Jeffrey Harold Maki1, 2, Gregory J. Wilson3, Miles A. Kirchin4, Sarah Bastawrous2, Puneet Bhargava2
1Radiology, University of Washington, Seattle, WA, United States; 2Radiology, Puget Sound VAHCS, Seattle, WA, United States; 3MR Clinical Science, Philips Medical, Cleveland, OH, United States; 4Medical Affairs, Bracco Diagnostics, Milan, Italy
High-relaxivity protein-binding contrast agents are believed to improve contrast-enhanced MRA. To effectively use these agents, knowing their true r1 and r2 relaxivities in human blood at MRA concentrations is vital. In Vitro relaxivity measurements (gadoteridol, gadobenate, gadofosveset) were performed in human blood at concentrations to 20 mmol (1.5, 3T). R1 and R2* were non-linear vs. [Gd] such that relaxivities r1 and r2* depended highly on [Gd]. At low concentrations r1 relaxivity behaved approximately per labeling data, but >3mmol the r1 of all agents decreased and became similar. This and r2* effects suggest higher Gd doses may be detrimental for CE-MRA.