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Inhomogeneity correction using an estimated linear field map
Author(s) -
Irarrazabal Pablo,
Meyer Craig H.,
Nishimura Dwight G.,
Macovski Albert
Publication year - 1996
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910350221
Subject(s) - field (mathematics) , nuclear magnetic resonance , mathematics , physics , pure mathematics
A fast and robust method for correcting magnetic resonance image distortion due to field in homogeneity is proposed and applied to spiral k ‐space scanning. The method consists of acquiring a local field map, finding the best fit to a linear map, and using it to deblur the image distortions due to local frequency variations. The linear field map is determined using a maximum likelihood estimator with weights proportional to the pixel intensity. The method requires little additional computation and is robust in low signal regions and near abrupt field changes. Additionally. It can be used in combination with other deblurring methods. The application of this method is illustrated in conjunction with a mura'slice, T 2 ‐weighted, breath‐held spiral scan of the liver.