Endoscopic ultrasonography-related diagnostic accuracy and clinical significance on small rectal neuroendocrine neoplasms

This research aimed to examine the diagnostic accuracy and clinical significance of endoscopic ultrasonography(EUS)in the context of small rectal neuroendocrine neoplasms(NENs).A total of 108 patients with rectal subepithelial lesions(SELs)with a diameter of<20 mm were included in the analysis.The diagnosis and depth assessment of EUS was compared to the histology findings.The prevalence of NENs in rectal SELs was 78.7%(85/108).The sensitivity of EUS in detecting rectal NENs was 98.9%(84/85),while the specificity was 52.2%(12/23).Overall,the diagnostic accuracy of EUS in identifying rectal NENs was 88.9%(96/108).The overall accuracy rate for EUS in assessing the depth of invasion in rectal NENs was 92.9%(78/84).Therefore,EUS demonstrates reasonable diagnostic accuracy in detecting small rectal NENs,with good sensitivity but inferior specificity.EUS may also assist physicians in assessing the depth of invasion in small rectal NENs before endoscopic excision.

Comprehensive review on the diagnostic strategies for esophageal tuberculosis:the role of endoscopic ultrasonography

Esophageal tuberculosis(ET)is a relatively rare clinical condition,characterized by often atypical clinical features.The lack of specificity in diagnostic methods,such as esophagogastroduodenoscopy and various imaging techniques,frequently leads to misdiagnosis and inappropriate treatments.Compared to esophagogastroduodenoscopy,endoscopic ultrasonography(EUS)offers a more comprehensive examination of esophageal tuberculosis lesions,including the extent of wall layer involvement and the internal structure characteristics of the lesions.Furthermore,when necessary,endoscopic ultrasonography-guided fine-needle aspiration can be employed to acquire deeper pathological tissue,significantly aiding diagnosis.When combined with the patient’s clinical presentation,endoscopic findings,and pathological features,EUS plays a crucial role in the definitive diagnosis of ET and in the differential diagnosis process.This article meticulously reviews both national and international literature to summarize the relevant features of ET,with a focus on its appearance under EUS,and to highlight the clinical value of EUS in enhancing the diagnosis of ET and in distinguishing it from other conditions.The aim is to offer guidance for the accurate diagnosis of ET.

Application of a novel kind of endoscopic sterile ultrasonic couplant using in miniprobe endoscopic ultrasonography

Objective:To investigate the efficacy of a novel endoscopic sterile ultrasonic couplant using miniprobe endoscopic ultrasonography(EUS).Methods:Twelve pigs were randomly assigned to experimental or control groups based on different couplants,with six pigs in each group.The experimental group underwent miniprobe endoscopic ultrasound examination using a sterile ultrasound couplant,whereas the control group underwent examination using purified water.Seven positions were examined:proximal esophagus,distal esophagus,gastric fundus,gastric angle,duodenal bulb,proximal colon,and distal colon.The examination time and imaging qualities of the two groups were compared.Results:The ultrasonic couplant group was superior to the purified water group in terms of examination time,injection volume,image clarity,adjustment frequency,one-time success rate,and number of effective images.The difference between the two groups was statistically significant(p<0.05).Conclusion:Using a sterile endoscopic ultrasound couplant during miniprobe EUS can shorten the examination time,reduce the medium injection volume,improve the one-time success rate and image clarity,and is worthy of clinical promotion and application.

