Doppler ultrasound
Diagnostic ultrasound used to detect moving blood cells or other moving structures and measure their direction and speed. The Doppler effect is used to evaluate movement by measuring changes in frequency of the echoes reflected from moving structures.

In many instances, it has replaced x-ray methods such as angiography, as a method to evaluate blood vessels and blood flow. It permits real-time viewing of blood flow that cannot be obtained by other methods. It has proved a boon in all areas of ultrasound, aiding in the evaluation of the major arteries and veins of the body, the heart, and in obstetrics for fetal monitoring.

Types of Doppler ultrasound include: