Long‐lived 15N Hyperpolarization and Rapid Relaxation as a Potential Basis for Repeated First Pass Perfusion Imaging – Marked Effects of Deuteration and Temperature. Issue 17 (11th June 2018)

• Record Type: Journal Article
• Authors: Harris, Talia; Gamliel, Ayelet; Uppala, Sivaranjan; Nardi‐Schreiber, Atara; Sosna, Jacob; Gomori, J. Moshe; Katz‐Brull, Rachel
• Is Part Of: Chemphyschem. Volume 19:Issue 17(2018)
• Page Start: 2148
• Page End: 2152
• Publication Date: 2018-06-11
• Subjects: dissolution dynamic nuclear polarization -- hyperpolarization -- isotopic effects -- nitrogen-15 -- NMR spectroscopy; Chemistry, Physical and theoretical -- Periodicals; 541.05
• DOI: 10.1002/cphc.201800261
• Languages: English
• ISSNs: 1439-4235

Abstract

Abstract: Deuteration of the exchangeable hydrogens of [ 15 N2 ]urea was found to prolong the T1 of the 15 N sites to more than 3 min at physiological temperatures. This significant increase in the lifetime of the hyperpolarized state of [ 15 N2 ]urea, compared to [ 13 C]urea – a pre‐clinically proven perfusion agent, makes [ 15 N2 ]urea a promising perfusion agent. The molecular parameters that may lead to this profound effect were assessed by investigating small molecules with different molecular structures containing 15 N sites bound to labile protons and determining the hyperpolarized 15 N T1 in H2 O and D2 O. Dissolution in D2 O led to marked prolongation for all of the selected sites. In whole human blood, the T1 of [ 15 N2 ]urea was shortened. We present a general strategy for exploiting the markedly longer T1 outside the body and the quick decay in blood for performing multiple hyperpolarized perfusion measurements with a single hyperpolarized dose. Improved storage of the generated [ 15 N2 ]urea polarization prior to the contact with the blood is demonstrated using higher temperatures due to further T1 prolongation. Abstract : Storing 15 N hyperpolarization for imaging : By dissolution of hyperpolarized molecules containing 15 N sites bound to labile protons in D2 O, the lifetime of the hyperpolarized signal can be dramatically increased and for [ 15 N2 ]urea, heating the sample will further increase its lifetime. Although the signal will decay rapidly in the blood, multiple first‐pass perfusion measurements may be acquired with a single hyperpolarized sample.