TY - JOUR

T1 - Automatic phasing of MR images. Part II

T2 - Voxel-wise phase estimation

AU - Larry Bretthorst, G.

N1 - Funding Information:
I thank Joseph J. H. Ackerman, Jeffrey J. Neil, Joel R. Garbow, Dmitriy Yablonskiy, Alex Sukstansky and Josh Shimony for encouragement, support, and helpful comments. This work was supported by the Small Animal Imaging Resources Program (SAIRP) of the National Cancer Institute, Grant R24CA83060, and by Grants NS35912, NS41519, NS41519 and HL70037.

PY - 2008/4

Y1 - 2008/4

N2 - 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.

AB - 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.

KW - Absorption-mode images

KW - Bayesian probability theory

KW - Zero-order phase estimation

UR - http://www.scopus.com/inward/record.url?scp=40949146127&partnerID=8YFLogxK

U2 - 10.1016/j.jmr.2007.12.011

DO - 10.1016/j.jmr.2007.12.011

M3 - Article

C2 - 18187351

AN - SCOPUS:40949146127

SN - 1090-7807

VL - 191

SP - 193

EP - 201

JO - Journal of Magnetic Resonance

JF - Journal of Magnetic Resonance

IS - 2

ER -