***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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    ***EXAMPLES*** 
    Input: BACKGROUND Endoscopic ultrasound is increasingly used for evaluation of pancreatic cancer . The potential of sonographic morphology to differentiate histology type and biological behaviour of pancreatic lesions is doubtful . METHODS We prospect ively studied 115 patients with focal pancreatic lesions on endoscopic ultrasound .  Morphology was assessed using Olympus UM3/20/200 echoendoscopes . Histologic confirmation of diagnosis was obtained in all patients . RESULTS Endoscopic ultrasound correctly diagnosed 18/34 benign and 77/81 malignant lesions . Sensitivity , specificity , accuracy , PPV and NPV for diagnosing malignancy were 95 % , 53 % , 83 % , 83 % and 82 % , respectively .  Endosonographic diagnosis of the lesions ( % correct ) were : pancreatic cancer , 84 ( 63.3 % ) ; chronic pancreatitis , 14 ( 71.4 % ) ; ampullary cancer , 9 ( 77.8 % ) ; cystadenoma , 5 ( 80 % ) ; ampullary adenoma , 2 ( 50 % ) ; acute pancreatitis , 1 ( 0 ) . In 13 patients of chronic pancreatitis , diagnosed as cancer , diagnosis was based on absence of sonographic features of chronic pancreatitis ( 7 ) or suspected involvement of adjacent structures ( 6 ) . In 3 patients malignancy was missed owing to features of chronic pancreatitis . Non-suspected neuroendocrine tumours were misjudged in all 10 cases using morphologic criteria as pancreatic cancer ( 8) , cystadenoma and chronic pancreatitis . Accuracy for prediction of metastatic lymph nodes and an advanced pancreatic cancer stage ( TxN1 or T3Nx ) was 61 % and 75 % , respectively . On retrospective analysis , a lesion > 2 cm , vessel ingrowth , absence of cystic spaces and absence of diffuse pancreatitis were associated with pancreatic cancer . CONCLUSIONS While overall sensitivity was high , specificity of endoscopic ultrasound for diagnosis of malignancy was low , especially in presence of chronic pancreatitis . In addition , endosonography had only a limited potential to predict the histological type of lesions BACKGROUND Magnetic resonance cholangiopancreatography ( MRCP ) is a non-invasive and increasingly used procedure in cases involving biliary and pancreatic diseases . However , the accuracy of MRCP in differential diagnosis between pancreatic cancer and chronic pancreatitis has never been documented in a large prospect i ve controlled study . METHODS 124 patients were recruited for the study , selected from 141 consecutive patients with an average age of 55 years ( range 19 - 80 ) who presented to our department between February , 1996 , and January , 1998 , with a strong clinical suspicion of pancreatic cancer .  MRCP images were interpreted by a radiologist and a gastroenterologist who were unaware of the clinical diagnosis of patients . The exact diagnosis was based upon histological evidence from biopsy examination ( surgical and fine needle biopsy ) or a follow-up of at least 12 months . FINDINGS Of the 124 patients , 37 ( 30 % ) had pancreatic carcinoma ; 17 ( 14 % ) had other neoplastic pancreatic diseases ; 57 ( 46 % ) had chronic pancreatitis ; 13 ( 10 % ) pancreatic ducts were clear . The sensitivity of MRCP  with respect to diagnosing pancreatic cancer was 84 % and its specificity 97 % . The corresponding values for endoscopic retro grade cholangiopancreatography ( ERCP ) were 70 % and 94 % , respectively . INTERPRETATION  MRCP  is as sensitive as ERCP when detecting pancreatic carcinomas . Furthermore , it is feasible to presume that the use of MRCP may prevent inappropriate explorations of the pancreatic and common bileducts in cases of suspected pancreatic carcinomas , where interventional endoscopic therapy ( ie , palliative common-bileduct drainage ) is unlikely Endoscopic ultrasonography ( EUS ) and endoscopic retro grade pancreatography ( ERP ) were prospect ively performed in 114 patients , 94 of whom ( 62 men , mean age 53 years ) had inflammatory pancreatic disease , either chronic pancreatitis or status post acute edematous pancreatitis . Twenty patients ( 14 men , mean age 54 years ) who were examined for other reasons and who had a normal ERP served as controls .  