[Therapeutic endoscopic ultrasound: current indications and future perspectives.]

Endoscopic ultrasound (EUS) is rapidly evolving from a diagnostic into a mainly therapeutic procedure, similarly to what previously occurred to endoscopic retrograde cholangio-pancreatography (ERCP). The capability to easily access adjacent organs and structures with a minimally invasive approach as well as the availability of dedicated devices are driving this process. Several therapeutic procedures can be performed under EUS-guidance, such as drainage of pancreatic fluid collections, of the biliary system after ERCP failure, of the gallbladder for acute cholecystitis in high-risk surgical patients, as well as endoscopic gastroenteral-anastomosis creation. The introduction of dedicated lumen-apposing metal stents in the latest years has made these procedures technically easier. However, further improvements of stent design will be required in the next future. Moreover, data on long-term efficacy and safety coming from well-designed randomized multicenter controlled trials are still needed to bring EUS-guided procedures to the next level.

Present status and perspectives of endosonography 2017 in gastroenterology

Endoscopic ultrasound has become an essential tool in modern gastroenterology and abdominal surgery. Compared with all other endoscopic methods, it has the most potential for innovation and its future looks bright. Thus, we compiled this summary of established and novel applications of endoscopic ultrasound methods to inform the reader about what is already possible and where future developments will lead in improving patient care further. This review is structured in four parts. The first section reports on developments in diagnostic endoscopic ultrasound, the second looks at semi-invasive endoscopic ultrasound, and the third discusses advances in therapeutic endoscopic ultrasound. An overview on the future prospects of endoscopic ultrasound methods concludes this article.

Endoscopic ultrasound-guided radiofrequency ablation in gastroenterology: New horizons in search

Radiofrequency ablation (RFA) has been widely used for the treatment of various solid organ malignancies. Over the last decade, endosonographers have gradually shifted the application of RFA from porcine models to humans to treat a spectrum of diseases. RFA is performed in patients with pancreatic carcinoma who are not candidates for surgery. In this paper, we will discuss various indications for RFA, its procedural details and complications. At present, endoscopic ultrasound-guided RFA is gradually incorporated into the management of various diseases and opens a new avenue for disease treatment.

Convex-probe Endobronchial Ultrasound: A Decade of Progress

Ever since the invention of the flexible bronchoscope, perhaps no other innovation in the field of interventional pulmonology has caused so much excitement the world over, as the convex probe endobronchial ultrasound (EBUS)-guided transbronchial needle aspiration (TBNA). While it took over a decade from 1992 to 2004 for the radial EBUS to evolve into the commercial convex probe EBUS scope, another exciting decade has gone by with the technology being thoroughly researched and appraised. The current evidence suggests that EBUS-TBNA can replace mediastinoscopy as the first investigation in the mediastinal staging of lung cancer. The use of EBUS-TBNA has been extended to several other areas including the diagnosis of undefined mediastinal lymphadenopathy, evaluation of intra-parenchymal lesions and others. In fact, EBUS-TBNA is the preferred modality for accessing mediastinal lesions in contact with the airways. The procedure not only has a high diagnostic efficiency (80%-90% for most indications) but is also safe compared to alternative options, such as image-guided fine needle aspiration and mediastinoscopy in the diagnosis of mediastinal lymphadenopathy. Apart from the traditional use of EBUS to perform TBNA, the last decade has seen the evolution of its transoesophageal use, development of novel EBUS-TBNA needles to obtain better histological specimens and a smaller EBUS scope. This review summarises the developments made in this field over the years since its inception.

[New trends and novel possibilities in the endoscopic diagnostics of gastrointestinal tumors]

This publication shortly reviews the attributes of cornerstones of the latest technical developments in the field of endoscopy (virtual chromoendoscopy, optical biopsy, etc.), as well as some technical details of novel endoscopic methods (deep enteroscopy, capsule endoscopy). It evaluates the clinical consequences of the technical progress concerning several diseases that are important from the point of view of oncology. Some novel endoscopic innovations till now with uncertain clinical relevance are also mentioned. We can face the fact what a huge gap exists between our everyday possibilities at almost all our workplaces and the up-to-date endoscopic diagnostic modalities of the developed world.

