What does a negative Doppler shift indicate about flow direction relative to the transducer?

• A. Flow Away From Transducer
• B. Flow Perpendicular To Transducer
• C. Turbulent Flow
• D. Flow Toward Transducer

Answer: (D)

The Doppler shift sign tells you which way the blood is moving along the ultrasound beam. In this context, a negative Doppler shift is interpreted as flow toward the transducer. That means the blood cells are moving in the direction of the transducer along the beam axis, which is why the shift is shown as negative.

Remember that the velocity you see is the component of flow along the beam (affected by the angle). If the flow were moving away, the shift would be positive. If the flow were exactly perpendicular to the beam, there would be essentially no Doppler shift.