FIGURE 6.

Although the r1 relaxivity for gadolinium contrast agents increases from 3T to 7T (3.2 mM/s for Magnivist), the r2^∗ relaxivity increases dramatically when compartmentalized as in blood and tissue. Nonlinear r2^∗ relaxivity in oxygenated human blood at 3T and 7T (A). At concentrations above 2 mM, a linear relationship relaxivity is observed (68.9 mM/s at 3T and 290.8 mM/s at 7T. Signal characteristics of a T1w GRE sequence (B) with increasing Gd concentration showing rapid signal loss at7T with higher concentrations. Arterial input function and tissue signal intensity curves from a DCE-MRI prostate study (C). Acquired with a multiple-echo acquisition allowed for correction of time intensity curves at the expense of temporal resolution.