***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND The cause of pancreatitis is unknown in as many as 30 % of cases of recurrent acute pancreatitis , even after ERCP . OBJECTIVE To investigate the role of intraductal US ( IDUS ) for managing idiopathic recurrent pancreatitis ( IRP ) . DESIGN Prospect i ve study . SETTING Tertiary referral hospital . PATIENTS Thirty-one patients with suspicious IRP with negative findings on ERCP . INTERVENTIONS IDUS during ERCP . MAIN OUTCOME MEASUREMENTS IDUS findings showing any possible cause of pancreatitis . RESULTS IDUS revealed small bile duct stones ( ≤3 mm ) in 5 patients ( 16.1 % ) and sludge in 3 patients ( 9.7 % ) . The detection rate for a bile duct stone and sludge was significantly higher in patients with a dilated CBD than a nondilated CBD on ERCP ( 71.4 vs 12.5 % ; P < .05 ) . Recurrent pancreatitis did not develop in 7 of 8 patients with biliary stones or sludge after an endoscopic sphincterotomy ( EST ) . Two patients ( 6.5 % ) demonstrated a small polypoid lesion on the distal end of the pancreatic duct . One patient underwent surgery for intra-ampullary cancer , and another one underwent EST without another attack of pancreatitis . Three patients ( 9.7 % ) showed evidence of chronic pancreatitis with small pancreatic stones and /or calcifications on IDUS . LIMITATIONS Small number of patients . IDUS results were not compared with those of conventional EUS . There was no reference st and ard for chronic pancreatitis as diagnosed by IDUS . CONCLUSIONS IDUS identified a possible cause of idiopathic recurrent pancreatitis in 42 % of patients with negative findings on ERCP . The IDUS-guided approach combined with ERCP and EST may be useful for decreasing recurring attacks of pancreatitis BACKGROUND The aim of this study was to evaluate the use of endoscopic ultrasonography ( EUS ) in detecting occult cholelithiasis and determining a probable etiology in patients classified as having idiopathic pancreatitis by conventional radiologic methods . METHODS A prospect i ve study was performed in 89 consecutive patients with acute pancreatitis .  Transcutaneous ultrasonography ( US ) , CT , or both was performed on all patients within 24 hours of admission .  Endoscopic retro grade cholangiopancreatography ( ERCP ) was performed in all patients with confirmed or suspected biliary pancreatitis .  EUS was performed in patients classified as having idiopathic pancreatitis . RESULTS Cholelithiasis was identified in 64 patients ( 72 % ) by conventional radiologic methods . Eighteen patients ( 20 % ) were classified as having idiopathic pancreatitis after evaluation by US ( all 18 patients ) , repeated US ( 9 patients ) , CT ( 6 patients ) and ERCP ( 13 patients ) . EUS performed in these 18 patients revealed small gallbladder stones ( 1 to 9 mm ) in 14 patients ; 3 were found to have concomitant choledocholithiasis . All stones were confirmed by subsequent ERCP and cholecystectomy . The remaining 4 patients in whom no etiology was identified had no clinical or radiologic evidence of cholelithiasis at a median follow-up of 22 months . CONCLUSION Cholelithiasis is detected by EUS in a large number of patients classified as having idiopathic pancreatitis by conventional radiologic examinations . With identification of a biliary cause of acute pancreatitis , treatment can be initiated early , thereby reducing the risk of recurrent pancreatitis with its associated morbidity and mortality . EUS is a valuable diagnostic modality in the management of patients with acute pancreatitis BACKGROUND Alcohol and gallstone are the 2 most common etiologies of acute pancreatitis ( AP ) . In Thail and , alcohol has been believed to be the leading etiology of AP . However , a thorough and systematic search may discover real etiology of AP . MATERIAL AND METHOD During 2006 to 2007 , seventy-eight patients with AP were prospect ively search ed for the etiology by : 1 . Performing liver chemistry tests and transabdominal ultrasonography ( US ) for gallstone in every case ; 2 . Measuring serum triglyceride and calcium in every case ; 3 . Investigating definite drugs use or other identified etiology ; 4 . Asking about the amount of alcohol ingestion ( amount > 80 g/day for > 5 years was required for alcoholic AP ; 5 . Performing CT scan ( if age > 40 years ) and EUS if no etiology was identified . Results were compared with the retrospective data from medical records of 66 AP patients during 2003 - 2005 . RESULTS Of the 78 patients , the etiologies were alcohol in 32 ( 41 % ) , gallstones in 29 ( 37 % ) , miscellaneous in 13 ( 17 % ) and idiopathic AP in 4 patients ( 5 % ) . When compared with the retrospective data of the 66 patients over the past 3 years , the etiologies were alcohol 53 % , gallstone 22 % , miscellaneous 11 % and idiopathic 14 % . Among the 45 patients of the study period ( 58 % ) who consumed alcohol more than the defined threshold for alcoholic AP , 13 ( 29 % ) were found to have other explainable causes of AP , i.e gallstones in 10 , hypertriglyceridemia in 2 and AIDS cholangiopathy in 1 patient . CONCLUSION Alcohol was probably over-diagnosed as a leading etiology of AP in the past . A systematic search of the etiologies lowered the frequency of alcoholic and idiopathic AP but discovered more patients with gallstone pancreatitis . One-fourth of AP patients who were heavy drinkers had other explainable etiologies of AP Background The efficacy of endoscopic ultrasonography ( EUS ) to diagnose idiopathic acute pancreatitis has been demonstrated but that of magnetic-resonance cholangiopancreatography ( MRCP ) remains unclear . Aims The aim of our study was to prospect ively compare the results of EUS and MRCP to diagnose idiopathic acute pancreatitis when performed later after an acute attack . Methods All patients admitted to our center for acute pancreatitis over a 2-year period received first-line investigations that included medical history , st and ard biological measurements , abdominal ultrasound , and computerized tomography . If no etiology was found , second-line investigations were scheduled at 2 months ( or more if there was severe pancreatitis ) , which included clinical examinations , biological parameters , EUS , and MRCP . Results A total of 128 consecutive patients were included ( male : 80 , mean age : 55.3 years ) . After first-line investigations , 41 patients with idiopathic acute pancreatitis underwent second-line investigations and were followed-up ( 38 patients had both EUS and MRCP ) . EUS and /or MRCP led to recognize a possible etiology of pancreatitis in 19 patients ( 50 % ) . The diagnostic yield for EUS was higher than for MRCP ( 29 vs. 10.5 % ) . EUS more accurately detected biliary stones whereas MRCP identified pancreatic duct abnormalities , such as intraductal papillary mucinous neoplasm of the pancreas or chronic pancreatitis . Conclusions The combination of EUS and MRCP , when performed later after idiopathic acute pancreatitis , revealed 50 % of etiologies . The association of these two procedures and the subsequent follow-up reduced the rate of idiopathic pancreatitis by ~66 % PURPOSE No underlying cause is found in as many as 30 % of patients with acute pancreatitis . The aim of this study was to evaluate the usefulness of endoscopic ultrasonography in the diagnosis of biliary tract pathology or chronic pancreatitis in these patients . SUBJECTS AND METHODS We evaluated 168 patients who were referred with idiopathic pancreatitis . Diagnoses obtained by endoscopic ultrasonography were prospect ively compared with those obtained at surgery in 101 patients , by endoscopic cholangiopancreatography in 49 patients , or by bile crystal analysis and medical follow-up in 18 patients . RESULTS  Endoscopic ultrasonography was abnormal in 135 ( 80 % ) patients , 124 of whom had biliary tract disease . When the results of endoscopic ultrasonography were compared with those made after multidisciplinary investigations , endoscopic ultrasonography correctly identified the cause-most commonly biliary tract disease-of the " idiopathic " pancreatitis in 155 ( 92 % ) of the 168 patients . CONCLUSIONS Endoscopic ultrasonography is valuable in determining the cause of acute pancreatitis in patients initially considered to have idiopathic pancreatitis OBJECTIVES New modalities , namely , endoscopic ultrasonography ( EUS ) , magnetic resonance cholangiopancreatography ( MRCP ) , and helical computed-tomographic cholangiography ( HCT-C ) , have been introduced recently for the detection of common bile duct ( CBD ) stones and