Characterization of intra-abdominal lesions of undetermined origin by contrast-enhanced harmonic EUS (with videos)

Contrast-enhanced endoscopic ultrasound for swollen lymph nodes

Endoscopic ultrasound (EUS) is an important tool for the evaluation of lymphadenopathy, especially in intra-thoracic or intra-abdominal regions. EUS also provides tissue diagnosis via EUS fine-needle aspiration or biopsy. To select the target for biopsy or aspiration, conventional B-mode images are used for the evaluation, but this approach still lacks diagnostic accuracy. Contrast-enhanced EUS has been used to evaluate the vascularity of lesions. Most malignant lymphadenopathy shows heterogenous enhancement or defect of enhancement, while quantitative studies using time-intensity curves in contrast-enhanced harmonic EUS show a rapid decline in enhancement pattern. These findings are useful as an auxiliary method for tissue diagnosis or in cases in which tissue diagnosis is contraindicated.

Efficacy of Contrast-Enhanced Endoscopic Ultrasonography for the Differentiation of Non-Hodgkin's Lymphoma: A Single-Center Retrospective Cohort Study

BACKGROUND

Contrast-enhanced endoscopic ultrasound (CE-EUS) is a promising diagnostic modality for differentiating malignant and benign lymph nodes. This study aimed to evaluate the diagnostic capability of CE-EUS in differentiating indolent non-Hodgkin's lymphoma (NHL) from aggressive NHL.

METHODS

Patients who underwent CE-EUS and endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) for lymphadenopathy and were diagnosed with NHL were included in this study. Echo features on B-mode endoscopic ultrasound (EUS) and vascular and enhancement patterns on CE-EUS were qualitatively evaluated. The enhancement intensity of the lymphadenopathy on CE-EUS over 60 s was also quantitatively evaluated using time-intensity curve (TIC) analysis.

RESULTS

A total of 62 patients who were diagnosed with NHL were enrolled in this study. Regarding qualitative evaluation using B-mode EUS, there were no significant differences in the echo features between aggressive NHL and indolent NHL. With regard to qualitative evaluation using CE-EUS, aggressive NHL showed a heterogeneous enhancement pattern that is significantly more frequent than indolent NHL (95% confidence interval: 0.57 to 0.79, p = 0.0089). When heterogeneous enhancement was defined as aggressive NHL, the sensitivity, specificity, and accuracy of the qualitative evaluation when using CE-EUS were 61%, 72%, and 66%, respectively. In TIC analysis, the velocity of reduction for homogeneous lesions was significantly higher in aggressive NHL than in indolent NHL (p < 0.0001). The sensitivity, specificity, and accuracy of CE-EUS in differentiating indolent NHL from aggressive NHL improved to 94%, 69%, and 82%, respectively, when combined with qualitative and quantitative evaluations.

CONCLUSIONS

CE-EUS before EUS-FNA for mediastinal or abdominal lymphadenopathy may be useful for improving the diagnostic capability of differentiating between indolent NHL and aggressive NHL (clinical trial registration number: UMIN000047907).

The Asian Federation of Societies for Ultrasound in Medicine and Biology (AFSUMB) Guidelines for Contrast-Enhanced Endoscopic Ultrasound

The Asian Federation of Societies for Ultrasound in Medicine and Biology aimed to provide information on techniques and indications for contrast-enhanced harmonic endoscopic ultrasound (CH-EUS), and to create statements including the level of recommendation. These statements are based on current scientific evidence reviewed by a Consensus Panel of 15 internationally renowned experts. The reliability of clinical questions was measured by agreement rates after voting. Six statements were made on techniques, including suitable contrast agents for CH-EUS, differences between contrast agents, setting of mechanical index, dual imaging and duration and phases for observation. Thirteen statements were made on indications, including pancreatic solid masses, pancreatic cancer staging, pancreatic cystic lesions and mural nodules, detection of subtle pancreatic lesions, gallbladder sludge and polyps, hepatic lesions, lymph nodes, subepithelial lesions, visceral vascular diseases, guidance of fine needle aspiration and evaluation for local therapy. These international expert consensus guidelines will assist endosonographers in conducting CH-EUS according to evidence-based information.

Enhanced EUS imaging (with videos)

BACKGROUND AND AIMS

EUS remains a primary diagnostic tool for the evaluation of pancreaticobiliary disease. Although EUS combined with FNA or biopsy sampling is highly sensitive for the diagnosis of neoplasia within the pancreaticobiliary tract, limitations exist in specific clinical settings such as chronic pancreatitis. Enhanced EUS imaging technologies aim to aid in the detection and diagnosis of lesions that are commonly evaluated with EUS.

METHODS

We reviewed technologies and methods for enhanced imaging during EUS and applications of these methods. Available data regarding efficacy, safety, and financial considerations are summarized.

