Shielded NMR System Suitable for Parahydrogen-Induced Polarization

Hyperpolarized (HP) ¹³C contrast agents have several and unique characteristics which hold great promise for qualitatively new angiography and molecular imaging applications. They have intrinsically large signal-to-noise, are not radioactive and may in principle be very benign, and the large ¹³C chemical shift offers the opportunity for molecule- and conformation/environment sensitivity. We have begun preliminary studies to investigate the feasibility of increasing the sensitivity and molecular specificity of HP ¹³C imaging through polarization transfer. These phantom studies are specifically designed to assess the difficulties encountered when performing polarization transfer in a normal clinical imaging environment. The eventual goal is to use low-gyromagnetic-ratio HP agents as long-T1 ‘carriers’ of spin order, and polarization transfer to realize the larger signal available from higher-gamma nuclei.

MRI imaging sequence for HP nucleus (I) to large-gamma (‘sensitive’, or S) nucleus