To convert Doppler shift frequency spectrum into velocities, which parameters must be known?

To convert Doppler shift frequency spectrum into velocities, which parameters must be known?

• A. Doppler frequencies
• B. Angle of incidence
• C. Speed of sound in tissue
• D. All of the above

Answer: (D)

Converting Doppler shift frequencies to velocity uses the Doppler relation f_D = 2 f0 v cos theta / c. To solve for velocity, you must know the Doppler frequency shifts from the spectrum (f_D), the angle between the flow and the ultrasound beam (theta), and the speed of sound in the tissue (c). The shifts give the measured frequency changes, the cosine term accounts for the beam angle, and the tissue sound speed sets how quickly the wave propagates, all of which the velocity calculation depends on. Since the velocity is determined by all three quantities, the three listed parameters are required.

Converting Doppler shift frequencies to velocity uses the Doppler relation f_D = 2 f0 v cos theta / c. To solve for velocity, you must know the Doppler frequency shifts from the spectrum (f_D), the angle between the flow and the ultrasound beam (theta), and the speed of sound in the tissue (c). The shifts give the measured frequency changes, the cosine term accounts for the beam angle, and the tissue sound speed sets how quickly the wave propagates, all of which the velocity calculation depends on. Since the velocity is determined by all three quantities, the three listed parameters are required.