RESULTS

Enhanced EUS imaging methods include elastography and contrast-enhanced EUS (CE-EUS). Both technologies have been best studied in the setting of pancreatic mass lesions. Robust data indicate that neither technology has adequate specificity to serve as a stand-alone test for pancreatic malignancy. However, there may be a role for improving the targeting of sampling and in the evaluation of peritumoral lymph nodes, inflammatory pancreatic masses, and masses with nondiagnostic FNA or fine-needle biopsy sampling. Further, novel applications of these technologies have been reported in the evaluation of liver fibrosis, pancreatic cysts, and angiogenesis within neoplastic lesions.

CONCLUSIONS

Elastography and CE-EUS may improve the real-time evaluation of intra- and extraluminal lesions as an adjunct to standard B-mode and Doppler imaging. They are not a replacement for EUS-guided tissue sampling but provide adjunctive diagnostic information in specific clinical situations. The optimal clinical use of these technologies continues to be a focus of ongoing research.

Interobserver Reliability of Endoscopic Ultrasonography: Literature Review

Endoscopic ultrasonography (EUS) has been applied to the diagnosis of various digestive disorders. Although it has been widely accepted and its diagnostic value is high, the dependence of EUS diagnosis on image interpretation done by the endosonographer has persisted as an important difficulty. Consequently, high interobserver reliability (IOR) in EUS diagnosis is important to demonstrate the reliability of EUS diagnosis. We reviewed the literature on the IOR of EUS diagnosis for various diseases such as chronic pancreatitis, pancreatic solid/cystic mass, lymphadenopathy, and gastrointestinal and subepithelial lesions. The IOR of EUS diagnosis differs depending on the disease; moreover, EUS findings with high IOR and those with IOR that was not necessarily high were used as diagnostic criteria. Therefore, to further increase the value of EUS diagnosis, EUS diagnostic criteria with high diagnostic characteristics based on EUS findings with high IOR must be established.

Efficacy of contrast-enhanced EUS for lymphadenopathy: a prospective multicenter pilot study (with videos)

BACKGROUND AND AIMS

Contrast-enhanced EUS (CE-EUS) allows qualitative and quantitative evaluation based on real-time perfusion imaging and may improve the diagnostic capability. The aim of this study was to evaluate the efficacy of CE-EUS in differentiating malignant from benign lymphadenopathy.

METHODS

Patients undergoing EUS-FNA for abdominal or mediastinal lymphadenopathy were prospectively enrolled. The echofeatures on B-mode EUS and the vascular and enhancement patterns in CE-EUS were qualitatively evaluated. The echo intensity change during 60 seconds in the lymphadenopathy was quantitatively evaluated by time intensity curve (TIC) analysis.

RESULTS

One hundred consecutive patients with 70 malignant and 30 benign lesions were enrolled. The sensitivity, specificity, and accuracy of the qualitative assessment in B-mode EUS were 77%, 17%, and 59%, respectively. When the heterogeneous enhancement was defined as malignancy, the sensitivity, specificity, and accuracy of the qualitative assessment in CE-EUS were 67%, 87%, and 73%, respectively. In TIC analysis, the velocity of reduction for homogeneous lesions showed a significant difference between malignant and benign lesions (P = .0011), and the receiver operating characteristic analysis showed an optimal cut-off value of .149 dB/s. The sensitivity, specificity, and diagnostic capabilities of CE-EUS for malignancy were improved to 89%, 77%, and 85%, respectively, on combining the qualitative and quantitative analyses. With regard to diagnostic accuracy, CE-EUS with combined qualitative and quantitative analyses was significantly higher than those of B-mode EUS or qualitative assessment of CE-EUS.

CONCLUSIONS

CE-EUS with the combined qualitative and quantitative analyses for lymphadenopathy might be useful to complement regular EUS and EUS-FNA. (Clinical trial registration number: UMIN000024298.).

Contrast-enhanced endoscopic ultrasound for the differential diagnosis between benign and malignant lymph nodes: a meta-analysis

