What positive result will occur from increasing the packet size while using color Doppler to evaluate flow?

• A. Improved signal-to-noise ratio
• B. Reduced aliasing
• C. Improved axial resolution
• D. Improved temporal resolution

Answer: (A)

Increasing the packet size in color Doppler means more Doppler samples are averaged together for each velocity estimate. This coherent averaging reduces random noise and variance in the Doppler signal, so the color display becomes clearer and slower or weaker flows are more detectable. However, gathering more pulses takes longer, so the frame-to-frame update rate drops, meaning temporal resolution worsens. Axial resolution isn’t changed by how many pulses are used in Doppler, and aliasing is tied to the PRF and Nyquist limit rather than ensemble length, so it isn’t directly improved by increasing the packet size. The net effect is a higher signal-to-noise ratio.