title: Respiratory-induced venous blood flow effects using flexible retrospective double-gating.
abstract: BACKGROUND
  To demonstrate a novel velocity sensitive acquisition and retrospective cardiorespiratory double-gated reconstruction scheme to examine respiratory effect on venous blood flow in healthy volunteers.
  
  
  METHODS
  Radial two dimensional (2D) phase contrast MR is performed at 3 Tesla in the internal jugular vein (IJV) of healthy volunteers (n = 6). Data are retrospectively partitioned based on respiratory waveforms using three schemes: moving average for respiration plateaus, gradient for active respiration, and ten respiratory phases that are cardiac time-averaged. A single 4D flow MR scan is performed in the neck of a healthy volunteer. After gradient operation, blood velocity measurements are made along the IJV length. Percent changes from expiration to inspiration for moving average and gradient techniques are statistically compared with paired t-tests.
  
  
  RESULTS
  Percent change increase in summed IJV mean and peak blood flow during active inspiration versus active expiration in 2D was significant (mean flow: 11.5 ± 8.0%, peak flow: 11.9 ± 5.9%, P < 0.01). Smallest cross-sectional area and largest blood velocity are seen during inspiration phases (phase number: area-6.5 ± 3.6, velocity-6.2 ± 3.2). Significant increase in mean velocity along the length of the IJV was observed in 3D, with increasing percent changes more proximal to the chest (mean, 39 ± 30%; range, 0-93%, P = 0.001).
  
  
  CONCLUSIONS
  With a radial acquisition, this pilot study demonstrates feasibility of simultaneous retrospective cardiorespiratory gating in IJV flow. Greatest differences in flow occur between active respiration phases, increasing in magnitude more proximal to the chest.
authors.affiliation: Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, USA.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Schrauben
authors.affiliation: Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, USA.
authors.forename: Ashley G
authors.initials: AG
authors.lastname: Anderson
authors.affiliation: Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, USA.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Johnson
authors.affiliation: Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, USA.|Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA.
authors.forename: Oliver
authors.initials: O
authors.lastname: Wieben
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology*; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007601:Jugular Veins / Q000502:physiology*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D010865:Pilot Projects; D015203:Reproducibility of Results; D015656:Respiratory Mechanics / Q000502:physiology*; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: blood flow; phase-contrast; respiration; retrospective gating; venous