title: Infiltrative patterns of glioblastoma: Identification of tumor progress using apparent diffusion coefficient histograms.
abstract: OBJECTIVE
  To investigate whether apparent diffusion coefficient (ADC) histogram analysis can differentiate between patients presenting T2-progress and patients presenting stable T2-signal in glioblastoma.
  
  
  METHODS
  Fourteen patients presenting an isolated T2-progress and a matched control group exhibiting stable disease were included. Relative ADC value distribution within tumoral and peritumoral FLAIR hyperintensities were evaluated using ADC-histogram analysis. Severity and frequency of ADC shift between baseline, T2-progress, and subsequent T1-progress were analyzed using the Wilcoxon test.
  
  
  RESULTS
  The shift of ADC histograms either to higher or to lower values in case of T2-progress was significantly more severe than in the control group (P value 0.05). Furthermore, a significant shift toward lower ADC values (P value 0.02) was detected when comparing ADC histograms of patients with T2-progress and subsequent T1-progress.
  
  
  CONCLUSIONS
  The basis for the observed ADC shift in isolated T2-progress may be time dependent: Initially, formation of peritumoral edema may cause an increase of ADC values that is followed by tumor cells infiltrating the surrounding tissue, causing a subsequent decrease of ADC values. The shift toward lower ADC values in case of subsequent T1-progress confirms this hypothesis and provides further evidence for T2-progress being an intermediate step between stable disease (SD) and T1-progress.
authors.affiliation: Department of Neuroradiology, University of Heidelberg, Medical Center, Heidelberg, Germany.
authors.forename: Kira
authors.initials: K
authors.lastname: Lutz
authors.forename: Benedikt
authors.initials: B
authors.lastname: Wiestler
authors.forename: Markus
authors.initials: M
authors.lastname: Graf
authors.forename: Philipp
authors.initials: P
authors.lastname: Bäumer
authors.forename: Ralf
authors.initials: R
authors.lastname: Floca
authors.forename: Heinz-Peter
authors.initials: HP
authors.lastname: Schlemmer
authors.forename: Sabine
authors.initials: S
authors.lastname: Heiland
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wick
authors.forename: Martin
authors.initials: M
authors.lastname: Bendszus
authors.forename: Alexander
authors.initials: A
authors.lastname: Radbruch
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001932:Brain Neoplasms / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D018450:Disease Progression; D005260:Female; D005909:Glioblastoma / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009716:Numerical Analysis, Computer-Assisted; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: ADC-histogram; RANO-criteria; T2-progress; glioblastoma