Application of the Steady-State Variable Nutation Angle Method for Faster Determinations of Long T1s—An Approach Useful for the Design of Hyperpolarized MR Molecular Probes

In the dissolution-dynamic nuclear polarization technique, molecular probes with long T1s are preferred. 13C nuclei of small molecules with no directly bonded protons or sp3 13C nuclei with proton positions substituted by deuterons may fulfill this requirement. The T1 determination of such new molecular probes is crucial for the success of the hyperpolarized observation. Although the inversion-recovery approach remained by and large the standard for T1 measurements, we show here that the steady-state variable nutation angle approach is faster and may be better suited for the determination of relatively long T1s in thermal equilibrium. Specifically, the T1 of a new molecular probe, [uniformly labeled (UL)-13C6, UL-2H8]2-deoxy-d-glucose, is determined here and compared to that of [UL-13C6, UL-2H7]d-glucose.