In order to allow visual perception of all the useful information contained in the echo signal, the ultrasound system manufacturers amplify the echo signal in a non-linear manner, so as to enhance the lower amplitude echo signals. Particularly, the video signal is always zero for values of the echo signal below a minimum value. The desired result implies a loss of proportionally between the video signal and the echo signal. Furthermore, each manufacturer of medical ultrasound scanner has a peculiar approach to the implementation of this log-compression.

Linearization of the video signal is therefore important for deriving correct functional information relating to the blood perfusion in the body-part under analysis. The linearization indicates the processing that makes the amplitude of the video signal (i.e., the pixel values) directly proportional to the local concentration of the contrast agent in the corresponding pixel locations. This linearized signal provides a direct representation of the (relative) local blood volume in the respective portions of the body-part (since the contrast agent concentration is related, i.e., proportional, to the blood volume). As a consequence, the linearized signal allows a correct assessment of the blood perfusion in the body-part.

VueBox^® linearization has been validated with multiple ultrasound systems during dose ranging experiments to demonstrate the proportionality between signal measured in VueBox^® and contrast agent concentration.