title: EUS compared with CT, magnetic resonance imaging, and angiography and the influence of biliary stenting on staging accuracy of ampullary neoplasms.
abstract: BACKGROUND
  Computerized tomography (CT), magnetic resonance imaging (MRI), and transabdominal ultrasound frequently fail to detect ampullary lesions. Endoscopic ultrasound (EUS) is a sensitive modality for detecting and staging ampullary tumors. Accurate staging may be affected by biliary stenting, which is frequently performed in these patients with obstructive jaundice. The present study assessed the accuracy of ampullary tumor staging with multiple imaging modalities in patients with and those without endobiliary stents.
  
  
  METHODS
  Fifty consecutive patients with ampullary neoplasms from two endosonography centers were preoperatively staged by EUS plus CT (37 patients), MRI (13 patients), or angiography (10 patients) over a 3(1/2) year period. Twenty-five of the 50 patients had a transpapillary endobiliary stent present at the time of endosonographic examination. Accuracy of EUS, CT, MRI, and angiography was assessed with the TNM classification system and compared with surgical-pathologic staging. The influence of an endobiliary stent present at the time of EUS on staging accuracy of EUS was also evaluated.
  
  
  RESULTS
  EUS was more accurate than CT and MRI in the overall assessment of the T stage of ampullary neoplasms (EUS 78%, CT 24%, MRI 46%). No significant difference in N stage accuracy was noted between the three imaging modalities (EUS 68%, CT 59%, MRI 77%). EUS T stage accuracy was reduced from 84% to 72% in the presence of a transpapillary endobiliary stent. This was most prominent in the understaging of T2/T3 carcinomas.
  
  
  CONCLUSIONS
  EUS is superior to CT and MRI in assessing T stage but not N stage of ampullary lesions. The presence of an endobiliary stent at EUS may result in underestimating the need for a Whipple resection because of tumor understaging.
authors.affiliation: Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, Michigan, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Cannon
authors.forename: S L
authors.initials: SL
authors.lastname: Carpenter
authors.forename: G H
authors.initials: GH
authors.lastname: Elta
authors.forename: T T
authors.initials: TT
authors.lastname: Nostrant
authors.forename: M L
authors.initials: ML
authors.lastname: Kochman
authors.forename: G G
authors.initials: GG
authors.lastname: Ginsberg
authors.forename: B
authors.initials: B
authors.lastname: Stotland
authors.forename: E F
authors.initials: EF
authors.lastname: Rosato
authors.forename: J B
authors.initials: JB
authors.lastname: Morris
authors.forename: F
authors.initials: F
authors.lastname: Eckhauser
authors.forename: J M
authors.initials: JM
authors.lastname: Scheiman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014670:Ampulla of Vater / Q000000981:diagnostic imaging / Q000473:pathology*; D000792:Angiography; D016009:Chi-Square Distribution; D003135:Common Bile Duct / Q000000981:diagnostic imaging* / Q000473:pathology; D003138:Common Bile Duct Neoplasms / Q000175:diagnosis / Q000473:pathology*; D019160:Endosonography / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010183:Pancreatic Ducts / Q000000981:diagnostic imaging* / Q000473:pathology; D015607:Stents; D014057:Tomography, X-Ray Computed