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Delayed Gadolinium-enhanced MR Imaging of Cartilage: A Comparative Analysis of Different Gadolinium-based Contrast Agents in an ex Vivo Porcine Model.

Purpose To compare the delayed gadolinium-enhanced magnetic resonance (MR) imaging of cartilage (dGEMRIC) indexes acquired with different gadolinium-based contrast agents (GBCAs), with emphasis on the difference in electrical charge, and to evaluate the feasibility of the use of GBCAs other than gadopentetate dimeglumine with a double negative charge (Gd-DTPA2-) as alternatives at dGEMRIC. Materials and Methods Intact porcine patellae (n = 44) were divided into four groups according to GBCA used: Gd-DTPA2-, double negative gadobenate dimeglumine (Gd-BOPTA2-), single negative gadoterate meglumine (Gd-DOTA-), and nonionic gadobutrol (Gd-DT-DO3A). Patellae in each group were further assigned to control (n = 3) or trypsin-treated (n = 8) groups and were immersed in GBCA solutions prepared at a concentration of 2.5 mmol/L. T1 maps were acquired at 10-minute intervals at 0-120 minutes. The difference between postcontrast R1 and precontrast R1 (ΔR) and the time ΔR curves were plotted. Patellae were stained with safranin-O to evaluate the proteoglycan content of the cartilage. A linear mixed-effects model was used to analyze the time ΔR curves, and Student t tests and Mann-Whitney U tests were used to compare dGEMRIC indexes between groups. Results The difference in the estimated slopes of the time ΔR curves between control and trypsin-treated groups were greatest with Gd-BOPTA2-, followed by Gd-DTPA2-, Gd-DOTA-, and Gd-DT-DO3A, with differences in the estimated slopes of 0.037, 0.022, 0.018, and 0.011, respectively. The slope difference between control and trypsin-treated groups was significantly greater with Gd-BOPTA2- (P < .001) and significantly smaller with Gd-DT-DO3A (P = .004) in comparison with that with Gd-DTPA2-. Only the GBCAs with double negative charges showed significant differences in both the T1 measured after equilibration of cartilage with GBCA solution and the ΔR at 90 and 120 minutes between the control and trypsin-treated groups. Conclusion Double negative GBCAs produced better contrast between normal and degenerated cartilage than did those with a single negative charge and nonionic GBCAs at the same concentration for dGEMRIC. Because Gd-BOPTA2-, a high-relaxivity GBCA, showed higher contrast than did Gd-DTPA2-, Gd-BOPTA2-may be useful as an alternative GBCA for dGEMRIC. © RSNA, 2016 Online supplemental material is available for this article.