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.

Echo-endoscopy: new therapeutic frontiers

Endoscopic ultrasound (EUS) has been established as a valuable diagnostic modality as it offers high-resolution imaging and fine-needle biopsy, which is essential in detecting and staging malignancies. Since the introduction of EUS-guided fine needle aspiration (EUS-FNA) in 1992, numerous novel EUS-based interventions and techniques have emerged. Currently, established interventional EUS techniques include celiac plexus block and neurolysis, drainage of pancreatic pseudocysts and pelvic fluid collections, and implantation of fiducial markers and radioactive seeds into the malignant tumors. Emerging EUS-guided experimental techniques include antitumor injection, ablation of tumors, and vascular access. Diagnostic and therapeutic access to the biliary tree and pancreatic duct is increasingly being used for failed ERCP procedures or inaccessible ducts. Interventional EUS is a very promising technique with many potential applications. The future holds promise for substantial progress in EUS-guided therapeutic interventions and their applications in clinical gastroenterology.

[Recent advances on EUS, EUS-FNA]

Endoscopic ultrasonography (EUS) has widened its applications and been become an indispensable examination. Recent advances is as follows: Electronic radial scanning EUS, three-dimensional EUS (3D-EUS), enhancement, elastography, and EUS-FNA. Because of electronic radial scanning EUS, we can employ Doppler function. 3D-EUS have introduced not only preciseness for preoperative evaluation for EMR and ESD but also surface rendering similar to endoscopic image. Enhancement and elastography have a possibility of tissue chracterization. First EUS-FNA, in which Vilmann reported fine needle aspiration cytology of pancreas cancer and Grimm treated a case with pseudocyst, were made in 1992. Then EUS-FNA has become popular in the clinical fields and the accuracy of diagnostic EUS-FNA has been reported 70 to 100%. Furthermore EUS-FNA has also widened its applications to therapeutic techniques such as pseudocyst drainage, biliary drainage, pancreatic duct drainage, celiac plexus neurolysis (CPN), ethanol injection therapy, radiofrequency ablation (RFA), immunotherapy, and gene therapy etc. Finally, EUS-FNA is the future promising technique which has potential for developing new treatments.

The place of endoscopic ultrasound in bilio-pancreatic pathology

The place of endoscopic ultrasound (EUS) in malignant pathology of the pancreas is two-fold: (1) EUS is the best examination for the diagnosis of small tumours (<3cm in diameter). Its sensitivity is greater than that of CT scan, percutaneous ultrasound or magnetic resonance imaging (MRI) and is equal to that of endoscopic retrograde cholangiopancreatography (ERCP) without sharing its invasive character; (2) EUS is also indicated in the assessment of locoregional extension of tumours judged resectable by tomodensitometric (TDM) (scanner) data. The performance of EUS seems to be greater than other imaging techniques for the diagnosis of vascular and lymph node invasion although recent studies report less good results than those of studies in 1992 to 1994, particularly for vascular involvement. Nevertheless, EUS cannot affirm the malignant or benign character of these pancreatic masses. The development over the last 20 years of linear sector-based EUS has enabled us to perform guided biopsies of such lesions. EUS-guided biopsy is today the best technique for obtaining the histology of a pancreatic mass, with a sensitivity of 85 to 87%. Furthermore, it also has a non-negligible impact on the deciding the treatment particularly in the case of adenocarcinomas (ADKP) not visible to TDM (scanners). This is currently of importance because trials are being developed of preoperative radio-chemotherapy for resectable lesions. probably in the next future, contrast-enhanced EUS (CE-EUS) and elastography will improve the results of EUS and will be necessary for a precise local staging before treatment.

