MR coronary angiography in pigs with intraarterial injections of a hyperpolarized (13)C substance.

A new diagnostic application of a water-soluble contrast medium (CM) based on the hyperpolarization of a 13C substance is introduced. The degree of polarization achieved is >30%, which is about a factor of 105 higher than the thermal equilibrium polarization level at 1.5 T. Imaging of hyperpolarized (HP) CM during a cardiac interventional MRI procedure was studied. Catheters were positioned in the left and right coronary arteries of pigs. A coil tuned to 13C was used for nonproton imaging. The HP-13C CM (∼5 ml, 0.5 M, ∼30% polarization) was injected during projection imaging using a fully balanced steady-state free precession (SSFP) pulse sequence with and without cardiac gating. The contrast agent-filled catheter was clearly visible during the procedure. The coronary arteries were well depicted and the signal-to-noise ratios (SNRs) were in the range of 10–40. The use of HP-13C CM may provide a new diagnostic procedure for interventional MRI. Magn Reson Med, 2006. © 2006 Wiley-Liss, Inc.