Differential diagnosis of benign and malignant branch duct intraductal papillary mucinous neoplasm using contrastenhanced endoscopic ultrasonography

AIM: To elucidate the role of contrast-enhanced endoscopic ultrasonography(CE-EUS) in the diagnosis of branch duct intraductal papillary mucinous neoplasm(BD-IPMN).METHODS: A total of 50 patients diagnosed with BDIPMN by computed tomography(CT) and endoscopic ultrasonography(EUS) at our institute were included in this study. CE-EUS was performed when mural lesions were detected by EUS. The diagnostic accuracy for identifying mural nodules(MNs) was evaluated by CT, EUS, and EUS combined with CE-EUS. In the patients who underwent resection, the accuracy of measuring MN height with each imaging modality was compared. The cut-off values to diagnose malignant BD-IPMNs based on MN height for each imaging modality were determined using receiver operating characteristic curve analysis.RESULTS: Fifteen patients were diagnosed with BD-IPMN with MNs and underwent resection. The remaining 35 patients were diagnosed with BD-IPMN without MNs and underwent follow-up monitoring. The pathological findings revealed 14 cases with MNs and one case without. The accuracy for diagnosing MNs was 92% using CT and 72% using EUS; the diagnostic accuracy increased to 98% when EUS and CE-EUS were combined. The accuracy for measuring MN height significantly improved when using CE-EUS compared with using CT or EUS(median measurement error value, CT: 3.3 mm vs CE-EUS: 0.6 mm, P < 0.05; EUS: 2.1 mm vs CE-EUS: 0.6 mm, P < 0.01). A cut-off value of 8.8 mm for MN height as measured by CE-EUS improved the accuracy of diagnosing malignant BDIPMN to 93%. CONCLUSION: Using CE-EUS to measure MN height provides a highly accurate method for differentiating benign from malignant BD-IPMN.

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

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.

Endoscopic ultrasonography:Transition towards the futureof gastro-intestinal diseases

Endoscopic ultrasonography(EUS) is a technique with an established role in the diagnosis and staging of gastro-intestinal tumors. In recent years, the spread of new devices dedicated to tissue sampling has improved the diagnostic accuracy of EUS fine-needle aspiration. The development of EUS-guided drainage of the biliopancreatic region and abdominal fluid collections has allowed EUS to evolve into an interventional tool that can replace more invasive procedures. Emerging techniques applying EUS in pancreatic cancer treatment and in celiac neurolysis have been described. Recently, confocal laser endomicroscopy has been applied to EUS as a promising technique for the in vivo histological diagnosis of gastro-intestinal, bilio-pancreatic and lymph node lesions. In this state-of-the-art review, we report the most recent data from the literature regarding EUS devices, interventional EUS, EUS-guided confocal laser endomicroscopy and EUS pancreatic cancer treatment, and we also provide an overview of their principles, clinical applications and limitations.

Diagnostic endoscopic ultrasonography:Assessment of safety and prevention of complications

Endoscopic ultrasonography (EUS) has gained wide acceptance as an important, minimally invasive diagnostic tool in gastroenterology, pulmonology, visceral surgery and oncology. This review focuses on data regarding risks and complications of non-interventional diagnostic EUS and EUS-guided fine-needle biopsy (EUS-FNB). Measures to improve the safety of EUS und EUS-FNB will be discussed. Due to the specific mechanical properties of echoendoscopes in EUS, there is a low but noteworthy risk of perforation. To minimize this risk, endoscopists should be familiar with the specific features of their equipment and their patients' specific anatomical situations (e.g., tumor stenosis, diverticula). Most diagnostic EUS complications occur during EUS-FNB. Pain, acute pancreatitis, infection and bleeding are the primary adverse effects, occurring in 1% to 2% ofpatients. Only a few cases of needle tract seeding and peritoneal dissemination have been reported. The mortality associated with EUS and EUS-FNB is 0.02%. The risks associated with EUS-FNB are affected by endoscopist experience and target lesion. EUS-FNB of cystic lesions is associated with an increased risk of infection and hemorrhage. Peri-interventional antibiotics are recommended to prevent cyst infection. Adequate education and training, as well consideration of contraindications, are essential to minimize the risks of EUS and EUS-FNB. Restricting EUS-FNB only to patients in whom the cytopathological results may be expected to change the course of management is the best way of reducing the number of complications.

