Inverting the color map

Echocardiographers use the non-inverted BART map.

However, in other applications, such as vascular ultrasound, the sonographer will frequently invert the color map as needed.

This is done in order to keep all the antegrade arterial blood flow displayed in red, regardless of its direction relative to the transducer.

The adjacent diagram provides an example.  In this case, the arterial blood is flowing from proximal to distal.  In the proximal portion of the vessel the blood is flowing towards the transducer.  In this region, the use of a non-inverted map will map the antegrade arterial flow in red.  However, in the distal portion of the vessel the blood is moving away from the transducer.  In this region, inverting the color map will maintain the display of the antegrade arterial flow in red.  

By doing this, the sonographer can ensure that all antegrade arterial flow is displayed in red.  This makes it easier for the interpreter to assess the direction of flow because all antegrade flow will be displayed in red, and any retrograde flow will be displayed in blue.