title: Tracer kinetics analysis of dynamic contrast-enhanced CT and MR data in patients with squamous cell carcinoma of the upper aerodigestive tract: comparison of the results.
abstract: OBJECTIVE
  (i) To evaluate the feasibility of tracer kinetics analysis of dynamic contrast-enhanced (DCE) CT and T2-weighted MR data of squamous cell carcinoma (SCCA) of the upper aerodigestive tract. (ii) To compare functional parameters derived by both modalities and examine the interchangeability of them as well as the intra- and inter-rater agreement.
  
  
  METHODS
  Dynamic contrast-enhanced-CT and MR images of 23 patients with SCCA were postprocessed using a distributed-parameter (DP) tracer kinetic model. The evaluated parameters included blood flow (F), intravascular blood volume (v(1)), extravascular extracellular blood volume (v(2)), intravascular mean transit time (t(1)), lag time (t(0)), permeability surface area product (PS) and extraction ratio (E). Mean perfusion values, based on region-of-interest analysis, of the tumors and the healthy muscle tissue were compared and correlated. Inter-rater and intra-rater variability were assessed. Interchangeability of the tumor functional parameters was tested using Pearson's correlation coeficients and Bland-Altman plots.
  
  
  RESULTS
  The mean values in tumor and healthy muscle tissues were significantly different for each modality (0.0001< or =P< or =0.03). The mean values of all tumor perfusion parameters apart from v(2) and E were significantly different (0.001< or =P< or =0.009) between the two modalities. The intra-rater variability was good to very good for all parameters. The inter-rater variability was moderate to good. Bland-Altman plots of F, t(1), t(0), and v(2) showed moderate interchangeability. There was a proportionality error in v(1) and PS graphs.
  
  
  CONCLUSIONS
  The estimation of functional parameters in SCCA is feasible using DCE-CT and -MR with a DP model. The parameters are mostly significantly different and the interchangeability of them is limited.
authors.affiliation: Department of Neuroradiology, Eberhard Karls University, Hoppe-Seyler-Str., Tübingen 3'D-72076, Germany. sotirios.bisdas@med.uni-tuebingen.de
authors.forename: Sotirios
authors.initials: S
authors.lastname: Bisdas
authors.forename: Mehran
authors.initials: M
authors.lastname: Baghi
authors.forename: Jens
authors.initials: J
authors.lastname: Wagenblast
authors.forename: Theodosios
authors.initials: T
authors.lastname: Bisdas
authors.forename: Choon Hua
authors.initials: CH
authors.lastname: Thng
authors.forename: Martin G
authors.initials: MG
authors.lastname: Mack
authors.forename: Tong San
authors.initials: TS
authors.lastname: Koh
authors.forename: Ulrike
authors.initials: U
authors.lastname: Ernemann
mesh_terms: D000465:Algorithms; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000378:metabolism; D003198:Computer Simulation; D003287:Contrast Media / Q000493:pharmacokinetics; D005260:Female; D019786:Gadolinium DTPA / Q000493:pharmacokinetics; D006258:Head and Neck Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007479:Iopamidol / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D007700:Kinetics; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D008954:Models, Biological; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; C057937:iomeprol; D007479:Iopamidol; D019786:Gadolinium DTPA