Usefulness of endoscopic ultrasonography in preoperative TNM staging of gastric cancer

AIM： To evaluate the value of endoscopic ultrasono- graphy （EUS） in the preoperative TNM staging of gastric cancer. METHODS ： Forty-one patients with gastric cancer （12 early stage and 29 advanced stage） proved by esophagogastroduodenoscopy and biopsies preoperatively evaluated with EUS according to TNM （1997） classification of International Union Contrele Cancer （UICC）. Pentax EG-3630U/Hitachi EUB-525 echo endoscope with real-time ultrasound imaging linear scanning transducers （7.5 and 5.0 MHz） and Doppler information was used in the current study. EUS staging procedures for tumor depth of invasion （T stage） were performed according to the widely accepted five-layer structure of the gastric wall. All patients underwent surgery. Diagnostic accuracy of EUS for TNM staging of gastric cancer was determined by comparing preoperative EUS with subsequent postoperative histopathologic findings. RESULTS： The overall diagnostic accuracy of EUS in preoperative determination of cancer depth of invasion was 68.3% （41/28） and 83.3% （12/10）, 60% （20/12）, 100% （5/5）, 25% （4/1） for T1, T2, T3, and T4, respectively. The rates for overstaging and understaging were 24.4% （41110）, and 7.3% （4113）, respectively. EUS tended to overstage T criteria, and main reasons for overstaging were thickening of the gastric wall due to perifocal inflammatory change, and absence of serosal layer in certain areas of the stomach. The diagnostic accuracy of metastatic lymph node involvement or N staging of EUS was 100% （17/17） for NO and 41.7% （24/10） for N＋, respectively, and 66% （41127） overall.Misdiagnosing of the metastatic lymph nodes was related to the difficulty of distinguishing inflammatory lymph nodes from malignant lymph nodes, which imitate similar echo features. Predominant location and distribution of tumors in the stomach were in the antrum （20 patients）, and the lesser curvature （17 patients）, respectively. Three cases were found as surgically unresectable （T4 N＋）, and included as being correctly diagnosed by EUS. CONCLUSION： EUS is a useful diagnostic method for preoperative staging of gastric cancer for T and N criteria. However, EUS evaluation of malignant lymph nodes is still unsatisfactory.

What types of early gastric cancer are indicated for endoscopic ultrasonography staging of invasion depth?

AIM To clarify the diagnostic efficacy and limitations of endoscopic ultrasonography(EUS) and the characteristics of early gastric cancers(EGCs) that are indications for EUS-based assessment of cancer invasion depth.METHODS We retrospectively investigated the cases of 153 EGC patients who underwent conventional endoscopy(CE) and EUS(20 MHz) before treatment.RESULTS We found that 13.7% were "inconclusive" cases with low-quality EUS images, including all nine of the cases with protruded(0-I)-type EGCs. There was no significant difference in the diagnostic accuracybetween CE and EUS. Two significant independent risk factors for misdiagnosis by EUS were identified-ulcer scarring [UL(+); odds ratio(OR) = 4.49, P = 0.003] and non-indication criteria for endoscopic resection(ER)(OR = 3.02, P = 0.03). In the subgroup analysis, 23.1% of the differentiated-type cancers exhibiting SM massive invasion(SM2) invasion(submucosal invasion ≥ 500 μm) by CE were correctly diagnosed by EUS, and 23.1% of the undifferentiated-type EGCs meeting the expanded-indication criteria for ER were correctly diagnosed by EUS.CONCLUSION There is no need to perform EUS for UL(+) EGCs or 0-I-type EGCs, but EUS may enhance the pretreatment staging of differentiated-type EGCs with SM2 invasion without UL or undifferentiated-type EGCs revealed by CE as meeting the expanded-indication criteria for ER.

Is endoscopic ultrasonography essential for endoscopic resection of small rectal neuroendocrine tumors?