EUS was performed in most cases with the knowledge of ERP results which had been classified according to the Cambridge classification system of chronic pancreatitis as being grade 0 ( normal ) or 1 - 3 ( inflammatory changes ) . Parenchymal and ductal changes on EUS were correlated with the ERP changes . Abnormal EUS features were found in all patients with grade 2 and 3 chronic pancreatitis , in 88 % with stage 1 , and in 63 % of cases with a normal ERP as well . These changes were , however , not detectable in any of the 20 control cases . Among the EUS features of chronic pancreatitis , diffuse changes predominated ( stage 1 : 75 % , 2 : 88 % , 3 : 96 % ) and consisted mainly of alternating echopoor and echorich areas and of a lobulated parenchymal pattern . In 80 % of patients , these findings were combined with an irregular pancreatic margin . Changes of the main pancreatic duct were found in stages 2 and 3 in 81 % and 96 % , respectively ; isolated side branch alterations , as detected mainly in stage 1 chronic pancreatitis on ERP , escaped endosonographic visualization . We conclude that EUS shows inflammatory changes in almost all patients in whom ERP suggests chronic pancreatitis . EUS , however , is also positive in a considerable number of cases with normal ERP but who have a clinical episode of pancreatic inflammation . ( ABSTRACT TRUNCATED AT 250 WORDS The usefulness and accuracy rate of endoscopic ultrasonography ( EUS ) in the diagnosis of chronic pancreatitis ( CP ) were prospect ively evaluated in 81 patients with suspected pancreatic disease . All underwent EUS , abdominal ultrasonography ( AUS ) , and computed tomography ( CT ) , and endoscopic retro grade cholangiopancreatography ( ERCP ) was performed in 55 of the cases . The diagnosis of CP was established in 44 patients ( CP group ) including 24 with a calcified form . No pancreatic disease was observed in 18 patients ( control group ) , and 19 patients had a pancreatic tumor . In the CP group AUS was less accurate than EUS in visualizing the pancreas , performances of CT scan being identical to EUS in this respect . A good correlation was observed between EUS and ERCP for visualization and measurement of the Wirsung duct . The most significant changes observed by EUS in the CP group were dilatation of the main pancreatic duct , heterogeneous echogenicity of the pancreatic parenchyma , and cysts < 20 mm in size even in noncalcified CP or with normal pancreatograms . Sensitivity of EUS for diagnosis of CP was 88 % ( AUS , 58 % ; ERCP , 74 % ; CT scan , 75 % ) , the specificity being 100 % for ERCP and EUS , 95 % for CT scan , and 75 % for AUS . The good performances of EUS allow early diagnosis of CP in symptomatic patients since heterogeneous echogenicity of the pancreatic parenchyma seems to be almost specifically associated with the disease The purpose of this study was to determine the improvement in sensitivity and specificity of magnetic resonance cholangiopancreaticography ( MRCP ) in the diagnosis of chronic pancreatitis due to the application of secretin .  Sixty-two consecutive patients with suspected chronic pancreatitis were prospect ively included in our study . All investigations were carried out in a clinical 1.0-T MR-scanner using heavily T2-weighted pre- and dynamic post secretin measurements . Dynamic images were acquired every 30 s for a total imaging time of 10 min . Two experienced radiologists blinded for all other results evaluated the images in r and om order in two sessions : one for the native images and one for the stimulated MRCP series . The gold st and ard for the final diagnosis was the summary of all clinical and radiological results . Sensitivity and specificity for the diagnosis of chronic pancreatitis and the kappa coefficient for the agreement between both observers were calculated . Prior to secretin application , investigators achieved sensitivities of 78 % and 56 % , respectively , and specificities of 89 % and 96 % , respectively . After secretin application , the sensitivity for the first observer remained at 78 % ; for the second observer it increased to 67 % , whereas specificities improved to 94 % and 98 % , respectively . Following secretin application , agreement determined between the two investigators improved from 0.73 to 0.84 . While MRCP already provides high sensitivity and specificity , application of secretin increases both values and the reliability of the diagnosis further Summary From February to November 1981 the diagnostic relevance of ultrasound ( US ) , computed tomography ( CT ) and endoscopic retro grade cholangiopancreatography ( ERCP ) was compared prospect ively in 75 patients with suspected pancreatic disease . Final diagnosis was confirmed by autopsy , surgery , clinical course , and further laboratory data . Thus it was possible to exclude pancreatic disorders in 32 patients . By ERCP we diagnosed all tumors ; sensitivity was 100 % . Sensitivity of US and CT were 63 % each . In five cases US made the false positive diagnosis ” pancreatic malignant tumor ” ( specifity 93 % ) , CT and ERCP in two cases ( specifity 97 % each ) . In chronic pancreatitis specifity of  US and ERCP  were 100 % and specifity of  CT  was 98 % . Sensitivity of ERCP  amounted to 93 % , CT and US revealed 74 % and 52 % , respectively . We conclude that  ERCP  is the best morphologic diagnostic tool in differentiating chronic pancreatitis from pancreatic carcinoma . US is a good screening method and CT reveals good diagnostic results in acute pancreatitis OBJECTIVE Magnetic resonance cholangiopancreatography ( MRCP ) is a rapidly developing method for the noninvasive assessment of the biliary tree and pancreatic duct that obviates the need for contrast medium . We describe our experience with this new diagnostic imaging method in patients with obstruction of the biliary tree . We assessed both the location and cause of obstruction , and compared the results with direct cholangiography . METHODS Between 1997 and 1998 , 81 patients underwent MRCP at our facility . Two different image acquisition protocol s ( half-Fourier acquisition single-shot turbo spin-echo -HASTE- and rapid acquisition with relaxation enhancement -RARE- ) for T2-weighted turbo spin echo sequences as well as cross-sectional fast multiplanar gradient-echo pulse ( T1-weighted FL2D ) and T2-weighted fast spin echo ( T2 TSE ) sequences were used . All patients underwent direct ( either percutaneous or endoscopic retro grade ) cholangiography or surgery for confirmation and /or treatment . The images obtained with MRCP were evaluated by two radiologists with expertise in biliary tree imaging who were unaware of the patient 's clinical characteristics , and their diagnostic interpretations were compared with the findings obtained upon surgery or direct cholangiography . RESULTS The sensitivity and specificity of MRCP  in ruling out pathologies and detecting the presence of dilatation of the biliary tree were 100 % . In assessing the level of the obstruction , sensitivity and specificity varied with location ( intrahepatic/hilar , suprapancreatic , intrapancreatic or ampullary ) . Sensitivity in these locations was 100 , 92 , 69 and 86 % , respectively , whereas specificity was 100 , 94 , 92 and 91 % , respectively . In determining the cause of the obstruction , the results were variable depending on the cause : choledocholithiasis ( sensitivity , 89 % ; specificity , 90 % ) malignant obstruction ( sensitivity , 92 % ; specificity , 88 % ) , benign stricture ( sensitivity , 63 % ; specificity , 90 % ) , and chronic pancreatitis ( sensitivity , 50 % ; specificity , 99 % ) . CONCLUSIONS MRCP offered high diagnostic accuracy in the assessment of the occurrence and location of biliary obstruction . Sensitivity and specificity in establishing the cause varied , and were highest for choledocholithiasis and malignant obstruction . MRCP may be used instead of ERCP , which may then be reserved for patients who are likely to require surgery OBJECTIVE The objective of our study was to assess the improvement of image quality and diagnostic accuracy of secretin-enhanced MR pancreatography compared with conventional MR pancreatography . SUBJECTS AND METHODS Ninety-five patients were studied with a 1.5-T scanner using a T2-weighted single-slice fast spin-echo sequence . Image quality and diameter of the head , body , and tail portion of the pancreatic main duct , the accessory duct , and the side branches were assessed before and after IV administration of secretin . Diagnoses before and after secretin administration were evaluated in a blinded fashion and correlated to the final diagnoses based on endoscopic retro grade cholangiopancreatography ( ERCP ) , intraoperative results , and 
    Output:
    
Conclusions EUS , ERCP , MRI and CT all have comparable high diagnostic accuracy in the initial diagnosis of CP .
EUS and ERCP are outperformers and US has the lowest accuracy .