Ultra-fast three dimensional imaging of hyperpolarized 13C in vivo

Objective: PASADENA, a chemical method of enhancing nuclear spin polarization has demonstrated C-13 polarizations of order unity for the nascent products of molecular addition by parahydrogen. The extreme brevity of signal enhancement obtained by herpolarization requires improved C-13 MR in vivo imaging techniques for their optimum utility. Materials and Methods: C-13 imaging sequences, including C-13 3D FIESTA, were compiled for a GE LX 1.5 T clinical MR scanner. Two water soluble C-13 imaging agents were hyperpolarized utilizing parahydrogen and an automated polarizer. C-13 polarization was quantified in flow phantoms and in rats with jugular vein catheters. Results: Fast 3D FIESTA C-13 MR imaging technique acquired sequential 3D images (3.66 s/acquisition) with superior SNR. Hyperpolarized C-13 solutions and vascular phantoms achieved a maximum signal of 26,624 +/- 593. In vivo C-13 MR images of the cardiopulmonary circulation showed maximum C-13 signal of 2,402 +/- 158. C-13 images acquired within 3.66 s showed signal enhancement over 10,000 compared to equilibrium polarization. Conclusion: 3D-FIESTA was effective for sub-second in vivo imaging of hyperpolarized C-13 reagents produced in a custom-built parahydrogen polarizer. Application to C-13 hyperpolarized by parahydrogen is demonstrated in vitro and in vivo.