***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 relatively rare carcinoma of the ampulla of Vater is a neoplasia with a good prognosis compared to pancreatic cancer . Preoperative staging is important in planning the most suitable surgical intervention . Aim To prospect ively evaluate the diagnostic accuracy of Endoscopic Ultrasonography ( EUS ) in comparison with conventional US and CT scan , in staging of patients with ampullary carcinoma . Patients and Methods 20 patients ( 7 women and 13 men ) with histologically proven carcinoma of the ampulla of Vater were assessed by EUS , CT scan and US . Results were compared to surgical findings . Results  Endoscopic biopsies  were diagnostic in 76 % of the patients . Detection of ampullary cancer with US and CT scan was 15 % and 20 % respectively . Only indirect signs of the disease were identified in the majority of cases using these methods . Overall accuracy of  EUS  in detection of ampullary tumours was 100 % . The EUS was significantly ( p < 0.001 ) superior than US and CT scan in ampullary carcinoma detection . Tumour size , tumour extension and the existence of metastatic lymph nodes were also identified and EUS proved to be very useful for the preoperative classification both for the T and the N components of the TNM staging of this neoplasia . The diagnostic accuracy for tumour extension ( T ) was 82 % and for detection of metastatic lymph nodes ( N ) was 71 % . Conclusion EUS is more accurate in detecting ampullary cancer than US and CT scan . Tumor extension and locally metastatic lymph nodes are more accurately assessed by means of EUS than with other imaging methods BACKGROUND The role of fluorodeoxyglucose ( FDG ) positron emission tomography ( PET/CT ) scanning in operable pancreas cancer is unclear . We , therefore , wanted to investigate the impact of PET/CT on management , by incorporating it into routine work-up . METHODS This was a single-institution prospect i ve study . Patients with suspected and potentially operable pancreas , distal bile duct or ampullary carcinomas underwent PET/CT  in addition to routine work-up . The frequency that PET/CT changed the treatment plan or prompted other investigations was determined . The distribution of st and ard uptake values ( SUV ) among primary tumours , and adjacent to biliary stents was characterised . RESULTS Fifty-six patients were recruited . The surgical plan was ab and oned in 9 ( 16 % ; 95 % CI : 6 - 26 ) patients as a result of PET/CT identified metastases . In four patients , metastases were missed and seven were inoperable at surgery , not predicted by PET/CT .  Unexpected FDG uptake result ed in seven additional investigations , of which two were useful . Among primary pancreatic cancers , a median SUV was 4.9 ( range 2 - 12.1 ) . SUV was highest around the biliary stent in 17 out of 28 cases . PET/CT detected metastases in five patients whose primary pancreatic tumours demonstrated mild to moderate avidity ( SUV < 5 ) . CONCLUSIONS PET/CT in potentially operable pancreas cancer has limitations . However , as a result of its ability to detect metastases , PET/CT scanning is a useful tool in the selection of such patients for surgery BACKGROUND High- quality preoperative radiographic evaluation is crucial in selecting patients with periampullary carcinomas who are c and i date s for surgical exploration and tumor resection while minimizing the rate of unnecessary laparotomy . METHODS Twenty-one consecutive patients were prospect ively investigated using helical computed tomography ( CT ) scanning , endoscopic ultrasonography ( EUS ) , and selective visceral angiography ( SVA ) to determine tumor resectability . All patients were explored and resectability determined . RESULTS Helical CT had a sensitivity of 63 % , a specificity of 100 % , and an overall accuracy of 86 % . EUS had a sensitivity of 75 % , a specificity of 77 % , and an overall accuracy of 76 % . SVA had a sensitivity of 38 % , a specificity of 92 % , and an overall accuracy of 71 % . CONCLUSIONS Helical CT scanning is the best preoperative imaging test to determine tumor resectability . EUS is more sensitive than CT for tumor detection , but underestimates resectability . SVA is no longer helpful in the preoperative