Which frequency range is typical for Doppler measurements?

Which frequency range is typical for Doppler measurements?

• A. 0.1-0.5 Hz
• B. 1-10,000 Hz
• C. 10-100 Hz
• D. 100-1000 Hz

Answer: (B)

Doppler frequency shifts produced by ultrasound fall in the kilohertz range because the high-frequency transmitted wave is shifted by the blood’s velocity a small amount. With transducer frequencies in the megahertz and typical blood speeds, the resulting Doppler shifts show up as a frequency change from about 1 kHz up to around 10 kHz. That’s why the common range for Doppler measurements is roughly 1–10,000 Hz. The exact shift depends on the transmitted frequency, the velocity component along the beam, and the speed of sound in tissue, but the outcome consistently lies in the kilohertz region, making this range the best fit.

Doppler frequency shifts produced by ultrasound fall in the kilohertz range because the high-frequency transmitted wave is shifted by the blood’s velocity a small amount. With transducer frequencies in the megahertz and typical blood speeds, the resulting Doppler shifts show up as a frequency change from about 1 kHz up to around 10 kHz. That’s why the common range for Doppler measurements is roughly 1–10,000 Hz. The exact shift depends on the transmitted frequency, the velocity component along the beam, and the speed of sound in tissue, but the outcome consistently lies in the kilohertz region, making this range the best fit.