title: Diagnostic value of PET/CT for the staging and restaging of pediatric tumors.
abstract: OBJECTIVE
  The objective of this retrospective study was to compare the diagnostic value of 2-[(18)F]fluoro-2-deoxy-D: -glucose positron emission tomography ((18)F-FDG PET)/CT versus (18)F-FDG PET and CT alone for staging and restaging of pediatric solid tumors.
  
  
  METHODS
  Forty-three children and adolescents (19 females and 24 males; mean age, 15.2 years; age range, 6-20 years) with osteosarcoma (n = 1), squamous cell carcinoma (n = 1), synovial sarcoma (n = 2), germ cell tumor (n = 2), neuroblastoma (n = 2), desmoid tumor (n = 2), melanoma (n = 3), rhabdomyosarcoma (n = 5), Hodgkin's lymphoma (n = 7), non-Hodgkin-lymphoma (n = 9), and Ewing's sarcoma (n = 9) who had undergone (18)F-FDG PET/CT imaging for primary staging or follow-up of metastases were included in this study. The presence, location, and size of primary tumors was determined separately for PET/CT, PET, and CT by two experienced reviewers. The diagnosis of the primary tumor was confirmed by histopathology. The presence or absence of metastases was confirmed by histopathology (n = 62) or clinical and imaging follow-up (n = 238).
  
  
  RESULTS
  The sensitivities for the detection of solid primary tumors using integrated (18)F-FDG PET/CT (95%), (18)F-FDG PET alone (73%), and CT alone (93%) were not significantly different (p > 0.05). Seventeen patients showed a total of 153 distant metastases. Integrated PET/CT had a significantly higher sensitivity for the detection of these metastases (91%) than PET alone (37%; p < 0.05), but not CT alone (83%; p > 0.05). When lesions with a diameter of less than 0.5 cm were excluded, PET/CT (89%) showed a significantly higher specificity compared to PET (45%; p < 0.05) and CT (55%; p < 0.05). In a sub-analysis of pulmonary metastases, the values for sensitivity and specificity were 90%, 14%, 82% and 63%, 78%, 65%, respectively, for integrated PET/CT, stand-alone PET, and stand-alone CT. For the detection of regional lymph node metastases, (18)F-FDG PET/CT, (18)F-FDG PET alone, and CT alone were diagnostically correct in 83%, 61%, and 42%. A sub-analysis focusing on the ability of PET/CT, PET, and CT to detect osseous metastases showed no statistically significant difference between the three imaging modalities (p > 0.05).
  
  
  CONCLUSIONS
  Our study showed a significantly increased sensitivity of PET/CT over that of PET for the detection of distant metastases but not over that of CT alone. However, the specificity of PET/CT for the characterization of pulmonary metastases with a diameter > 0.5 cm and lymph node metastases with a diameter of <1 cm was significantly increased over that of CT alone.
authors: Department of Radiology, University of California, 505 Parnassus Avenue, San Francisco, CA 94143-0628, USA.
authors: Margit
authors: M
authors: Kleis
authors: Heike
authors: H
authors: Daldrup-Link
authors: Katherine
authors: K
authors: Matthay
authors: Robert
authors: R
authors: Goldsby
authors: Ying
authors: Y
authors: Lu
authors: Tibor
authors: T
authors: Schuster
authors: Carole
authors: C
authors: Schreck
authors: Philip W
authors: PW
authors: Chu
authors: Randall A
authors: RA
authors: Hawkins
authors: Benjamin L
authors: BL
authors: Franc
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009362:Neoplasm Metastasis / Q000000981:diagnostic imaging; D009367:Neoplasm Staging; D009369:Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology*; D049268:Positron-Emission Tomography; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed