Although relatively few types of pancreatic neoplasms are normally encountered in the clinic, understanding their ultrasonographic findings based on histopathology is important in their differential diagnosis. Pancreatic neoplasms are generally classified as solid or cystic. The solid neoplasms include pancreatic carcinoma, endocrine tumor, Solid-pseudopapillary neoplasm (SPN), adenosquamous carcinoma, anaplastic carcinoma, and acinar cell carcinoma; cystic neoplasms, serous cystic neoplasm (SCN), mucinous cystic neoplasm) (MCN), and intraductal papillary mucinous neoplasm (IPMN). However, differential diagnosis must be carefully carried out when the tumor is solid and presents such cystic features as a solid neoplasm with cystic degeneration with a retention cyst or a pseudocyst. With solid neoplasms, it is sometimes difficult to distinguish among adenosquamous carcinoma, anaplastic carcinoma, acinar cell carcinoma, and endocrine tumor with atypical features. Endocrine tumors in particular often show diverse features resulting from cystic degeneration or tumor thrombus in the main pancreatic duct. With cystic neoplasms, it is important to acknowledge that SCN often consists of both micro and macro cysts, or mainly macro cysts. It is also important to recognize the cyst-in-cyst structure of MCN and the cyst-by-cyst structure of IPMN. Ultrasonographic examinations play a critical role in the differential diagnosis of pancreatic neoplasms.

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Plaque instability exists at multiple sites in the systemic vascular bed. Assessment of plaque contents could provide useful information on plaque vulnerability. Recently, plaque morphology and composition can be clinically analyzed using Virtual Histology^TM intravascular ultrasound (VH-IVUS). Echolucent carotid plaque with low integrated backscatter (IBS) values has been recognized as lipid-rich, which can predict future cardiovascular complications. We hypothesized that echolucent carotid plaque with low IBS values might be associated with the lipid-rich condition of coronary plaque. We measured maximum intima-media thickening (IMT), plaque score (PS), and echogenicity of carotid plaque using ultrasound with IBS in 14 consecutive patients undergoing coronary intervention. Using VH-IVUS, the coronary plaque component was assessed in a 20mm segment of coronary artery containing the target lesion. In carotid arteries, maximum IMT was 2.1±1.2 mm, plaque score was 8.5±9.0, plaque mean IBS value was -11.4±1.9 dB. In coronary plaque, the percentage of fibrous, fibro-fatty lesion, necrotic core, and dense calcium was 66±9%, 20±9%, 8±6%, and 6±3%, respectively. PS and maximum IMT of carotid plaque were not correlated with coronary plaque component assessed by VH-IVUS. Patients were divided into two groups according to carotid echogenicity: low IBS and high IBS. The percentage of fibro-fatty lesion in coronary plaque was significantly greater in the low IBS group than in the high IBS group (27±2% versus 13±6%, p⟨0.001). By linear regression analysis, the percentage of a combination of fibro-fatty lesion and necrotic core in coronary lesions was significantly correlated with IBS values of carotid plaque (p=0.03). These results indicated that low IBS values in carotid plaque correlated with the lipid-rich condition in coronary plaque. From these results, we concluded that noninvasive qualitative ultrasound evaluation of carotid plaque with IBS is clinically useful to assess coronary plaque vulnerability.

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IVUS-guided PCI has become a standard interventional procedure because IVUS can provide important information not only about vessel diameter and characteristics of plaque but also about stent expansion and apposition, and this information leads to a better prognosis after the procedure. Virtual histology (VH)-IVUS is a unique system to provide plaque tissue typing as four major components using radiofrequency analysis. The necrotic core is the component most related to plaque vulnerability, and plaque that has both NC ⟩10% without evident overlying fibrous tissue and percent atheroma volume ⟩40% in at least three consecutive frames is considered to be VH-thin cap fibroatheroma (TCFA). The PROSPECT trial revealed that VH-TCFA is an important predictor of future coronary events. We investigated which coronary risk factors are related to the amount of NC. Among several factors, AA/EPA ratio is the strongest factor positively related to the amount of NC in both SAP and ACS. Recent studies used VH-IVUS^® to elucidate the pharmacological effect of statin on plaque volume and component changes. VH-IVUS^® is a unique tool to reveal the pathology and pathophysiology of plaque, and its importance will likely continue to grow.