shown improved detectability compared to conventional ultrasound or computed tomography . We conducted this study to compare the diagnostic ability of EUS , MRCP , and HCT-C in patients with suspected choledocholithiasis . METHODS Twenty-eight patients clinical ly suspected of having CBD stones were enrolled , excluding those with cholangitis or a definite history of choledocholithiasis . Each patient underwent EUS , MRCP , and HCT-C prior to endoscopic retro grade cholangio-pancreatography ( ERCP ) , the result of which served as the diagnostic gold st and ard . RESULTS CBD stones were detected in 24 ( 86 % ) of 28 patients by ERCP/IDUS . The sensitivity of EUS , MRCP , and HCT-C was 100 % , 88 % , and 88 % , respectively . False negative cases for MRCP and HCT-C had a CBD stone smaller than 5 mm in diameter . No serious complications occurred while one patient complained of itching in the eyelids after the infusion of contrast agent on HCT-C. CONCLUSIONS When examination can be scheduled , MRCP or HCT-C will be the first choice because they were less invasive than EUS . MRCP and HCT-C had similar detectability but the former may be preferable considering the possibility of allergic reaction in the latter . When MRCP is negative , EUS is recommended to check for small CBD stones Objectives : The objectives of the study were to compare endoscopic ultrasonography ( EUS ) and magnetic resonance cholangiopancreatography ( MRCP ) in the etiological diagnosis of patients initially diagnosed with idiopathic acute pancreatitis and to determine the clinical and analytical factors related to the end result of these techniques . Methods : Forty-nine patients , initially diagnosed with idiopathic acute pancreatitis , were evaluated prospect ively with  EUS and MRCP . Diagnoses were compared between the 2 procedures . The clinical -evolutionary characteristics of these patients with regard to the results obtained with these techniques were compared . Results : In twenty-eight patients ( 57 % ) , EUS and /or MRCP diagnosed at least 1 possible cause of acute pancreatitis . The diagnostic yield of EUS was higher than that of MRCP ( 51 % vs 20 % ; P = 0.001 ) . Cholelithiasis and biliary sludge ( 24 % ) were the most frequent EUS diagnoses , and pancreas divisum ( 8 % ) was the most frequent MRCP diagnosis . Only in 3 cases ( 6 % ) did MRCP identify additional features in patients etiologically undiagnosed using EUS . The  EUS yield was lower in patients who had a previous cholecystectomy ( 11 % vs 60 % ; P = 0.008 ) . Conclusions : Endoscopic ultrasonography and MRCP are useful techniques in the etiological diagnosis of acute pancreatitis of nonestablished cause . Endoscopic ultrasonography should be preferred for establishing a possible biliary etiology in patients who have not had a cholecystectomy Gallstone pancreatitis is usually related to small stones , which may not be detected by conventional cholecystographic techniques . In the current study , it was hypothesized that some patients with acute pancreatitis of unknown cause could harbor occult microstones in the gallbladder . Therefore , evidence was sought prospect ively of missed gallstones by biliary drainage and microscopic examination of centrifuged duodenal bile in 51 patients recovering from an attack of acute pancreatitis , including 24 patients with relapsing episodes . Clusters of cholesterol monohydrate crystals , calcium bilirubinate granules , and /or CaCO3 microspheroliths were found in 67 % of the patients . Biliary drainage showed no abnormal findings in 12 patients convalescing from a bout of known alcoholic pancreatitis . Examination of gallbladder bile at cholecystectomy and /or serial ultrasonography of the gallbladder for up to 12 months showed that 73 % of the patients with unexplained pancreatitis had biliary sludge or microlithiasis ; the prior finding of biliary crystal/solid markers predicted their existence with both a sensitivity and a specificity of 86 % and a 
    Output:
    
EUS more accurately detected biliary stones , whereas magnetic resonance cholangiopancreatography more often identified pancreatic duct abnormalities .
The yield of EUS  was lower in patients postcholecystectomy but was not influenced by gender , severity of pancreatitis , or recurrent disease .