Improving chemical shift encoded water–fat separation using object-based information of the magnetic field inhomogeneity
Article first published online: 28 FEB 2014
© 2014 Wiley Periodicals, Inc.
Magnetic Resonance in Medicine
Volume 73, Issue 2, pages 597–604, February 2015
How to Cite
Sharma, S. D., Artz, N. S., Hernando, D., Horng, D. E. and Reeder, S. B. (2015), Improving chemical shift encoded water–fat separation using object-based information of the magnetic field inhomogeneity. Magn Reson Med, 73: 597–604. doi: 10.1002/mrm.25163
- Issue published online: 16 JAN 2015
- Article first published online: 28 FEB 2014
- Manuscript Accepted: 14 JAN 2014
- Manuscript Revised: 18 DEC 2013
- Manuscript Received: 1 OCT 2013
- NIH. Grant Numbers: RC1 EB010384, R01 DK083380, R01 DK088925, R01 DK096169
- magnetic resonance imaging;
- Dixon imaging;
- chemical shift encoded water–fat separation;
- water–fat imaging;
- B0 field estimation
The purpose of this work was to improve the robustness of existing chemical shift encoded water–fat separation methods by incorporating object-based information of the B0 field inhomogeneity.
The primary challenge in water–fat separation is the estimation of phase shifts that arise from B0 field inhomogeneity, which is composed of the background field and susceptibility-induced field. The susceptibility-induced field can be estimated if the susceptibility distribution is known or can be approximated. In this work, the susceptibility distribution is approximated from the source images using the known susceptibility values of water, fat, and air. The field estimate is then demodulated from the source images before water–fat separation.
Chemical shift encoded source images were acquired in anatomical regions that are prone to water–fat swaps. The images were processed using algorithms from the ISMRM Fat-Water Toolbox, with and without the object-based field map information. The estimates were compared to examine the benefit of using the object-based field map information.
Multiple cases are shown in which water–fat swaps were avoided by using the object-based information of the B0 field map.
Object-based information of the B0 field may improve the robustness of existing chemical shift encoded water–fat separation methods. Magn Reson Med 73:597–604, 2015. © 2014 Wiley Periodicals, Inc.