title: Comparison of PET-CT and conventional imaging in staging pediatric rhabdomyosarcoma.
abstract: BACKGROUND
  Over the past decade, PET-CT has been used to assess rhabdomyosarcoma (RMS) in children. However, the role of PET-CT in staging RMS is unknown.
  
  
  METHODS
  Thirty subjects with RMS, median age 7.3 years, underwent PET-CT before therapy. PET-CTs and conventional imaging (CI) were independently reviewed by two radiologists and two nuclear medicine physicians to determine the presence of metastases. Accuracy, sensitivity, and specificity of PET-CT for detecting metastases were compared to CI using biopsy and clinical follow-up as reference standards. Maximum standardized uptake values (SUV(max)) of primary tumors, lymph nodes, and pulmonary nodules were measured.
  
  
  RESULTS
  Primary tumors had an average SUV(max) of 7.2 (range, 2.5-19.2). Accuracy rates for 17 subjects with nodal disease were 95% for PET-CT and 49% for CI. PET-CT had 94% sensitivity and 100% specificity for nodal disease. Of seven pulmonary nodules detected by CI, three were not identified by PET-CT, two were indeterminate, and one was malignant with a SUV(max) (3.4) > twice that of benign nodules. Two subjects had bone disease; both were identified by PET-CT but only one by CI. Four subjects had bone marrow disease, two had positive PET-CTs but none had positive CI. Two subjects had soft tissue metastases detected by PET-CT but not CI.
  
  
  CONCLUSIONS
  PET-CT performed better than CI in identifying nodal, bone, bone marrow, and soft tissue disease in children with RMS. CI remains essential for detection of pulmonary nodules. We recommend PET-CT for staging of children with RMS. CI with Tc(99m) bone scan can be eliminated.
authors.affiliation: Division of Solid Tumors, Department of Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA. sara.federico@stjude.org
authors.forename: Sara M
authors.initials: SM
authors.lastname: Federico
authors.forename: Sheri L
authors.initials: SL
authors.lastname: Spunt
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Krasin
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Billup
authors.forename: Jianrong
authors.initials: J
authors.lastname: Wu
authors.forename: Barry
authors.initials: B
authors.lastname: Shulkin
authors.forename: Gerald
authors.initials: G
authors.lastname: Mandell
authors.forename: M Beth
authors.initials: MB
authors.lastname: McCarville
mesh_terms: D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D064847:Multimodal Imaging; D009362:Neoplasm Metastasis / Q000000981:diagnostic imaging*; D009367:Neoplasm Staging / Q000379:methods*; D049268:Positron-Emission Tomography; D012189:Retrospective Studies; D012208:Rhabdomyosarcoma / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed