Doppler ultrasound it is used to assess blood flow and whether or not it is directed correctly. (It also assesses whether there is a decrease or increase in blood flow velocity.) Doppler ultrasound is a noninvasive test that allows you to analyze blood flow.
spectral doppler uses standard ultrasound methods to produce an image of a blood vessel and surrounding organs. A computer converts the Doppler ultrasounds into a graph that provides information about the speed and direction of blood flow through the blood vessel being tested. Duplex Doppler describes the combination of real-time B-mode images with Doppler flow detection.
color Doppler produces a 2D image of the blood vessel. A computer converts the Doppler ultrasound sounds into colors that are superimposed on the image of the blood vessel, representing the speed and direction of blood flow through the blood vessel. Color Doppler images represent stationary objects in grayscale and moving objects in different shades of color depending on the chosen color scale. Generally, red indicates motion toward the transducer, darker tones indicate slower motion, blue represents motion away from the transducer, and lighter tones indicate faster motion.
power doppler (Angio) is more sensitive than color Doppler. Power Doppler works differently from Color Doppler because the moving amplitudes are illustrated, not the change in frequency. Stationary objects are still shown in gray, but moving targets are usually shown in different shades of one color (depending on the chosen scale). Lighter shades represent stronger amplitudes and not faster motion. With Power Doppler no specific hemodynamic information is provided.
- Duplex: B-mode and Doppler at the same time
- Triple: B-mode/Doppler/Color
- Pulsed wave: hemodynamic; peak systole and peak diastole. Velocity and resistance to flow throughout the cardiac cycle.
Reference: 2002 by the American Institute of Ultrasound in Medicine, What you should know about your ultrasound exam.
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