title: Removal of olefinic fat chemical shift artifact in diffusion MRI.
abstract: Diffusion-weighted (DW) MRI has emerged as a key tool for assessing the microstructure of tissues in healthy and diseased states. Because of its rapid acquisition speed and insensitivity to motion, single-shot echo-planar imaging is the most common DW imaging technique. However, the presence of fat signal can severely affect DW-echo planar imaging acquisitions because of the chemical shift artifact. Fat suppression is usually achieved through some form of chemical shift-based fat saturation. Such methods effectively suppress the signal originating from aliphatic fat protons, but fail to suppress the signal from olefinic protons. Olefinic fat signal may result in significant distortions in the DW images, which bias the subsequently estimated diffusion parameters. This article introduces a method for removing olefinic fat signal from DW images, based on an echo time-shifted acquisition. The method is developed and analyzed specifically in the context of single-shot DW-echo-planar imaging, where image phase is generally unreliable. The proposed method is tested with phantom and in vivo datasets, and compared with a standard acquisition to demonstrate its performance.
authors.affiliation: Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
authors.forename: D
authors.initials: D
authors.lastname: Hernando
authors.forename: D C
authors.initials: DC
authors.lastname: Karampinos
authors.forename: K F
authors.initials: KF
authors.lastname: King
authors.forename: J P
authors.initials: JP
authors.lastname: Haldar
authors.forename: S
authors.initials: S
authors.lastname: Majumdar
authors.forename: J G
authors.initials: JG
authors.lastname: Georgiadis
authors.forename: Z-P
authors.initials: ZP
authors.lastname: Liang
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology* / Q000737:chemistry*; D000465:Algorithms; D000818:Animals; D016477:Artifacts; D002417:Cattle; D038524:Diffusion Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique