Principles of Color and Power Doppler in Neck Ultrasound Imaging

Abstract

Doppler ultrasound, especially color Doppler imaging, is used extensively in the evaluation of thyroid and parathyroid anatomy and pathology. The principles of the basic Doppler effect, describing frequency shifts resulting from nonstationary sound sources and receivers, will be reviewed. An overview of spectral Doppler methods will be briefly presented, illustrating how the Doppler effect is utilized clinically to allow detailed blood velocity information to be measured from a small region of a blood vessel. Color Doppler imaging will then be discussed in detail, showing how clinical ultrasound scanners can obtain mean blood velocities over an extended spatial region. This will include some explanation of acquisition methods, image characteristics, and artifacts and pitfalls commonly seen when scanning the neck with color Doppler imaging. Power Doppler imaging mode and its relationship to color Doppler will also be described.