To investigate cardiac- and respiratory-driven CSF motions in the intracranial space, asynchronous phase contrast (Async-PC) imaging with Stockwell transform (ST) and power mapping was conducted for 3 healthy volunteers under free breathing. ST can separate the cardiac- and respiratory-driven CSF motions as spectrogram. Power mapping visualizes the power of the spectrum voxel-by-voxel. Async-PC with ST presented the time-frequency property of the cardiac- and respiratory-driven CSF motions, while that with the power mapping technique visualized the spatial distribution of both the motion contributions. Combination of those techniques may provide new findings related with CSF dynamics.