Which display method will help you demonstrate flow turbulence with color Doppler?

Which display method will help you demonstrate flow turbulence with color Doppler?

• A. Autocorrelation
• B. Variance
• C. Fast Fourier analysis
• D. Phase quadrature detection

Answer: (B)

Demonstrating flow turbulence with color Doppler relies on showing the range of velocities present within the sampled volume. That’s exactly what the variance display does. It maps how dispersed the Doppler shifts are inside a voxel, so regions with turbulent flow—where many different velocities occur—appear with a broader, more varied color pattern. Laminar flow, with a narrow range of velocities, looks much more uniform because its velocity spread is small. Autocorrelation is used to estimate the mean velocity and direction for color flow, which works well for showing overall flow but not the velocity spread that signals turbulence. Fast Fourier analysis is a tool for spectral Doppler, analyzing velocity over time rather than displaying turbulence in color Doppler. Phase quadrature detection underpins how Doppler shift is extracted, but it isn’t a display method for conveying turbulence itself.

Demonstrating flow turbulence with color Doppler relies on showing the range of velocities present within the sampled volume. That’s exactly what the variance display does. It maps how dispersed the Doppler shifts are inside a voxel, so regions with turbulent flow—where many different velocities occur—appear with a broader, more varied color pattern. Laminar flow, with a narrow range of velocities, looks much more uniform because its velocity spread is small.

Autocorrelation is used to estimate the mean velocity and direction for color flow, which works well for showing overall flow but not the velocity spread that signals turbulence. Fast Fourier analysis is a tool for spectral Doppler, analyzing velocity over time rather than displaying turbulence in color Doppler. Phase quadrature detection underpins how Doppler shift is extracted, but it isn’t a display method for conveying turbulence itself.