Hyperpolarized (HP) tracers dramatically increase the sensitivity of magnetic resonance imaging (MRI) to monitor metabolism non-invasively and in vivo. Their production, however, requires an extra polarizing device (polarizer) whose complexity, operation and cost can exceed that of an MRI system itself. Furthermore, the lifetime of HP tracers is short and some of the enhancement is lost during transfer to the application site. Here, we present the production of HP tracers in water without an external polarizer: by Synthesis Amid the Magnet Bore, A Dramatically Enhanced Nuclear Alignment (SAMBADENA) is achieved within seconds, corresponding to a hyperpolarization of ∼20%. As transfer of the tracer is no longer required, SAMBADENA may permit a higher polarization at the time of detection at a fraction of the cost and complexity of external polarizers. This development is particularly promising in light of the recently extended portfolio of biomedically relevant para-hydrogen-tracers and may lead to new diagnostic applications.

Purpose To introduce an RF coil system consisting of an 8‐channel transmit (Tx) and 8‐channel receive (Rx) coil arrays for 19F MRI of large animals. Methods The Tx efficiency and homogeneity of the 8‐element loop coil array (loop size: 6 × 15 cm2) were simulated for two different pig models rendered from MR images. An 8‐channel Rx coil array consisting of a flexible 6‐channel posterior and a 2‐channel planar anterior array was designed to fit on the abdomen of an average‐sized pig in supine position. Measurements were performed in a grid phantom and ex vivo on a pig model with perfluoroctylbromide (PFOB)–filled tubes inserted in the thorax. Results Measured and simulated Tx efficiency and homogeneity for the 8‐channel and 5‐channel arrays were in good agreement: 1.87 ± 0.22μT/√kW versus 1.96 ± 0.29μT/√kW, and 2.29 ± 0.39μT/√kW versus 2.41 ± 0.37μT/√kW. An isolation of 38 ± 8 dB is achieved between the 19F Tx and Rx elements, and over 30 dB between the 1H and 19F elements. The PFOB‐filled vials could be clearly identified within the cadaver abdomen with an SNR of 275 ± 51 for a 3D gradient‐echo sequence with 2‐mm isotropic resolution and 12 averages, acquired in 9:52 min:s. Performance of the Tx array was robust against phase and amplitude mismatches at the input ports. Conclusions A modular and scalable Tx array offers improved Tx efficiency in 19F MRI of large animals with various sizes. Although conventional birdcage coils have superior Tx efficiency within the target region of interest, scalability of the Tx array to animal size is a major benefit. The described 19F coil provides homogeneous excitation and high sensitivity detection in large pig models.

In this study, we have developed an 8-channel transmit/ 8-channel receive coil array system for cardiac and thoracic MRI in pigs. Transmit array is scalable in size to increase transmit efficiency in pigs with smaller abdomen size. Receive array is semi-flexible to fit tightly on the dome-shaped thorax of pigs. We present a detailed transmit efficiency analysis of the Tx array including tolerance to mismatches at the input ports. We also present 19F MRI results from a cadaver measurement.