Endoscopic Ultrasound in Gastroenteropancreatic Neuroendocrine Tumors

Endoscopic ultrasound (EUS) is an advanced endoscopic technique currently used in the staging and diagnosis of many gastrointestinal neoplasms. The proximity of the echoendoscope to the gastrointestinal tract lends itself to a detailed view of the luminal pathology and the pancreas. This unique ability enables endoscopists to use EUS in patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Diagnostic EUS allows previously unidentified NETs to be localized. EUS also determines tumor management by staging the GEP-NETS, enabling the clinicians to choose the appropriate endoscopic or surgical management. The ability to obtain a tissue diagnosis with EUS guidance enables disease confirmation. Finally, recent developments suggest that EUS may be used to deliver therapeutic agents for the treatment of NETs. This review will highlight the advances in our knowledge of EUS in the clinical management of these tumors.     

Acoustic Liver Biopsy Using Endoscopic Ultrasound

Background Transabdominal ultrasound cannot be used to quantitate fibrosis in patients with cirrhosis because of variability in the abdominal wall thickness and variability in the components of the abdominal wall (fat versus muscle). Endoscopic ultrasound through the gastric wall is always at a constant distance, approximately 3 mm, away from the liver when the transducer is just below the gastroesophageal junction, thereby eliminating this variability. Purpose To differentiate between cirrhotic and noncirrhotic liver using endoluminal ultrasound. Methods Eleven patients without known liver disease and eight patients with cirrhosis underwent endoscopic ultrasound using an Olympus linear ultrasound scope. The gain, contrast, frequency, and acoustic power were kept constant on the Aloka ultrasound processor. Videotaped images of the liver were recorded and then digitized on Image-Pro Plus software. The brightness of the image was adjusted to a standard brightness for each image and an area of interest was chosen using Photoshop 7.0. Vessels and artifacts were eliminated digitally and a histogram was produced using Photoshop to quantitate the pixel density for the area of interest from 0 (black) to 255 (white). Approximately 250,000 pixels were evaluated for each subject. The mean ± standard deviation (SD) pixel density of the noncirrhotic subjects was evaluated against the cirrhotic patients using a Student unpaired t-test. Results The mean echogenecity in patients with cirrhosis was 116.85 and the mean echogenecity in patients without cirrhosis was 92.75 (P < 0.002). The mean standard deviation of the pixel density in patients with cirrhosis was 19.08 and the mean standard deviation of the pixel density in patients without cirrhosis was 13.25 (P < 0.0004). Using these criteria the subjects with cirrhosis were segregated from the noncirrhotic subjects (normal subjects and the subjects with steatosis) with 100% sensitivity and 100% specificity. Conclusion A new method of evaluating the liver parenchyma (acoustic liver biopsy) that takes advantage of the proximity of the endoscopic ultrasound transducer to the liver and uses commercial image analysis technology that is inexpensive and widely available was developed. This is a preliminary study of this new technology, which demonstrates that endoscopic ultrasound, can be standardized in order to image, analyze, and compare the mean echogenecity and mean standard deviation of the pixel density in the liver in order to distinguish cirrhotic patients from patients without cirrhosis.     

Endoscopic Ultrasound in Patients Over 80 Years Old

Background  

The data on the safety and utility of EUS in patients over 80 years of age is limited.     

The Role of Endoscopic Ultrasound in Biliary Obstruction

The role of endoscopic ultrasound (EUS) in the diagnosis of biliary obstruction is well established, and emerging evidence suggests it may also play a therapeutic role. Differentiating between benign and malignant causes of biliary obstruction can be challenging, but EUS is a crucial tool in the armamentarium of the physician. Evolving technologies such as elastography and contrast enhancement may further supplement the diagnostic abilities of EUS. Therapeutic applications of EUS are evolving rapidly, and EUS-guided cholangiography may aid biliary decompression when endoscopic retrograde cholangiopancreatography (ERCP) has failed or is not possible.     

