Many experiments in indirect detection use the 1H steady-state polarization (the magnetization present prior to the beginning of the pulse sequence after multiple repetitions) to provide the coherence that is eventually measured, even if that coherence passes through other nuclei prior to detection of protons.

Some experiments such as TROSY are indirect detection, but it is possible by proper pulse sequence design to add the X-nucleus steady-state magnetization to the coherence coming from protons, within the pulse sequence.

Any experiments that use X pulse(s) followed by gradients prior to the first proton pulse are designed to get rid of the steady state magnetization in order to prevent artifact peaks or intensities. In these cases there is no additional magnetization to add to the coherence originating from the protons.