1. A method of providing a medical image of a region of interest (ROI) of a patient, the method comprising: acquiring a time ordered sequence of measurements of radiation used to provide the medical image; generating a Fourier transform of the time ordered sequence or a function thereof; using the Fourier transform to determine which of the frequencies characterize real motion of tissue in the ROI and which characterize noise; generating a corrected Fourier transform that is exclusive of frequencies that characterize noise; and providing a medical image of the ROI using the corrected Fourier transform.