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.