AIM To evaluate the importance of endoscopic ultrasonography(EUS) for small(≤ 10 mm) rectal neuroendocrine tumor(NET) treatment.METHODS Patients in whom rectal NETs were diagnosed by endoscopic resection(ER) at the Pusan National University Yangsan Hospital between 2008 and 2014 were included in this study. A total of 120 small rectal NETs in 118 patients were included in this study. Histologic features and clinical outcomes were analyzed, and the findings of endoscopy, EUS and histology were compared. RESULTS The size measured by endoscopy was not significantly different from that measured by EUS and histology(r = 0.914 and r = 0.727 respectively). Accuracy for the depth of invasion was 92.5% with EUS. No patients showed invasion of the muscularis propria or metastasis to the regional lymph nodes. All rectal NETswere classified as grade 1 and demonstrated an L-cell phenotype. Mean follow-up duration was 407.54 ± 374.16 d. No patients had local or distant metastasis during the follow-up periods. CONCLUSION EUS is not essential for ER in the patient with small rectal NETs because of the prominent morphology and benign behavior.

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 EUS-fine 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 EUS-FNA 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 cut-off &#x02265; 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 &#x02265; 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.

endoscopic ultrasonography-guided biliary drainage:Who,when,which,and how?

Both endoscopic ultrasonography(EUS)-guided choledochoduodenostomy( EUS- CDS) and EUS-guided hepaticogastrostomy(EUS-HGS) are relatively well established as alternatives to percutaneous transhepatic biliary drainage(PTBD). Both EUSCDS and EUS-HGS have high technical and clinical success rates(more than 90%) in high-volume centers. Complications for both procedures remain high at 10%-30%. Procedures performed by endoscopists who have done fewer than 20 cases sometimes result in severe or fatal complications. When learning EUSguided biliary drainage(EUS-BD), we recommend a mentor's supervision during at least the first 20 cases. For inoperable malignant lower biliary obstruction, a skillful endoscopist should perform EUS-BD before EUS-guided rendezvous technique(EUS-RV) and PTBD. We should be select EUS-BD for patients having altered anatomy from malignant tumors before balloon-enteroscope-assisted endoscopic retrograde cholangiopancreatography, EUS-RV, and PTBD. If both EUS-CDS and EUS-HGS are available, we should select EUS-CDS, according to published data. EUSBD will potentially become a first-line biliary drainage procedure in the near future.

Values of endoscopic ultrasonography for diagnosis and treatment of duodenal protruding lesions

Objective： The diagnoses of patients with duodenal protruding lesions are difficult when using conventional examinations such as computed tomography （CT） and conventional endoscope etc. Thus, we investigated the clinical value of endoscopic ultrasonography （PUS） with miniature ultrasonic probes on the diagnosis and treatment of duodenal protruding lesions. Methods： Patients with duodenal protruding lesions who were indicated for PUS were examined by PUS with 12-15 MHz miniature ultrasonic probes and double-cavity electronic endoscope. According to diagnosis of PUS, those patients were indicated for biopsy and treatment received biopsy, endoscopic resection or surgical excision. The postoperative histological results were compared with the preoperative diagnosis of PUS. Those patients without endoscopic resection or surgical excision were periodically followed up with PUS. Results： A total of 169 patients with duodenal protruding lesions were examined by PUS, of which 40 were diagnosed with cysts, 36 with inflammatory protruding or polyp, 25 with Brunner＇s gland adenoma, 19 with ectopic pancreas, 17 with gastrointestinal stromal tumor, 12 with extrinsic compression, 12 with minor papilla, 6 with lipoma, 1 with adenocarcinoma and 1 with lymphoma. After PUS examinations, 75 patients received biopsy, endoscopic resection or surgical excision respectively. The postoperative histological results of 70 patients were completely consistent with the preoperative diagnosis of PUS, with 93.33% diagnostic accuracy. The results of follow-up with PUS indicated that duodenal cyst, Brunner＇s gland adenoma, ectopic pancreas, gastrointestinal stromal tumor and lipoma remained unchanged within 1-3 years. No related complications occurred among all patients that received PUS examinations. Conclusion： PUS is an effective and reliable diagnostic method for duodenal protruding lesions.

