title: Free-breathing contrast-enhanced multiphase MRI of the liver using a combination of compressed sensing, parallel imaging, and golden-angle radial sampling.
abstract: OBJECTIVE
  The objectives of this study were to develop a new method for free-breathing contrast-enhanced multiphase liver magnetic resonance imaging (MRI) using a combination of compressed sensing, parallel imaging, and radial k-space sampling and to demonstrate the feasibility of this method by performing image quality comparison with breath-hold cartesian T1-weighted (conventional) postcontrast acquisitions in healthy participants.
  
  
  METHODS
  This Health Insurance Portability and Accountability Act-compliant prospective study received approval from the institutional review board. Eight participants underwent 3 separate contrast-enhanced fat-saturated T1-weighted gradient-echo MRI examinations with matching imaging parameters: conventional breath-hold examination with cartesian k-space sampling volumetric interpolate breath hold examination (BH-VIBE) and free-breathing acquisitions with interleaved angle-bisection and continuous golden-angle radial sampling schemes. Interleaved angle-bisection and golden-angle data from each 100 consecutive spokes were reconstructed using a combination of compressed sensing and parallel imaging (interleaved-angle radial sparse parallel [IARASP] and golden-angle radial sparse parallel [GRASP]) to generate multiple postcontrast phases.Arterial- and venous-phase BH-VIBE, IARASP, and GRASP reconstructions were evaluated by 2 radiologists in a blinded fashion. The readers independently assessed quality of enhancement (QE), overall image quality (IQ), and other parameters of image quality on a 5-point scale, with the highest score indicating the most desirable examination. Mixed model analysis of variance was used to compare each measure of image quality.
  
  
  RESULTS
  Images of BH-VIBE and GRASP had significantly higher QE and IQ values compared with IARASP for both phases (P < 0.05). The differences in QE between BH-VIBE and GRASP for the arterial and venous phases were not significant (P > 0.05). Although GRASP had lower IQ score compared with BH-VIBE for the arterial (3.9 vs 4.8; P < 0.0001) and venous (4.2 vs 4.8; P = 0.005) phases, GRASP received IQ scores of 3 or more in all participants, which was consistent with acceptable or better diagnostic image quality.
  
  
  CONCLUSIONS
  Contrast-enhanced multiphase liver MRI of diagnostic quality can be performed during free breathing using a combination of compressed sensing, parallel imaging, and golden-angle radial sampling.
authors.affiliation: Center for Biomedical Imaging, Department of Radiology, New York University Langone Medical Center, NY, USA. hersh.chandarana@nyumc.org
authors.forename: Hersh
authors.initials: H
authors.lastname: Chandarana
authors.forename: Li
authors.initials: L
authors.lastname: Feng
authors.forename: Tobias K
authors.initials: TK
authors.lastname: Block
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Rosenkrantz
authors.forename: Ruth P
authors.initials: RP
authors.lastname: Lim
authors.forename: James S
authors.initials: JS
authors.lastname: Babb
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Sodickson
authors.forename: Ricardo
authors.initials: R
authors.lastname: Otazo
mesh_terms: D000328:Adult; D003287:Contrast Media; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008099:Liver / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D055815:Young Adult
chemical_list: D003287:Contrast Media