title: Chemotherapy response monitoring of colorectal liver metastases by dynamic Gd-DTPA-enhanced MRI perfusion parameters and 18F-FDG PET metabolic rate.
abstract: In this study, we examined the in vivo relationship between functional tumor vasculature, determined by dynamic contrast-enhanced (DCE-) MRI, and tumor metabolism, determined by dynamic (18)F-FDG PET, during cytotoxic treatment of patients with colorectal liver metastases.
  
  
  METHODS
  Twenty-three patients underwent DCE-MRI (using gadolinium dimeglumine) and dynamic (18)F-FDG PET at baseline and after 3 treatment cycles, unless treatment was terminated because of toxicity. Parameters for vasculature (rate constant between extravascular extracellular space and blood plasma [k(ep)] and volume transfer constant [K(trans)]), extracellular space (v(e)), tumor size (the maximal axial diameter of each included lesion [MAD]), and metabolism (glucose metabolic rates [MR(glc)]) were derived, and changes during treatment were correlated. Overall survival (OS) and progression-free survival (PFS) served as outcome measures for the predictive abilities of pretreatment parameters and of treatment-related parameter changes.
  
  
  RESULTS
  Pretreatment MR(glc) and MAD were individually predictive for OS and PFS. During treatment, K(trans) increased significantly, but this increase could not be confirmed in a lesion-by-lesion analysis. MR(glc) decreased significantly (P < 0.001). No correlations were found for changes in DCE-MRI parameters and DeltaMR(glc). No relationship was found between changes in DCE-MRI parameters and OS or PFS. DeltaMR(glc) was able to predict OS (P = 0.008) after correction for confounders.
  
  
  CONCLUSIONS
  The efficacy of cytotoxic chemotherapy assessed by reduction in tumor metabolism does not depend on pretreatment properties of the tumor vasculature determined by DCE-MRI. Cytotoxic chemotherapy does not alter DCE-MRI-derived properties of tumor vasculature but decreases glucose consumption of tumor cells.
authors.affiliation: Department of Nuclear Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. D.Vriens@nucmed.umcn.nl
authors.forename: Dennis
authors.initials: D
authors.lastname: Vriens
authors.forename: Hanneke W M
authors.initials: HW
authors.lastname: van Laarhoven
authors.forename: Jack J A
authors.initials: JJ
authors.lastname: van Asten
authors.forename: Paul F M
authors.initials: PF
authors.lastname: Krabbe
authors.forename: Eric P
authors.initials: EP
authors.lastname: Visser
authors.forename: Arend
authors.initials: A
authors.lastname: Heerschap
authors.forename: Cornelis J A
authors.initials: CJ
authors.lastname: Punt
authors.forename: Lioe-Fee
authors.initials: LF
authors.lastname: de Geus-Oei
authors.forename: Wim J G
authors.initials: WJ
authors.lastname: Oyen
mesh_terms: D000368:Aged; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use; D015179:Colorectal Neoplasms / Q000098:blood supply* / Q000473:pathology*; D018450:Disease Progression; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D019786:Gadolinium DTPA / Q000493:pharmacokinetics; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000378:metabolism* / Q000556:secondary; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D015996:Survival Rate; D016896:Treatment Outcome
chemical_list: D000970:Antineoplastic Agents; D019788:Fluorodeoxyglucose F18; D019786:Gadolinium DTPA