title: Iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) fast spin-echo imaging of the ankle: initial clinical experience.
abstract: OBJECTIVE
  Reliable, uniform fat suppression is important. Multiple approaches currently exist, many of which suffer from either suboptimal signal-to-noise ratio (SNR), or the inability to obtain consistent fat suppression around the ankle joint. Our purpose was to test iterative decomposition of water and fat with echo asymmetry and the least-squares estimation (IDEAL) method in combination with fast spin-echo imaging, which is able to achieve reliable high SNR images with uniform fat-water separation.
  
  
  METHODS
  We compared IDEAL fast spin-echo with conventional fat-suppressed fast spin-echo imaging in 33 ankles in 32 patients. Quantitative measurements of SNR and contrast-to-noise ratio efficiency were made, and qualitative diagnostic image quality and fat-suppression scores were determined.
  
  
  RESULTS
  We found that the SNR efficiency for both cartilage and fluid was similar for both techniques, and fluid/cartilage contrast-to-noise ratio efficiency was higher with IDEAL fast spin-echo imaging. Fat suppression and diagnostic quality scores using the IDEAL method were superior (p < 0.01) to fat-suppressed fast spin-echo imaging.
  
  
  CONCLUSIONS
  IDEAL fast spin-echo imaging is a promising technique for MRI of the ankle.
authors.affiliation: Department of Radiology, Grant Building S0-68B, Stanford University, 300 Pasteur Drive, Stanford, CA 94305-5105, USA.
authors.forename: Samuel
authors.initials: S
authors.lastname: Fuller
authors.forename: Scott
authors.initials: S
authors.lastname: Reeder
authors.forename: Ann
authors.initials: A
authors.lastname: Shimakawa
authors.forename: Huanzhou
authors.initials: H
authors.lastname: Yu
authors.forename: Jane
authors.initials: J
authors.lastname: Johnson
authors.forename: Christopher
authors.initials: C
authors.lastname: Beaulieu
authors.forename: Garry E
authors.initials: GE
authors.lastname: Gold
mesh_terms: D000273:Adipose Tissue; D000328:Adult; D000368:Aged; D000842:Ankle / Q000473:pathology*; D016512:Ankle Injuries / Q000175:diagnosis*; D002356:Cartilage / Q000473:pathology*; D005260:Female; D006801:Humans; D016018:Least-Squares Analysis; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D014867:Water / Q000032:analysis
chemical_list: D014867:Water