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In the case of atherosclerotic plaques, irregular surface plaques, ulcerated plaques, and mobile plaques are classified as complex plaques. Complex plaques in the aortic arch and carotid arteries detected by vascular ultrasound imaging such as transesophageal echocardiography and carotid ultrasound have been shown to contribute to an increased risk of stroke. On the other hand, several inflammatory biomarkers such as C-reactive protein (CRP) have been reported to be associated with atherosclerosis and plaque destabilization. Neopterin has been reported to be an activation marker for monocytes/macrophages. It has been shown that neopterin is closely associated with unstable coronary plaques in patients with unstable angina pectoris. Furthermore, we recently demonstrated that the complex carotid plaques detected by carotid ultrasound were related to increased circulating levels of high-sensitivity CRP and neopterin, and immunohistochemical localization of neopterin was observed in the complex carotid plaques obtained from carotid endarterectomy in patients with stable angina pectoris. These observations suggest that the complex plaques detected by vascular ultrasound may be associated with plaque instability. Therefore, plaque complexities assessed by vascular ultrasound should be considered in the evaluation of plaque destabilization.

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Purpose: To elucidate the critical role of intraplaque neovascularization of microvessel-derived intraplaque hemorrhage in the development of acute lesion instability. We designed this study to visualize carotid plaque neovascularization using B-flow imaging, which can visualize microvascular flow. Subjects and Methods: Seven patients (7 men, 68.6±4.8 yrs) who had been referred for carotid endarterectomy were enrolled.Carotid ultrasound examinations were carried out using a Vivid 7 system with a multifrequency linear array transducer. Measurement of carotid plaque echogenity was based on gray-scale median (GSM) value. Intraplaque microvascular flow signals were carefully assessed by B-flow imaging. Results and Discussion: Intraplaque flow signals were observed in six patients. Gray-scale median values of these plaques were low (32±10). Multiple flow signals were observed in three patients in whom histologic studies revealed enhanced neovascularization with a lipid-rich core. In two patients whose intraplaque flow signals were situated at the peri-adventia, histologic studies revealed massive intraplaque hemorrhage with a necrotic core. In one patient, plaque producing no flow signals showed greater fibrous change, more calcification, and less neovascularization. Conclusion: B-flow imaging visualized intraplaque flow signals and provided additional information on plaque characterization.

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Percutaneousl US including carotid ultrasonographic examination is a promising noninvasive method for evaluating atherosclerosis and is finding increasing use in clinical settings. Atherosclerosis comprises two components: atherosis and sclerosis. Ultrasonography can be used to evaluate atherosis and sclerosis simultaneously: atherosis being assessed based on intima-media thickness; sclerosis, by stiffness parameter β. Moreover, recently developed ultrasound systems often provide tracking systems that can calculate stiffness parameter β automatically. Therefore, surface echo, especially that observed in carotid ultrasonography, is useful in evaluating atherosclerosis. Further, percutaneousl US examination also has a place in treating peripheral artery disease (PAD). New techniques and devices for percutaneous peripheral intervention (PPI) have been developed, while interventional cardiologists use percutaneous peripheral intervention to treat more difficult cases of peripheral artery disease. Percutaneousl US-guidance effectively decreases exposure to radiation and improves the success rate in percutaneous peripheral intervention. An ultrasound unit is thus essential in the catheter laboratory when carrying out surface echo-guided percutaneous peripheral intervention. These facts support the conclusion that percutaneousl US is a valuable tool in evaluating atherosclerosis as well as in performing percutaneous peripheral intervention to treat it.

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Destabilization of coronary plaque is one of the key features in the process of acute coronary syndrome. However, a quantitative way of assessing plaque vulnerability has not yet been established. Previous pathologic studies have revealed that plaque vulnerable to rupture is usually eccentric and non-calcified with positive remodeling, a thin fibrous cap, a large lipid core, and accumulated infiltrations of inflammatory cells. Recent plaque imaging modalities, including intravascular ultrasound (IVUS), have been developed for the purpose of detection of plaque with such specific features. Furthermore, structural mechanics imaging modalities, such as in-plaque or shear stress imaging, have also been proposed in this field. Future perspectives in the development of new IVUS imaging technologies involve three-dimensional plaque imaging, more sophisticated tissue characterizing imaging, as well as hybrid ultrasound-infrared-light imaging catheter systems.

