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.

Contrast-enhanced endoscopic ultrasonography

Contrast agents are increasingly being used to characterize the vasculature in an organ of interest,to better delineate benign from malignant pathology and to aid in staging and directing therapeutic procedures.We review the mechanisms of action of first,second and third generation contrast agents and their use in various endoscopic procedures in the gastrointestinal tract.Various applications of contrast-enhanced endoscopic ultrasonography include differentiating benign from malignant mediastinal lymphadenopathy,assessment of depth of invasion of esophageal,gastric and gall bladder cancers and visualization of the portal venous system and esophageal varices.In addition,contrast agents can be used to differentiate pancreatic lesions.The use of color Doppler further increases the ability to diagnose and differentiate various pancreatic malignancies.The sensitivity of power Doppler sonography to depict tumor neovascularization can be increased by contrast agents.Contrast-enhanced harmonic imaging is a useful aid in identifying the tumor vasculature and studying pancreatic microperfusion.In the future,these techniques could potentially be used to quantify tumor perfusion,to assess and monitor the efficacy of antiangiogenic agents,to assist targeted drug delivery and allow molecular imaging.

Contrast-enhanced guided endoscopic ultrasound procedures

Contrast-enhanced endoscopic ultrasound(CH-EUS)can overcome the limi-tations of endoscopic ultrasound-guided acquisition by identifying microvessels inside inhomogeneous tumours and improving the characterization of these tumours.Despite the initial enthusiasm that oriented needle sampling under CH-EUS guidance could provide better diagnostic yield in pancreatic solid lesions,further studies did not confirm the supplementary values in cases of tissue acquisition guided by CH-EUS.This review details the knowledge based on the available data on contrast-guided procedures.The indications for CH-EUS tissue acquisition include isoechoic EUS lesions with poor visible delineation where CH-EUS can differentiate the lesion vascularisation from the surrounding parenchyma and also the mural nodules within biliopancreatic cystic lesions,which occur in select cases.Additionally,the roles of CH-EUS-guided therapy in patients whose pancreatic fluid collections or bile ducts that have an echogenic content have indications for drainage,and patients who have nonvisualized vessels that need to be highlighted via Doppler EUS are presented.Another indication is represented if there is a need for an immediate assessment of the post-radiofrequency ablation of pancreatic neuroendocrine tumours,in which case CH-EUS can be used to reveal the incomplete tumour destruction.

Double contrast-enhanced ultrasonography improves diagnostic accuracy of T staging compared with multi-detector computed tomography in gastric cancer patients

BACKGROUND Gastric cancer(GC)is the most common malignant tumor and ranks third for cancer-related deaths among the worldwide.The disease poses a serious public health problem in China,ranking fifth for incidence and third for mortality.Knowledge of the invasive depth of the tumor is vital to treatment decisions.AIM To evaluate the diagnostic performance of double contrast-enhanced ultrasonography(DCEUS)for preoperative T staging in patients with GC by comparing with multi-detector computed tomography(MDCT).METHODS This single prospective study enrolled patients with GC confirmed by preoperative gastroscopy from July 2021 to March 2023.Patients underwent DCEUS,including ultrasonography(US)and intravenous contrast-enhanced ultrasonography(CEUS),and MDCT examinations for the assessment of preoperative T staging.Features of GC were identified on DCEUS and criteria developed to evaluate T staging according to the 8th edition of AJCC cancer staging manual.The diagnostic performance of DCEUS was evaluated by comparing it with that of MDCT and surgical-pathological findings were considered as the gold standard.RESULTS A total of 229 patients with GC(80 T1,33 T2,59 T3 and 57 T4)were included.Overall accuracies were 86.9%for DCEUS and 61.1%for MDCT(P<0.001).DCEUS was superior to MDCT for T1(92.5%vs 70.0%,P<0.001),T2(72.7%vs 51.5%,P=0.041),T3(86.4%vs 45.8%,P<0.001)and T4(87.7%vs 70.2%,P=0.022)staging of GC.CONCLUSION DCEUS improved the diagnostic accuracy of preoperative T staging in patients with GC compared with MDCT,and constitutes a promising imaging modality for preoperative evaluation of GC to aid individualized treatment decision-making.

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.

