title: Effect of acquisition parameters on the accuracy of velocity encoded cine magnetic resonance imaging blood flow measurements.
abstract: OBJECTIVE
  To investigate the effect of acquisition parameters on the accuracy of 2D velocity encoded cine magnetic resonance imaging (VEC MRI) flow measurements.
  
  
  METHODS
  Using a pulsatile flow phantom, through-plane flow measurements were performed on a flexible vessel made of polyvinyl alcohol cryogel (PVA), a material that mimics the MR signal and biomechanical properties of aortic tissue.
  
  
  RESULTS
  Repeated VEC MRI flow measurements (N = 20) under baseline conditions yielded an error of 0.8 +/- 1.5%. Slice thickness, angle between flow and velocity encoding directions, spatial resolution, velocity encoding range, and radio frequency (RF) flip angles were varied over a clinically relevant range. Spatial resolution had the greatest impact on accuracy, with a 9% overestimation of flow at 16 pixels per vessel cross-section.
  
  
  CONCLUSIONS
  VEC MRI proved to be an accurate and reproducible technique for pulsatile flow measurements over the range of acquisition parameters examined as long as sufficient spatial resolution was prescribed.
authors.affiliation: Department of Cardiology, Children's Hospital, Boston, Massachusetts 02115, USA.
authors.forename: Gerald
authors.initials: G
authors.lastname: Greil
authors.forename: Tal
authors.initials: T
authors.lastname: Geva
authors.forename: Stephan E
authors.initials: SE
authors.lastname: Maier
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Powell
mesh_terms: D000704:Analysis of Variance; D001011:Aorta / Q000502:physiology; D001783:Blood Flow Velocity; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008955:Models, Cardiovascular; D019047:Phantoms, Imaging; D011145:Polyvinyls; D011673:Pulsatile Flow; D015203:Reproducibility of Results
chemical_list: D011145:Polyvinyls