title: Validation of 18F-FDG PET at conventional and delayed intervals for the discrimination of high-grade from low-grade gliomas: a stereotactic PET and MRI study.
abstract: OBJECTIVE
  The aim of this study was to validate 18F-FDG PET imaging for differentiating high-grade gliomas (HGGs) from low-grade gliomas (LGGs).
  
  
  METHODS
  Twenty-one patients with gliomas undergoing a stereotactic biopsy underwent PET scanning at conventional and delayed intervals, diagnostic and stereotactic MR examinations. To calculate the uptake at the biopsy site, a 2-mm voxel was selected. Uptake in this voxel was expressed as a percentage of the average uptake per voxel in the normal brain. The difference in uptake between HGG and LGG at conventional and late intervals and the difference in uptake difference between HGG and LGG at both intervals were analyzed using t tests as well as a mixed-model analysis of variance.
  
  
  RESULTS
  At conventional intervals, uptake in LGG was 67% of that in the normal brain. Between early and late intervals, a significant decrease in uptake of 11% (±2.5%) was noted (P = 0.001). Uptake in HGG at conventional intervals was 138% of that in the normal brain. Between early and late intervals, a significant increase in uptake of 43% (±11%) was noted (P = 0.005). The difference in uptake between HGG and LGG was significant both at conventional and delayed intervals (P < 0.001). Moreover, the difference in uptake between both groups was significantly greater (31%) at delayed than at conventional intervals (2%) (P < 0.001).
  
  
  CONCLUSIONS
  The results of this correlative study between tumor grade and 18F-FDG uptake both determined at the stereotactic biopsy site indicate that PET, particularly at delayed intervals, is valid for discriminating LGG from HGG.
authors: Department of Nuclear Medicine, Ghent University Hospital, Ghent, Belgium.
authors: Koen
authors: K
authors: Mertens
authors: Marjan
authors: M
authors: Acou
authors: Jel
authors: J
authors: Van Hauwe
authors: Ine
authors: I
authors: De Ruyck
authors: Caroline
authors: C
authors: Van den Broecke
authors: Jean-Pierre Okito
authors: JP
authors: Kalala
authors: Yves
authors: Y
authors: D'Asseler
authors: Ingeborg
authors: I
authors: Goethals
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D005910:Glioma / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D064847:Multimodal Imaging; D060787:Neoplasm Grading; D049268:Positron-Emission Tomography; D015203:Reproducibility of Results; D013238:Stereotaxic Techniques
chemical_list: D019788:Fluorodeoxyglucose F18