title: 18F-FCho PET and MRI for the prediction of response in glioblastoma patients according to the RANO criteria.
abstract: OBJECTIVE
  In this study, we investigated fluorine-18 fluoromethylcholine (F-FCho) PET and contrast-enhanced MRI for predicting therapy response in glioblastoma (GB) patients according to the Response Assessment in Neuro-Oncology criteria. Our second aim was to investigate which imaging modality enabled prediction of treatment response first.
  
  
  METHODS
  Eleven GB patients who underwent no surgery or debulking only and received concomitant radiation therapy (RT) and temozolomide were included. The gold standard Response Assessment in Neuro-Oncology criteria were applied 6 months after RT to define responders and nonresponders. F-FCho PET and MRI were performed before RT, during RT (week 2, 4, and 6), and 1 month after RT. The contrast-enhancing tumor volume on T1-weighted MRI (GdTV) and the metabolic tumor volume (MTV) were calculated. GdTV, standardized uptake value (SUV)mean, SUVmax, MTV, MTV×SUVmean, and percentage change of these variables between all time-points were assessed to differentiate responders from nonresponders.
  
  
  RESULTS
  Absolute SUV values did not predict response. MTV must be taken into account. F-FCho PET could predict response with a 100% sensitivity and specificity using MTV×SUVmean 1 month after RT. A decrease in GdTV between week 2 and 6, week 4 and 6 during RT and week 2 during RT, and 1 month after RT of at least 31%, at least 18%, and at least 53% predicted response with a sensitivity and specificity of 100%. As such, the parameter that predicts therapy response first is MR derived, namely, GdTV.
  
  
  CONCLUSIONS
  Our data indicate that both F-FCho PET and contrast-enhanced T1-weighted MRI can predict response early in GB patients treated with RT and temozolomide.
authors.affiliation: Departments of aNuclear Medicine bRadiology cRadiation Oncology dPathology, Ghent University Hospital eMEDISIP, Department of Electronics and Information Systems, iMinds Medical IT fDepartment of Radiopharmacy, Ghent University, Ghent, Belgium.
authors.forename: Julie
authors.initials: J
authors.lastname: Bolcaen
authors.forename: Marjan
authors.initials: M
authors.lastname: Acou
authors.forename: Tom
authors.initials: T
authors.lastname: Boterberg
authors.forename: Christian
authors.initials: C
authors.lastname: Vanhove
authors.forename: Filip
authors.initials: F
authors.lastname: De Vos
authors.forename: Caroline
authors.initials: C
authors.lastname: Van den Broecke
authors.forename: Roel
authors.initials: R
authors.lastname: Van Holen
authors.forename: Karel
authors.initials: K
authors.lastname: Deblaere
authors.forename: Ingeborg
authors.initials: I
authors.lastname: Goethals
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy*; D002794:Choline / Q000031:analogs & derivatives*; D005260:Female; D005909:Glioblastoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D016896:Treatment Outcome; D047368:Tumor Burden
chemical_list: C516370:fluoromethylcholine; D002794:Choline