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Over the three last decades, endosonography ultrasound (EUS) has evolved from a diagnostic tool to an interventional modality through cumulative advances in experience, knowledge, equipment, and devices. EUS-guided therapeutic procedures appear feasible and safe when performed in highly-experienced centers. This review covers the technical aspects, indications, and results of the most commonly performed procedures. Celiac plexus neurolysis and collection drainages are now well-established techniques and considered to be first-line treatments. Biliary and pancreatic EUS-guided drainages are, conversely, more challenging, and there is currently insufficient clinical evidence documenting their superiority over established practice. Well-designed prospective trials are thus needed in order to accurately assess this modality's risks and long-term outcomes compared to radiological or surgical techniques.

Background and Study Aims: Transoesophageal endosonography with fine needle aspiration (EUS-FNA) and 2-deoxy-2-[fluorine-18]fluoro-D-glucose positron emission tomography (FDG-PET) are now standard diagnostic procedures of the mediastinum. Our aim was to compare their value in the assessment of enlarged mediastinal lymph nodes detected by computed tomography., Patients and Methods: Forty consecutive patients with a suspicion of cancer or a history of pulmonary, digestive, urogenital or mammary neoplasia and presenting with supracentimetric lymph nodes on computed tomography underwent whole body FDG-PET and EUS-FNA. Final diagnosis of malignancy was obtained by cytology, surgery or long-term follow-up., Results: EUS-FNA showed a sensitivity, specificity and accuracy for detection of malignancy of 793, 100 and 85%, respectively. The biopsy material was adequate for cytological examination in 37 patients. Sensitivity, specificity and accuracy of PET were 100, 54.5 and 87.5%, respectively. FDG-PET correctly diagnosed the primary site in 27 patients, and showed additional unknown extrathoracic metastatic sites in 15 patients. The five false positive results observed with FDG-PET consisted in a final diagnosis of sarcoidosis, tuberculosis, anthracosilicosis and reactive lymph nodes, respectively. The association of FDG-PET and EUS-FNA avoided more invasive procedures (mediastinoscopies or staging surgery) in 34 patients., Conclusions: EUS-FNA and FDG-PET are complementary diagnostic procedures combining the high sensitivity of FDG-PET and the high specificity of EUS-FNA to accurately diagnose malignancy in enlarged mediastinal lymph nodes identified by CTscan. The combination of the two procedures in selected cases with pulmonary cancer or extra-thoracic tumours avoided more invasive diagnostic and surgical procedures.

Background and Study Aims: The purpose of this study was to identify possible associated factors that may have contributed to failure to detect a pancreatic neoplasm during endoscopic ultrasound (EUS) examinations by experienced endosonographers., Patients and Methods: A multicenter retrospective study was organized, and 20 cases of pancreatic neoplasms missed by nine experienced endosonographers were identified. Careful analysis of each case was carried out to identify the factors that might have led to the missed diagnosis on EUS., Results: Twelve patients with a missed pancreatic neoplasm had EUS features of chronic pancreatitis. Other factors that might have increased the likelihood of a false-negative EUS examination included a diffusely infiltrating carcinoma (n = 3), a prominent ventral/dorsal split (n = 2), and a recent episode (within the previous 4 weeks) of acute pancreatitis (n = 1). Five patients with a negative initial EUS underwent a follow-up EUS after 2-3 months, with a pancreatic mass being found in all cases. Three patients had a diffusely infiltrating pancreatic adenocarcinoma., Conclusions: EUS is not a foolproof method of detecting a pancreatic neoplasm. Possible associated factors that may increase the likelihood of a false-negative EUS examination include chronic pancreatitis, a diffusely infiltrating carcinoma, a prominent ventral/dorsal split and a recent episode (< 4 weeks) of acute pancreatitis. If there is a high clinical suspicion of pancreatic neoplasm, if EUS and other imaging methods are negative, and if the patient does not undergo surgery, this study suggests that a repeat EUS after 2-3 months may be useful for detecting an occult pancreatic neoplasm.

Recent studies have shown that endoscopic ultrasonography (EUS) is the most sensitive method for diagnosing choledocholithiasis. High sensitivities of more than 95% have been reported by several authors. Imaging the extrahepatic bile ducts and the gallbladder and searching for biliary stones are easy tasks for EUS. EUS has the advantages over ERCP to be less invasive (complication rate similar to diagnostic upper GI endoscopy) and to be able to detect small stones and sludge that can easily be masked by contrast medium during ERCP. In comparison with magnetic resonance imaging (MRI), EUS has the advantage to be close to the investigated areas and to allow the detection of very small stones or sludge, even in non dilated bile ducts. Technical limitations of biliary imaging by EUS are few: upper GI stenosis, previous gastrectomy or Billroth II resection. Imaging can be obscured by the presence of air (previous sphincterotomy or surgical bypass), surgical clips calcifying pancreatitis or a duodenal diverticulum. Main indications of EUS include the detection of choledocholithiasis in patients with a low and intermediate probability of presence of stones, in idiopathic acute pancreatitis, in mild and moderate pancreatitis after normal transabdominal ultrasonography, in pregnant women, in intensive care patients, in the diagnosis of gallbladder lithiasis or sludge, and also when MRI is contraindicated (claustrophobia and metallic implants) or fails to provide a diagnosis or is not available. Screening of choledocholithiasis with EUS has also been proposed in patients scheduled for laparoscopic cholecystectomy, but this is not common practice in Belgium.

Background and Study Aims: The aim of this study was to compare prospectively the diagnostic efficacy of magnetic resonance (MR) imaging and endoscopic ultrasonography (EUS) in extrahepatic biliary obstruction., Patients and Methods: A total of 50 patients with suspected benign or malignant extrahepatic biliary obstruction underwent MR imaging, including MR cholangiopancreatography, and EUS, within a median time delay of 1 day. The final diagnosis was established by endoscopic retrograde cholangiopancreatography in 37 cases, intraoperative cholangiography in nine cases, and clinical and biochemical follow-up in four cases., Results: In total, 33 patients had extrahepatic biliary obstruction, of benign origin in 21 cases and of malignant origin in 12 cases, whereas 17 had no evidence of obstruction. The sensitivity and specificity of MR imaging were 91% and 94 %, respectively. There were one false-positive and three false-negative results, all related to choledochal sludge. The corresponding values for EUS were 97% and 88%. There were two false-positive results and one false-negative result. False-positive diagnoses were related to the presumed presence of biliary sludge and choledocholithiasis, whereas the false-negative diagnosis occurred in one patient with a final diagnosis of sludge. No significant difference in sensitivity and specificity was observed between the two imaging methods (P>0.05)., Conclusion: In our study MR imaging was as accurate as EUS in the diagnosis of extrahepatic biliary obstruction.

Endosonography may be considered as a very special area in endoscopy. It really revolutionised endoscopy in allowing seeing behind the digestive lumen, in accessing the mediastinum and the pancreas, and in performing the first “NOTES” procedures. Endoscopists have usually mixed feelings towards endosonography: most of them consider EUS as the “Holy Grail” since it is one of the most complex diagnostic and therapeutic endoscopic procedures, but many users are still uncomfortable with some anatomical landmarks and with the choice of equipment. Echoendoscopes are indeed known to be costly and fragile, and quite versatile with the choice between different manufacturers, and between radial or linear (convex array) oriented instruments. This review aims at providing up-to-date information on the different types of echoendoscopes and processors and on normal endosonographic anatomy of the digestive tract, the mediastinum, the pancreas and the biliary tree. [Copyright &y& Elsevier]