Chapter 1

💡 What Is Doppler Ultrasound?

Doppler ultrasound is a special type of scan that shows movement of blood inside the body.
It uses sound waves to show how fast and in what direction blood is flowing in a blood vessel.

🔄 Types of Doppler Ultrasound

Type

Description

Color Doppler

Shows blood flow in color (usually red = toward probe, blue = away)

Spectral Doppler

Shows a wave pattern of blood flow over time

Power Doppler

More sensitive to slow flow; shows stronger color but no direction

Duplex Scan

Combines normal image + Doppler flow

🩸 What Doppler Can Check

• Blood flow in arteries and veins (like leg veins, neck arteries)
  
  

• Detect blockages, narrow vessels, or clots
  
  

• Umbilical cord blood flow in pregnancy
  
  

• Heart valves and flow across chambers
  
  

🔬 How to Use Doppler

1. Find the blood vessel on 2D scan
   
   

2. Turn on color Doppler
   
   

3. Adjust angle to 45–60° for best result
   
   

4. Use spectral Doppler to check the flow pattern
   
   

5. Freeze and measure flow speed if needed
   
   

⚠️ Doppler in Pregnancy

• Used after 12 weeks only
  
  

• Checks baby’s heart, umbilical cord, and placenta flow
  
  

• Helps detect growth restriction or poor oxygen flow