title: Evaluation of 18F-FDG PET and MRI associations in pediatric diffuse intrinsic brain stem glioma: a report from the Pediatric Brain Tumor Consortium.
abstract: The purpose of this study was to assess (18)F-FDG uptake in children with a newly diagnosed diffuse intrinsic brain stem glioma (BSG) and to investigate associations with progression-free survival (PFS), overall survival (OS), and MRI indices.
  
  
  METHODS
  Two Pediatric Brain Tumor Consortium (PBTC) therapeutic trials in children with newly diagnosed BSG were designed to test radiation therapy combined with molecularly targeted agents (PBTC-007: phase I/II study of gefitinib; PBTC-014: phase I/II study of tipifarnib). Baseline brain (18)F-FDG PET scans were obtained in 40 children in these trials. Images were evaluated by consensus between 2 PET experts for intensity and uniformity of tracer uptake. Associations of (18)F-FDG uptake intensity and uniformity with both PFS and OS, as well as associations with tumor MRI indices at baseline (tumor volume on fluid-attenuated inversion recovery, baseline intratumoral enhancement, diffusion and perfusion values), were evaluated.
  
  
  RESULTS
  In most of the children, BSG (18)F-FDG uptake was less than gray-matter uptake. Survival was poor, irrespective of intensity of (18)F-FDG uptake, with no association between intensity of (18)F-FDG uptake and PFS or OS. However, hyperintense (18)F-FDG uptake in the tumor, compared with gray matter, suggested poorer survival rates. Patients with (18)F-FDG uptake in 50% or more of the tumor had shorter PFS and OS than did patients with (18)F-FDG uptake in less than 50% of the tumor. There was some evidence that tumors with higher (18)F-FDG uptake were more likely to show enhancement, and when the diffusion ratio was lower, the uniformity of (18)F-FDG uptake appeared higher.
  
  
  CONCLUSIONS
  Children with BSG for which (18)F-FDG uptake involves at least half the tumor appear to have poorer survival than children with uptake in less than 50% of the tumor. A larger independent study is needed to verify this hypothesis. Intense tracer uptake in the tumors, compared with gray matter, suggests decreased survival. Higher (18)F-FDG uptake within the tumor was associated with enhancement on MR images. Increased tumor cellularity as reflected by restricted MRI diffusion may be associated with increased (18)F-FDG uniformity throughout the tumor.
authors.affiliation: Department of Imaging, Dana-Farber Cancer Institute, Boston, Massachusetts, USA.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Zukotynski
authors.forename: Frederic H
authors.initials: FH
authors.lastname: Fahey
authors.forename: Mehmet
authors.initials: M
authors.lastname: Kocak
authors.forename: Abass
authors.initials: A
authors.lastname: Alavi
authors.forename: Terence Z
authors.initials: TZ
authors.lastname: Wong
authors.forename: S Ted
authors.initials: ST
authors.lastname: Treves
authors.forename: Barry L
authors.initials: BL
authors.lastname: Shulkin
authors.forename: Daphne A
authors.initials: DA
authors.lastname: Haas-Kogan
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Geyer
authors.forename: Sridhar
authors.initials: S
authors.lastname: Vajapeyam
authors.forename: James M
authors.initials: JM
authors.lastname: Boyett
authors.forename: Larry E
authors.initials: LE
authors.lastname: Kun
authors.forename: Tina Young
authors.initials: TY
authors.lastname: Poussaint
mesh_terms: D000293:Adolescent; D020295:Brain Stem Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D005260:Female; D019788:Fluorodeoxyglucose F18; D005910:Glioma / Q000000981:diagnostic imaging* / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18