Background  The differential diagnosis between benign and malignant lymph nodes (LNs) is crucial for patient management and clinical outcome. The use of contrast-enhanced endoscopic ultrasound (EUS) has been evaluated in several studies with diverse results. The aim of this meta-analysis was to evaluate the pooled diagnostic accuracy of contrast-enhanced EUS (CE-EUS) and contrast-enhanced harmonic EUS (CH-EUS) in this setting. Methods  A systematic electronic search was performed, including all original papers dealing with assessment of the nature of the LNs using CE-EUS or CH-EUS. A meta-analysis was performed to obtain pooled sensitivity, specificity, positive and negative likelihood ratio, and diagnostic odds ratio. The Summary Receiver Operating Characteristic (ROC) Curve method was used to calculate the area under the curve. Statistical analysis was carried out using Meta-Disc V.1.4, Stata V.12.0 and Review Manager V.5.2. Results  Among 210 pertinent studies, four (336 patients) were included in the analysis. The pooled sensitivity was 82.1 % (75.1 - 87.7 %) and pooled specificity was 90.7 % (85.9 - 94.3 %) with significant heterogeneity found in sensitivity; the positive-likelihood ratio (LR) was 7.77 (5.09 - 11.85) and the negative-LR was 0.15 (0.05 - 0.46); the pooled diagnostic odds ratio (DOR) was 54 (15 - 190). Subgroup analysis including studies performed using CH-EUS (two studies, 177 LNs) showed a pooled sensitivity of 87.7 % (77.0 - 93.9 %) and a pooled specificity of 91.8 % (84.5 % - 96.4 %) with no significant heterogeneity; the pooled positive-LR was 9.51 (4.95 - 18.28) and the pooled negative-LR was 0.14 (0.06 - 0.35); pooled DOR was 68.42 (15.5 - 301.4). Conclusions  From these data, CE-EUS is not recommended due to inadequate sensitivity. On the other hand, CH-EUS studies showed optimal accuracy (pooled sensitivity 87.7 % and specificity 91.8 %), comparable to elastography and even EUS-guided fine needle aspiration (EUS-FNA), suggesting a role in the diagnostic algorithm.

Contrast-enhanced harmonic endoscopic ultrasonography in gallbladder cancer and pancreatic cancer

Endoscopic ultrasonography (EUS) plays a major role in diagnosing gallbladder (GB) cancer and pancreatic cancer (PC). In cases of GB cancer, EUS allows for precise observations of morphology and wall layers. However, proficiency is required for the morphologic diagnosis of GB tumors. Therefore, contrast-enhanced harmonic EUS (CH-EUS) began to be performed to diagnose GB lesions. CH-EUS enables real-time observation of the hemodynamics of GB tumors. The enhanced patterns generated by CH-EUS improve precision in the diagnosis of such tumors.PC appears as a hypoechoic mass on EUS. However, distinguishing between PC and mass-forming pancreatitis or focal autoimmune pancreatitis (AIP) is difficult via conventional EUS. CH-EUS allows for differentiating among these diseases (PC is hypoenhanced and heterogeneously enhanced, pancreatitis is isoenhanced, and a pancreatic neuroendocrine tumor is hyperenhanced). EUS-guided fine needle aspiration (EUS-FNA) also contributes to pathological diagnoses of pancreatic lesions. However, certain PC patients cannot be diagnosed via EUS-FNA. PC is heterogeneously enhanced on CH-EUS, and unenhanced regions have been reported to be areas of fibrosis or necrosis. CH-EUS-guided fine needle aspiration (CH-EUS-FNA) permits puncturing of the enhanced area while avoiding necrotic and fibrotic regions. Moreover, as CH-EUS findings have been quantitatively analyzed, a time-intensity curve (TIC) has become usable for diagnosing solid pancreatic lesions. CH-EUS-related techniques have been developed and increasingly utilized in the pancreaticobiliary area.

Dual-Frequency Piezoelectric Endoscopic Transducer for Imaging Vascular Invasion in Pancreatic Cancer

Cancers of the pancreas have the poorest prognosis among all cancers, as many tumors are not detected until surgery is no longer a viable option. Surgical viability is typically determined via endoscopic ultrasound imaging. However, many patients who may be eligible for resection are not offered surgery due to diagnostic challenges in determining vascular or lymphatic invasion. In this paper, we describe the development of a dual-frequency piezoelectric transducer for rotational endoscopic imaging designed to transmit at 4 MHz and receive at 20 MHz in order to image microbubble-specific superharmonic signals. Imaging performance is assessed in a tissue-mimicking phantom at depths from 1 cm [contrast-to-tissue ratio (CTR) = 21.6 dB] to 2.5 cm (CTR = 11.4 dB), in ex vivo porcine vessels, and in vivo in a rodent. The prototyped 1.1-mm aperture transducer demonstrates contrast-specific imaging of microbubbles in a 200- [Formula: see text]-diameter tube through the wall of a 1-cm-diameter porcine artery, suggesting such a device may enable direct visualization of small vessels from within the lumen of larger vessels such as the portal vein or superior mesenteric vein.

