessment of musculoskeletal disorders. Three-dimensional reconstructed imaging made possible effective presentation and preoperative simulation of arthroscopic surgery. Elastography, which represents the compressibility of soft tissue, is used for the quantitative assessment of the material properties related to the mechanism of musculoskeletal disorders. Progress in this technology has been seen in Japan, but its use is not as widespread as in foreign countries. Proactive efforts will be necessary with respect to education and activities to raise awareness.

View full abstract

Maintaining adequate vascular access for hemodialysis is a major problem for patients with end-stage renal disease from the standpoint of QOL. Ultrasonography is a mobile, simple, and noninvasive technique that provides both anatomic (blood vessel lumen and wall) and physiologic (access flow measurement) data. Preoperative ultrasound scan artery and vein mapping by the B-mode method is useful for decreasing the failure rate of forearm fistula. The B-mode and color Doppler methods are able to successfully detect stenosis, thrombus, and aneurysm. The pulse Doppler method is useful for observation of the pattern of the bloodstream and measurement of the blood flow and blood volume in order to analyze the hemodynamics of vascular access. From the measurement of resistance index (RI) and blood flow, subclinical stenosis of vascular access can be detected early, and prophylactic PTA of the stenotic region before complete obstruction has been shown to prolong the patency period of vascular access. New laboratory procedures such as ultrasonic 3-D imaging system (Vol-mode) or Fusion 3D that combine a B-mode image and a power Doppler 3D image and display are useful for evaluation of the objectivity of vascular access. In addition, the B-mode method is useful for monitoring during puncture to a central vein or to the forearm vascular access in which insertion of a canula is difficult, and the B-mode and color Doppler methods are useful for monitoring interventional treatment.

View full abstract

Because echoendoscopes equipped with a linear or convex array visualize the needle protruding from its channel, they are used in ultrasound-guided aspiration and therapy. Recently, endoscopic ultrasound (EUS)-guided aspiration has been the interventional EUS method of choice in an array of treatments. EUS-guided fine-needle aspiration is used in the differential diagnosis and staging of pancreatic tumors, where the pancreatic tissue or its surrounding lymph nodes are punctured through the gastrointestinal wall. In EUS-guided celiac plexus neurolysis, injecting ethanol around the celiac artery through the gastric body to block pain in patients with pancreatic carcinoma is considered safer and more accurate than ordinary celiac plexus neurolysis. EUS is valuable in transmural pseudocyst drainage. Because an echoendoscope equipped with a linear or convex array visualizes the large vessels, vessels lying between the needle and the pseudocyst can be avoided, preventing bleeding that might otherwise result. Other reports cover such uses as EUS-guided stenting by puncturing the bile duct or pancreatic duct after unsuccessful transpapillary stenting by ERCP. Further application of interventional EUS to other treatments is anticipated.

View full abstract

Purpose: To develop a method for estimating the medium constant from the temperature rise produced by ultrasound irradiation. Subjects and Methods: Ultrasound was irradiated to a sample medium placed in the path of propagation through water. We used a thin thermocouple to measure the temperature in the medium. The temperature in the medium was calculated using a simulation method that combined ultrasonic propagation and heat conduction. Results and Discussion: (1)Temperature rise of the medium, (2) temperature rise of the thermocouple, and (3) artifacts generated when ultrasound reaches the temperature sensor are included in the temperature measurement. The measured temperature differs from the simulation in which only the temperature rise of the medium is calculated. These three factors of the measured temperature depend on the distance characteristic of ultrasound intensity and the characteristic is proportional to the exponential curve on which the constant is the absorption coefficient. The normalized temperature distribution of measurement agrees with that derived from the simulation. Conclusion: Since the influence of the thermal conductivity and specific heat are not reflected in the normalized temperature distribution, this study shows that the absorption coefficient is significantly affected by the inclination of the temperature distribution. This practical estimation method is thus expected to prove useful in estimating the absorption coefficient.

