What is the difference in range resolution between pulsed wave and continuous wave Doppler?

What is the difference in range resolution between pulsed wave and continuous wave Doppler?

• A. PW has range resolution; CW has no range resolution.
• B. PW has range resolution; CW has no range resolution.
• C. PW has no range resolution; CW has range resolution.
• D. PW has range resolution; CW has range resolution.

Answer: (B)

Range resolution in Doppler ultrasound depends on whether the system uses pulses or continuous transmission. Pulsed wave Doppler sends short pulses and listens during a defined time window, so echoes from a specific depth can be isolated. The ability to distinguish two reflectors at different depths (range resolution) scales with the pulse length (shorter pulses give finer range resolution). Continuous wave Doppler, on the other hand, transmits continuously and lacks a range gate, so echoes from all depths along the beam are mixed together and depth cannot be resolved. Therefore, pulsed wave has range resolution while continuous wave has no range resolution.

Range resolution in Doppler ultrasound depends on whether the system uses pulses or continuous transmission. Pulsed wave Doppler sends short pulses and listens during a defined time window, so echoes from a specific depth can be isolated. The ability to distinguish two reflectors at different depths (range resolution) scales with the pulse length (shorter pulses give finer range resolution). Continuous wave Doppler, on the other hand, transmits continuously and lacks a range gate, so echoes from all depths along the beam are mixed together and depth cannot be resolved. Therefore, pulsed wave has range resolution while continuous wave has no range resolution.