title: Comparison of Gd-DTPA and Gd-BOPTA for studying renal perfusion and filtration.
abstract: OBJECTIVE
  To measure the systematic error in perfusion and filtration parameters derived from magnetic resonance (MR) renography caused by protein binding of MR contrast agents.
  
  
  METHODS
  Eight healthy Danish Landrace pigs were examined with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). In four pigs a bolus of gadopentetate-dimeglumine (Gd-DTPA; no protein binding) was injected, followed by gadobenate-dimeglumine (Gd-BOPTA; 10% protein binding). The order was reversed in the other four pigs. A two-compartment filtration model was generalized to allow for protein binding and fitted to whole-cortex region of interest (ROI) curves. Single-kidney plasma flow and volume, tubular flow (or GFR), and tubular transit time of both agents were compared.
  
  
  RESULTS
  The data show a strong systematic underestimation (P < 0.001) in GFR by Gd-BOPTA (33 ± 7.2%), and no significant differences (P > 0.05) in plasma flow (2.2 ± 18%), plasma volume (-1.7 ± 7.8%) and tubular transit time (3.1 ± 7.2%). The order of injection had no significant effect.
  
  
  CONCLUSIONS
  Theory and experiments agree that perfusion parameters of both agents are comparable, whereas GFR is underestimated with Gd-BOPTA due to the dependence of relaxivity on protein content. Hence, GFR cannot be measured with protein-bound contrast agents, but the proposed dual-agent protocol may produce new functional indices measuring protein filtration.
authors.affiliation: Department of Clinical Radiology, University Hospitals Munich, Munich, Germany. mike.notohamiprodjo@med.uni-muenchen.de
authors.forename: Mike
authors.initials: M
authors.lastname: Notohamiprodjo
authors.forename: Michael
authors.initials: M
authors.lastname: Pedersen
authors.forename: Christian
authors.initials: C
authors.lastname: Glaser
authors.forename: Andreas D
authors.initials: AD
authors.lastname: Helck
authors.forename: Klaus-Peter
authors.initials: KP
authors.lastname: Lodemann
authors.forename: Bente
authors.initials: B
authors.lastname: Jespersen
authors.forename: Michael
authors.initials: M
authors.lastname: Fischereder
authors.forename: Maximilian F
authors.initials: MF
authors.lastname: Reiser
authors.forename: Steven P
authors.initials: SP
authors.lastname: Sourbron
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D003287:Contrast Media; D019786:Gadolinium DTPA; D005919:Glomerular Filtration Rate / Q000502:physiology*; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008536:Meglumine / Q000031:analogs & derivatives*; D009942:Organometallic Compounds; D012079:Renal Circulation / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine; D019786:Gadolinium DTPA