Ultrasound (doppler effect)

The Doppler effect in ultrasound refers to the change in frequency or wavelength of sound waves as the source and observer move relative to each other. This phenomenon is utilized in various medical imaging techniques, such as Doppler ultrasound, to assess blood flow and detect abnormalities in vascular systems.

dopper imaging

  • Blood flow causes compression (moving towards the transducer) or rarefaction (travelling away from the transducer) of ultrasound waves.

  • A computer is used to detect the change in frequency to determine the direction and speed of the blood flow.

Doppler - Radiology Cafe

f = original ultrasound frequency

  • f' = f(1 + v/c) for moving towards the transducer

  • f' = f(1 - v/c) for moving away from the transducer

Where:

  • f' = observed frequency

  • v = speed of the blood flow

  • c = speed of sound in the medium.