title: Prognostic Value of O-(2-[18F]-Fluoroethyl)-L-Tyrosine-Positron Emission Tomography Imaging for Histopathologic Characteristics and Progression-Free Survival in Patients with Low-Grade Glioma.
abstract: OBJECTIVE
  O-(2-[18F]-fluoroethyl)-L-tyrosine positron emission tomography ((18)F-FET-PET) imaging is applied for tumor grading, prognostic stratification, and diagnosis of tumor recurrence, especially in high-grade gliomas. Experience with (18)F-FET-PET imaging in low-grade gliomas is limited. Therefore, the objective of the present study was to assess (18)F-FET-PET tracer uptake in low-grade gliomas and to investigate possible correlations with contrast enhancement in magnetic resonance imaging (MRI) and histopathology.
  
  
  METHODS
  A total of 65 patients (29 female, 36 male, median age 38 years) with newly diagnosed or recurrent low-grade gliomas for whom preoperative MRI and (18)F-FET-PET imaging were available were included. Tumor entity, tumor location, as well as histopathology (isocitrate dehydrogenase [IDH] 1/2 mutation, Ki67, p53, oligodendroglial differentiation, 1p19q codeletion), and progression-free survival were assessed. (18)F-FET-PET images were acquired and fused to MRI (T2-weighted fluid-attenuated inversion recovery) and tumor volume was measured in areas with a tumor-to-background ratio >1.3, >1.6, and >2.0 and in MRI.
  
  
  RESULTS
  PET tracer uptake was observed in 78.5% of all World Health Organization Grade I and II tumors. (18)F-FET uptake showed a high negative predictive value for oligodendroglial components and for 1p19q codeletion. No further significant correlation between histologic features, progression-free survival, or IDH1/2 mutation status and tracer uptake was observed.
  
  
  CONCLUSIONS
  We found that 78.5% of low-grade gliomas do show elevated tracer uptake in (18)F-FET-PET imaging. Low-grade glioma without tracer uptake exclude oligodendroglial differentiation and 1p19q codeletion. Further differentiation between molecular subtypes is not possible with static (18)F-FET-PET. No correlation of progression-free survival to tracer uptake and IDH1/2-mutation status was observed.
authors: Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors: Stefanie
authors: S
authors: Bette
authors: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors: Jens
authors: J
authors: Gempt
authors: Department of Neuropathology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors: Claire
authors: C
authors: Delbridge
authors: Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors: Jan S
authors: JS
authors: Kirschke
authors: Department of Neuropathology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors: Juergen
authors: J
authors: Schlegel
authors: Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors: Stefan
authors: S
authors: Foerster
authors: Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors: Thomas
authors: T
authors: Huber
authors: Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors: Thomas
authors: T
authors: Pyka
authors: Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors: Claus
authors: C
authors: Zimmer
authors: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors: Bernhard
authors: B
authors: Meyer
authors: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany. Electronic address: florian.ringel@tum.de.
authors: Florian
authors: F
authors: Ringel
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D018572:Disease-Free Survival; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D053208:Kaplan-Meier Estimate; D008279:Magnetic Resonance Imaging; D008297:Male; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D049268:Positron-Emission Tomography; D011379:Prognosis; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D047368:Tumor Burden; D014443:Tyrosine / Q000031:analogs & derivatives
chemical_list: D014408:Biomarkers, Tumor; C117289:O-(2-fluoroethyl)tyrosine; D019275:Radiopharmaceuticals; D014443:Tyrosine
keywords: IDH1/2-mutation; Low-grade glioma; Oligodendroglial differentiation; Static (18)F-FET-PET