title: Modeling DCE-MRI at low temporal resolution: a case study on rheumatoid arthritis.
abstract: OBJECTIVE
  To identify the optimal tracer-kinetic modeling strategy for dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) data acquired at low temporal resolution.
  
  
  METHODS
  DCE-MRI was performed on 13 patients with rheumatoid arthritis of the hand before and after anti-tumor necrosis factor alpha (TNFα) therapy, using a 3D sequence with a temporal resolution of 13 seconds, imaging for 4 minutes postcontrast injection. Concentration-time curves were extracted from regions of interest (ROIs) in enhancing synovium and fitted to the 3-parameter modified Tofts model (MT) and the 4-parameter two-compartment exchange model (2CXM). To assist the interpretation of the data, the same analysis was applied to simulated data with similar characteristics.
  
  
  RESULTS
  Both models fitted the data closely, and showed similar therapy effects. The MT plasma volume was significantly lower than with 2CXM, but the differences in permeability and interstitial volume were not significant. 2CXM was less precise than MT, with larger standard deviations relative to the mean in most parameters. The additional perfusion parameter determined with 2CXM did not provide a statistically significant trend due to low precision.
  
  
  CONCLUSIONS
  The standard MT model is the optimal modeling strategy at low temporal resolution. Advanced models improve the accuracy and generate an additional parameter, but these benefits are offset by low precision.
authors.affiliation: Division of Medical Physics, University of Leeds, Leeds, UK.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Ledsam
authors.forename: Richard
authors.initials: R
authors.lastname: Hodgson
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Moots
authors.forename: Steven P
authors.initials: SP
authors.lastname: Sourbron
mesh_terms: D000465:Algorithms; D001172:Arthritis, Rheumatoid / Q000175:diagnosis* / Q000378:metabolism*; D003198:Computer Simulation; D005260:Female; D006571:Heterocyclic Compounds / Q000493:pharmacokinetics*; 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: D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C050823:gadolinium 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetate
keywords: MRI; Tofts model; dynamic contrast-enhanced; perfusion; permeability; rheumatoid arthritis; tracer kinetics; two-compartment model