Diagnosis of subepithelial tumors in the upper gastrointestinal tract by endoscopic ultrasonography

Endoscopic ultrasonography(EUS) is the most accurate procedure for detecting and diagnosing subepithelial tumors,due to its higher sensitivity and specificity than other imaging modalities.EUS can characterize lesions by providing information on echogenic origin,size,borders,homogeneity,and the presence of echogenic or anechoic foci.Linear echoendoscopes,and recently also electronic radial echoendoscopes,can be used with color Doppler or power Doppler to assess the vascular signals from subepithelial masses,and thus permit the differentiation of vascular structures from cysts,as well as the assessment of the tumor blood supply.However,the diagnostic accuracy of EUS imaging alone has been shown to be low in subepithelial lesions with 3rd and 4th layers.It is also difficult to differentiate exactly between benign and malignant tumors and to gain an accurate picture of histology using EUS.On the other hands,EUS guided fine needle aspiration(EUS-FNA) can provide samples for cytologic or histologic analysis.Hypoechoic lesions of the 3rd and the 4th EUS layers,more than in 1 cm diameter are recommended,and histologic confirmation using endoscopic submucosal resection or EUSFNA should be obtained when possible.Therefore,EUSFNA plays an important role in the clinical management of subepithelial tumors.Furthermore improvements in endoscopic technology are expected to be more useful modalities in differential diagnosis and discrimination between benign and malignant subepithelial

Contrast-enhanced harmonic endoscopic ultrasonography for assessment of lymph node metastases in pancreatobiliary carcinoma

AIM: To assess the usefulness of contrast-enhanced harmonic endoscopic ultrasonography(CH-EUS) for lymph node metastasis in pancreatobiliary carcinoma.METHODS: All patients suspected of pancreatobiliary carcinoma with visible lymph nodes after standard EUS between June, 2009 and January, 2012 were enrolled.In the primary analysis, patients with successful EUSfine needle aspiration(FNA) were included. The lymph nodes were assessed by several standard EUS variables(short and long axis lengths, shape, edge characteristic and echogenicity), color Doppler EUS variable [central intranodal blood vessel(CIV) presence] and CH-EUS variable(heterogeneous/homogeneous enhancement patterns). The diagnostic accuracy relative to EUSFNA was calculated. In the second analysis, N-stage diagnostic accuracy of CH-EUS was compared with EUS-FNA in patients who underwent surgical resection.RESULTS: One hundred and nine patients(143 lymph nodes) fulfilled the criteria. The short axis cutoff ≥ 13 mm predicted malignancy with a sensitivity and specificity of 72% and 85%, respectively. These values were 72% and 63% for the long axis cut-off ≥ 20 mm, 62% and 75% for the round shape variable, 81% and 30% for the sharp edge variable, 66% and 61% for the hypoechogenicity variable, 70% and 72% for the CIV-absent variable, and 83% and 91% for the heterogeneous CH-EUS-enhancement variable, respectively. CH-EUS was more accurate than standard and color Doppler EUS, except the short axis cut-off. Notably, three patients excluded because of EUS-FNA failure were correctly N-staged by CH-EUS.CONCLUSION: CH-EUS complements standard and color Doppler EUS and EUS-FNA for assessment of lymph node metastases.