Laparoscopic ultrasound: a survey of its current and future use, requirements, and integration with navigation technology

BACKGROUND

Laparoscopic ultrasound (LUS) increases surgical safety by allowing the surgeon to see beyond the organ surface, by visualizing vascular structures and by improving surgical precision of tumor resection. A questionnaire-based survey was used to investigate the current use and future expectations of LUS technology.

METHODS

A questionnaire consisting of 26 questions was distributed manually at four different conferences (60% at the European Association for Endoscopic Surgery (EAES) conference, Stockholm 2008). The answers were summarized with descriptive statistics and nonparametric tests at a significance level of 0.05.

RESULTS

The questionnaire was answered by 177 surgeons from 40 different countries (85% from Europe). Of these surgeons, 43% use ultrasound during laparoscopic procedures. Generally, more LUS users are found at university hospitals than at general community hospitals. Surgeons use LUS primarily in procedures related to the liver (67% of the surgeons who use LUS), but LUS also is used in other procedures related to the pancreas, biliary tract, and colon. In a 5-year perspective, 82% of surgeons believe in an increased use of LUS, and 79% of surgeons also think that the use of LUS combined with navigation technology will increase and that the most important requirements for such a system are good image quality, easy interpretation, and a high degree of precision.

CONCLUSIONS

Although the surgeons believe LUS has advantages, only 43% of the respondents reported using it. The surveyed surgeons were largely positive toward an increased use of LUS in a 5-year perspective and believe that LUS combined with navigation technology will contribute to improving the surgical precision of tumor resection.

Endoscopic ultrasound in solid pancreatic masses--current state and review of the literature

Some 25 years ago endoscopic ultrasound (EUS) was introduced in clinical practice for better visualization of pancreas. At the time of introduction EUS was superior to other methods in detection of pancreatic masses allowing tissue diagnosis by later introduced EUS-guided fine needle aspiration (FNA). During the time EUS was improved, electronic probes replaced mechanical probes adding ability of color Doppler, power Doppler, contrast enhanced endosonography as well as EUS elastography analysis. Meanwhile, CT technology has also experienced significant improvements raising the question whether EUS has lost ground in diagnostics of solid pancreatic masses. The aim of this review was to discuss the current evidence of clinical impact of EUS and EUS-FNA in evaluation of solid pancreatic masses with special emphasis on differentiation between benign and malignant pancreatic lesions. According to the literature, the detection of small pancreatic tumors, preoperative localization of pancreatic endocrine tumors and tissue sampling by fine-needle aspiration of pancreatic masses in cases with therapeutic consequences are considered firm indications for EUS. Cytological tissue analysis remains undisputed in differentiation benign from malignant lesions, but the question when FNA is needed is discussed. Color Doppler, power Doppler, contrast enhanced endosonography and especially elastography are also discussed as tools that are bringing additional information in evaluation of pancreatic masses, however insufficient for definitive judgment of the lesion's nature. Pancreatic cancer staging as indication for EUS is discussed controversially, inconsistent results and conflicting evidence in literature making adequate conclusion impossible. However, this indicates that at least the role of EUS is no longer undisputed in this matter. Resuming the role of EUS we can state that despite some controversies EUS is very valuable method in evaluation of solid pancreatic masses and with EUS guided FNA is nowadays by far the best method for obtaining tissue diagnosis.

Surgeons without scalpels. A review of natural orifice translumenal endoscopic surgery

Natural orifice translumenal endoscopic surgery (NOTES) is a new technique that allows access to the peritoneal cavity without passing through the anterior abdominal wall. This article reviews the evolution of NOTES and describes how it is currently being evaluated in animal models. It also discusses the potential benefits of the technique as well as the challenges it faces.

