Partition coefficients for gadolinium chelates in the normal myocardium: Comparison of gadopentetate dimeglumine and gadobenate dimeglumine

Purpose: 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). Materials and 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). Conclusion: 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. J. Magn. Reson. Imaging 2012;36:733-737.