The physical principles of continuous-wave and pulsedwave Doppler as well as the processing methods to detect the direction of flow are reviewed. An overview of Doppler instrumentation, including duplex, zero crossing, range-gated, and color flow imaging detection systems is presented. The technique of spectral analysis is explained with multiple illustrative examples. Aliasing, which arises from the limited sampling rate of pulsed wave instruments, is discussed in detail.
1. Hykes DL, Hedrick WR, Starchman DE: Ultrasound Physics and Instrumentation. New YorkChurchill Livingstone, 1985, pp 101-108.
2.
2. Zagzebski JA: Physics and Instrumentation in Doppler and B-Mode Ultrasonography. In Zweibel WJ, ed. Introduction to Vascular Ultrasonography. 2nd edition, Orlando, Florida, Grune and Stratton, 1986, pp 21-51.
3.
3. Wells PNT: Ultrasonic Doppler Equipment. In: Fullerton GD and Zagzebski JA, eds. Medical Physics of CT and Ultrasound-Tissue Imaging and Characterization. New York, American Institute of Physics, 1980, pp 343-366.
4.
4. Powis RL: Angiodynography-A new look at the vascular system. Applied Radiology1986;15,1-1:55-59.
