title: Relevance of T2 signal changes in the assessment of progression of glioblastoma according to the Response Assessment in Neurooncology criteria.
abstract: BACKGROUND
  According to the Response Assessment in Neurooncology (RANO) criteria, significant nonenhancing signal increase in T2-weighted images qualifies for progression in high-grade glioma (T2-progress), even if there is no change in the contrast-enhancing tumor portion. The purpose of this retrospective study was to assess the frequency of isolated T2-progress and its predictive value on subsequent T1-progress, as determined by a T2 signal increase of 15% or 25%, respectively. The frequency of T2-progress was correlated with antiangiogenic therapy.
  
  
  METHODS
  MRI follow-up examinations (n = 777) of 144 patients with histologically proven glioblastoma were assessed for contrast-enhanced T1 and T2-weighted images. Examinations were classified as T1-progress, T2-progress with 15% or 25% T2-signal increase, stable disease, or partial or complete response.
  
  
  RESULTS
  Thirty-five examinations revealed exclusive T2-progress using the 15% criterion, and only 2 examinations qualified for the 25% criterion; 61.8% of the scans presenting T2-progress and 31.5% of the scans presenting stable disease revealed T1-progress in the next follow-up examination. The χ(2) test showed a highly significant correlation (P < .001) between T2-progress, with the 15% criterion and subsequent T1-progress. No correlation between antiangiogenic therapy and T2-progress was shown.
  
  
  CONCLUSIONS
  Tumor progression, as determined by both contrast-enhanced T1 and T2 sequences is more frequently diagnosed than when considering only contrast-enhanced T1 sequences. Definition of T2-progress by a 15% T2-signal increase criterion is superior to a 25% criterion. The missing correlation of T2-progress and antiangiogenic therapy supports the hypothesis of T2-progress as part of the natural course of the tumor disease.
authors.affiliation: Department of Neuroradiology, University of Heidelberg Medical Center, Im Neuenheimer Feld 400, Heidelberg 69120, Germany. alexander.radbruch@med.uni-heidelberg.de
authors.forename: Alexander
authors.initials: A
authors.lastname: Radbruch
authors.forename: Kira
authors.initials: K
authors.lastname: Lutz
authors.forename: Benedikt
authors.initials: B
authors.lastname: Wiestler
authors.forename: Philipp
authors.initials: P
authors.lastname: Bäumer
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
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000175:diagnosis*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D005909:Glioblastoma / Q000145:classification / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies