An acoustic injection test object for colour flow imaging systems.

There are few test objects suitable for colour-flow ultrasound scanners. An acoustic injection device is described that enables the production of a 2-D region of colour on a colour-flow image. The device involves detection of the transmitted ultrasound pulse from the scanner, followed by the emission of a synthesized echo that consists of a radiofrequency burst modulated by an audiofrequency signal in such a way that, on reception by the ultrasound scanner, it is interpreted as a signal arising from a region of flow. The depth of the colour region may be controlled by adjustment of the length of the synthesised echo. The audiofrequency content may be altered as desired, enabling examination of the relationship between the displayed colour and the signal spectral content.