title: Optimization of the reference region method for dual pharmacokinetic modeling using Gd-DTPA/MRI and (18) F-FDG/PET.
abstract: OBJECTIVE
  The combination of MRI and positron emission tomography (PET) offers new possibilities for the development of novel methodologies. In pharmacokinetic image analysis, the blood concentration of the imaging compound as a function of time, [i.e., the arterial input function (AIF)] is required for MRI and PET. In this study, we tested whether an AIF extracted from a reference region (RR) in MRI can be used as a surrogate for the manually sampled (18) F-FDG AIF for pharmacokinetic modeling.
  
  
  METHODS
  An MRI contrast agent, gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) and a radiotracer, (18) F-fluorodeoxyglucose ((18) F-FDG), were simultaneously injected in a F98 glioblastoma rat model. A correction to the RR AIF for Gd-DTPA is proposed to adequately represent the manually sampled AIF. A previously published conversion method was applied to convert this AIF into a (18) F-FDG AIF.
  
  
  RESULTS
  The tumor metabolic rate of glucose (TMRGlc) calculated with the manually sampled (18) F-FDG AIF, the (18) F-FDG AIF converted from the RR AIF and the (18) F-FDG AIF converted from the corrected RR AIF were found not statistically different (P>0.05).
  
  
  CONCLUSIONS
  An AIF derived from an RR in MRI can be accurately converted into a (18) F-FDG AIF and used in PET pharmacokinetic modeling.
authors.affiliation: Centre d'imagerie moléculaire de Sherbrooke, Département de médecine nucléaire et radiobiologie, Université de Sherbrooke, Sherbrooke, Canada.
authors.forename: Éric
authors.initials: É
authors.lastname: Poulin
authors.forename: Réjean
authors.initials: R
authors.lastname: Lebel
authors.forename: Étienne
authors.initials: É
authors.lastname: Croteau
authors.forename: Marie
authors.initials: M
authors.lastname: Blanchette
authors.forename: Luc
authors.initials: L
authors.lastname: Tremblay
authors.forename: Roger
authors.initials: R
authors.lastname: Lecomte
authors.forename: M'hamed
authors.initials: M
authors.lastname: Bentourkia
authors.forename: Martin
authors.initials: M
authors.lastname: Lepage
mesh_terms: D000818:Animals; D001932:Brain Neoplasms / Q000175:diagnosis / Q000378:metabolism*; D045744:Cell Line, Tumor; D003287:Contrast Media / Q000008:administration & dosage / Q000493:pharmacokinetics; D019788:Fluorodeoxyglucose F18 / Q000008:administration & dosage / Q000493:pharmacokinetics*; D019786:Gadolinium DTPA / Q000008:administration & dosage / Q000493:pharmacokinetics*; D005909:Glioblastoma / Q000175:diagnosis / Q000378:metabolism*; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000592:standards; D008954:Models, Biological; D064847:Multimodal Imaging / Q000379:methods; D049268:Positron-Emission Tomography / Q000379:methods* / Q000592:standards; D019275:Radiopharmaceuticals / Q000008:administration & dosage / Q000493:pharmacokinetics; D011916:Rats, Inbred F344; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D019786:Gadolinium DTPA
keywords: MRI; PET; arterial input function; combined MRI-PET; pharmacokinetic modeling; rats; reference region