title: The role of 18F-FDG-PET/CT in the preoperative staging and posttherapy follow up of gastric cancer: comparison with spiral CT.
abstract: BACKGROUND
  The aim of this study was to investigate the role of F-18 fluoro-deoxy-glucose (FDG) positron emission tomography and computed tomography (PET/CT) in the preoperative and posttherapy restaging of gastric cancer and to compare with spiral computerized tomography (CT).
  
  
  METHODS
  A total of 42 PET/CT scans of 36 gastric cancer patients (28M, 8F; mean age: 56.0±15) were included in the study. A retrospective analysis of the PET/CT results of the patients were compared with concurrent CT results. Confirmation was made by clinical course and serial imaging studies in the follow up. The compatibility ratios were calculated and the accuracy of the PET/CT was assessed. Agreement between PET/CT and concurrent CT was calculated using kappa statistics.
  
  
  RESULTS
  Patients were separated into 3 groups: the patients who were referred to our clinic for preoperative staging (4 patients), for posttherapy evaluation (24 patients) and for the suspicion of local recurrence and/or metastasis exploration after a disease free period (8 patients). Groups 1 and 3 included a small number of patients so they were omitted from the statistical analysis. Focusing on Goup 2, the overall concordance rate was 50% (12 patients). Region based analysis showed the rates of concordance for local recurrence, local lymph node metastasis and distant metastasis were 91% (Kappa: 0.70), 95% (Kappa: 0.86) and 50% (Kappa: 0.26) respectively. Distant metastases were also investigated in detail and the two techniques showed a concordance of 91% (Kappa: 0.75) for liver, 79% (Kappa:0.31) for distant lymph node, 79% (0.42) for lung, 87% (Kappa:0.33) for bone and 95% for intestinal wall metastasis.
  
  
  CONCLUSIONS
  PET/CT is a complementary imaging method which can be successfully used in both preoperative and posttherapy evaluation of gastric cancer.
authors.affiliation: Department of Nuclear Medicine, Ankara University, Medical Faculty, Ankara, Turkey.
authors.forename: Elgin
authors.initials: E
authors.lastname: Ozkan
authors.forename: Mine
authors.initials: M
authors.lastname: Araz
authors.forename: Cigdem
authors.initials: C
authors.lastname: Soydal
authors.forename: Ozlem N
authors.initials: ON
authors.lastname: Kucuk
mesh_terms: D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D005743:Gastrectomy / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D049268:Positron-Emission Tomography / Q000379:methods*; D011300:Preoperative Care / Q000379:methods*; D011379:Prognosis; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000175:diagnosis* / Q000601:surgery; D036542:Tomography, Spiral Computed / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18