Automatic phasing of MR images. Part II: voxel-wise phase estimation.
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Magnetic resonance images are typically displayed as the absolute value of the discrete Fourier transform of the k-space data. However, absorption-mode images, the real part of the discrete Fourier transform of the data after applying an appropriate phase correction, have significant advantages over absolute-value images. In a companion paper, the problem of estimating the phase parameters needed to produce an absorption-mode image when the phase of the complex image varies linearly as a function of position, a situation common in magnetic resonance images, was addressed. However, some magnetic resonance images have phases that can vary in a complicated, nonlinear, positionally dependent fashion. To produce an absorption-mode image from these data, one must first estimate the positionally dependent phase, and then use that phase estimate to produce an absorption-mode image. This paper addresses both of these problems by first using Bayesian probability theory to estimate the constant or zero-order phase as a function of image position, and then the calculations are illustrated by using them to generate absorption-mode images from data where the phase of the image is a nonlinear function of position.
[1] Salah Karout,et al. Two-dimensional phase unwrapping , 2007 .
[2] Marvin H. J. Guber. Bayesian Spectrum Analysis and Parameter Estimation , 1988 .
[3] T. Bayes. An essay towards solving a problem in the doctrine of chances , 2003 .
[4] G. Larry Bretthorst,et al. Automatic Phasing of Mr Images. Part I: Linearly Varying Phase , 2007 .