The degree that a transducer is finely tuned to specific narrow frequency range. For example: A low Q-value means wide bandwidth and high Q-value means narrow bandwidth.

See also Pulse Inversion Doppler, Narrow Bandwidth, Dead Zone, Ultrasound Phantom.

The ultrasound bandwidth describes the number or range of frequencies. The reflected Doppler bandwidth increase when the Doppler beam strikes red blood cells traveling at many different speeds (as in turbulent flow).

See also Q-value.

The perfect image quality is dependent on some assumptions of the propagation of ultrasound waves in tissues after generating in an imaging system. These assumptions are important for the developing of optimal ultrasound imaging systems.
A lot of steps can be taken to prevent artifacts and to improve image quality, for example beamforming is used to focus the ultrasound beam, and contrast agents decrease the reflectivity of the undesired interfaces or increase the backscattered echoes from the desired regions.

See also Coded Excitation, Validation and Refraction Artifact, Q-Value, Ultrasound Phantom, Dead Zone, Narrow Bandwidth.

(PRF) The pulse repetition frequency is the number of pulses per second. The usual range for echocardiographs is between 200 and 5000 pulses per second. The PRF varies with the type of mode in operation.

See also Q-value.