title: Static FET-PET and MR Imaging in Anaplastic Gliomas (WHO III).
abstract: OBJECTIVE
  O-(2-[18F]-fluoroethyl)-L-tyrosine-positron emission tomography (FET-PET) imaging is an additional tool for tumor grading and surgery planning. Up to now, not much is known about FET-PET imaging in anaplastic gliomas. Our objective was to assess the FET uptake in anaplastic gliomas, compared with magnetic resonance imaging (MRI), histopathologic markers, and its prognostic value.
  
  
  METHODS
  Forty-six patients (27 males/19 females) with an anaplastic glioma (WHO III) who received MRI and FET-PET imaging before surgery were retrospectively analyzed. Tumor volume was calculated in MRI and FET-PET imaging using a tumor-to-background ratio (TBR), and maximum FET uptake (TBRmax) was calculated. Overall survival (OS) and histopathologic markers (isocitrate-dehydrogenase 1/2-mutation, oligodendrial differentiation, and Ki67 proliferation index) were assessed. Univariate and multivariate analysis was performed for OS.
  
  
  RESULTS
  In univariate analysis a significant correlation of TBRmax to OS was observed (P = 0.031). Tumor volume in FET-PET imaging (TBR > 2.0) (P = 0.028) showed a higher correlation to OS than the volume of the contrast-enhancing tumor part (P = 0.031). The highest correlation was observed for intersection of volume TBR > 1.3 and the volume of the contrast-enhancing tumor part (P = 0.005); fluid-attenuated inversion recovery volume showed no significant correlation to OS (P = 0.401) in the univariate analysis. Anaplastic glioma with oligodendrial differentiation showed significantly higher TBRmax values (P = 0.029), while no significant difference was observed for isocitrate hydrogenase 1/2-mutation (P = 0.752).
  
  
  CONCLUSIONS
  Static FET-PET provides significant prognostic information in anaplastic gliomas, which adds to the value of MRI, supporting the use of both modalities preoperatively to assess individual risks and estimate prognosis. Definition of the histopathologic subtype using static FET-PET remains challenging.
authors.affiliation: Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany. Electronic address: Stefanie.bette@tum.de.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Bette
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Peschke
authors.affiliation: Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Kaesmacher
authors.affiliation: Department of Neuropathology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Claire
authors.initials: C
authors.lastname: Delbridge
authors.affiliation: Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Pyka
authors.affiliation: Department of Neurology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Friederike
authors.initials: F
authors.lastname: Schmidt-Graf
authors.affiliation: Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Claus
authors.initials: C
authors.lastname: Zimmer
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Meyer
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Ringel
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Gempt
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001254:Astrocytoma / Q000175:diagnosis / Q000628:therapy; D001932:Brain Neoplasms / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D003131:Combined Modality Therapy; D005260:Female; D005910:Glioma / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D006801:Humans; D017567:Karnofsky Performance Status; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009837:Oligodendroglioma / Q000175:diagnosis / Q000628:therapy; D049268:Positron-Emission Tomography; D012189:Retrospective Studies; D016019:Survival Analysis; D047368:Tumor Burden
keywords: Anaplastic gliomas; Oligodendrial differentiation; Static FET-PET