Correlation of dynamic contrast-enhanced ultrasonography and the Ki-67 labelling index in pancreatic ductal adenocarcinoma

BACKGROUND Pancreatic ductal adenocarcinoma(PDAC)is a highly malignant and aggressive tumor,and high Ki-67 expression indicates poor histological differentiation and prognosis.Therefore,one of the challenges in diagnosing preoperatively patients with PDAC is predicting the degree of malignancy.Dynamic contrast-enhanced ultrasonography(DCE-US)plays a crucial role in abdominal tumor diagnosis,and can adequately show the microvascular composition within the tumors.However,the relationship between DCE-US and the Ki-67 labelling index remains unclear at the present time.AIM To predict the correlation between Ki-67 expression and the parameters of DCEUS.METHODS Patients with PDAC who underwent DCE-US were retrospectively analyzed.Patients who had received any treatment(radiotherapy or chemotherapy)prior to DCE-US;had incomplete clinical,imaging,or pathologic information;and had poor-quality image analysis were excluded.Correlations between Ki-67 expression and the parameters of DCE-US in patients with PDAC were assessed using Spearman’s rank correlation analysis.The diagnostic performances of these parameters in high Ki-67 expression group were evaluated according to receiver operating characteristic curve.RESULTS Based on the Ki-67 labelling index,30 patients were divided into two groups,i.e.,the high expression group and the low expression group.Among the relative quantitative parameters between the two groups,relative half-decrease time(rHDT),relative peak enhancement,relative wash-in perfusion index and relative wash-in rate were significantly different between two groups(P=0.018,P=0.025,P=0.028,P=0.035,respectively).The DCE-US parameter rHDT was moderately correlated with Ki-67 expression,and rHDT≥1.07 was more helpful in accurately diagnosing high Ki-67 expression,exhibiting a sensitivity and specificity of 53.8%and 94.1%,respectively.CONCLUSION One parameter of DCE-US,rHDT,correlates with high Ki-67 expression.It demonstrates that parameters obtained noninvasively by DCE-US could better predict Ki-67 expression in PDAC preoperatively.

Clinical value of oral contrast-enhanced ultrasonography in diagnosis of gastric tumors

BACKGROUND The incidence of gastric cancer remains high,and it is the sixth most common cancer and the fourth leading cause of cancer deaths worldwide.Oral contrastenhanced ultrasonography is a simple,non-invasive,and painless method for the diagnosis of gastric tumors.AIM To explore the diagnostic value of oral contrast-enhanced ultrasonography for the detection of gastric tumors.METHODS The screening results based on oral contrast-enhanced ultrasonography and electronic gastroscopy were compared with those of the postoperative pathological examination.RESULTS Among 42 patients with gastric tumors enrolled in the study,the diagnostic accordance rate was 95.2%for oral contrast-enhanced ultrasonography(n=40)and 90.5%for electronic gastroscopy(n=38)compared with postoperative pathological examination.The Kappa value of consistency test with pathological findings was 0.812 for oral contrast-enhanced ultrasonography and 0.718 for electronic gastroscopy,and there was no significant difference between them(P=0.397).For the TNM staging of gastric tumors,the accuracy rate of oral contrast enhanced ultrasonography was 81.9%for the overall T staging and 50%,77.8%,100%,and 100%for T1,T2,T3,and T4 staging,respectively.The sensitivity and specificity were both 100%for stages T3 and T4.The diagnostic accuracy rate of oral contrast-enhanced ultrasonography was 93.8%,80%,100%,and 100%for stages N0,N1-N3,M0,and M1,respectively.CONCLUSION The accordance rate of qualitative diagnosis by oral contrast-enhanced ultrasonography is comparable to that of gastroscopy,and it could be used as the preferred method for the early screening of gastric tumors.

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.

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.

Early endoscopic management of an infected acute necrotic collection misdiagnosed as a pancreatic pseudocyst: A case report

BACKGROUND Infected acute necrotic collection(ANC)is a fatal complication of acute pancre-atitis with substantial morbidity and mortality.Drainage plays an exceedingly important role as the first step in invasive intervention for infected necrosis;however,there is great controversy about the optimal drainage time,and better treatment should be explored.CASE SUMMARY We report the case of a 43-year-old man who was admitted to the hospital with severe intake reduction due to early satiety 2 wk after treatment for acute pancre-atitis;conservative treatment was ineffective,and a pancreatic pseudocyst was suspected on contrast-enhanced computed tomography(CT).Endoscopic ultra-sonography(EUS)suggested hyperechoic necrotic tissue within the cyst cavity.The wall was not completely mature,and the culture of the puncture fluid was positive for A-haemolytic Streptococcus.Thus,the final diagnosis of ANC in-fection was made.The necrotic collection was not walled off and contained many solid components;therefore,the patient underwent EUS-guided aspiration and lavage.Two weeks after the collection was completely encapsulated,pancreatic duct stent drainage via endoscopic retrograde cholangiopancreatography(ERCP)was performed,and the patient was subsequently successfully discharged.On repeat CT,the pancreatic cysts had almost disappeared during the 6-month fo-llow-up period after surgery.CONCLUSION Early EUS-guided aspiration and lavage combined with late ERCP catheter drainage may be effective methods for intervention in infected ANCs.

