Passive catheter tracking during interventional MRI using hyperpolarized 13C.

nterventional procedures in MRI can be performed preclinically using active or passive catheter-tracking methods. A novel passive nonproton technique is suggested that uses a catheter filled with a hyperpolarized C-13 contrast agent. A prototype three-lumen catheter was built with two closed lumens containing a flowing hyperpolarized C-13 contrast agent. Entire-length C-13 catheter projection visualization could be performed in vivo with a catheter SNR of similar to 80, one dual projection frame per similar to 700 ms, and an in-plane resolution of 2 x 2 mm(2) while traveling through the aorta of a pig. The traveling path of the C-13 catheter was visualized after back-projection catheter reconstruction and after image fusion with an anatomical offline proton road map. Catheter length visualization was aided by an oblique planar visualization mode. The high catheter signal demonstrated, together with the entire catheter length visualization and high surrounding soft-tissue contrast, warrants further development into a real-time technique.