title: T2*-correction in dynamic contrast-enhanced MRI from double-echo acquisitions.
abstract: OBJECTIVE
  To evaluate the importance of T2*-effects on the arterial input function (AIF) and on the resulting dynamic parameter estimation in dynamic contrast-enhanced (DCE) MRI of high-grade gliomas.
  
  
  METHODS
  Seven patients with high-grade gliomas were imaged in total 50 times using a double-echo DCE sequence. Kinetic analysis using the extended Tofts model was performed using AIFs with and without correction for T2*-effects, and the resulting estimates of the transfer constant (K(trans) ), blood plasma volume (vp ), and the rate constant (kep ) were compared. Numerical simulations were done for comparison with clinical results as well as to further investigate the dependency of parameter values on the magnitude of T2*-induced errors.
  
  
  RESULTS
  All kinetic parameters were found to be overestimated if T2*-effects in the AIF were not accounted for; with vp being most severely affected. The relative error in each parameter was dependent on the absolute parameter magnitude, resulting in incorrect parametric tumor distributions in the presence of uncorrected AIF T2*-effects.
  
  
  CONCLUSIONS
  In DCE, a sufficiently short echo time should be used or corrections for T2*-effects based on double-echo acquisition should be made for correct quantification of kinetic parameters.
authors.affiliation: The Intervention Centre, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
authors.forename: Magne
authors.initials: M
authors.lastname: Kleppestø
authors.forename: Christopher
authors.initials: C
authors.lastname: Larsson
authors.forename: Inge
authors.initials: I
authors.lastname: Groote
authors.forename: Raimo
authors.initials: R
authors.lastname: Salo
authors.forename: Jonas
authors.initials: J
authors.lastname: Vardal
authors.forename: Frédéric
authors.initials: F
authors.lastname: Courivaud
authors.forename: Alte
authors.initials: A
authors.lastname: Bjørnerud
mesh_terms: D000465:Algorithms; D016477:Artifacts; D001932:Brain Neoplasms / Q000378:metabolism / Q000473:pathology*; D003198:Computer Simulation; D003287:Contrast Media / Q000493:pharmacokinetics; D005260:Female; D005910:Glioma / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009942:Organometallic Compounds / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C090600:gadobutrol
keywords: AIF; DCE-MRI; T2* correction; T2*-effect; dynamic contrast-enhanced MRI; glioma