What does red mean on an abdominal ultrasound? The red and blue colours on the screen during your ultrasound in London indicate the direction of blood flow. You can read more about Doppler ultrasound Imaging. You Might Also Like Will abdominal ultrasound hurt? 25/01/2022 What happens if you eat and drink before an abdominal ultrasound? 25/01/2022 Can liver disease be detected on an abdominal ultrasound? 25/01/2022