Sub‐second proton imaging of 13C hyperpolarized contrast agents in water

Indirect proton detection of 13C hyperpolarized contrast agents potentially enables greater sensitivity. Presented here is a study of sub‐second projection imaging of hyperpolarized 13C contrast agent addressing the obstacle posed by water suppression for indirect detection in vivo. Sodium acetate phantoms were used to develop and test water suppression and sub‐second imaging with frequency‐selective RF pulses using spectroscopic and imaging indirect proton detection. A 9.8 mm aqueous solution of 13C PHIP hyperpolarized 2‐hydroxyethyl‐13C‐propionate‐d2,3,3 (HEP), <P > ~25% was used for demonstration of indirect proton sub‐second imaging detection. Balanced 2D FSSFP (fast steady‐state free precession) allowed the recording of proton images with a field of view of 64 × 64 mm2 and spatial resolution 2 × 2 mm2 with total acquisition time of less than 0.2 s. In thermally polarized sodium 1‐13C‐acetate, 13C to 1H polarization transfer efficiency of 45.1% of the theoretically predicted values was observed in imaging detection corresponding to an 11‐fold overall sensitivity improvement compared with direct 13C FSSFP imaging. 13C to 1H polarization transfer efficiency of 27% was observed in imaging detection, corresponding to a 3.25‐fold sensitivity improvement compared with direct 13C FSSFP imaging with hyperpolarized HEP. The range of potential applications and limitations of this sub‐second and ultra‐sensitive imaging approa...

Source: Contrast Media and Molecular Imaging - April 22, 2014 Category: Radiology Authors: Milton L. Truong, Aaron M. Coffey, Roman V. Shchepin, Kevin W. Waddell, Eduard Y. Chekmenev Tags: Full Paper Source Type: research