Dissolution dynamic nuclear polarization-enhanced magnetic resonance spectroscopy and imaging: Chemical and biochemical reactions in nonequilibrium conditions

Hyperpolarization techniques, in particular dissolution dynamic nuclear polarization (D-DNP), make a contribution to overcoming sensitivity limitations of magnetic resonance (MR) spectroscopy through signal enhancement, leading to the study of new fields of research in real time. Utilizing the large signal enhancement initially produced on small molecules, it has become possible to study systems with low g nuclei, such as C-13, N-15, and Si-29. This review summarizes recent studies that have extended the applicability of D-DNP into various areas of research, especially for systems in nonequilibrium conditions that involve in vivo metabolic/molecular MR imaging for early stage disease diagnosis and real-time MR analysis of various chemical/biochemical reactions for kinetic and mechanistic studies. This review also deals with the theoretical aspects of DNP mechanisms and experimental arrangements of the dissolution setup.