15N-carnitine, a novel endogenous hyperpolarized MRI probe with long signal lifetime

Cornelius von Morze, John A. Engelbach, Galen D. Reed, Albert P. Chen, James D. Quirk, Tyler Blazey, Rohit Mahar, Craig R. Malloy, Joel R. Garbow, Matthew E. Merritt

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: The purpose of this study was to investigate hyperpolarization and in vivo imaging of [15N]carnitine, a novel endogenous MRI probe with long signal lifetime. Methods: L-[15N]carnitine-d9 was hyperpolarized by the method of dynamic nuclear polarization followed by rapid dissolution. The T1 signal lifetimes were estimated in aqueous solution and in vivo following intravenous injection in rats, using a custom-built dual-tuned 15N/1H RF coil at 4.7 T. 15N chemical shift imaging and 15N fast spin-echo images of rat abdomen were acquired 3 minutes after [15N]carnitine injection. Results: Estimated T1 times of [15N]carnitine at 4.7 T were 210 seconds (in H2O) and 160 seconds (in vivo), with an estimated polarization level of 10%. Remarkably, the [15N]carnitine coherence was detectable in rat abdomen for 5 minutes after injection for the nonlocalized acquisition. No downstream metabolites were detected on localized or nonlocalized 15N spectra. Diffuse liver enhancement was detected on 15N fast spin-echo imaging 3 minutes after injection, with mean hepatic SNR of 18 ± 5 at a spatial resolution of 4 × 4 mm. Conclusion: This study showed the feasibility of hyperpolarizing and imaging the biodistribution of HP [15N]carnitine.

Original languageEnglish (US)
Pages (from-to)1814-1820
Number of pages7
JournalMagnetic resonance in medicine
Volume85
Issue number4
DOIs
StatePublished - Apr 2021

Keywords

  • dynamic nuclear polarization
  • liver
  • molecular imaging

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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