Presented in part at the 11th Annual Meeting of ISMRM, Toronto, Canada, 2003.
Two-point water-fat imaging with partially-opposed-phase (POP) acquisition: An asymmetric Dixon method†
Article first published online: 7 AUG 2006
Copyright © 2006 Wiley-Liss, Inc.
Magnetic Resonance in Medicine
Volume 56, Issue 3, pages 572–584, September 2006
How to Cite
Xiang, Q.-S. (2006), Two-point water-fat imaging with partially-opposed-phase (POP) acquisition: An asymmetric Dixon method. Magn Reson Med, 56: 572–584. doi: 10.1002/mrm.20984
- Issue published online: 24 AUG 2006
- Article first published online: 7 AUG 2006
- Manuscript Accepted: 3 MAY 2006
- Manuscript Revised: 20 APR 2006
- Manuscript Received: 20 JUN 2005
- water-fat imaging;
- Dixon method;
- asymmetric sampling;
- phase correction;
- regional iterative phasor extraction (RIPE)
A novel two-point water-fat imaging method is introduced. In addition to the in-phase acquisition, water and fat magnetization vectors are sampled at partially-opposed-phase (POP) rather than exactly antiparallel as in the original Dixon method. This asymmetric sampling encodes more valuable phase information for identifying water and fat. From the magnitudes of the two complex images, a big and a small chemical component are first robustly obtained pixel by pixel and then used to form two possible error phasor candidates. The true error phasor is extracted from the two error phasor candidates through a simple procedure of regional iterative phasor extraction (RIPE). Finally, least-squares solutions of water and fat are obtained after the extracted error phasor is smoothed and removed from the complex images. For noise behavior, the effective number of signal averages NSA* is typically in the range of 1.87–1.96, very close to the maximum possible value of 2. Compared to earlier approaches, the proposed method is more efficient in data acquisition and straightforward in processing, and the final results are more robust. At both 1.5T and 0.3T, well separated and identified in vivo water and fat images covering a broad range of anatomical regions have been obtained, supporting the clinical utility of the method. Magn Reson Med, 2006. © 2006 Wiley-Liss, Inc.