***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: BACKGROUND EUS may be used to reduce the need of diagnostic ERCP . OBJECTIVE Our purpose was to investigate the benefits and safety of an EUS-guided versus an ERCP-guided approach in the management of suspected biliary obstructive diseases caused by choledocholithiasis , in whom a US study is not diagnostic . DESIGN A r and omized study . SETTING A university medical unit . PATIENTS Patients with clinical , biochemical , or radiologic suspicion of biliary obstruction . INTERVENTIONS In the EUS group , therapeutic ERCP was performed at the same EUS session if a lesion was found . In the ERCP group , therapeutic treatment was carried out at the discretion of the endoscopist . MAIN OUTCOME MEASUREMENTS The number of ERCPs avoided , procedure-related complications , and recurrent biliary symptoms on follow-up at 1 year . RESULTS Thirty-three patients were r and omized to EUS and 32 to ERCP .  Three patients ( 9.4 % ) had failed ERCPs , whereas all EUS procedures were successful . Nine ( 27.3 % ) patients in the EUS group were found to have biliary lesions that were all treated by ERCP . In the ERCP group , 7 ( 22 % ) patients had biliary lesions detected that were treated in the same session . More patients had serious complications ( bleeding , acute pancreatitis , and umbilical abscess ) in the ERCP group . One patient in each group had recurrent biliary symptoms during follow-up . With EUS used as a triage tool , diagnostic ERCP and its related complications could be spared in 49 ( 75.4 % ) patients . CONCLUSIONS In patients suspected to have biliary obstructive disease , EUS is a safe and accurate test to select patients for therapeutic ERCP Twenty patients with symptomatic cholelithiasis and suspected choledocholithiasis were evaluated in an ongoing prospect i ve trial using endoscopic ultrasonography ( EUS ) , st and ard abdominal ultrasonography ( US ) and ERCP for the detection of choledocholithiasis prior to laparoscopic cholecystectomy . EUS was used successfully to image the extrahepatic bile duct in all patients . EUS detected three of four proven bile duct stones and correctly identified 16 bile ducts as stone free , thus being more accurate than st and ard abdominal US . The preliminary results of this ongoing prospect i ve trial and the experience reported by other authors suggest that  EUS may be as sensitive as ERCP  in the detection of choledocholithiasis Objective The authors determined the most useful predictors of  common bile duct ( CBD ) stones as diagnosed by endoscopic retro grade cholangiopancreatography ( ERCP ) in patients who underwent laparoscopic cholecystectomy ( LC ) .  Methods Prospect i ve and retrospective collection of historical , biochemical and ultrasonographic data was used . Receiver operating characteristics curve analysis was used to determine optimal biochemical cut-off values . Multivariate analysis using logistic regression with generation of the best model identifying independent predictors of CBD stones also was employed . Prospect i ve validation of the model was performed on an independent group of patients . Results Endoscopic retro grade cholangiopancreatographies were performed before LC in 106 patients , and after LC in 33 . Only four of ten clinical variables evaluated independently predicted the presence of CBD stones . The optimal model predicted a 94 % probability of CBD stones in a patient older than 55 years of age who presented with an elevated biliubin ( over 30 μmol/L ) and positive ultrasound findings ( a dilated CBD , and a CBD stone seen on ultrasound ) . This model was vali date d prospect ively in a subsequent series of 49 patients in which the probability of CBD stone was only 8 % when all four predictors were absent . Conclusions The identified independent clinical predictors of a CBD stone helps select a population of symptomatic gallstone bearers who benefit most from cholangiographic assessment BACKGROUND & AIMS The role and potential benefits of endoscopic ultrasonography ( EUS ) in the management of acute biliary pancreatitis have not been documented . We report a large prospect i ve r and omized study comparing early EUS and endoscopic retro grade cholangiopancreatography ( ERCP ) in the