A New Echocardiographic Method for Identifying Vortex Flow in the Left Ventricle: Numerical Validation

A new mathematical method for estimating velocity vectors from color Doppler datasets is proposed to image blood flow dynamics; this method has been called echodynamography or vector flow mapping (VFM). In this method, the concept of stream function is exploited to expand a 2-D distribution of radial velocities in polar coordinates, observed with color Doppler, to a 2-D distribution of velocity vectors. This study was designed to validate VFM using 3-D numerical flow models. Velocity fields were reconstructed from the virtual color Doppler datasets derived from the models. VFM captured the gross features of flow structures and produced comparable images of the distribution of vorticity, which correlated significantly with the original field (for velocity magnitudes, standard error of estimate = 0.003 to 0.007m/s; for vorticity, standard error of estimate = 0.35 to 2.01/s). VFM may be sensitive for depicting flow structures derived from color Doppler velocities with reasonable accuracy. (E-mail: t.uejima@nifty.ne.jp)