Are biopsies during endoscopic ultrasonography necessary for a suspected esophageal leiomyoma?Is laparoscopy always feasible?

The present letter to the editor is related to the work entitled“Large leiomyoma of lower esophagus diagnosed by endoscopic ultrasonography-fine needle aspiration:A case report.”Although endoscopic ultrasonography seems necessary in a suspected leiomyoma of the esophagus,the performance of biopsies via fine needle aspiration is controversial as it increases the risk of complications such as bleeding,infection,and intraoperative perforations.Laparoscopy is the best treatment strategy for small tumors.Laparotomy with tumor enucleation or esophageal resection can be considered in large leiomyomas.

TACC diagnosed by transoesophageal endoscopic ultrasonography:A case report

BACKGROUND Primary adenoid cystic carcinoma in the trachea(TACC)is a rare tumour.Tracheal bronchoscopy is always chosen as a routine approach to obtain a pathological diagnosis,but it can be associated with an increased risk of asphyxia.CASE SUMMARY We describe a case of TACC in a patient evaluated by chest computed tomography(CT)with three-dimensional reconstruction imaging and diagnosed by transoesophageal endoscopic ultrasonography.The pathological diagnosis confirmed tracheal adenoid cystic carcinoma.CONCLUSION We highlight the importance of CT and provide a successful exploration of transoesophageal biopsy as a safe alternative approach.

New treatment for gastric duplication cyst:Endoscopic ultrasonography-guided fine-needle aspiration combined with lauromacrogol sclerotherapy:A case report

BACKGROUND Gastric duplication cysts are very rare disease that are mainly diagnosed by endoscopic ultrasonographic fine-needle aspiration biopsy.In the past,this disease was usually treated with traditional surgery and rarely with minimally invasive endoscopic surgery.However,minimally invasive endoscopic therapy has many advantages,such as no skin wound,organ preservation,postoperative pain reduction,early food intake,fewer postoperative complications,and shorter post-procedure hospitalization.CASE SUMMARY We report a case of endoscopic ultrasonography-guided fine-needle aspiration(EUS-FNA)combined with lauromacrogol sclerotherapy for pyloric obstruction due to gastric duplication cysts.CONCLUSION EUS-FNA combined with lauromacrogol sclerotherapy provides a new option for the treatment of gastrointestinal duplication cysts.

Contrast-enhanced harmonic endoscopic ultrasound imaging: Basic principles, present situation and future perspectives

Over the last decade, the development of stabilised microbubble contrast agents and improvements in available ultrasonic equipment, such as harmonic imaging, have enabled us to display microbubble enhancements on a greyscale with optimal contrast and spatial resolution. Recent technological advances made contrast harmonic technology available for endoscopic ultrasound(EUS) for the first time in 2008. Thus, the evaluation of microcirculation is now feasible with EUS, prompting the evolution of contrast-enhanced EUS from vascular imaging to images of the perfused tissue. Although the relevant experience is still preliminary, several reports have highlighted contrast-enhanced harmonic EUS(CHEUS) as a promising noninvasive method to visualise and characterise lesions and to differentiate benign from malignant focal lesions. Even if histology remains the gold standard, the combination of CH-EUS and EUS fine needle aspiration(EUS-FNA) can not only render EUS more accurate but may also assist physicians inmaking decisions when EUS-FNA is inconclusive,increasing the yield of EUS-FNA by guiding the puncture with simultaneous imaging of the vascularity.The development of CH-EUS has also opened up exciting possibilities in other research areas,including monitoring responses to anticancer chemotherapy or to ethanolinduced pancreatic tissue ablation,anticancer therapies based on ultrasound-triggered drug and gene delivery,and therapeutic adjuvants by contrast ultrasound-induced apoptosis.Contrast harmonic imaging is gaining popularity because of its efficacy,simplicity and noninvasive nature,and many expectations are currently resting on this technique.If its potential is confirmed in the near future,contrast harmonic imaging will become a standard practice in EUS.