Maximizing the endosonography: The role of contrast harmonics, elastography and confocal endomicroscopy

New technologies in endoscopic ultrasound (EUS) evaluation have been developed because of the need to improve the EUS and EUS-fine needle aspiration (EUS-FNA) diagnostic rate. This paper reviews the principle, indications, main literature results, limitations and future expectations for each of the methods presented. Contrast-enhanced harmonic EUS uses a low mechanical index and highlights slow-flow vascularization. This technique is useful for differentiating solid and cystic pancreatic lesions and assessing biliary neoplasms, submucosal neoplasms and lymph nodes. It is also useful for the discrimination of pancreatic masses based on their qualitative patterns; however, the quantitative assessment needs to be improved. The detection of small solid lesions is better, and the EUS-FNA guidance needs further research. The differentiation of cystic lesions of the pancreas and the identification of the associated malignancy features represent the main indications. Elastography is used to assess tissue hardness based on the measurement of elasticity. Despite its low negative predictive value, elastography might rule out the diagnosis of malignancy for pancreatic masses. Needle confocal laser endomicroscopy offers useful information about cystic lesions of the pancreas and is still under evaluation for use with solid pancreatic lesions of lymph nodes.

Dynamic contrast-enhanced endoscopic ultrasound: A quantification method

Dynamic contrast-enhanced ultrasound (DCE-US) has been recently standardized by guidelines and recommendations. The European Federation of Societies for US in Medicine and Biology position paper describes the use for DCE-US. Comparatively, little is known about the use of contrast-enhanced endoscopic US (CE-EUS). This current paper reviews and discusses the clinical use of CE-EUS and DCE-US. The most important clinical use of DCE-US is the prediction of tumor response to new drugs against vascular angioneogenesis.

Role of contrast-enhanced endoscopic ultrasound in lymph nodes

Diagnosing unclear lymph node (LN) enlargements in the mediastinum and abdomen is the most important indication of endoscopic ultrasound (EUS)-fine needle aspiration (FNA) after the diagnosis and treatment of pancreatic diseases. Investigating LNs in these areas can happen in different clinical settings. Mostly, it is the first modality in general LN diseases without any peripheral LN enlargements. On the other hand, it can be the question of LN involvement in a known or suspected primary tumor. Due to EUS-FNA cytology, those questions can be answered highly, accurately. However, a primary discrimination of LNs might be helpful to increase the diagnostic value of the FNA cytology, especially in cases with multiple LN enlargements and hard to reach enlarged LNs for example by vessel interposition. Because of the unreliability of B-mode criteria, further diagnostic improvements such as elastography and contrast-enhanced EUS are investigated to increase the accuracy of the initial diagnosis.

The clinical impact of ultrasound contrast agents in EUS: a systematic review according to the levels of evidence

BACKGROUND AND AIMS

The use of contrast-harmonic EUS (CH-EUS) in routine clinical practice is increasing rapidly but is not yet standardized. We present the levels of evidence (LEs) found in the literature to put its clinical outcomes in the appropriate perspective.

METHODS

We conducted a systematic review of the available English-language articles. The LEs were stratified according to the Oxford Centre for Evidence-Based Medicine guidelines.

RESULTS

Overall, 210 articles were included and presented according to different pathologic conditions. For pancreatic solid neoplasms, the pooled sensitivity and specificity in the diagnosis of pancreatic carcinoma were very high (LE 1); quantitative analysis and guidance of FNA were reported as investigational research (LE 2-3). For pancreatic cystic lesions, the identification of neoplastic solid components as hyperenhanced lesions represented a promising application of CH-EUS (LE 2). For lymph nodes, CH-EUS increased the diagnostic yield of B-mode EUS for the detection of malignancy (LE 2). For submucosal tumors, CH-EUS seemed useful for differential diagnosis and risk stratification (LE 2-3). For other applications, differential diagnosis of gallbladder and vascular abnormalities by CH-EUS were reported (LE 2-3).

CONCLUSIONS

The LEs of CH-EUS in the literature have evolved from the initial descriptive studies to multicenter and prospective trials, and even meta-analyses. The differential diagnosis between benign and malignant lesions is the main field of application of CH-EUS. With regard to pancreatic solid neoplasms, the concomitant use of both CH-EUS and EUS-FNA may have additive value in increasing the overall accuracy by overcoming the false-negative results associated with each individual technique. Other applications are promising but still investigational.

The efficacy of contrast-enhanced harmonic endoscopic ultrasonography in diagnosing gallbladder cancer

The aim of this study was to review the efficacy of contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) in diagnosing gallbladder (GB)-protruded lesions. Thirty-eight patients underwent CH-EUS for the diagnosis of GB-protruded lesions. Twenty-four patients whose major axes of their largest lesions were longer than 10 mm were recruited. The ability of CH-EUS to diagnose malignant or benign lesions was reviewed. We treated lesions with brindled enhanced patterns as malignant and those with uniformly enhanced or unenhanced patterns as benign. Furthermore, three gastroenterologists who were not familiar with pancreaticobiliary EUS compared the diagnostic abilities of CH-EUS and conventional EUS using photographs. The sensitivity, specificity, and malignant accuracy of CH-EUS were 100, 94.4, and 95.8%, respectively. The number of lesions that presented with enhanced patterns was significantly different between the malignant lesions and the benign lesions (P < 0.001). In the comparison of diagnostic abilities between CH-EUS and conventional EUS by the three gastroenterologists, CH-EUS was significantly superior to conventional EUS in terms of sensitivity, specificity, and accuracy (76.1 vs. 42.9%, P = 0.029; 66.7 vs. 39.2%, P = 0.005; and 69.4 vs. 40.3%, P < 0.001; respectively). In conclusion, CH-EUS was useful for diagnosing malignant and benign GB-protruded lesions.