management of these patients . METHODS A prospect i ve r and omized study was performed on 140 patients with acute pancreatitis suspected to have a biliary cause . The patients were r and omized to have EUS ( n = 70 ) or ERCP ( n = 70 ) within 24 hours from admission . In the EUS group , when EUS detected choledocholithiasis , therapeutic ERCP was performed during the same endoscopy session . In the ERCP group , diagnostic ERCP was performed , followed by therapeutic endoscopy when choledocholithiasis was detected . RESULTS Examination of the biliary tree by  EUS  was successful in all patients in the EUS group , whereas cannulation of the common duct during ERCP was unsuccessful in 10 patients ( 14 % ) in the ERCP group ( P = .001 ) . Combined percutaneous ultrasonography and  ERCP missed detection of cholelithiasis in 6 patients in the ERCP group . The overall morbidity rate was 7 % in the EUS group , and that in the ERCP group was 14 % ( P = .172 ) . The hospital stay and mortality rates were comparable in both groups . CONCLUSIONS In selected patients with acute biliary pancreatitis , EUS could safely replace diagnostic ERCP in the management for selecting patients with choledocholithiasis for therapeutic ERCP with a higher successful examination rate , a higher sensitivity in the detection of cholelithiasis , and a comparable morbidity rate BACKGROUND AND STUDY AIMS Diagnostic endoscopic retro grade cholangiography ( ERC ) is being replaced by endoscopic ultrasonography ( EUS ) in patients with suspected bile duct stones . The assumption that such an approach is advantageous , however , has never been tested in a r and omized trial . PATIENTS AND METHODS 100 patients with intermediate probability of bile duct stones were r and omly allocated to EUS or ERC .  Two patients in the ERC group were excluded ; the remaining 98 patients received the allocated intervention and were entered into the analysis ( EUS , 50 patients ; ERC , 48 patients ) . Detected stones were removed endoscopically ; patients without stones were followed for 1 year . The primary end point was the proportion of patients with a negative outcome , related to either endoscopic procedures ( complications ) or to false-negative diagnosis of stones . Investigators assessing the negative outcomes were not blinded to group assignment . The secondary end point was the total number of endoscopic procedures ( EUS and ERC ) performed in each group to diagnose and treat stones . RESULTS Bile duct stone prevalence was 28 % and 25 % in the EUS and ERC groups , respectively ( P > 0.05 ) . In the EUS group , 71 endoscopic procedures were performed , and 63 in the ERC group ( mean per patient , 1.42 + /- 0.76 , and 1.31 + /- 0.55 , respectively ; P > 0.05 ) . In the EUS group , these included 49 successful and one failed initial EUS , 15 ERCs for bile duct stone treatment , and six procedures required during follow-up . In the ERC group there were 36 successful and 12 failed initial ERCs , 13 repeat procedures ( EUS or ERC ) performed after failed or equivocal initial ERC , and two procedures during follow-up . Five patients in the EUS group ( 10 % , 95 % CI 4 - 22 ) and 19 patients in the ERC group ( 40 % , 95 % CI 27 - 54 ) experienced a negative outcome ( P < 0.001 ) . No difference was observed when only moderate to severe complications were considered ( 6 % , 95 % CI 1 - 17 , and 10 % , 95 % CI 4 - 23 , respectively ) . CONCLUSIONS In patients with intermediate probability of bile duct stones , the management strategy based on EUS ( with selective ERC in patients with confirmed stones ) is safer and not associated with an excess of endoscopic procedures compared with a strategy based on ERC alone BACKGROUND This prospect i ve study of the use of EUS to prevent unnecessary endoscopic retro grade cholangiography in patients with suspected choledocholithiasis has two aims : to evaluate the effectiveness , based on patient outcome , and the potential clinical and economic benefits of EUS . METHODS A prospect i ve series of 485 patients ( 202 men , 283 women ; mean age 66.2 years , range 20 - 94 years ) suspected to have choledocholithiasis based on clinical , biochemical , and cross-sectional imaging ( US or CT ) data underwent EUS .  