title: Analysis of fractional anisotropy facilitates differentiation of glioblastoma and brain metastases in a clinical setting.
abstract: OBJECTIVE
  Differentiating glioblastoma from brain metastases is important for therapy planning. Diffusion tensor imaging (DTI) was described as a promising tool, however with conflicting results.
  
  
  OBJECTIVE
  of this study was to analyze the clinical utility of DTI for the differentiation of brain metastases and glioblastoma.
  
  
  METHODS
  294 patients (165 glioblastoma, 129 brain metastases) with preoperative DTI were included in this retrospective study. Fractional anisotropy (FA) was measured via regions of interest (ROIs) in the contrast-enhancing tumor, the necrosis and the FLAIR-hyperintense non-enhancing peritumoral region (NEPTR). Two neuroradiologists classified patient cases as glioblastoma or brain metastases without and with knowledge of FA values.
  
  
  RESULTS
  Glioblastoma showed significantly higher FAcontrast(median glioblastoma=0.33, metastases=0.23; P<0.001) whereas no significant difference was observed for FANEPTR(0.21 vs. 0.22; P=0.28) and for FAnecrosis(0.17 vs. 0.18, P=0.37). FA improved diagnostic accuracy of the neuroradiologists significantly from an AUC of 0.84/0.85 (Reader1/Reader2) to 0.89/0.92.
  
  
  CONCLUSIONS
  Glioblastoma show significantly higher FA values in the contrast enhancing tumor part than brain metastases. Implementation of a ROI-based measurement of FA values and FA color maps in clinical routine helps to differentiate between glioblastoma and brain metastases.
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 Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Huber
authors.affiliation: Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Benedikt
authors.initials: B
authors.lastname: Wiestler
authors.affiliation: Department of Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Boeckh-Behrens
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Gempt
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: Bernhard
authors.initials: B
authors.lastname: Meyer
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 Neuroradiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Jan S
authors.initials: JS
authors.lastname: Kirschke
mesh_terms: D016880:Anisotropy; D001921:Brain / Q000473:pathology; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000556:secondary; D015331:Cohort Studies; D003287:Contrast Media; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005909:Glioblastoma / Q000175:diagnosis*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D009336:Necrosis; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media
keywords: Brain metastases; Diffusion tensor imaging; Fractional anisotropy; Glioblastoma