Pulse repetition frequency echocardiography

Pulse repetition frequency (PRF) indicates the number of ultrasound pulses emitted by the transducer over a designated period of time. It is typically measured as cycles per second or hertz (Hz).

1. What determines pulse repetition frequency?
2. What does increasing pulse repetition frequency do?
3. How do you calculate pulse repetition interval?
4. How is PRF related to frequency shift?

What determines pulse repetition frequency?

Pulse repetition frequency (PRF)

PRF is determined by the speed of sound and the distance it must travel. Since the speed of sound in the human body is constant (1540 m/s), the PRF only depends on the distance the sound waves must travel.

What does increasing pulse repetition frequency do?

A number of artifacts are directly influenced by the pulse repetition frequency, e.g. increasing it diminishes the aliasing artifact commonly encountered during color and spectral Doppler imaging, while decreasing it facilitates e.g. the display of the useful twinkling artifact occurring behind stones and ...

How do you calculate pulse repetition interval?

PRT = pulse repetition time. PRT has units of time and is commonly expressed in ms. PRT is the interval between the start of one pulse and the start of another. PRT is also equal to the sum, PRT = PW+RT.

How is PRF related to frequency shift?

PRF is the Doppler sampling frequency of the transducer and is reported in kilo Hertz (KHz). The frequency with which these pulses are emitted determines the maximum Doppler shifts obtainable. The maximum Doppler shift frequency that can be sampled without aliasing is PRF/2, called the Nyquist limit [14].