title: Velocity profiles in mitral blood flow based on three-dimensional freehand colour flow imaging acquired at high frame rate.
abstract: OBJECTIVE
  To describe the mitral blood flow velocity distribution, we applied a freehand dynamic three-dimensional (3D) colour flow method using a moving sample surface that followed the mitral apparatus during diastole.
  
  
  METHODS
  Nineteen healthy volunteers were studied. The ultrasound data were captured from 10-20 heartbeats at high frame rate (mean 46 frames/s) while freely tilting the transducer in an apical position. A magnetic position sensor system recorded the spatial position and orientation of the probe. Blood flow velocities were integrated across a spherical surface. In volumetric blood flow measurements this would yield angle independence of the Doppler beam. Raw digital data were analysed off-line with no loss of temporal resolution.
  
  
  RESULTS
  The ratio of the maximum velocity time integral (VTI) to the mean VTI was mean 1.3 (range 1.1-1.6). At the time of peak flow the ratio of the maximum to the mean velocity was mean 1.5 (range 1.2-2.6).
  
  
  CONCLUSIONS
  The blood flow velocity profile was non-uniform. By using a single sample volume in Doppler measurements of the maximum VTI errors ranging from 10 to 60% may be introduced in calculations of stroke volumes.
authors.affiliation: Department of Cardiology and Lung Medicine, Norwegian University of Science and Technology, N-7006 Trondheim, Norway.
authors.forename: B O
authors.initials: BO
authors.lastname: Haugen
authors.forename: S
authors.initials: S
authors.lastname: Berg
authors.forename: K M
authors.initials: KM
authors.lastname: Brecke
authors.forename: S O
authors.initials: SO
authors.lastname: Samstad
authors.forename: S A
authors.initials: SA
authors.lastname: Slørdahl
authors.forename: T
authors.initials: T
authors.lastname: Skjaerpe
authors.forename: H
authors.initials: H
authors.lastname: Torp
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology*; D003951:Diagnostic Errors; D018618:Echocardiography, Doppler, Color; D019560:Echocardiography, Three-Dimensional; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging*; D012016:Reference Values