ECHO MACHINE-IMPOSED LIMIT ON TRANSMITRAL SPECTRAL DOPPLER VELOCITY-PROFILE ANALYSIS

We have previously developed a kinematic model of ventricular filling, Its application to in vivo transmitral Doppler velocity profiles prov ides a quantitative characterization of filling, However, the model pa rameters computed by solving the ''inverse problem'' may depend on ult rasound machine type and setting (e.g., gain, baseline filter, dynamic range), To determine machine-based effects on the computed model para meters, we performed a how phantom study using Acuson and RP echocardi ography machines at various settings, We compared maximum velocity env elopes (MVEs), as well as the model fit to these MVEs, for 3 simulated waveforms imaged by both machines, For all 3 waveforms, the machines generated comparable MVEs, fit by the model within a mean-square diffe rence of 5E-5 (m/s)(2), The associated variations in model parameters for the 3 waveforms were not uniform, Two waveforms showed slight vari ation between machines, with model parameters varying by less than 6%. The shortest duration waveform showed model parameter variations of 1 0-15%. Analysis of the parameter space for this waveform showed a cons tant mean-square error contour that was larger than that for the other two, causing similar small variations in measured MVEs to result in l arger differences in the parameter estimates for this waveform, Becaus e this method completely eliminates inter-and intraobserver variabilit y, we conclude that, within the limits established, the slight contour variations due to machine type and setting should not affect this met hod's applicability in clinical Doppler-Bon analysis. (C) 1997 World F ederation for Ultrasound in Medicine & Biology.