Fig. 13.

Mn-enhanced CMR of the mouse heart. (A–D) Mid-ventricular short-axis T₁ weighted images from a mouse demonstrate increasing SNR over time during IP infusion of MnCl₂. Images were acquired over 90 minutes, while MnCl₂ was infused from 20min until 50min. The specific times corresponding to each image are 15min, 30min, 50min, and 80min for A–D, respectively. (E) When acquiring images using the technique outlined in [127], accumulation of Mn²⁺ within cardiomyocytes results in a linear increase in SNR during infusion. The rate of increase in SNR (solid black line) over the points corresponding to MnCl₂ infusion (filled gray symbols between the start and end of infusion), provides an index of integrated Mn²⁺ flux through the L-type calcium channel (LTCC) (LTCCI, bold numbers). Sample data from one WT mouse demonstrate an increase in LTCCI over baseline in response to β-adrenergic stimulation with dobutamine, and a decrease from baseline in response to partial LTCC inhibition with nifedipine. Figure reprinted with permission from [127] Vandsburger et al. Circulation. 2010; 122:A12386