Keyhole Dixon method for faster, perceptually equivalent fat suppression

Chris A. Flask, Kyle A. Salem, Hisamoto Moriguchi, Jonathan S. Lewin, David L. Wilson, Jeffrey L. Duerk

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Purpose: To reduce the acquisition time associated with the two-point Dixon fat suppression technique by combining a keyhole in-phase (Water + Fat) k-space data set with a full out-of-phase (Water - Fat) k-space data set and optimizing the keyhole size with a perceptual difference model. Materials and Methods: A set of keyhole Dixon images was created by varying the number of lines in the keyhole data set. Off-resonance correction was incorporated into the image reconstruction process to improve the homogeneity of the fat suppression. A perceptual difference model (PDM) was validated with human observer experiments and used to compare the keyhole images to images from a full two-point Dixon acquisition. The PDM was used to determine the smallest keyhole width required to obtain perceptual equivalence to images obtained from the full two-point Dixon method. Results: In experimental phantom studies, the keyhole Dixon image reconstructed from 96 of 192 Water + Fat k-space lines and 192 Water - Fat k-space lines was perceptually equivalent to the full (192 + 192) two-point Dixon images, resulting in a 25% reduction in scan time. Clinical images of a volunteer's knee, orbits, and abdomen created from the smallest, perceptually equivalent keyhole width resulted in a 27%-38% reduction in total scan time. Conclusion: This method improves the temporal efficiency of the conventional two-point Dixon technique and may prove especially useful for high-field systems where specific absorption rate (SAR) limits will constrain radiofrequency (RF)-based fat suppression techniques.

Original languageEnglish (US)
Pages (from-to)103-112
Number of pages10
JournalJournal of Magnetic Resonance Imaging
Issue number1
StatePublished - Jul 1 2003
Externally publishedYes


  • Dixon technique
  • Fat suppression
  • Image analysis
  • Off-resonance correction
  • Perceptual difference model
  • Rapid MRI

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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