title: Utility of the proximal jet width in the assessment of regurgitant and stenotic orifices--effect of low velocity filter and comparison to actual vena contracta width: an in vitro and numerical study.
abstract: OBJECTIVE
  The colour Doppler proximal jet width (CDPJW) has been shown to be directly related to the severity of regurgitant and stenotic valve lesions. It is generally assumed that the CDPJW is equivalent to the vena contracta width (VCW). The purpose of this numerical and in vitro study was to evaluate how changing low velocity filter (LVF) settings on colour Doppler imaging devices may affect the CDPJW and its estimate of the VCW.
  
  
  METHODS
  Computational fluid dynamic software was used to create models of round orifices (0.785, 1.13, 1.76, 3.14 cm2) at set flow rates (0.37-25 1/min). In vitro experiments were performed with round orifices (0.2, 0.95 and 1.76 cm2) with set flow rates (1.8-3.6 1/min). Laser flow visualization was used to obtain gold standard vena contracta widths for comparison to CDPJW for various LVF settings (4-24 cm/s).
  
  
  RESULTS
  With the LVF set 'too low', overestimation errors occur. In contrast, with the LVF set 'too high', underestimation errors occur. Optimal LVF settings are required to avoid over- and underestimation errors of up to 280%.
  
  
  CONCLUSIONS
  The VCW is related to regurgitant or stenotic lesion severity, and the CDPJW is an approximation of the VCW. The CDPJW closely resembles the actual VCW only at optimally chosen LVF settings. LVF settings can have a significant impact on the accuracy of the CDPJW. Inter mediate filter settings remove unnecessary background noise while maintaining actual flow regions, thereby providing the best agreement between the CDPJW and the VCW. If treatment decisions are to be based on these measurements, understanding such dependencies becomes quite important.
authors.affiliation: University of Colorado Health Sciences Center, The Children's Hospital, Denver 80218, USA.
authors.forename: C G
authors.initials: CG
authors.lastname: DeGroff
authors.forename: R
authors.initials: R
authors.lastname: Shandas
authors.forename: L
authors.initials: L
authors.lastname: Valdes-Cruz
mesh_terms: D001783:Blood Flow Velocity; D003251:Constriction, Pathologic; D018618:Echocardiography, Doppler, Color; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008955:Models, Cardiovascular; D008962:Models, Theoretical; D009716:Numerical Analysis, Computer-Assisted