Diagnosis of pancreatic tumors by endoscopic ultrasonography

Pancreatic tumors are highly diverse, as they can be solid or cystic, and benign or malignant. Since their imaging features overlap considerably, it is often difficult to characterize these tumors. In addition, small pancreatic tumors, especially those less than 2 cm in diameter, are difficult to detect and diagnose. For characterizing pancreatic tumors and detecting small pancreatic tumors, endoscopic ultrasonography (EUS) is the most sensitive of the imaging procedures currently available. This technique also provides good results in terms of the preoperative staging of pancreatic tumors. EUS-guided fine needle aspiration (EUS-FNA) has also proved to be a safe and useful method for tissue sampling of pancreatic tumors. Despite these advantages, however, it is still difficult to differentiate between be-nign and malignant, solid or cystic pancreatic tumors, malignant neoplasms, and chronic pancreatitis using EUS, even when EUS-FNA is performed. Recently, contrast-enhanced EUS with Doppler mode (CE-EUS) employing ultrasound contrast agents, which indicate vascularization in pancreatic lesions, has been found to be useful in the differential diagnosis of pancreatic tumors, especially small pancreatic tumors. However, Doppler ultrasonography with contrast-enhancement has several limitations, including blooming artifacts, poor spatial resolution, and low sensitivity to slow flow. Consequently, an echoendoscope was developed recently that has a broad-band transducer and an imaging mode that was designed specifically for contrastenhanced harmonic EUS (CEH-EUS) with a secondgeneration ultrasound contrast agent. The CEH-EUS technique is expected to improve the differential diagnosis of pancreatic disease in the future. This review describes the EUS appearances of common solid and cystic pancreatic masses, the diagnostic accuracy of EUS-FNA, and the relative efficacies and advantages of CE-EUS and CEH-EUS along with their relative advantages and their complementary roles in clinical practice.

Small invasive ductal carcinoma of the pancreas distinct from branch duct intraductal papillary mucinous neoplasm

Endoscopic ultrasonography(EUS)is a highly sensitive diagnostic method for the detection of small pancreatic carcinomas.Recently,there have been some reports describing the utility of contrast-enhanced harmonic EUS(CEH-EUS)which uses sonographic contrast agent for differentiation of a pancreatic mass.This report describes a case of small adenocarcinoma of the pancreas distinct from branch duct intraductal papillary mucinous neoplasm(IPMN)in which investigation by EUS took place every 6 mo and diagnosis was made accurately by additional CEH-EUS during the follow- up of the branch duct IPMN.A 68-year-old female was admitted to our hospital because of a branch duct IPMN in the pancreatic body.She had been followedup by EUS every 6 mo.However,after 2 years EUSdemonstrated a low echoic area distinct from the branch duct IPMN which was vaguely discernible by EUS,and accurate sizing and differential diagnosis were considered difficult on the EUS imaging.CHEUS with Sonazoid revealed a hypovascular tumor and we suspected small pancreatic carcinoma.The histopathological diagnosis was adenocarcinoma (10 mm)in the pancreatic tail,distinct from the branch duct IPMN of the pancreatic body.EUS and CEH-EUS may play an important role in the correct diagnosis of small pancreatic tumors,including synchronous and metachronous occurrence of IPMN and ductal adenocarcinoma of the pancreas.

Effectiveness of Compatibilizer on Mechanical Properties of Recycled PET Blends with PE, PP, and PS

Recycled PET (R-PET) is well known to exhibit brittle behavior in the presence of notches and indicated the low heat distortion temperature. In addition, it is hard to prevent some impurities such as cap or label of the bottle that mixed into R-PET during the recycling process. In this paper, the effect of the amounts and kinds of compatibilizers on the morphological characteristics and mechanical performance of recycled poly(ethylene terephthalate) (R-PET) compounded with polyethylene (PE), polypropylene (PP), and polystyrene (PS) was investigated. From the results, with an increase in the glycidyl methacrylate modified PE (EGMA) additive contents, in the increment of the Izod impact strength of Composite-G was obtained. In addition, it was found that the miscibility of Composite-G was improved with increasing the amount of EGMA, which indicated from the result of SEM images.

Phenomenological aspects of possible vacua of a neutrino flavor model

We discuss a supersymmetric model with discrete flavor symmetry A4×Z3. The additional scalar fields which contribute masses of leptons in the Yukawa terms are introduced in this model. We analyze their scalar potential and find that they have various vacuum structures. We show the relations among 24 different vacua and classify them into two types. We derive expressions of the lepton mixing angles, Dirac CP violating phase and Majorana phases for the two types. The model parameters which are allowed by the experimental data of the lepton mixing angles are different for each type. We also study the constraints on the model parameters which are related to Majorana phases. The different allowed regions of the model parameters for the two types are shown numerically for a given region of two combinations of the CP violating phases.