A system and method for MR imaging is disclosed that includes an MRI system having a plurality of gradient coils positioned about a bore of a magnet to impress a polarizing magnetic field and an RF transceiver system and an RF switch controlled by a pulse module to transmit RF signals to an RF coil assembly to acquire MR images. A computer is included that is programed to generate a motion waveform from a physiological signal acquired from a subject to be imaged and compare a shape of the motion waveform to a shape of a reference motion waveform to identify points in the motion waveform corresponding to a periodic complex. The computer is also programed to trigger MR data acquisition from the subject upon identification of the periodic complex.