title: Quantification of flow volume with a new digital three-dimensional color Doppler flow approach: an in vitro study.
abstract: OBJECTIVE
  The quantification of flow stroke volume is important for evaluation of patients with cardiac dysfunction and cardiovascular disease. Three-dimensional digital color Doppler flow imaging allows the acquisition of flow data in an orientation approximately parallel to flow and analysis of the Doppler flow velocities perpendicular to flow (cross-sectional flow calculation). This in vitro study assessed the applicability of this method for quantifying cardiac output in a funnel-shaped tube model similar to mitral inflow or the left ventricular outflow tract.
  
  
  METHODS
  A new digital three-dimensional color Doppler method was used to acquire Doppler flow information. Raw scan line data with digital velocity assignments were obtained on a conventional Doppler color flow imaging system with a 180 degrees rotating multiplanar transesophageal probe connected to a computer workstation. Nine stroke volumes (20-60 mL) with flow rates ranging from 1.5 to 5.28 L/min in a funnel-shaped pulsatile laminar flow model were studied. Three-dimensional flow rates were compared with standard-of-reference measurements of flow obtained from timed collection in a graduated cylinder and with an ultrasonic flow meter.
  
  
  RESULTS
  Within the funnel tube, the flow volumes that were calculated from the first, second, and third depths and the average of all 3 depths correlated well with the actual flow rate (r = 0.97-0.99). Results from the middle and second levels and from the average of all 3 depths provided the closest fit to the actual flow rates (r = 0.99; y = 0.96x + 0.14; and r = 0.98; y = 1.14x - 0.43, respectively).
  
  
  CONCLUSIONS
  Although a work in progress, this digital three-dimensional color Doppler flow measurement method is feasible, accurate, and simple, and it may offer in vivo evaluation of blood volume flow given a favorable orientation between the valve orifice and the scanning device.
authors.affiliation: Clinical Care Center for Congenital Heart Disease, Oregon Health Sciences University, Portland 97201-3098, USA.
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.forename: X
authors.initials: X
authors.lastname: Li
authors.forename: Y
authors.initials: Y
authors.lastname: Mori
authors.forename: R A
authors.initials: RA
authors.lastname: Rusk
authors.forename: J S
authors.initials: JS
authors.lastname: Lee
authors.forename: C H
authors.initials: CH
authors.lastname: Davies
authors.forename: I
authors.initials: I
authors.lastname: Hashimoto
authors.forename: G O
authors.initials: GO
authors.lastname: El-Sedfy
authors.forename: X N
authors.initials: XN
authors.lastname: Li
authors.forename: D J
authors.initials: DJ
authors.lastname: Sahn
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology*; D018618:Echocardiography, Doppler, Color; D006801:Humans; D021621:Imaging, Three-Dimensional; D008955:Models, Cardiovascular; D013318:Stroke Volume / Q000502:physiology*