Positive EUS findings were confirmed by endoscopic retro grade cholangiography with sphincterotomy and /or by surgery ; negative findings were confirmed by clinical follow-up . An EUS result was considered a true negative if the patient was confirmed symptom-free with normal tests on follow-up of at least 6 months . The costs of EUS ( procedure , days of hospitalization , any morbidity ) were compared with the estimated costs of the endoscopic retro grade cholangiography avoided in patients with true-negative EUS findings . RESULTS EUS findings were verified in 463 patients : EUS diagnosed choledocholithiasis in 239 ( 51.6 % ) and the absence of stones in 220 patients . In 4 patients ( 0.8 % ) , EUS was incomplete . By sphincterotomy ( 209 patients ) , surgical bile duct exploration ( 39 ) , percutaneous cholangiography ( 1 case in which EUS demonstrated a bile duct tumor ) , and follow-up ( 214 ) , EUS diagnoses were confirmed as follows : 237 true-positive , 216 true-negative , 2 false-positive , 4 false-negative , 4 incomplete ( sensitivity 98 % , specificity 99 % , positive predictive value 99 % , negative predictive value 98 % , accuracy 97 % ) . In 214 ( 46 % ) patients , more invasive investigations of the bile duct were avoided . The mean cost for patients managed by the EUS-based strategy was ' 374.50 ( -284.72 ) , which was significantly less than the theoretical mean cost of ' 443.80 ( p < 0.001 ) for patients undergoing endoscopic retro grade cholangiography . CONCLUSIONS The results of this study confirm that EUS is highly reliable for the diagnosis of choledocholithiasis . Its use offers considerable clinical and economic advantages by preventing inappropriate and more invasive evaluation of the bile duct Endosonography , ultrasonography , and computed tomography ( CT ) were carried out prospect ively in 52 patients with extrahepatic cholestasis . 35 patients had extrahepatic biliary obstructions ( 21 tumorous , 14 non-tumorous ) and 17 , with recent gallstone migration within the bile duct , had no extrahepatic obstruction at the time of investigation . The definitive diagnosis was established by surgery ( in 39 patients ) , by transendoscopic sphincterotomy ( 11 patients ) , or by retro grade biliary opacification ( 2 patients ) .  Endosonography  was significantly more sensitive than ultrasonography or CT ( 100 % vs 80 % and 83 % , respectively ) in making a positive diagnosis of obstruction . Endosonography  was also significantly more accurate than ultrasonography or CT  ( 97 % vs 49 % and 66 % ) in diagnosing the cause of the obstruction and more effective in the assessment of the locoregional spread of tumorous obstructions ( 75 % vs 38 % and 62 % ) . Thus , endosonography was superior to ultrasonography and CT in the diagnosis and staging of biliary obstructions BACKGROUND Factors affecting diagnostic accuracy and comparison of patients in the follow-up period for negative outcomes are not thoroughly investigated in a r and omized trial . OBJECTIVE Our purpose was to compare diagnostic accuracy , complications , and number of interventions . DESIGN Prospect i ve , unicentric , single-blind , r and omized study . SETTING Single tertiary referral university hospital . PATIENTS One hundred twenty patients with intermediate risk for common bile duct ( CBD ) stones were r and omized to either an EUS-first , endoscopic retro grade cholangiography (ERC)-second ( n = 60 ) versus an ERC-only ( n = 60 ) procedure . INTERVENTIONS EUS , ERC , sphincterotomy , and balloon sweeping of CBD when needed . MAIN OUTCOME MEASUREMENTS Sensitivity of EUS versus ERC , factors affecting diagnostic capability , complications , total number of endoscopic procedures . RESULTS The sensitivity and specificity of ERC were 75 % ( 95 % CI , 42%-93 % ) and 100 % ( 95 % CI , 95%-100 % ) , respectively . The sensitivity and specificity of EUS were 91 % ( 95 % CI , 59%-99 % ) and 100 % ( 95 % CI , 95%-100 % ) , respectively . EUS is more sensitive than ERC in detecting stones smaller than 4 mm ( 90 % vs 23 % , P < .01 ) . 
    Output:
    
By performing EUS first , ERCP may be safely avoided in two-thirds of patients with common bile duct stones .
Application of EUS in the selection of patients for therapeutic ERCP significantly reduces the complication rate