title: Is positron emission tomography using 18F-fluorodeoxyglucose and 11C-acetate valuable in diagnosing indeterminate pancreatic masses?
abstract: BACKGROUND
  It can be impossible to differentiate a mass forming chronic pancreatitis from adenocarcinoma of the pancreas using standard anatomical imaging. Positron emission tomography using 2-[18F] fluoro-2deoxy-D-glucose (18FDG-PET) and 1-[11C]-acetate (11C-acetate-PET) are methods taking advantage of the metabolic differences between benign and malignant tissues.
  
  
  OBJECTIVE
  To determine the diagnostic accuracy of 18FDG-PET and 11C-acetate-PET in indeterminate pancreatic masses.
  
  
  METHODS
  Twenty patients with an indeterminate mass of the head of the pancreas were prospectively studied. All patients underwent 18FDG-PET and eighteen of them 11C-acetate-PET. Scans were evaluated qualitatively and quantitatively; the later by using regional standardised uptake value (SUV). Final diagnosis was established using histopathologic evaluation of resected specimen or biopsy.
  
  
  RESULTS
  Adenocarcinoma was diagnosed in twelve patients and chronic pancreatitis in eight. Qualitative evaluation of 18FDG-PET imaging revealed three false negative and one false-positive results. The sensitivity, specificity, and diagnostic accuracy were 75 %, 88 %, and 80 %, respectively. The cut-off SUV to differentiate malignant from benign disease was 3,5 demonstrating a sensitivity of 91.7 % and a specificity of 75 %.
  
  
  CONCLUSIONS
  18FDG-PET imaging could not confirm or exclude malignancy in indeterminate masses of the head of the pancreas with high sensitivity and diagnostic accuracy. 11C-acetate-PET provided no additional diagnostic benefits.
authors.affiliation: Department of Surgery, University Hospital, Uppsala, Sweden. ib.rasmussen@kirurgi.uu.se
authors.forename: I
authors.initials: I
authors.lastname: Rasmussen
authors.forename: J
authors.initials: J
authors.lastname: Sörensen
authors.forename: B
authors.initials: B
authors.lastname: Långström
authors.forename: U
authors.initials: U
authors.lastname: Haglund
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging*; D002250:Carbon Radioisotopes; D002908:Chronic Disease; D003937:Diagnosis, Differential; D005189:False Positive Reactions; D019788:Fluorodeoxyglucose F18; D006801:Humans; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging*; D010195:Pancreatitis / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography; D012680:Sensitivity and Specificity
chemical_list: D002250:Carbon Radioisotopes; D019788:Fluorodeoxyglucose F18