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 ≥ 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.

Can contrast-enhanced harmonic endosonography predict malignancy risk in gastrointestinal subepithelial tumors?

Background and Objectives:

Contrast-enhanced harmonic endoscopic ultrasound (CEH-EUS) is a novel technology that can identify subepithelial tumors (SETs) by detecting the degree of enhancement, but whether CEH-EUS can predict the malignancy risk of gastrointestinal stromal tumors (GISTs) remains unclear. The aim of our study was to evaluate the diagnostic accuracy of CEH-EUS and its ability to discriminate among SETs and predict the malignancy risk of GISTs.

Materials and Methods:

We retrospectively included patients with suspected subepithelial lesions who underwent CEH-EUS preoperatively. Thirty-five patients with histologically proven GISTs and benign neoplasms were enrolled in the study. The images of CEH-EUS were categorized in accordance with microvasculature, parenchymal perfusion, and nonenhancing spots. The diagnostic performance of CEH-EUS was evaluated by comparing these findings with the histological diagnosis.

Results:

When we divided the enrolled patients into high- and low-grade malignancy and benign groups, nonenhancing spots on CEH-EUS were found more frequently in the high-grade malignancy group (63.6%), followed by the low-grade malignancy (46.7%) and benign groups (25.7%) (P = 0.022). However, based on the statistical validity of the CEH-EUS findings for the discrimination of SETs, the sensitivity was 53.8% for diagnostic performance and 63.6% for prediction of malignancy risk of GISTs.

Conclusions:

From our study results, it is unclear whether CEH-EUS alone has a diagnostic role in the discrimination of SETs and the prediction of malignancy risk of GISTs. Further studies with larger samples from multiple centers and use of other imaging analysis modalities are needed.

New endoscopic ultrasound techniques for digestive tract diseases: A comprehensive review

Endoscopic ultrasound (EUS) is one of the most important modalities for the diagnosis of digestive tract diseases. EUS has been evolving ever since it was introduced. New techniques such as elastography and contrast enhancement have emerged, increasing the accuracy, sensitivity and specificity of EUS for the diagnosis of digestive tract diseases including pancreatic masses and lymphadenopathy. EUS-elastography evaluates tissue elasticity and therefore, can be used to differentiate various lesions. Contrast-enhanced EUS can distinguish benign from malignant pancreatic lesions and lymphadenopathy using the intravenous injection of contrast agents. This review discusses the principles and types of these new techniques, as well as their clinical applications and limitations.

Contrast-enhanced harmonic endoscopic ultrasonography for pancreatobiliary diseases

The combination of second-generation ultrasound contrast agents and an endoscopic ultrasonography (EUS) system with a broad-band transducer has allowed contrast-enhanced harmonic imaging in the field of EUS. In contrast-enhanced harmonic EUS (CH-EUS), diffuse homogeneous enhancement is obtained in normal parenchyma of the pancreas. The bile duct and pancreatic duct are depicted as non-enhanced ductal structures with strong contrast in comparison to the surrounding parenchyma. CH-EUS identifies pancreatic adenocarcinomas as solid lesions exhibiting hypo-enhancement with a sensitivity and specificity of 88-96% and 88-94%, respectively. In particular, 80-100% of false-negative cases in endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) are correctly classified by CH-EUS, suggesting CH-EUS complements EUS-FNA. Moreover, CH-EUS improves depiction of some subtle lesions in conventional EUS, thus facilitating EUS-FNA. For quantitative perfusion analysis, a time-intensity curve (TIC) for the region of interest can be generated during CH-EUS. The maximum intensity gain and the echo intensity reduction rate from the peak at 1 min obtained by TIC can be used for differentiation of pancreatic adenocarcinoma from other tumors. CH-EUS is also useful for differentiation of invasive intraductal papillary mucinous neoplasms (IPMN) from non-invasive IPMN, identification of malignant lesions in the gallbladder, and T- and N-staging of pancreatobiliary tumors.