The role of endoscopic ultrasound in biliary strictures

The role of endoscopic ultrasound (EUS) in the diagnosis of biliary strictures is well established, and emerging evidence suggests it may also play a therapeutic role. Differentiating between benign and malignant causes of biliary strictures can be challenging, but EUS can aid in their diagnosis and may predict resectability. The diagnostic yield of EUS combined with fine-needle aspiration (FNA) is excellent, especially in distal bile duct strictures, and far surpasses endoscopic retrograde cholangiopancreatography (ERCP) with brushings. Intraductal ultrasound may add to the diagnostic sensitivity of ERCP with brushings when no mass is seen on cross-sectional imaging or EUS, or when EUS with FNA is negative and suspicion of cancer persists. EUS-guided cholangiography is an emerging technique that may aid biliary decompression when ERCP has failed or is not possible; however, new therapeutic echoendoscopes or accessories are needed before the use of this technique can become more widespread.

Doppler-endosonography with the GF-UE 160 electronic radial echoendoscope - current use and future potential

This tutorial survey with images examines current and possible future applications of the recently introduced 360-degree Doppler capable echoendoscopes. The better gray-scale resolution together with flow, spectral and color Doppler can improve EUS investigations in the mediastinum, abdomen and pelvis. There is no or very little EUS literature covering such important fields a Budd-Chiari syndrome, anatomic variations of the celiac trunk and hepatic artery, mesenteric artery flow determinations in the evaluation of mesenteric ischemia and arterial compression syndromes (celiac, superior mesenteric artery and hepatic artery). Additional other areas of possible future research are suggested.

Changing trends in endosonography: linear imaging and tissue are increasingly the issue

The indications and uses of endoscopic ultrasound (EUS) are expanding. The role of EUS-guided fine needle aspiration (EUS-FNA) is considered an essential aspect of EUS practice. A significant change in the indications and technology used for EUS has occurred. This study was designed to compare the use of radial, linear, and miniprobe endosonography equipment during a 10-year period in a single, large, EUS practice. A retrospective review of an EUS experience at a single high-volume center was performed. In this single-center experience, there has been an increase in the volume of EUS and EUS-FNA. For luminal cancer-staging cases, the radial echoendoscope is the predominant scope used for examination and has not changed significantly. In contrast, for pancreaticobiliary and mediastinal indications, the use of the linear array echoendoscope alone has increased and currently is the preferred scope for examination (33% vs. 76%, P < 0.001; 46% vs. 96%, P < 0.001). In these cases requiring EUS-FNA, the use of the linear array scope alone has increased from 17% to 73%. In this single-center experience, EUS has shifted from an imaging technology to an image-guided biopsy and therapeutic technology. The use of the linear array EUS alone has increased, especially in the evaluation of pancreatobiliary and mediastinal disease and when fine-needle aspiration is performed.

Endosonography: new developments in 2006

Recent progress of the data processing applied to ultrasound (US) examination made it possible to develop new software. The US workstation of the last generation thus incorporated a computer into their center that allowed a very precise treatment of the US image. This made it possible to work out new images like three-dimensional (3-D) US, the US of contrast-harmonic associated with the intravenous injection with product with contrast for US, and finally even more recently, elastography. These techniques, currently quite elaborate in percutaneous US, are to be adapted and evaluated with echoendoscopy (EUS). We thus will approach the 3-D EUS successively, then the contribution of the products of contrast for US with the pancreatic EUS, and finally, elastography guided by endosonography.

Interventional endoscopic ultrasound in pancreatic diseases

During the last 15 years, endoscopic ultrasound (EUS) has become an important imaging procedure for diagnosis and management of pancreatic diseases. The clinical interest of EUS is now enhanced by interventional procedures. Noteworthy, fine-needle aspiration biopsy is one of the most important contributions of EUS, in particular for the investigation of patients with pancreatic cancer and cystic tumors. EUS-guided fine-needle aspiration appears to be a safe and reliable technique to obtain tissue from pancreatic masses with a low risk of complications. EUS became also a therapeutic procedure, especially applied for celiac plexus neurolysis, pseudocyst drainage, and pancreaticogastrostomy. Further developments are expected by improvement of needle devices such as pancreatic pseudocyst drainage kits. In the future, EUS might be also a support for local application of new treatments of pancreatic tumors, such as gene or cellular therapy products. In this review, we discuss the current clinical applications of interventional EUS and the future development for diagnosis and management of pancreatic diseases.