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Purpose: To elucidate whether myocardial blood volume is associated with resting left ventricular (LV) function and/or contractile reserve in patients with dilated cardiomyopathy (DCM) using myocardial contrast echocardiography (MCE). Subjects and Methods: Twenty-one patients with DCM who had LV ejection fraction (LVEF)⟨45% were enrolled. Under continuous infusion of Levovist, harmonic power Doppler images were acquired at end systole every 6th beat using the apical two- and four-chamber views. Dividing the LV wall into six myocardial segments, myocardial contrast intensity (CI_myo) and the contrast intensity of the adjacent intracavity blood pool (CI_blood) were measured. Relative CI (RelCI), calculated as CI_myo-CI_blood [dB], logarithmically represents the ratio of microbubble concentrations between the myocardium and blood pool. Myocardial blood volume can be derived as 10^(RelCI/10)×100 [%]. Dobutamine stress echocardiography (up to 20 μg/kg/min) was performed, and LVEF was measured at baseline and at peak dose. Results and Discussion: Myocardial blood volume did not correlate with any parameters of resting LV function, but it significantly correlated with percent change in LVEF during dobutamine stress echocardiography (r0.54, p0.01). Myocardial histomorphometric features in patients with DCM conceivably cause the reduction in myocardial blood volume, being related to the depressed contractile reserve. Conclusion: Myocardial blood volume measured by MCE was associated with LV contractile reserve in patients with DCM.

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Purpose: The purpose of this study is to show the relationship between LV geometry (spherical or ellipsoid) and LV dyssynchrony. Subjects and Methods: The study population consisted of 25 patients (5 females and 20 males, ages 64±14 years) with severe LV systolic dysfunction (LV ejection fraction⟨35%). LV geometry was assessed with the ratio of LV longitudinal dimension / radial dimension (sphericity index: SI) in the 2D echo. LV dyssynchrony was assessed with Ts-SD, determined with 2D tissue Doppler, and systolic dyssynchrony index (SDI), determined with 3D full volume. We examined the relation between SI and the degree of dyssynchrony, and the effect of medical treatment on the relation. Results and Discussion: SI correlated with SDI (r=-0.44, p⟨ 0.05), while there was no correlation between SI and Ts-SD (r=-0.22). LV geometry was more ellipsoid and LV dyssynchrony was smaller in those receiving beta-blockers, angiotensin-converting enzyme inhibitors / angiotensin receptor blockers, and statins than in those not receiving these. Conclusion: There was a correlation between LV geometry and LV dyssynchrony. LV geometrical change from ellipse to sphere may facilitate LV dyssynchrony in patients with severe LV systolic dysfunction.

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Purpose: The aim of this study was to determine if transcutaneous and transrectal ultrasonography of the male urethra with retrograde jelly injection into the urethra (sonourethrography) was clinically useful. Subjects and Methods: Sonourethrography was performed in cases in which indwelling urethral catheter insertion was difficult, cases with urethral stricture, and a case with urethral injury. Cases with urethral stricture were placed in the lithotomy position. Cases in which indwelling urethral catheter insertion was difficult and the case with urethral injury were placed in the supine position. In the cases with urethral stricture, transcutaneous and transrectal sonourethrography was performed and the urethra was observed from the anterior urethra to the bladder neck. The location, number, and length of urethral strictures were evaluated. In the cases in which indwelling urethral catheter insertion was difficult and the case with urethral injury, only transrectal sonourethrography was performed. The reason for the difficulty of indwelling urethral catheter insertion and the continuous urethral lumen after injury were evaluated. Sonourethrography-guided urethral catheter insertion was also performed. Results and Discussion: Five cases in which indwelling urethral catheter insertion was difficult, four cases of urethral stricture, and one case of urethral injury were enrolled. Two cases of false tracts, two cases of benign prostate hyperplasia, and one case of normal urethra made up the cases in which indwelling urethral catheter insertion was difficult. In all five cases, the reason for the difficulty of indwelling catheter insertion were identified, and sonourethrography-guided indwelling urethral catheter insertion was effective and safe. Of the four cases of urethral stricture, three cases were bulbar urethral strictures and one case was anastomotic urethral stricture after radical prostatectomy. In all cases, the strictures were clearly observed using sonourethrography. The anastomotic urethral stricture after radical prostatectomy was clearly observed using transrectal sonourethrography. In all of the cases of urethral stricture, the stricture findings were the same as the intraoperative urethroscopic findings. In the case of urethral injury, continuous urethral lumen, hematoma around the urethra, and false tract were observed. Severe adverse events were not seen in any cases. Conclusion: Anatomical evaluation of the male urethra from the anterior urethra to the bladder neck can be precisely done using transcutaneous and transrectal sonourethrography. In addition, sonourethrography can be used to reliably and safely assist indwelling urethral catheter insertion.

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