Gastric foregut cystic developmental malformation: Case series and literature review

Foregut cystic developmental malformation (FCDM) is a very rare lesion of the alimentary tract, especially in the stomach. We discuss the concepts of gastric duplication cyst, bronchogenic cysts, and FCDM. Nomenclature has been inconsistent and confusing, but, by some definitions, gastric duplication cysts involve gastric mucosa and submucosal glands, bronchogenic cysts involve respiratory mucosa with underlying cartilage and glands, and FCDM lacks gastric mucosa or underlying glands or cartilage but has pseudostratified ciliated columnar epithelium (PCCE). We searched our departmental case files from the past 15 years and identified 12 cases of FCDM in the alimentary tract. We summarize the features of these 12 cases including a report in detail on a 52-year-old man with a submucosal cyst lined with simple PCCE and irregular and stratified circular muscle layers that merged with gastric smooth muscle bundles near the lesser curvature of the gastric cardia. A literature review of cases with this histology yielded 25 cases. We propose the term gastric-FCDM for such cases. Our own series of 12 cases confirms that preoperative recognition of the entity is infrequent and problematic. The rarity of this developmental disorder, as well as a lack of understanding of its embryologic origins, may contribute to missing the diagnosis. Not appreciating the diagnosis preoperatively can lead to an inappropriate surgical approach. In contrast, presurgical recognition of the entity will contribute to a good outcome and reduced risk of complications.

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 (CH-EUS) 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 in making 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 ethanol-induced 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 non-invasive 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.

Contrast-enhanced endoscopic ultrasonography: advance and current status

Endoscopic ultrasonography (EUS) technology has undergone a great deal of progress along with the color and power Doppler imaging, three-dimensional imaging, electronic scanning, tissue harmonic imaging, and elastography, and one of the most important developments is the ability to acquire contrast-enhanced images. The blood flow in small vessels and the parenchymal microvasculature of the target lesion can be observed non-invasively by contrast-enhanced EUS (CE-EUS). Through a hemodynamic analysis, CE-EUS permits the diagnosis of various gastrointestinal diseases and differential diagnoses between benign and malignant tumors. Recently, mechanical innovations and the development of contrast agents have increased the use of CE-EUS in the diagnostic field, as well as for the assessment of the efficacy of therapeutic agents. The advances in and the current status of CE-EUS are discussed in this review.

Contrast-enhanced endoscopic ultrasound

Compared to other imaging modalities, endoscopic ultrasound (EUS) has limitations in terms of image enhancement. However, with the availability of contrast agents in ultrasonography, EUS has evolved. Contrast-enhanced Doppler EUS (CD-EUS) enhances Doppler signals from vessels and is useful for characterizing lesions detected by EUS. Moreover, contrast-enhanced harmonic EUS (CH-EUS) with second-generation ultrasound contrast agents and a broad band transducer allows microvessels and parenchymal perfusion to be visualized. Vascularity can also be quantitatively analyzed during CH-EUS by generating a time-intensity curve. CE-EUS is useful for characterizing pancreatic lesions and can detect pancreatic adenocarcinomas with a sensitivity of 94%and a specificity of 89% as a result of the hypo-enhancement of these lesions. Indeed, CH-EUS is superior to multiple detector-computed tomography in terms of the differential diagnosis of small lesions that are ≤2 cm. CH-EUS complements EUS-guided fine-needle aspiration (EUS-FNA) as it identifies the EUS-FNA target and lesions with false-negative EUS-FNA findings. CH-EUS is also used to estimate the malignant potential of gastrointestinal stromal tumors and helps to differentiate between malignant and benign lymphadenopathy.

New ultrasound techniques for lymph node evaluation

Conventional ultrasound (US) is the recommended imaging method for lymph node (LN) diseases with the advantages of high resolution, real time evaluation and relative low costs. Current indications of transcutaneous ultrasound and endoscopic ultrasound include the detection and characterization of lymph nodes and the guidance for LN biopsy. Recent advances in US technology, such as contrast enhanced ultrasound (CEUS), contrast enhanced endoscopic ultrasound (CE-EUS), and real time elastography show potential to improve the accuracy of US for the differential diagnosis of benign and malignant lymph nodes. In addition, CEUS and CE-EUS have been also used for the guidance of fine needle aspiration and assessment of treatment response. Complementary to size criteria, CEUS could also be used to evaluate response of tumor angiogenesis to anti-angiogenic therapies. In this paper we review current literature regarding evaluation of lymphadenopathy by new and innovative US techniques.

Clinical controversies in endoscopic ultrasound

The field of diagnostic and therapeutic endoscopic ultrasound (EUS) is growing rapidly. Although EUS has enhanced our ability to diagnose and treat a wide variety of GI conditions, there are many controversial issues regarding the appropriate application of EUS techniques. In this review we discuss five controversial topics in EUS: the utility of EUS in staging of esophageal and gastric cancer; selection of appropriate needle gauge for fine needle aspiration (FNA); use of the stylet in FNA; and the emerging role of contrast agents in endoscopic ultrasound.