Endoscopic ultrasonography-guided drainage for patients with symptomatic obstruction and enlargement of the pancreatic duct

AIM: To evaluate the use of translumenal pancreatography with placement of endoscopic ultrasonography(EUS)-guided drainage of the pancreatic duct.METHODS: This study enrolled all consecutive patients between June 2002 and April 2014 who underwent EUSguided pancreatography and subsequent placement of a drain and had symptomatic retention of fluid in the pancreatic duct after one or more previous unsuccessful attempts at endoscopic retrograde cannulation of the pancreatic duct. In all,94 patients underwent 111 interventions with one of three different approaches:(1) EUS-endoscopic retrograde drainage with a rendezvous technique;(2) EUS-guided drainage of the pancreatic duct; and(3) EUS-guided,internal,antegrade drainage of the pancreatic duct.RESULTS: The mean duration of the interventions was 21 min(range,15-69 min). Mean patient age was 54 years(range,28-87 years); the M:F sex ratio was 60:34. The technical success rate was 100%,achieving puncture of the pancreatic duct including pancreatography in 94/94 patients. In patients requiring drainage,initial placement of a drain wassuccessful in 47/83 patients(56.6%). Of these,26 patients underwent transgastric/transbulbar positioning of a stent for retrograde drainage; plastic prostheses were used in 11 and metal stents in 12. A ring drain(antegrade internal drainage) was placed in three of these 26 patients because of anastomotic stenosis after a previous surgical intervention. The remaining 21 patients with successful drain placement had transpapillary drains using the rendezvous technique; the majority(n = 19) received plastic prostheses,and only two received metal stents(covered self-expanding metal stents). The median follow-up time in the 21 patients with transpapillary drainage was 28 mo(range,1-79 mo),while that of the 26 patients with successful transgastric/transduodenal drainage was 9.5 mo(range,1-82 mo). Clinical success,as indicated by reduced or absence of further pain after the EUS-guided intervention was achieved in 68/83 patients(81.9%),including several who improved without drainage,but with manipulation of the access route.CONCLUSION: EUS-guided drainage of the pancreatic duct is a safe,feasible alternative to endoscopic retrograde drainage when the papilla cannot be reached endoscopically or catheterized.

EUS for choosing best endoscopic treatment of mesenchymal tumors of upper gastrointestinal tract

AIM: To evaluate the value of endoscopic ultrasonography (EUS) in the choice of endoscopic therapy strategies for mesenchymal tumors of the upper gastrointestinal tract. METHODS: From July 2004 to September 2010, 1050 patients with upper gastrointestinal mesenchymal tumors (GIMTs) were diagnosed using EUS. Among them, 201 patients underwent different endoscopic therapies based on the deriving layers, growth patterns and lesion sizes. RESULTS: Using EUS, we found 543 leiomyomas and 507 stromal tumors. One hundred and thirty-three leiomyomas and 24 stromal tumors were treated by snare electrosection, 6 leiomyomas and 20 stromal tumorswere treated by endoloop, 10 stromal tumors were treated by endoscopic mucosal resection and 8 stromal tumors were treated by endoscopic submucosal dissection. Complete resection of the lesion was achieved in all cases. Of the mesenchymal tumors, 90.38% diagnosed by EUS were also identified by pathohistology. All wounds were closed up nicely and no recurrence was found in the follow-up after 2 mo. CONCLUSION: EUS is an effective means of diagnosis for upper GIMTs and is an important tool in choosing the endoscopic therapy for GIMTs, by which the lesions can be treated safely and effectively.

