title: Evaluation of soft-tissue lesions with (18)F-FDG PET/CT: initial results of a prospective trial.
abstract: OBJECTIVE
  Although MRI is utilized for planning the resection of soft-tissue tumors, it is not always capable of differentiating benign from malignant lesions. The risk of local recurrence of soft-tissue sarcomas is increased when biopsies are performed before resection and by inadequate resections. PET associated with computed tomography using fluorodeoxyglucose labeled with fluorine-18 ((18)F-FDG PET/CT) may help differentiate between benign and malignant tumors, thus avoiding inadequate resections and making prior biopsies unnecessary. The purpose of this study was to evaluate the usefulness of (18)F-FDG PET/CT in differentiating benign from malignant solid soft-tissue lesions.
  
  
  METHODS
  Patients with solid lesions of the limbs or abdominal wall detected by MRI were submitted to (18)F-FDG PET/CT. The maximum standardized uptake value (SUVmax) cutoff was determined to differentiate malignant from benign tumors. Regardless of the (18)F-FDG PET/CT results all patients underwent biopsy and surgery.
  
  
  RESULTS
  MRI was performed in 54 patients, and 10 patients were excluded because of purely lipomatose or cystic lesions. (18)F-FDG PET/CT was performed in the remaining 44 patients. Histopathology revealed 26 (59%) benign and 18 (41%) malignant soft-tissue lesions. A significant difference in SUVmax was observed between benign and malignant soft-tissue lesions. The SUVmax cutoff of 3.0 differentiated malignant from benign lesions with 100% sensitivity, 83.3% specificity, 89.6% accuracy, 78.3% positive predictive value, and 100% negative predictive value.
  
  
  CONCLUSIONS
  (18)F-FDG PET/CT seems to be able to differentiate benign from malignant soft-tissue lesions with good accuracy and very high negative predictive value. Incorporating (18)F-FDG PET/CT into the diagnostic algorithm of these patients may prevent inadequate resections and unnecessary biopsies.
authors.affiliation: aDepartment of Radiology, Division of Nuclear Medicine Departments of bRadiology cOrthopedics dPathology, Campinas State University (UNICAMP) eNuclear Medicine of Campinas (MN&D) fCampinas Radiology Clinic (RCC), Campinas, Brazil.
authors.forename: Aline L
authors.initials: AL
authors.lastname: Leal
authors.forename: Maurício
authors.initials: M
authors.lastname: Etchebehere
authors.forename: Allan O
authors.initials: AO
authors.lastname: Santos
authors.forename: Gustavo
authors.initials: G
authors.lastname: Kalaf
authors.forename: Elisa B
authors.initials: EB
authors.lastname: Pacheco
authors.forename: Eliane M
authors.initials: EM
authors.lastname: Amstalden
authors.forename: Elba C
authors.initials: EC
authors.lastname: Etchebehere
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D012983:Soft Tissue Neoplasms / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D019788:Fluorodeoxyglucose F18