title: Partition coefficients for gadolinium chelates in the normal myocardium: comparison of gadopentetate dimeglumine and gadobenate dimeglumine.
abstract: OBJECTIVE
  To evaluate the influence of contrast agents with different relaxivity on the partition coefficient (λ) and timing of equilibration using a modified Look-Locker inversion recovery (MOLLI) sequence in cardiac magnetic resonance imaging (MRI).
  
  
  METHODS
  MOLLI was acquired in 20 healthy subjects (1.5T) at the mid-ventricular short axis precontrast and 5, 10, 20, 25, and 30 minutes after administration of a bolus of 0.15 mmol/kg gadobenate dimeglumine (Gd-BOPTA) (n = 10) or gadopentetate dimeglumine (Gd-DTPA) (n = 10). T1 times were measured in myocardium and blood pool. λ was approximated by ΔR1(myocardium) /ΔR1(blood) . Values for Gd-BOPTA and Gd-DTPA were compared. Interobserver agreement was evaluated (intraclass correlation coefficient [ICC]).
  
  
  RESULTS
  T1 times of myocardium and blood pool (P < 0.001) and λ (0.42 ± 0.03 and 0.47 ± 0.04, respectively, P < 0.001; excluding 5 minutes for Gd-BOPTA) were significantly lower for Gd-BOPTA than Gd-DTPA. The λ((Gd-DTPA)) showed no significant variation between 5 and 30 minutes. The λ((Gd-BOPTA)) values were significantly lower at 5 minutes compared to other times (0.38 vs. 0.42; P < 0.05). Interobserver agreement for λ values was excellent with Gd-BOPTA (ICC = 0.818) and good for Gd-DTPA (ICC = 0.631).
  
  
  CONCLUSIONS
  The λ((Gd-BOPTA)) values were significantly lower compared to λ((Gd-DTPA)) at the same administered dose. Using Gd-BOPTA, the equilibrium between myocardium and blood pool was not achieved at 5 minutes postcontrast.
authors.affiliation: Radiology and Imaging Sciences, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892, USA.
authors.forename: Nadine
authors.initials: N
authors.lastname: Kawel
authors.forename: Marcelo
authors.initials: M
authors.lastname: Nacif
authors.forename: Francesco
authors.initials: F
authors.lastname: Santini
authors.forename: Songtao
authors.initials: S
authors.lastname: Liu
authors.forename: Jens
authors.initials: J
authors.lastname: Bremerich
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Arai
authors.forename: David A
authors.initials: DA
authors.lastname: Bluemke
mesh_terms: D000328:Adult; D002614:Chelating Agents / Q000493:pharmacokinetics; D003198:Computer Simulation; D003287:Contrast Media / Q000493:pharmacokinetics; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008536:Meglumine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D008657:Metabolic Clearance Rate; D008955:Models, Cardiovascular; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology*; D009942:Organometallic Compounds / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D002614:Chelating Agents; D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine; D019786:Gadolinium DTPA