A new endoscopic ultrasonography image processing method to evaluate the prognosis for pancreatic cancer treated with interstitial brachytherapy

AIM:To develop a fuzzy classification method to score the texture features of pancreatic cancer in endoscopic ultrasonography(EUS)images and evaluate its utility in making prognosis judgments for patients with unresectable pancreatic cancer treated by EUS-guided interstitial brachytherapy.METHODS:EUS images from our retrospective database were analyzed.The regions of interest were drawn,and texture features were extracted,selected,and scored with a fuzzy classification method using a C++program.Then,patients with unresectable pancreatic cancer were enrolled to receive EUS-guided iodine 125 radioactive seed implantation.Their fuzzy classification scores,tumor volumes,and carbohydrate antigen 199(CA199)levels before and after the brachytherapy were recorded.The association between the changes in these parameters and overall survival was analyzed statistically.RESULTS:EUS images of 153 patients with pancreatic cancer and 63 non-cancer patients were analyzed.A total of 25 consecutive patients were enrolled,and they tolerated the brachytherapy well without any complications.There was a correlation between the change in the fuzzy classification score and overall survival(Spearman test,r=0.616,P=0.001),whereas no correlation was found to be significant between the change in tumor volume(P=0.663),CA199 level(P=0.659),and overall survival.There were 15 patients with a decrease in their fuzzy classification score after brachytherapy,whereas the fuzzy classification score increased in another 10 patients.There was a significant difference in overall survival between the two groups(67 d vs 151 d,P=0.001),but not in the change of tumor volume and CA199 level.CONCLUSION:Using the fuzzy classification method to analyze EUS images of pancreatic cancer is feasible,and the method can be used to make prognosis judgments for patients with unresectable pancreatic cancer treated by interstitial brachytherapy.

Biliary and pancreatic stenting:Devices and insertiontechniques in therapeutic endoscopic retrogradecholangiopancreatography and endoscopic ultrasonography

Stents are tubular devices made of plastic or metal. Endoscopic stenting is the most common treatment for obstruction of the common bile duct or of the main pancreatic duct, but also employed for the treatment of bilio-pancreatic leakages, for preventing post- endoscopic retrograde cholangiopancreatography pancreatitis and to drain the gallbladder and pancreatic fluid collections. Recent progresses in techniques of stent insertion and metal stent design are represented by new, fullycovered lumen apposing metal stents. These stents are specifically designed for transmural drainage, with a saddle-shape design and bilateral flanges, to provide lumen-to-lumen anchoring, reducing the risk of migration and leakage. This review is an update of the technique of stent insertion and metal stent deployment, of the most recent data available on stent types and characteristics and the new applications for biliopancreatic stents.

Diagnostic accuracy of endoscopic ultrasonography for rectal neuroendocrine neoplasms

AIM: To investigate the diagnostic accuracy of endoscopic ultrasonography (EUS) for rectal neuroendocrine neoplasms (NENs) and the differential diagnosis of rectal NENs from other subepithelial lesions (SELs).

Current status and future applications of contrast-enhanced endoscopic ultrasonography

Endoscopic ultrasonography(EUS) is currently an in-tegral investigation of many gastrointestinal disorders.It has been shown to have a higher efficacy thanconventional computed tomography in detection andcharacterization of small lesions especially in the pan-creas. Much effort has been put to further improvethe sensitivity, specificity and overall accuracy of EUS.One of the major advances is the utilization of contrastagents for better delineation of the vascularity and tis-sue perfusion of the target lesion. This article describesthe basic principles of ultrasound contrast agents andthe different modalities used in contrast-enhanced EUS(CE-EUS) including contrast-enhanced Doppler EUS(CED-EUS) and contrast-enhanced harmonic EUS(CEH-EUS). In addition, the current applications of contrastenhanced EUS in different gastrointestinal conditionswere discussed. Furthermore, the future developmentof hybrid approaches combining CE-EUS with other im-aging modalities and the potential therapeutic aspectof using it as a vector for drug delivery were also dis-cussed.