How can I differentiate between artery vs vein?

There are three techniques that can be used:

1. The pressure test. By bringing the transducer closer to the animal and adding pressure, any venous vessel will collapse, whereas arterial vessels will move closer to the transducer, but maintain their shape.

2. Using PW Doppler to visualize the flow pattern. Arteries will have a pulsitile flow, whereas vein will show little pulsitility.

3. Using anatomical knowledge and Color Doppler. For example, if you see two vessels going into the kidney, Color Doppler will tell you which vessel is bringing blood into the kidney (artery) and which one is bringing it out (vein).