title: Lipid elimination with an echo-shifting N/2-ghost acquisition (LEENA) MRI.
abstract: OBJECTIVE
  The Dixon techniques provide uniform water-fat separation but require multiple image sets, which extend the overall acquisition time. Here, an alternative rapid single acquisition method, lipid elimination with an echo-shifting N/2-ghost acquisition (LEENA), was introduced.
  
  
  METHODS
  The LEENA method utilized a fast imaging with steady-state free precession sequence to obtain a single k-space dataset in which successive k-space lines are acquired to allow the fat magnetization to precess 180°. The LEENA data were then unghosted using either image-domain (LEENA-S) or k-space domain (LEENA-G) parallel imaging techniques to reconstruct water-only and fat-only images. An off-resonance correction technique was incorporated to improve the uniformity of the water-fat separation.
  
  
  RESULTS
  Uniform water-fat separation was achieved for both the LEENA-S and LEENA-G methods for phantom and human body and leg imaging applications at 1.5T and 3T. The resultant water and fat images were qualitatively similar to conventional 2-point Dixon and fat-suppressed images.
  
  
  CONCLUSIONS
  The LEENA-S and LEENA-G methods provide uniform water and fat images from a single MRI acquisition. These straightforward methods can be adapted to 1.5T and 3T clinical MRI scanners and provide comparable fat/water separation with conventional 2-point Dixon and fat-suppression techniques.
authors.affiliation: Department of Radiology, Case Western Reserve University, Cleveland, Ohio, USA; Department of Urology, Case Western Reserve University, Cleveland, Ohio, USA.
authors.forename: Lan
authors.initials: L
authors.lastname: Lu
authors.forename: Shannon B
authors.initials: SB
authors.lastname: Donnola
authors.forename: Michaela
authors.initials: M
authors.lastname: Koontz
authors.forename: Mark A
authors.initials: MA
authors.lastname: Griswold
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Duerk
authors.forename: Chris A
authors.initials: CA
authors.lastname: Flask
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology*; D000465:Algorithms; D016477:Artifacts; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008055:Lipids / Q000032:analysis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D010363:Pattern Recognition, Automated / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique
chemical_list: D008055:Lipids
keywords: GRAPPA; SENSE; fat suppression MRI; parallel imaging; water fat imaging