Application of time-frequency distributions to magnetic resonance imaging of non-constant flow

The exponential distribution (ED) developed by H.-I. Choi and W.J. Williams (see IEEE Trans. Acoust. Speech, Sig. Proc., ASSP-37, no.6, p.862-71, 1989) is applied to the problem of simultaneous determination of the velocity and spin density of a moving object in magnetic resonance imaging (MRI). The object velocity is assumed to be an affine function of location (reasonable for selectively imaged thin slice) and is determined from the trajectory of the maxima of the time-frequency distribution. Once the velocity is computed, its effects can be deconvolved from the MRI signal. This improves on previous results which require prior knowledge of either the velocity or discontinuities in the spin density. Numerical examples are presented