Prognostic Value of Endoscopic Ultrasound in Acute Pancreatitis

Background/Aims: Endoscopic ultrasonography (EUS) is a useful modality to diagnose causes of pancreatitis. The role of EUS for prediction of pancreatitis severity has not been studied. The aim of this study was to identify the utility of EUS in determining the severity of acute pancreatitis (AP). Methods: All patients diagnosed with pancreatitis consecutively underwent EUS on the 2nd day of their admission. Atlanta criteria were used as the severity index of pancreatitis. Results: During the study period, 114 patients (74 females, 40 males; mean age of 53.03 ± 17.7 years) were enrolled in the study. The most common cause of AP was gallstone (78.9%). According to the Atlanta criteria, pancreatitis was mild in 72 (63.2%) and severe in 42 (36.8%) patients. In univariate analysis, the presence of peri pancreatic edema, pancreas inhomogeneity, common bile duct dilation and ascites were associated with severe pancreatitis. In multivariate analysis, only the presence of peri pancreatic edema in EUS correlated with the severity of AP according to the Atlanta criteria (sensitivity, specificity and accuracy: 65.8, 75.7 and 72.2%, respectively). Conclusion: EUS may be a new useful imaging modality for prediction of severity of AP and may have prognostic significance in the early phase of AP.     

Complications of diagnostic and therapeutic Endoscopic Ultrasound

Endoscopic Ultrasound (EUS) provides the unique opportunity to visualize, interrogate and intervene gastrointestinal (GI) luminal, mural or peri-luminal structures and pathology with negligible adverse effects. Diagnostic, upper GI and rectal EUS is feasible, extremely safe, and efficacious. Most EUS guided interventions are safe, effective and minimally invasive, compared to peers in the percutaneous radiological or surgical procedures.As with any endoscopic procedure, EUS and its guided interventions may be accompanied by adverse events. EUS related complications are generally infrequent in expert hands, and mainly include bleeding and perforation. However, the nature and severity of adverse events associated with each EUS guided procedure are unique. Hence, it is paramount for endosonographer to have sufficient knowledge of the indications, techniques, and potential risks involved before contemplating any given procedure.Most common intervention with EUS is transmural fine needle aspiration (FNA), which is an extremely safe procedure. EUS guided drainage procedures are rapidly evolving with newer devices and methods being employed. Among them, EUS guided drainage of pancreatic fluid collection-pseudocyst or walled off necrosis (WON), has largely replaced other methods (surgical, percutaneous or non-EUS endoscopic) with acceptable complications. Currently, dedicated metal stents are more widely used compared to plastic stents for drainage of PFC, especially WON. EUS has made a definite impact in biliary access and drainage of obstructed biliary system, in patients where ERCP has failed or is technically not possible, closely competing with percutaneous biliary drainage. In spite of some complications, recent improvement in devices for bilio-enteric fistula creation and stent designs, has added to its safety and efficacy. EUS guided pancreatic duct drainage remains the most challenging of EUS guided interventions where in-roads are being made.     

Combined Endoscopic Ultrasound and Secretin Endoscopic Pancreatic Function Test in Patients Evaluated for Chronic Pancreatitis

Background  

Endoscopic ultrasound and endoscopic secretin pancreatic function test may be combined in a single endoscopic session (EUS/ePFT) to diagnose chronic pancreatitis (CP).     

Therapeutic Endoscopic Ultrasound for Biliary and Pancreatic Disorders

The role of endoscopic ultrasound (EUS) has greatly expanded since the first clinical examination performed nearly 30 years ago. The introduction of linear instruments allowed tissue sampling (Kulesza and Eltoum Clin Gastroenterol Hepatol 5:1248–1254, 2007; Levy and Wiersema Gastrointest Endosc 62:417–426, 2005) and therapeutic interventions applications, including celiac plexus and ganglia blockade and neurolysis (Wiersema and Wiersema Gastrointest Endosc 44:656–662, 1996; Levy and Wiersema Gastroenterol Clin North Am, 35:153–165, 2006; Levy et al. Am J Gastroenterol 103:98–103, 2008), pancreatic fluid drainage (Lopes et al. Arq Gastroenterol 45:17–21, 2008; Norton et al. Mayo Clin Proc 76:794–798, 2001; Kruger et al. Gastrointest Endosc 63:409–416, 2006; Seifert et al.: Endoscopy 32:255–259, 2000), cholecystenterostomy (Kwan et al. Gastrointest Endosc 66:582–586, 2007), and delivery of cytotoxic agents (eg, chemotherapy, radioactive seeds, and gene therapy) (Chang et al.: Cancer 88:1325–1335, 2000; Chang Endoscopy 38(Suppl 1):S88–S93, 2006). The continued need to develop less invasive alternatives to surgical and interventional radiologic therapies drove the development of EUS-guided methods for biliary and pancreatic intervention. This article reviews existing data and focuses on established and emerging EUS techniques for accessing and draining the bile and pancreatic ducts.