Pulse sequences for the
31P saturation-transfer experiment. (A) Pulse-acquire sequence with RF saturation. A long, low power, frequency-selective saturation pulse precedes signal excitation/detection. Adiabatic excitation pulses are optimal for
in vivo MRS using surface coils. (B) Inversion-recovery with RF saturation for

calibration. Frequency-selective saturation of the γ-ATP peak is applied prior to the adiabatic inversion pulse, and during the variable inversion-delay to maintain steady-state spin saturation throughout the inversion-recovery measurement.