title: 18F-FDG PET and MR imaging associations across a spectrum of pediatric brain tumors: a report from the pediatric brain tumor consortium.
abstract: The purpose of this study was to describe (18)F-FDG uptake across a spectrum of pediatric brain tumors and correlate (18)F-FDG PET with MR imaging variables, progression-free survival (PFS), and overall survival (OS).
  
  
  METHODS
  A retrospective analysis was conducted of children enrolled in phase I/II clinical trials through the Pediatric Brain Tumor Consortium from August 2000 to June 2010. PET variables were summarized within diagnostic categories using descriptive statistics. Associations of PET with MR imaging variables and PFS and OS by tumor types were evaluated.
  
  
  RESULTS
  Baseline (18)F-FDG PET was available in 203 children; 66 had newly diagnosed brain tumors, and 137 had recurrent/refractory brain tumors before enrolling in a Pediatric Brain Tumor Consortium trial. MR imaging was performed within 2 wk of PET and before therapy in all cases. The (18)F-FDG uptake pattern and MR imaging contrast enhancement (CE) varied by tumor type. On average, glioblastoma multiforme and medulloblastoma had uniform, intense uptake throughout the tumor, whereas brain stem gliomas (BSGs) had low uptake in less than 50% of the tumor and ependymoma had low uptake throughout the tumor. For newly diagnosed BSG, correlation of (18)F-FDG uptake with CE portended reduced OS (P = 0.032); in refractory/recurrent BSG, lack of correlation between (18)F-FDG uptake and CE suggested decreased PFS (P = 0.023). In newly diagnosed BSG for which more than 50% of the tumor had (18)F-FDG uptake, there was a suggestion of lower apparent diffusion coefficient (P = 0.061) and decreased PFS (P = 0.065).
  
  
  CONCLUSIONS
  (18)F-FDG PET and MR imaging showed a spectrum of patterns depending on tumor type. In newly diagnosed BSG, the correlation of (18)F-FDG uptake and CE suggested decreased OS, likely related to more aggressive disease. When more than 50% of the tumor had (18)F-FDG uptake, the apparent diffusion coefficient was lower, consistent with increased cellularity. In refractory/recurrent BSG, poor correlation between (18)F-FDG uptake and CE was associated with decreased PFS, which may reflect concurrent tissue breakdown at sites of treated disease and development of new sites of (18)F-FDG-avid malignancy.
authors: Department of Medical Imaging, Sunnybrook Health Sciences Centre, University of Toronto, Ontario, Canada Department of Radiology, Harvard Medical School, Boston, Massachusetts.
authors: Katherine
authors: K
authors: Zukotynski
authors: Department of Radiology, Harvard Medical School, Boston, Massachusetts Department of Radiology, Boston Children's Hospital, Boston, Massachusetts.
authors: Frederic
authors: F
authors: Fahey
authors: Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, Tennessee.
authors: Mehmet
authors: M
authors: Kocak
authors: Department of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee.
authors: Larry
authors: L
authors: Kun
authors: Department of Biostatistics, St. Jude Children's Research Hospital, Memphis, Tennessee; and.
authors: James
authors: J
authors: Boyett
authors: Department of Hematology/Oncology, Cincinnati Children's Medical Center, Cincinnati, Ohio.
authors: Maryam
authors: M
authors: Fouladi
authors: Department of Radiology, Harvard Medical School, Boston, Massachusetts Department of Radiology, Boston Children's Hospital, Boston, Massachusetts.
authors: Sridhar
authors: S
authors: Vajapeyam
authors: Department of Radiology, Harvard Medical School, Boston, Massachusetts Department of Radiology, Boston Children's Hospital, Boston, Massachusetts.
authors: Ted
authors: T
authors: Treves
authors: Department of Radiology, Harvard Medical School, Boston, Massachusetts Department of Radiology, Boston Children's Hospital, Boston, Massachusetts tinayoung.poussaint@childrens.harvard.edu.
authors: Tina Y
authors: TY
authors: Poussaint
mesh_terms: D000293:Adolescent; D000328:Adult; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D005260:Female; D019788:Fluorodeoxyglucose F18; D005910:Glioma / Q000000981:diagnostic imaging / Q000401:mortality / Q000473:pathology; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D012189:Retrospective Studies
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: 18F-FDG PET; MR diffusion; brain tumor; pediatric