Table 1.

Main functions of Doppler device parameter

Name of Doppler device parameter	Main functions
Mean velocity evaluation	This exam supply evaluation of the precision of the Doppler system’s evaluate of the mean Doppler scattered speed. In addition to the precision of the colour Doppler evaluate of the mean scattered speed
Range gate	Helps reveal blood flow signal wave
Sample volume or sample length	This exam evaluate the sensitivity of range gate to make sure if it is extreme sensitive at the centre position of the gate
Maximum velocity precision	This exam supply evaluation of the precision of the Doppler system’s evaluate of the maximum Doppler scattered speed. In addition to the precision of the reveal the degree of arterial narrowing or stenosis
Lowest detectable speed	This exam supply evaluation of the lowest speed that it is likely to show unambiguously
Highest detectable speed	This exam supply evaluation of the highest speed that it is likely to show unambiguously on both the colour Doppler image or on the PW Doppler spectrum. The highest speed with some diseases or stenosis may be reach up to 500-600 cm/s and can show this speed on the spectrum without aliasing
Spectral broadening	This exsam supply evaluation of the spectral Doppler broadening which cause by range of angles
Flow direction	This exam supply ability of the differentiate between flow towards and away from the probe
Angle correction	This exam supply ability to measures the accuracy of the angle correction the device
Wall filter	This exam remove intense signals from the vessel wall motion

Source from: Browne, J.E., A review of Doppler ultrasound quality assurance protocols and test devices. Physica Medica, 2014. 30(7): p. 742-751. PW: Pulsed wave