title: Usefulness of 18-F FDG PET/CT in the pre-treatment evaluation of thymic epithelial neoplasms.
abstract: BACKGROUND
  To assess the usefulness of (18)fluorine-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) for differentiating the grade of malignancy of thymic epithelial neoplasm, and to determine whether (18)F-FDG PET/CT can have a role in pretreatment evaluation and possibly modify treatment strategy.
  
  
  METHODS
  The data of 26 consecutive patients (14 males and 12 females) diagnosed with a thymic epithelial neoplasm were prospectively collected and analyzed retrospectively. All patients underwent standard clinical assessment and (18)F-FDG PET/CT. The patients were divided into two subgroups according to a simplified histologic classification: low-risk thymoma (types A, AB and B1) and high-risk thymoma (types B2, B3 and C). The maximum standardized uptake value (SUV(max)) of the tumor, the mean SUV of mediastinum, and the tumor/mediastinum (T/M) ratio (ratio of peak SUV of the tumor to mean SUV of mediastinum) were compared to determine whether the two subgroups (low-risk versus high-risk tumors) could be distinguished by (18)F-FDG PET/CT, and to test for possible correlations between (18)F-FDG uptake and disease stage.
  
  
  RESULTS
  There was a strong statistical correlation between SUV(max) and patient subgroup and between SUV(max) and disease stage, and an even stronger correlation between SUV(max) and patient subgroup and the T/M ratio; a T/M ratio of 2.75 emerged as the cut-off value for differentiating between low-risk and high-risk thymomas.
  
  
  CONCLUSIONS
  (18)F-FDG PET/CT can be used a "metabolic biopsy" to divide thymic epithelial neoplasm into two subgroups of high and low risk and is useful in pretreatment staging.
authors: Thoracic Surgery Unit, S. Croce e Carle Hospital, Via Michele Coppino 26, 12100 Cuneo, Italy.
authors: Alberto
authors: A
authors: Terzi
authors: Luca
authors: L
authors: Bertolaccini
authors: Giovanna
authors: G
authors: Rizzardi
authors: Luca
authors: L
authors: Luzzi
authors: Andrea
authors: A
authors: Bianchi
authors: Andrea
authors: A
authors: Campione
authors: Alberto
authors: A
authors: Comino
authors: Alberto
authors: A
authors: Biggi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D003937:Diagnosis, Differential; D005240:Feasibility Studies; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011379:Prognosis; D012016:Reference Values; D012189:Retrospective Studies; D013953:Thymus Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D014057:Tomography, X-Ray Computed
chemical_list: D019788:Fluorodeoxyglucose F18