Laparoscopic resection and endoscopic submucosal dissection for treating gastric ectopic pancreas

BACKGROUND Gastric ectopic pancreas(GEP)is a rare developmental abnormality that refers to the existence of pancreatic tissue in the stomach with no anatomical relationship with the main pancreas.It is usually difficult to diagnose through histological examination,and the choice of treatment method is crucial.AIM To describe the endoscopic ultrasound characteristics of GEP and evaluate the value of laparoscopic resection(LR)and endoscopic submucosal dissection(ESD).METHODS Forty-nine patients with GEP who underwent ESD and LR in the Second Affiliated Hospital of Fujian Medical University from May 2018 to July 2023 were retrospectively included.Data on clinical characteristics,endoscopic ultrasonography(EUS),ESD,and LR were collected and analyzed.The characteristics of EUS and the efficacy of the two treatments were analyzed.RESULTS The average age of the patients was 43.31±13.50 years,and the average maximum diameter of the lesions was 1.55±0.70 cm.The lesion originated from the mucosa in one patient(2.04%),from the submucosa in 42 patients(85.71%),and from the muscularis propria in 6 patients(12.25%).Twenty-nine patients(59.20%)with GEP showed umbilical depression on endoscopy.The most common initial symptom of GEP was abdominal pain(40.82%).Tumor markers,including carcinoembryonic antigen(CEA)and carbohydrate antigen 19-9(CA19-9),were generally within the normal range.One patient(2.04%)with GEP had increased CEA and CA-19-9 levels.However,no cancer tissue was found on postoperative pathological examination,and tumor markers returned to normal levels after resecting the lesion.There was no significant difference in surgery duration(72.42±23.84 vs 74.17±12.81 min)or hospital stay(3.70±0.91 vs 3.83±0.75 d)between the two methods.LR was more often used for patients with larger tumors and deeper origins.The amount of bleeding was significantly higher in LR than in ESD(11.28±16.87 vs 16.67±8.76 mL,P<0.05).Surgery was associated with complete resection of the lesion without any serious complications;there were no cases of recurrence during the follow-up period.CONCLUSION GEP has unique characteristics in EUS.LR and ESD seem to be good choices for treating GEP.LR is better for large GEP with a deep origin.However,due to the rarity of GEP,multicenter large-scale studies are needed to describe its characteristics and evaluate the safety of LR and ESD.

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.

Double contrast-enhanced two-dimensional and three-dimensional ultrasonography for evaluation of gastric lesions

AIM： To investigate the value of two-dimensional （2D） and three-dimensional （3D） double contrast-enhanced ultrasonography （DCUS） imaging for evaluation of gas- tric lesions. METHODS： 2D and 3D DCUS imaging with both oral and intravenous administrations of contrast agents was used to assess gastroscopiclly-confirmed gastric lesions in 46 patients with benign and malignant diseases. Initially, liquid-based ultrasound contrast agent （Xinzhang） was given orally at dose of 500-600 mL for conventional ultrasound examination of the gastric lesions, and then a microbubble-based contrast agent （SonoVue） was injected intravenously at dose of 1.2-2.4 mL in bolus fashion to assess the perfusion pattern of the lesions using contrast imaging modes. The parameters derived from time-intensity curves including the arrival time （AT）, time to peak （lq-P）, peak intensity （PI） and en- hanced intensity （EI） were measured on the 2D DCUS imaging. 3D DCUS of the lesions was acquired to dem- onstrate the value of this imaging mode. RESULTS： There were 22 cases with benign lesions including chronic gastritis （n= 5）, gastric ulcer （n = 9）, gastric polyps （n = 3）, gastric stromal tumors （n = 5）, and 24 cases with malignant lesions including gastric cancer （n = 20）, gastric cardia carcinoma （n = 3） and post-operative recurrent gastric cancer （n = 1） in the study, The oral contrast-enhanced ultrasonography （CEUS） imaging of the stomach clearly demonstrated the anatomy of the stomach and morphologic features of gastric lesions, With optimal scanning window and imaging display under oral CEUS, intravenous CEUS clearly showed the perfusion of gastric lesions with various characteristic manifestations. Both 2D and 3D DCUS images clearly demonstrated normal gastric wall as a three-layer structure, from the inside out, hypere- choic mucosa, hypoechoic muscularis and hyperechoic serosa, respectively. There were statistical significant differences of AT （8.68±2.06 vs 10.43 ±2.75, P = 0.017）, PI （34.64 ± 6.63 vs 29.58 ± 8.22, P = 0.023） and EI （29.72 ± 6.69 vs 22.66 ± 7.01, P = 0.001） between malignant lesions and normal gastric wall. However, no differences of AT, PI and EI between benign lesions and normal gastric wall tissue were found. 3D DCUS could intuitively display morphological features and vascularities of the lesions with multiplanar and volume views. 3D DCUS imaging provided comprehen- sive information complementary to 2D imaging. The crater or wellhead appearances and feeding vessels as well as distorted nourishing vasculature of gastric carcinoma were better seen with 3D imaging than 2D imaging. CONCLUSION： DCUS imaging can simultaneouslydisplay the anatomic and perfusion features of gastric lesions. 3D DCUS can provide additional information to 2D DCUS for evaluation of gastric lesions.