title: Direct computation of multiple 3D flow convergence isovelocity surfaces from digital 3D reconstruction of colour Doppler data of the flow convergence region: an in vitro study with differently shaped orifices.
abstract: OBJECTIVE
  Evaluation of the accuracy of direct computation of multiple three-dimensional (3D) flow convergence (FC) isovelocities by using digital reconstruction of colour Doppler data of the flow convergence region.
  
  
  RESULTS
  We used a conventional ultrasound system (ATL HDI 3000) connected to a computer workstation via Ethernet link. The digital 3D datasets were directly transferred to a Silicon Graphic Imaging Octane workstation for later measurement. We generated nine pulsatile flows (20-60 ml/beat), with peak flow rates (67-180 ml/s), through three orifices (circular, rectangular and triangular, S=0.24 cm(2)). The 3D reconstructions of FC surface areas from multi-threshold velocities, including aliasing velocities were analysed to quantify the peak flow rate. For all orifices, linear regression demonstrated excellent correlation between the 3D calculated and electromagnetic flow meter recorded data. While there was a high correlation for 3D computation of flow rate from the single best Nyquist of 24 cm/s (r=0.97-0.98, SEE=7 .75-12.58 ml/s), the ability to average three threshold velocities (15, 18 and 24 cm/s) yielded an improved correlation (r=0.98-0.99, SEE=5.70-7.73 ml/s).
  
  
  CONCLUSIONS
  Direct computation of multiple 3D FC isovelocities from digital reconstruction of colour Doppler data of the FC region provides the potential to accurately quantify the complex asymmetric spatial flow events at any selected velocity.
authors.affiliation: The Clinical Care Center for Congenital Heart Disease, Oregon Health Sciences University, Portland, OR 97201, USA.
authors.forename: X K
authors.initials: XK
authors.lastname: Li
authors.forename: T
authors.initials: T
authors.lastname: Irvine
authors.forename: S
authors.initials: S
authors.lastname: Wanitkun
authors.forename: Y
authors.initials: Y
authors.lastname: Mori
authors.forename: P R
authors.initials: PR
authors.lastname: Detmer
authors.forename: X N
authors.initials: XN
authors.lastname: Li
authors.forename: Y
authors.initials: Y
authors.lastname: Wu
authors.forename: R W
authors.initials: RW
authors.lastname: Martin
authors.forename: D J
authors.initials: DJ
authors.lastname: Sahn
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology*; D018618:Echocardiography, Doppler, Color / Q000379:methods*; D019560:Echocardiography, Three-Dimensional / Q000379:methods*; D004867:Equipment Design; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D015588:Observer Variation; D011237:Predictive Value of Tests