Method for continuous measurement of nuclear para state enrichment in hydrogen gas with applications to hyperpolarized heteronuclear contrast agents
Yu J, Ishii M, Kadlecek S, MacDuffie Woodburn J, Emami K, Rajaei S, Hammond F, Vahdat V, Rizi R
University of Pennsylvania
We present a method for quantifying the enrichment of the nuclear para statein a sample of hydrogen based on a measurement of the speed of sound in thegas. This approach makes use of a pair of spherical, resonant cavitiesfilled with normal hydrogen and the sample to be tested, and driven by piezotransducers. Production and quantification of parahydrogen is critical inseveral industries, but its application in the MR community stems from itsuse in the production of novel, hyperpolarized contrast agents for MRIangiography, perfusion measurements, and MRI/MRS examination of in vitro andin vivo molecular transformations. The apparatus described provides acontinuous measurement of the reagent quality during production andimmediately before use.