Contrast-enhanced endoscopic ultrasonography in digestive diseases

Contrast-enhanced endoscopic ultrasonography (CE-EUS) was introduced in the early 1990s. The concept of the injection of carbon dioxide microbubbles into the hepatic artery as a contrast material (enhanced ultrasonography) led to "endoscopic ultrasonographic angiography". After the arrival of the first-generation contrast agent, high-frequency (12 MHz) EUS brought about the enhancement of EUS images in the diagnosis of pancreatico-biliary diseases, upper gastrointestinal (GI) cancer, and submucosal tumors. The electronic scanning endosonoscope with both radial and linear probes enabled the use of high-end ultrasound machines and depicted the enhancement of both color/power Doppler flow-based imaging and harmonic-based imaging using second-generation contrast agents. Many reports have described the usefulness of the differential diagnosis of pancreatic diseases and other abdominal lesions. Quantitative evaluation of CE-EUS images was an objective method of diagnosis using the time-intensity curve (TIC), but it was limited to the region of interest. Recently developed Inflow Time Mapping™ can be generated from stored clips and used to display the pattern of signal enhancement with time after injection, offering temporal difference of contrast agents and improved tumor characterization. On the other hand, three-dimensional CE-EUS images added new information to the literature, but lacked positional information. Three-dimensional CE-EUS with accurate positional information is awaited. To date, most reports have been related to pancreatic lesions or lymph nodes. Hemodynamic analysis might be of use for diseases in other organs: upper GI cancer diagnosis, submucosal tumors, and biliary disorders, and it might also provide functional information. Studies of CE-EUS in diseases in many other organs will increase in the near future.

Endoscopic ultrasound: contrast enhancement

The development of ultrasound contrast agents has allowed for the evaluation of vascularity in digestive organs by contrast-enhanced endoscopic ultrasonography (EUS). Contrast-enhanced Doppler EUS and contrast-enhanced harmonic EUS (CH-EUS) have improved characterization of pancreatic tumors, lymph nodes, and gastrointestinal submucosal tumors and compliment EUS fine-needle aspiration (FNA) in identifying malignant tumors. Moreover, CH-EUS can be used to identify the target for EUS-guided FNA by clearly depicting the outline of the lesions.

Endo-hepatology: a new paradigm

Recent advances in hepatology have included a new and effective treatment of viral hepatitis, with an increased need for the assessment of liver function and histology. At the same time, there have been a growing number of endoscopic procedures that are pertinent to patients with liver disease. It would be ideal if the assessment and treatment of liver disease and portal hypertension could be performed and assimilated by the liver/gastrointestinal specialist. The authors like to consider this area of integration or overlap of endoscopic procedures within the practice of hepatology as endo-hepatology.

Characterization of small solid tumors in the pancreas: the value of contrast-enhanced harmonic endoscopic ultrasonography

OBJECTIVES

Contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS), a novel technology, visualizes parenchymal perfusion in the pancreas. This study prospectively evaluated how accurately CH-EUS characterizes pancreatic lesions and compared its diagnostic ability with that of contrast-enhanced multidetector-row computed tomography (MDCT) and endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA).

METHODS

A total of 277 consecutive patients with pancreatic solid lesions that were detected by conventional EUS underwent CH-EUS for evaluation of vascularity. After infusing an ultrasound contrast, CH-EUS was performed by using an echoendoscope and a specific mode for contrast harmonic imaging. On the basis of the intensity of enhancement, the lesions were categorized into four patterns: nonenhancement, hypoenhancement, isoenhancement, and hyperenhancement. For comparison, all patients underwent MDCT. The ability of CH-EUS to differentiate ductal carcinomas from the other solid tumors, particularly small lesions (≤2 cm in diameter) was assessed, and compared with the differentiating abilities of MDCT and EUS-FNA.

RESULTS

In terms of reading the CH-EUS images, the κ-coefficient of the interobserver agreement test was 0.94 (P<0.001). CH-EUS-depicted hypoenhancement diagnosed ductal carcinomas with a sensitivity and specificity of 95.1% (95% confidence interval (CI) 92.7-96.7%) and 89.0% (95% CI 83.0-93.1%), respectively. For diagnosing small carcinomas by CH-EUS, the sensitivity and specificity were 91.2 % (95% CI 82.5-95.1%) and 94.4% (95% CI 86.2-98.1%), respectively. CH-EUS-depicted hypervascular enhancement diagnosed neuroendocrine tumors with a sensitivity and specificity of 78.9% (95% CI 61.4-89.7%) and 98.7% (95% CI 96.7-98.8%), respectively. Although CH-EUS and MDCT did not differ significantly in diagnostic ability with regard to all lesions, CH-EUS was superior to MDCT in diagnosing small (≤2 cm) carcinomas (P<0.05). In 12 neoplasms that MDCT failed to detect, 7 ductal carcinomas and 2 neuroendocrine tumors had hypoenhancement and hyperenhancement on CH-EUS, respectively. When CH-EUS was combined with EUS-FNA, the sensitivity of EUS-FNA increased from 92.2 to 100%.