evaluation of these malignancies PURPOSE To compare the diagnostic performance ( detection , local staging ) of multiphasic 64-detector row computed tomography ( CT ) with that of gadobenate dimeglumine-enhanced 3.0-T magnetic resonance ( MR ) imaging in patients suspected of having pancreatic cancer . MATERIAL S AND METHODS The institutional review board approved this prospect i ve study , and all patients provided written informed consent . Multidetector CT and MR imaging were performed in 89 patients ( 48 women aged 46 - 89 years [ mean , 65.6 years ] and 41 men aged 46 - 86 years [ mean , 65.3 years ] ) suspected of having pancreatic cancer on the basis of findings from clinical examination or previous imaging studies . Two readers independently assessed the images to characterize lesions and determine the presence of focal masses , vascular invasion , distant metastases , and resectability . Findings from surgery , biopsy , endosonography , or follow-up imaging were used as the st and ard of reference . Logistic regression , the McNemar test , and κ values were used for statistical analysis . RESULTS Focal pancreatic masses were present in 63 patients ; 43 patients had adenocarcinoma . For reader 1 , the sensitivities and specificities in the detection of pancreatic adenocarcinoma were 98 % ( 42 of 43 patients ) and 96 % ( 44 of 46 patients ) , respectively , for CT and 98 % ( 42 of 43 patients ) and 96 % ( 44 of 46 patients ) for MR imaging . For reader 2 , the sensitivities and specificities were 93 % ( 40 of 43 patients ) and 96 % ( 44 of 46 patients ) , respectively , for CT and 95 % ( 41 of 43 patients ) and 96 % ( 44 of 46 patients ) for MR imaging . Vessel infiltration was determined in 22 patients who underwent surgery , and reader 1 obtained sensitivities and specificities of 90 % ( nine of 10 vessels ) and 98 % ( 119 of 122 vessels ) , respectively , for CT and 80 % ( eight of 10 vessels ) and 96 % ( 117 of 122 vessels ) for MR imaging ; for reader 2 , those values were 70 % ( seven of 10 vessels ) and 98 % ( 120 of 122 vessels ) for CT and 50 % ( five of 10 vessels ) and 98 % ( 120 of 122 vessels ) for MR imaging . Both readers correctly assessed resectability in 87 % ( 13 of 15 patients ) of cases with CT and 93 % ( 14 of 15 patients ) of cases with MR imaging . Nonresectability was assessed correctly with CT in 75 % ( six of eight patients ) of cases by reader 1 and 63 % ( five of eight patients ) of cases by reader 2 ; nonresectability was correctly assessed with MR imaging in 75 % ( six of eight patients ) of cases by reader 1 and 50 % ( four of eight patients ) of cases by reader 2 . None of the differences between modalities and readers were statistically significant ( P > .05 ) . CONCLUSION Both CT and MR imaging are equally suited for detecting and staging pancreatic cancer . SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101189/-/DC1 Objective : We sought to determine the impact of positron emission tomography/computed tomography ( PET/CT ) on the management of presumed resectable pancreatic cancer and to assess the cost of this new staging procedure . Summary Background Data : PET using 18F-fluorodeoxyglucose ( FDG ) is increasingly used for the staging of pancreatic cancer , but anatomic information is limited . Integrated PET/CT enables optimal anatomic delineation of PET findings and identification of FDG-negative lesions on computed tomography ( CT ) images and might improve preoperative staging . Material and Methods : Patients with suspected pancreatic cancer who had a PET/CT between June 2001 to April 2004 were entered into a prospect i ve data base . Routine staging included abdominal CT , chest x-ray , and CA 19 - 9 measurement . FDG-PET/CT was conducted according to a st and ardized protocol , and findings were confirmed by histology . Cost benefit analysis was performed based on charged cost of PET/CT and pancreatic resection and included the time frame of staging and surgery . Results : Fifty-nine patients with a median age of 61 years ( range , 40–80 years ) were included in this analysis . Fifty-one patients had lesions in the head and 8 in the tail of the pancreas . The positive and negative predictive values for pancreatic cancer were 91 % and 64 % , respectively . PET/CT detected additional distant metastases in 5 and synchronous rectal cancer in 2 patients . PET/CT findings changed the management in 16 % of patients with pancreatic cancer deemed resectable after routine staging ( P = 0.031 ) and was cost saving . Conclusions : PET/CT represents an important staging procedure prior to pancreatic resection for cancer , since it significantly improvespatient selection and is cost-effective Endoscopic ultrasonography ( EUS ) was compared to ultrasonography ( US ) and CT scan ( CT ) in order to evaluate its role in the diagnosis and the locoregional spread assessment of pancreatic cancer . Sixty-four patients suspected of pancreatic cancer were studied prospect ively , and the results of imaging techniques were compared to histology and surgical exploration . There were 49 cases of pancreatic adenocarcinoma , 11 of pancreatitis , 2 of common bile duct carcinoma , 1 lymphoma and 1 hepatocellular carcinoma with peripancreatic metastatic lymph nodes . EUS was significantly more accurate ( 91 % ) than CT ( 66 % ) and US ( 64 % ) for diagnosis of pancreatic cancer . EUS was able to image all 7 cancers less than 25 mm in diameter , US and CT only one . There were 4 false positives with EUS which were all cases of pseudotumorous pancreatitis . For detecting lymph node involvement , EUS was significantly more sensitive ( 62 % ) and accurate ( 74 % ) than US ( 8 % and 37 % ) and CT ( 19 % and 42 % ) , respectively . Invaded lymph nodes adjacent to large tumors and micrometastatic involvement were responsible for this lack of sensitivity . EUS was significantly more sensitive ( 100 % ) than CT ( 71 % ) and US ( 17 % ) for detecting venous involvement . The specificity of EUS  was lower ( 67 % ) because of duodenal bulb stenosis and large tumors . In conclusion , this prospect i ve and comparative study confirms that EUS is an accurate tool for diagnosis and locoregional spread assessment of pancreatic cancer when performed in a reference center . EUS is of particular interest for small tumours . However , EUS does not enable differentiation of pseudotumorous pancreatitis from adenocarcinoma BACKGROUND Endoscopic ultrasonography ( EUS ) is highly accurate for the staging of tumors , but its role in the management of periampullary carcinoma is still being defined . METHODS Seventy-nine patients with pancreatic ( n = 73 ) or ampullary ( n = 6 ) carcinoma underwent prospect i ve evaluation by means of assessment of resectability and survival according to the following three-step staging algorithm : ( 1 ) ultrasonography and computed tomography ; ( 2 ) if tumor appears resectable , EUS ; ( 3 ) if criteria of resectability are found at EUS , laparotomy for curative resection . RESULTS The first step of the algorithm helped predict unresectability of tumors and need for palliative treatment for 36 patients . Among the other 43 patients EUS revealed signs of unresectability in 20 additional patients who then underwent palliative surgical or medical treatment ( median survival time 7 to 8 months ) . Twenty-three carcinomas were considered resectable according to EUS findings : Palliative surgery was performed in 9 cases ( survival time 6 months ) , and 14 tumors could be resected in a curative way with a median survival period of 15 ( pancreatic ) to 16 months ( ampullary ) . In evaluation of resectability , EUS had a 50 % sensitivity ( positive examination ) , 100 % specificity , 100 % positive predictive value , 61 % negative predictive value , and 72 % accuracy . CONCLUSIONS EUS is accurate for evaluating resectability of ampullary and pancreatic cancer . EUS staging can prevent unnecessary surgery , and the findings correlate well with prognosis . The management of ampullary and pancreatic cancer could be improved with EUS BACKGROUND / AIMS Demonstration of unresectability often requires diagnostic laparotomy with high co-morbidity in pancreatic carcinoma . The value of detected peritoneal tumor cells and influence on outcome should be determined . METHODOLOGY In a prospect i ve 
    Output:
    
There is no evidence to suggest that it should be performed routinely in people with pancreatic cancer or periampullary cancer found to have resectable disease on CT scan