Purpose: The purpose of this study was to investigate the feasibility of in vivo 13C->1H hyperpolarization transfer, which has significant potential advantages for detecting the distribution and metabolism of hyperpolarized 13C probes in a clinical MRI scanner. Methods: A standalone pulsed 13C RF transmit channel was developed for operation in conjunction with the standard 1H channel of a clinical 3T MRI scanner. Pulse sequences for 13C power calibration and polarization transfer were programmed on the external hardware and integrated with a customized water-suppressed 1H MRS acquisition running in parallel on the scanner. The newly developed RF system was tested in both phantom and in vivo polarization transfer experiments in 1JCH-coupled systems: phantom experiments in thermally polarized and hyperpolarized [2-13C]glycerol, and 1H detection of [2-13C]lactate generated from hyperpolarized [2-13C]pyruvate in rat liver in vivo. Results: Operation of the custom pulsed 13C RF channel resulted in effective 13C->1H hyperpolarization transfer, as confirmed by the characteristic antiphase appearance of 1H-detected, 1JCH-coupled doublets. In conjunction with a pulse sequence providing 190-fold water suppression in vivo, 1H detection of hyperpolarized [2-13C]lactate generated in vivo was achieved in a rat liver slice. Conclusion: The results show clear feasibility for effective 13C->1H hyperpolarization transfer in a clinical MRI scanner with customized heteronuclear RF system.
- dynamic nuclear polarization