CONCLUSIONS

CH-EUS is useful for characterizing conventional EUS-detected solid pancreatic lesions. EUS equipped with contrast harmonic imaging may play an important role in the characterization of small tumors that other imaging methods fail to depict and may improve the diagnostic yield of EUS-FNA.

New techniques and future perspective of EUS for the differential diagnosis of pancreatic malignancies: contrast harmonic imaging

Although endoscopic ultrasonography (EUS) has the advantage over other imaging methods in that it is possible to obtain high resolution images of the pancreas, it is limited in its ability to characterize pancreatic masses. Contrast-enhanced power Doppler ultrasonography suffers from several limitations such as blooming artifacts, poor spatial resolution, low sensitivity to slow flow and high sensitivity to motion artifacts. Recently, EUS system specific for contrast harmonic imaging has been developed. The use of this EUS system enabled us to observe images of microcirculation and parenchymal perfusion without Doppler-related artifacts in the pancreas. Contrast-enhanced harmonic EUS could diagnose pancreatic carcinomas as hypovascular masses with a high sensitivity (89-96%) and specificity (64-88%). Contrast-enhanced harmonic EUS also discriminates mural nodules from mucous clots in the intraductal papillary mucinous neoplasms.

Endoscopic ultrasonography and contrast-enhanced endoscopic ultrasonography

Endoscopic ultrasonography (EUS) is superior to all other imaging modalities in detecting small pancreatic cancers. However, its ability to characterize hypoechoic pancreatic masses is limited: most carcinomas, neuroendocrine tumors, and inflammatory pseudotumors are simply depicted as hypoechoic masses. Contrast enhancement helps EUS to characterize such hypoechoic masses. Intravenous ultrasound (US) agents increase the signal from the blood and, thus, act as amplifiers and improve visualization of blood flow in small vessels using Doppler US. Contrast-enhanced Doppler EUS can differentiate small pancreatic carcinomas that cannot be detected by other imaging modalities. The development of second-generation US contrast agents and an EUS system with a broad-band transducer enabled the visualization of microvessels and the parenchymal perfusion in the pancreas. This contrast-enhanced harmonic EUS has shown that most pancreatic cancers exhibit hypovascular heterogeneous enhancement with irregular network-like microvessels. Moreover, it can diagnose pancreatic cancers with a high sensitivity (89-92%).

Estimation of malignant potential of GI stromal tumors by contrast-enhanced harmonic EUS (with videos)

BACKGROUND

Contrast-enhanced harmonic EUS (CEH-EUS) is a new sonographic technique that uses US contrast agents and depicts intratumoral vessels in real time.

OBJECTIVE

To evaluate whether assessment of tumor vascularity by CEH-EUS can predict the preoperative malignancy risk of GI stromal tumors (GISTs).

DESIGN

Prospective study to observe GIST vascularity.

SETTING

Kinki University School of Medicine.

PATIENTS

Between June 2007 and September 2009, 76 consecutive patients suspected of having subepithelial lesions underwent CEH-EUS.

INTERVENTION

CEH-EUS was performed by using a prototype echoendoscope in an extended pure harmonic detection mode.

MAIN OUTCOME MEASUREMENTS

Resected GIST specimens in 29 patients who underwent surgical resection were divided into high-grade (n=16) and low-grade (n=13) malignancy groups based on mitotic activity. The abilities of EUS-guided FNA and CEH-EUS to diagnose the malignant potential were compared. The sensitivities with which contrast-enhanced multidetector CT, power-Doppler EUS, and CEH-EUS detected intratumoral vessels in high-grade malignancy GISTs also were compared.

RESULTS

CEH-EUS identified irregular vessels and thereby predicted GIST malignancies with a sensitivity, specificity, and accuracy of 100%, 63%, and 83%, respectively. Diagnosis of high-grade malignancy GISTs by EUS-guided FNA had a sensitivity, specificity, and accuracy of 63%, 92%, and 81%, respectively. Contrast-enhanced multidetector CT, power-Doppler EUS, and CEH-EUS detected intratumoral vessels in high-grade malignancy GISTs with sensitivities of 31%, 63%, and 100%, respectively (P<.05).

LIMITATIONS

A single center was involved in this study.

CONCLUSIONS

CEH-EUS successfully visualized intratumoral vessels and may play an important role in predicting the malignancy risk of GISTs.