Interventional applications of endoscopic ultrasound

Endoscopic ultrasound, which was developed more than 20 years ago, is currently a valuable investigative tool for endoscopists. It began as a diagnostic instrument and in the short span of a decade made a clinical impact as a therapeutic tool with a promising potential for various interventional applications. The introduction of the curved linear array echoendoscope in the 1990s enabled a whole range of interventional applications of endoscopic ultrasound ranging from fine needle aspiration of lesions surrounding the gastrointestinal tract to celiac plexus block and drainage of pancreatic pseudocyst. This review article outlines the current interventional applications of endoscopic ultrasound and discusses potential future procedures. These procedures include endoscopic ultrasound guided creation of communication between the gastrointestinal tract and adjacent organs, such as hepaticogastrostomy and choledochoduodenostomy.

Current status of laparoscopic ultrasound

The purpose of this chapter is to introduce the beginning surgeon ultrasonographer to the use of ultrasound during laparoscopic surgery. The authors routinely use ultrasound in the intraoperative, endoscopic, and office settings. The importance of ultrasound in the various surgical specialties is well documented in the literature. Since the introduction of minimally invasive techniques to General Surgery, many advanced applications of ultrasonography have been developed. Confident examinations of intraabdominal anatomy, pathologic conditions, and therapeutic procedures can readily be performed. In this chapter, a comprehensive introduction to laparoscopic ultrasound is presented to the practicing General Surgeon. The basic equipment requirements and setup are explained. Fundamental techniques of laparoscopic ultrasound examination are described. The authors' method of screening for common bile duct stones during routine laparoscopic cholecystectomy is illustrated. Examination of the normal biliary tree with helpful hints is presented. The authors' systematic technique of visualizing the normal liver parenchyma is described. Common benign and malignant findings are elucidated. A brief synopsis of pancreatic ultrasonography with attention to pathologic findings is provided. Uses of ultrasound in unanticipated situations are introduced. With perseverance, the reader will discover that laparoscopic ultrasound skills can be readily attained.

Present and future of endoscopic ultrasonography

Endoscopic ultrasonography and endoscopic ultrasonography-guided fine needle aspiration are well-established techniques, encompassing a variety of diagnostic and therapeutic applications. Along with traditional indications that constitute everyday clinical practice in all endoscopic ultrasonography centres, new indications are emerging that resemble the continuing research carried on in this field. Some of these are innovative applications, developed by highly experienced endosonographers and with a putative role for clinical practice in the near future. Others are merely experimental applications, carried out on in animal models or in highly selected groups of patients, opening up new fascinating areas of research but not for imminent introduction in clinical practice. The purpose of this review, after summarising the present indications of endoscopic ultrasonography, is to focus on the future applications and try to establish their possible advent, either in the near or in the far future.

The era of ultrasonography during laparoscopic cholecystectomy

BACKGROUND

The use of ultrasound cholangiography during cholecystectomy has been well described. This study was undertaken to assess the use of the umbilical port exclusively for ultrasound and to assess its employment on the use of fluoroscopy resources. In addition, we also looked at the increased use of ultrasound from 2000 to 2004.

METHODS

The use of imaging techniques during all cholecystectomies was analyzed from January 2000 to July 2001 for one surgeon and compared with that surgeon's present use from January 2004 to June 2004. Patient demographics, intraoperative finding, and postoperative results were reviewed.

