Parahydrogen‐Induced Hyperpolarization of Gases #DNPNMR

Published: January 18, 2021

Kovtunov, Kirill V., Igor V. Koptyug, Marianna Fekete, Simon B. Duckett, Thomas Theis, Baptiste Joalland, and Eduard Y. Chekmenev. “Parahydrogen‐Induced Hyperpolarization of Gases.” Angewandte Chemie International Edition 59, no. 41 (October 5, 2020): 17788–97.

https://doi.org/10.1002/anie.201915306

Imaging of gases is a major challenge for any modality including MRI. NMR and MRI signals are directly proportional to the nuclear spin density and the degree of alignment of nuclear spins with applied static magnetic field, which is called nuclear spin polarization. The level of nuclear spin polarization is typically very low, i.e., one hundred thousandth of the potential maximum at 1.5 T and a physiologically relevant temperature. As a result, MRI typically focusses on imaging highly concentrated tissue water. Hyperpolarization methods transiently increases nuclear spin polarizations up to unity, yielding corresponding gains in MRI signal level of several orders of magnitude that enable the 3D imaging of dilute biomolecules including gases. Parahydrogen-induced polarization is a fast, highly scalable, and low-cost hyperpolarization technique. The focus of this Minireview is to highlight selected advances in the field of parahydrogen-induced polarization for the production of hyperpolarized compounds, which can be potentially employed as inhalable contrast agents.