Abstract #1919

Hyperpolarization Quenching in 13C Nuclei Bound to Fast Relaxing Quadrupolar 14N Mediated by Scalar Coupling Relaxation in Amide Groups Exposed to Earth's Magnetic Field

Enrico Chiavazza¹,², Eugen Kubala²,³, Concetta V. Gringeri²,⁴, Stephan Dwel²,⁵, Markus Durst²,⁵, Rolf F. Schulte², Marion I. Menzel²

¹Chemistry, University of Turin, Turin, Italy; ²GE Global Research, Munich, Germany; ³Johannes Kepler University, Linz, Austria; ⁴Klinik im Klinikum Rechts der Isar, Technische Universitt Mnchen, Munich, Germany; ⁵Institute of Medical Engineering, Technische Universitt Mnchen, Munich, Germany

Working on hyperpolarized [5-¹³C]glutamine, a fast liquid-state polarization quenching during the transfer to the MRI scanner has been observed. This behavior can be explained with a substantial ¹³C T₁ shortening caused by scalar coupling relaxation contribution (type II) of the quadrupolar ¹⁴N in the amide group. This contribution is effective only low magnetic fields <800&[mu]T, impairing the use of ¹³C-amides as hyperpolarized MRS/MRI probes. It is shown that high hyperpolarization level can be retained either using ¹⁵N labeled amide or applying a sustained magnetic field during the transfer of the sample from the polarizer to the MRI scanner.