title: View-sharing PROPELLER with pixel-based optimal blade selection: application on dynamic contrast-enhanced imaging.
abstract: OBJECTIVE
  To achieve better spatial and temporal resolution of dynamic contrast-enhanced MR imaging, the concept of k-space data sharing, or view sharing, can be implemented for PROPELLER acquisition. As found in other view-sharing methods, the loss of high-resolution dynamics is possible for view-sharing PROPELLER (VS-Prop) due to the temporal smoothing effect. The degradation can be more severe when a narrow blade with less phase encoding steps is chosen in the acquisition for higher frame rate. In this study, an iterative algorithm termed pixel-based optimal blade selection (POBS) is proposed to allow spatially dependent selection of the rotating blades, to generate high-resolution dynamic images with minimal reconstruction artifacts.
  
  
  METHODS
  In the reconstruction of VS-Prop, the central k-space which dominates the image contrast is only provided by the target blade with the peripheral k-space contributed by a minimal number of consecutive rotating blades. To reduce the reconstruction artifacts, the set of neighboring blades exhibiting the closest image contrast with the target blade is picked by POBS algorithm. Numerical simulations and phantom experiments were conducted in this study to investigate the dynamic response and spatial profiles of images generated using our proposed method. In addition, dynamic contrast-enhanced cardiovascular imaging of healthy subjects was performed to demonstrate the feasibility and advantages.
  
  
  RESULTS
  The simulation results show that POBS VS-Prop can provide timely dynamic response to rapid signal change, especially for a small region of interest or with the use of narrow blades. The POBS algorithm also demonstrates its capability to capture nonsimultaneous signal changes over the entire FOV. In addition, both phantom and in vivo experiments show that the temporal smoothing effect can be avoided by means of POBS, leading to higher wash-in slope of contrast enhancement after the bolus injection.
  
  
  CONCLUSIONS
  With the satisfactory reconstruction quality provided by the POBS algorithm, VS-Prop acquisition technique may find useful clinical applications in DCE MR imaging studies where both spatial and temporal resolutions play important roles.
authors.affiliation: Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan.
authors.forename: Tzu-Chao
authors.initials: TC
authors.lastname: Chuang
authors.affiliation: Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan.
authors.forename: Hsuan-Hung
authors.initials: HH
authors.lastname: Huang
authors.affiliation: Brain Imaging and Analysis Center, Duke University Medical Center, Durham, North Carolina 27710.
authors.forename: Hing-Chiu
authors.initials: HC
authors.lastname: Chang
authors.affiliation: School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan and Department of Radiology, Kaohsiung Veteran General Hospital, Kaohsiung 81362, Taiwan.
authors.forename: Ming-Ting
authors.initials: MT
authors.lastname: Wu
mesh_terms: D000328:Adult; D000465:Algorithms; D016477:Artifacts; D003198:Computer Simulation; D003287:Contrast Media; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008297:Male; D019047:Phantoms, Imaging; D012399:Rotation; D055815:Young Adult
chemical_list: D003287:Contrast Media