Cardiology MCQ: Doppler Basics

The ultrasound reflected from red blood cells moving away from the transducer has:

A. Higher frequency and is colour coded red

B. Higher frequency and colour coded blue

C. Lower frequency and colour coded red

D. Lower frequency and colour coded blue

Correct answer: D. Lower frequency and colour coded blue

Ultrasound reflected from red blood cells moving towards the transducer will be perceived as having higher frequency. By notation, in colour Doppler imaging, they are given red colour. In pulsed wave and continuous wave Doppler, they are depicted above the baseline. Signals reflected from red blood cells moving away from the transducer are perceived as having lower frequency and depicted in blue colour on colour Doppler and below the baseline in pulsed wave and continuous wave Doppler.