View full abstract

Purpose: To compare the prominence of echogenic spots with the surrounding hisopathologic findings in breast cancer demonstrating only small round or amorphous microcalcifications on mammography. Subjects and methods: Ultrasonographic findings were investigated in 14 cases of non-invasive ductal carcinoma, with or without minimal invasion, in which small round or amorphous microcalcifications were noted on preoperative mammography. The obviousness of the echogenic spots was classified into three degrees; the histologic subtypes were divided into the comedo type and non-comedo type; and the diameters of the calcifications, degree of ductal dilatation, density of the ducts, and cellularity in the ducts were grouped into three grades. Results: Echogenic spots were demonstrated in 7 of the 8 cases with comedo type lesions, but were not detected in 5 of the 6 cases with only non-comedo lesions. The former demonstrated significantly more obvious echogenic spots than the latter (P=0.007). Histopathologic study of the surrounding tissue revealed that, larger diameter of calcification (P=0.02), greater ductal dilation (P=0.003), and higher duct density (P=0.01) correlated significantly with prominence of echogenic spots; however, no correlation was found between cellularity in the ducts and prominence of the echogenic spots (P=0.58). Conclusion: The histopathologic findings showed that echogenic spots were clearly imaged in cases with comedo-type lesions. In the surrounding tissue, larger diameter of calcification, more dilated ducts, and higher duct density was associated with more prominent echogenic spots.

View full abstract

Purpose: Regarding mass image-forming lesions, the 2005 Guidelines for Ultrasonic Diagnosis of Breast Diseases, published by the Japan Society of Ultrasonics in Medicine (JSUM), includes the evaluation of tumor compressibility, which is visually assessed by the degree of deformation caused by applying external pressure to the tumor. However, this is only a subjective estimation under real-time observation; consequently, quantitative evaluation of tumor deformation and the percentage change in internal echo intensity was attempted based on changes in the depth-width ratio and in the internal echo intensity on hand-held probe compression. We evaluated the usefulness of these measurements in the differential diagnosis of benign and malignant tumors. Method: The subjects were 139 patients (89 benign and 50 malignant cases) who underwent breast ultrasonography with a 10-MHz (from 4- to 10-MHz) linear probe. The deformation index (D.I.) of the tumor was defined as: [1−(depth-width ratio with 3.0±0.6-kg-weighted compression)/(depth-width ratio without compression)]×100 (%). The rate of change in internal echo intensity was defined as the echo intensity with compression divided by the echo intensity without compression×100 (%). Result: There was a significant difference in the D.I. between benign lesions (35.5%±14.7%) and malignant lesions (15.4%±6.2%) (P<0.001). The cut-off ratio in differentiating benign from malignant lesions was approximately 25%. The rate of change in echo intensity of benign lesions (149.7%±34.3%) was significantly higher than that of malignant lesions (122.9%±19.9%) (P<0.001). Conclusion: Using an electronic linear probe, quantitative indexes including the D.I. and the rate of change in internal echo intensity could be obtained with the help of a weight meter, and could prove effective for the differential diagnosis of breast mass-image forming lesions.

View full abstract

Fetal intestinal atresia (IA) presents as multiple dilated bowel loops. We report two cases of IA that presented as multiple swirling cysts and dilated bowel loops followed by fetal ascites and calcification in the abdomen on prenatal sonography. A 27-year-old woman presented with fetal dilated bowel loops at 25 gestational weeks. Sonography revealed a dilated bowel loop around a highly echogenic area along with multiple cysts and fetal ascites. Because prenatal ultrasonography at 37 weeks showed a highly echogenic small intestine, calcification in the abdomen, and no fetal ascites, fetal meconium peritonitis after intestinal perforation was suspected. At 38.4 weeks, a male infant weighing 2,270 g was delivered by caesarian section. A 30-year-old woman presented with fetal dilated, swirling bowel loops and fetal ascites at 29 gestational weeks. Because prenatal ultrasonography at 36 weeks showed dilated bowel loops, a highly echogenic small intestine, calcification, and no fetal ascites, fetal meconium peritonitis after intestinal perforation was suspected. At 38.6 weeks, a female infant weighing 2,958 g was delivered transvaginaly. In both the cases, IA and meconium peritonitis were confirmed at laparotomy. If looped dilatation of fetal intestines is suspected from fetal ultrasonography findings, changes in ultrasonographic findings that indicate IA, intestinal perforation, and meconium peritonitis should be anticipated.

View full abstract