title: Correction for displacement artifacts in 3D phase contrast imaging.
abstract: OBJECTIVE
  To correct for displacement artifacts in 3D phase contrast imaging.
  
  
  METHODS
  A 3D phase contrast pulse sequence was modified so that displacements of velocity measurements were restricted to one direction. By applying a postprocessing method, displaced measurements could be traced back to their accurate positions. Flow studies were performed using a phantom that generated flow through a stenosis, directed oblique relative to the phase and frequency encoding directions. Velocity profiles and streamline visualization were used to compare displaced and corrected velocity data to a reference.
  
  
  RESULTS
  Velocity profiles obtained from the original measurement showed skewed profiles due to the displacement artifact, both at close proximity to the orifice as well as further downstream. After correction, concordance with the reference improved considerably.
  
  
  CONCLUSIONS
  The displacement artifact, which restricts the accuracy of phase contrast measurements, can be corrected for using the proposed method. Correction of the phase contrast velocity data may improve the accuracy of subsequent flow analysis and visualization.
authors.affiliation: Department of Biomedical Engineering, Orebro University Hospital, Orebro, Sweden. per.thunberg@orebroll.se
authors.forename: Per
authors.initials: P
authors.lastname: Thunberg
authors.forename: Lars
authors.initials: L
authors.lastname: Wigström
authors.forename: Tino
authors.initials: T
authors.lastname: Ebbers
authors.forename: Matts
authors.initials: M
authors.lastname: Karlsson
mesh_terms: D016477:Artifacts; D001783:Blood Flow Velocity; D003287:Contrast Media; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019047:Phantoms, Imaging
chemical_list: D003287:Contrast Media