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Correction of concomitant magnetic field‐induced image artifacts in nonaxial echo‐planar imaging
Author(s) -
Du Yiping P.,
Joe Zhou Xiaohong,
Bernstein Matt A.
Publication year - 2002
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.10249
Subject(s) - ghosting , distortion (music) , sagittal plane , line (geometry) , echo planar imaging , magnetic field , computer science , planar , physics , optics , computer vision , magnetic resonance imaging , mathematics , medicine , radiology , telecommunications , amplifier , geometry , computer graphics (images) , bandwidth (computing) , quantum mechanics
Echo‐planar images acquired in nonaxial planes are often distorted. Such image distortion has limited the applications of the echo‐planar imaging (EPI) technique. In this article, it is demonstrated that a considerable amount of the distortion is caused by the higher‐order magnetic field concomitant with the linear magnetic field gradient, or the concomitant magnetic field. The image distortion caused by the concomitant magnetic field is more prominent when a higher gradient amplitude is used for readout. It is also shown that the concomitant magnetic field can cause ghosting and blurring. A theoretical analysis is performed for the concomitant field effect in nonaxial EPI images. A point‐by‐point (or line‐by‐line) phase correction algorithm is developed to correct the image distortion, ghosting, and blurring. A postreconstruction processing algorithm is also developed to correct image distortion with much higher computational efficiency. Experimental results show that both correction methods effectively reduce the image distortion in coronal or sagittal images. Magn Reson Med 48:509–515, 2002. © 2002 Wiley‐Liss, Inc.