title: Regurgitant heart valve flow from 2-D proximal velocity field: continued search for the ideal method.
abstract: It has been suggested that flow through a leaking heart valve can be determined by studying the proximal velocity field. Normally, only the centre-line velocity is studied as a potential method. The aim of the study is to improve this method by using information from the entire reconstructed proximal velocity field. Four methods are compared: use of the centre-line velocity; use of velocities at three different angles; integration of velocities over a hemisphere; and integration of velocities over an estimated hemi-elliptical isovelocity line. Measurements are performed in a hydraulic model with 4, 6 and 8 mm circular orifices, and these are compared with those from computer simulation. From the results presented in the study, it is suggested that the velocities should be integrated over a hemisphere within a best zone. This zone is dependent on the instrument settings, but in this case it is positioned 1.2-1.4 orifice diameters from the orifice inlet, with an angle of up to +/- 45 degrees from the centre axis, and contains velocities in the range 0.15-0.45 ms-1.
authors.affiliation: Department of Biomedical Engineering, University of Linköping, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Eidenvall
authors.forename: S
authors.initials: S
authors.lastname: Barclay
authors.forename: D
authors.initials: D
authors.lastname: Loyd
authors.forename: B
authors.initials: B
authors.lastname: Wrannel
authors.forename: P
authors.initials: P
authors.lastname: Ask
mesh_terms: D001783:Blood Flow Velocity; D018618:Echocardiography, Doppler, Color; D018056:Hemorheology / Q000379:methods*; D006801:Humans; D008433:Mathematics; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging*; D008955:Models, Cardiovascular