MRI of 1 H Long-Lived States Originated from ParaHydrogen Induced Polarization in Cs-Symmetric Molecules using a Clinical MRI System

DIRK GRAAFEN; MARÍA BELÉN FRANZONI; KERSTIN MÜNNEMANN; HANS W. SPIESS; LAURA M. SCHREIBER

Congreso; ISMRM 2013; 2013

Parahydrogen Induced Polarization (PHIP) creates a hyperpolarized spin state by hydrogenation of a double or triple bond with parahydrogen. A drawback of all the hyperpolarization techniques, in particular those based on 1H, is the limited lifetime T1 . A longer lifetime can be achieved by storing the hyperpolarization as a singlet spin state. A requirement for the singlet state preservation is the reduction of the chemical shift difference usually achieved by moving the sample to a low field, or applying dedicated pulse sequences . Recently, it was shown for the Cs-symmetric molecule dimethyl maleate that the hyperpolarized proton singlet state can be stored at 7 T for 4 min with no need of RF pulses. To yield measurable magnetization the sample was transported to the resonance magnetic field at 0.1 T allowing for singlet-triplet conversion via level anti-crossing. Here, the singlet-triplet conversion is performed inside the observation field by an RF pulse sequence and combined with imaging.