RESULTS

During the first study period, ultrasound was used in 29% of 189 laparoscopic cholecystectomies. During 2004, ultrasound was used in 77% of 66 laparoscopic cholecystectomies. Throughout both periods, fluoroscopy was only used during 6 laparoscopic common bile duct explorations (2.4% of all cases). There were no false-positive or -negative ultrasounds, and there were no bile duct injuries.

CONCLUSIONS

As experience with ultrasound cholangiography increases, there is little indication for fluoroscopic cholangiography except for rare questions concerning anatomy and during therapeutic maneuvers for common bile duct stones.

Future therapeutic indications for endoscopic ultrasound

Attempts to perform therapy guided by endoscopic ultrasound (EUS) are rare. Some new indications for interventional and therapeutic endoscopic procedures performed under EUS control have been developed in areas that have been purely surgical for many years. Indications, procedures, and related tools for EUS-guided endosurgery are described, all of which are experimental but may open a new corridor for endoscopists to enter a variety of transluminal procedures in real time without soiling the peritoneal or mediastinal cavity.

Technology Insight: current status of endoscopic ultrasonography

Endoscopic ultrasound (EUS) has become the most accurate imaging modality for locoregional cancer staging of the gastrointestinal tract. Fine-needle aspiration (FNA) has added a new level of accuracy for EUS in nodal staging, with reported numbers in the 90% range for luminal and pancreaticobiliary disease. In addition, new non-gastrointestinal applications are being evaluated, such as the role of EUS-FNA for the staging of non-small-cell lung cancer and exploration of the posterior mediastinum. Furthermore, the same techniques that make safe tissue sampling possible are being explored for their use as interventional applications, such as EUS-guided celiac plexus neurolysis, fine-needle injection, EUS-guided pseudocyst drainage, and EUS-guided cholangiography and pancreatography. This review describes the current clinical status of EUS in gastrointestinal oncology, as well as future and novel indications and therapeutic strategies for this technology.

The substitution of endoscopic ultrasonography for endoscopic retrograde cholangio-pancreatography: implications for service development and training

Diagnostic indications of endoscopic retrograde cholangio-pancreatography (ERCP) have not completely disappeared. But the substitution of this examination by endoscopic ultrasonography (EUS) in the work-up of biliary and pancreatic diseases is supported by EUS's reliability and cost-effectiveness. In the future EUS will be challenged by magnetic resonance cholangiopancreatography (MRCP), when easily available. Therefore, the choice between EUS, MRCP and ERCP will become simplified: MRCP as the first option for diagnosis, EUS in doubtful cases needing sampling for pathology and ERCP as a therapeutic alternative to some surgical procedures.

Fine needle aspiration biopsy of gastric duplication cysts with endoscopic ultrasound guidance

OBJECTIVE

To evaluate the ability of endoscopic ultrasound (EUS)-guided fine needle aspiration biopsy (FNAB) to diagnose gastric duplication cysts.

STUDY DESIGN

FNAB reports from the Department of Pathology, Saint Louis University Hospital, were retrospectively searched for reports of EUS-guided FNABs of the stomach. These reports were then reviewed to find instances in which gastric duplication cysts were diagnosed. The charts of patients diagnosed with gastric duplication cysts were reviewed.

RESULTS

Two patients were identified. The first was a 35-year-old, Caucasian male with an asymptomatic submucosal (versus extrinsic) gastric mass discovered during computed tomography of the abdomen. The second was a 44-year-old, Caucasian male with a history of treated low grade B cell lymphoma of mucosa-associated lymphoid tissue (MALToma) who was found to have an asymptomatic gastric wall abnormality by EUS when undergoing follow-up for the MALToma. Respiratory-type epithelial cells were present in each of these gastric duplication cysts. At this writing, both patients were being followed clinically and with imaging.

CONCLUSION

Gastric duplication cysts, particularly those that have respiratory-type epithelium, can be diagnosed by EUS-guided FNAB. The diagnosis of gastric duplication cysts by EUS-guided FNAB can preclude surgery, with its associated morbidity.